text:
Page 1
Amer ican Society of Echocar diogr aphy Recommendations for Quantification of Doppler Echocar diogr aphy
A Repor t fr om the Doppler Quantification Task For ce of the Nomenclatur e and Standar ds Committee of the Amer ican Society of Echocar diogr aphy, r epr esented by: Miguel A. Quiñones, MD, Chair; Catherine M. Otto, MD, Marcus Stoddard, MD, Alan Waggoner, MHS, RDMS, William A. Zoghbi, MD A.
Intr oduction Doppler echocardiography is a noninvasive technique that provides unique
hemodynamic information otherwise not available without invasive monitoring. The accuracy of the results depends, however, on meticulous technique and an understanding of Doppler principles and flow dynamics. This document provides recommendations based on the scientific literature and a consensus from a body of experts to guide the recording and measurement of Doppler data. The document is not a comprehensive review of all the clinical applications of Doppler echocardiography. B.
Gener al pr inciples The Doppler principle states that the frequency of reflected ultrasound is altered
by a moving target, such as red blood cells. The magnitude of this Doppler shift relates to the velocity of the blood cells, whereas the polarity of the shift reflects the direction of blood flow toward (positive) or away (negative) from the transducer.
The Doppler
equation ∆F =
V x 2Fo x cos θ c
states that the Doppler shift (∆F) is directly proportional to the velocity (V) of the moving target (i.e., blood cells), the transducer frequency (Fo), and the cosine of the angle of
Page 2
incidence (θ) and is inversely proportional to the velocity of sound in tissue (c = 1540 m/s). The Doppler equation can be solved for blood flow velocity as follows:
∆F x c
2 Fo x cos θ When solving the Doppler equation, an angle of incidence of 0 or 180 degrees (cosine = 1.0) is assumed for cardiac applications.
Currently, Doppler echocardiography consists of three modalities: pulsed-wave (PW) Doppler, continuous-wave (CW) Doppler, and color
Doppler imaging.
Doppler measures flow velocity within a specific site (or sample volume) but is limited by the aliasing phenomenon that prevents it from measuring velocities beyond a given threshold (called the Nyquist limit). CW Doppler, on the other hand, can record very high blood flow velocities but cannot localize the site of origin of these velocities along the pathway of the sound beam. Color flow Doppler uses PW Doppler technology but with the addition of multiple gates or regions of interest within the path of the sound beam. In each of these regions, a flow velocity estimate is superimposed on the twodimensional (2D) image with a color scale based on flow direction, mean velocity, and sometimes velocity variance. Doppler echocardiography is used to evaluate blood flow velocity with red blood cells as the moving target. Current ultrasound systems can also apply the Doppler principle to assess velocity within cardiac tissue. The moving target in this case is tissue, such as myocardium, that has higher amplitude of backscatter ultrasound and a lower velocity compared with red blood cells. This new application is called tissue Doppler and can be performed in the PW or the color mode. A comprehensive discussion of this new technology is beyond the scope of this document; however, some of the newer applications for measuring regional myocardial velocities using the PW mode will be discussed.
Page 3
Doppler echocardiography has two uses: detection and quantitation of normal and disturbed flow velocities.
For detection purposes, all three modalities have high
sensitivity and specificity. However, color flow Doppler often allows faster detection of abnormal flows and provides a spatial display of velocities in a 2D plane. Quantification of flow velocity is typically obtained with either PW or CW Doppler. Measuring velocity with color Doppler is possible but the methods are still under development and have not been standardized across different brands of ultrasound equipment. (One exception is the proximal isovelocity surface acceleration method, used in the evaluation of valvular regurgitation.) The primary use of PW Doppler is to assess velocities across normal valves or vessels to evaluate cardiac function or calculate flow. Common applications include measurements of cardiac output (CO) and regurgitant volumes, quantitation of intracardiac shunts, and evaluation of diastolic function. CW Doppler, on the other hand, is used to measure high velocities across restrictive orifices, such as stenotic or regurgitant valve orifices. These velocities are converted into pressure gradients by applying the simplified Bernoulli equation: pressure gradient = 4V2.
This equation has been demonstrated to be accurate in flow models, animal studies, and in the cardiac catheterization laboratory as long as the velocity proximal to the obstruction does not exceed 1.5 m/s. Common clinical applications include determining pressure gradients in stenotic native valves, estimating pulmonary artery (PA) systolic pressure from the velocity of tricuspid regurgitation (TR), and determining prosthetic valve gradients. The combination of PW and CW Doppler has been used with great accuracy to determine stenotic valve areas with the continuity equation. An alternative technique also used for recording high flow velocities is the high pulse repetition frequency (PRF) modification of the PW Doppler. High PRF uses range ambiguity to increase the maximum velocity that can be detected with PW Doppler. Multiple sample volumes are placed proximal to and at the depth of interest. PRF is determined by the depth of the most proximal sample volume, which allows measurement of higher velocities without signal aliasing at the depth of interest. Although the resulting spectral output includes frequencies from each of the sample volume depths, the origin of
Page 4
the high-velocity signal is inferred from other anatomic and physiologic data, as with CW Doppler. C.
Recommendations on r ecor ding and measur ement techniques The accuracy of measuring blood cell velocities by Doppler relies on maintaining
a parallel orientation between the sound waves and blood flow.
Although most
ultrasound systems allow correction of the Doppler equation for the angle of incidence, this measurement is difficult to perform accurately because of the three-dimensional (3D) orientation of the blood flow. Angle correction is therefore not recommended. The Doppler sound beam should be oriented as parallel as possible to the flow, guided both by the 2D image (sometimes assisted by color flow imaging) and the quality of the Doppler recording. Small (<20째) deviations in angle produce mild (<10%) errors in velocity measurements. Although these errors may be acceptable for low-velocity flows, when Doppler is used to derive pressure gradients even a small error in velocity measurement can lead to significant underestimation of the gradient because of the quadratic relation between velocity and pressure gradient. 1.
PW Doppler PW Doppler is used in combination with the 2D image to record flow velocities
within discrete regions of the heart and great vessels. Measurements derived from these velocities are used to evaluate cardiac performance (Figure 1). The most common sites are the left ventricular outflow tract (LVOT), mitral annulus and left ventricular inflow (at the tips of the mitral valve leaflets), pulmonic valve annulus and PA, tricuspid valve inflow, hepatic veins, and pulmonary veins. The flow volume passing through these sites can be calculated as the product of the velocity-time integral (VTI) and the cross-sectional area (CSA) of the respective site. When recording velocities for flow measurements, the sample volume be placed at the same location as the 2D measurements of CSA. Adjust the sample volume axial length to 5 to 7 mm and set the wall filters at low levels to ensure that lower velocities adjacent to the baseline are recorded for the timing of flow to be measured correctly. The velocities should be recorded over at least two or three respiratory cycles at a paper or sweep speed of 50 or 100 mm/s; the faster speed is
Page 5
essential for measurements that require precise time resolution, such as time intervals, integrals, and velocity slopes. A typical PW Doppler velocity consists of a spectral recording of varying intensity, depending on the acoustic density of the reflected interface, i.e., the mass of blood cells (Figure 1).
The most dense (or brightest) portion of the spectral tracing
represents the velocity of the majority of blood cells, also known as the modal velocity. Likewise, less dense areas depict the velocity of a lesser mass of blood cells. When measuring velocities, use the outer edge of the dense (or bright) envelope of the spectral recording.
CW Doppler In contrast to PW Doppler, CW Doppler records the velocities of all the red blood
cells moving along the path of the sound beam (Figure 2). Consequently, a CW Doppler recording always consists of a full spectral envelope with the outer border corresponding to the fastest moving blood cells. No simple guidelines guarantee a parallel orientation of the CW beam with blood flow in all instances. However, color flow Doppler can help determine the direction of the jet in a 2D plane, particularly in regurgitant lesions. A nonimaging CW transducer is recommended to search for the highest velocity, particularly in aortic stenosis (AS), in which multiple windows of examination may be required to detect the highest velocity. Measurements of velocities recorded by CW Doppler are always taken from the outer border. The site of origin of a high-velocity jet is inferred from the particular lesion that is being examined. For instance, if the CW beam is directed through a stenotic aortic valve, the outer edge of the recording is assumed to represent the stenotic jet velocity. Therefore only well-defined envelopes should be used for quantitation of velocities to obviate significant errors. These recommendations are also applied when using high PRF to record a high-velocity jet, except that high PRF should be used in combination with the 2D image. 3.
Color flow Doppler A comprehensive discussion of color flow Doppler is beyond the scope of this
document. Nevertheless, following are some basic recommendations that apply to any
Page 6
ultrasound machine. Processing the multigate Doppler information and creating the color pixels take a certain amount of time; therefore the larger the area of interest, the slower the frame rate. For this reason a smaller area of interest should be used and depth settings kept at the lowest possible level that allows visualization of the structure in question. When high-velocity blood flows are analyzed, set the color scale at the maximum allowed for that given depth. Color Doppler gain should be set just below the threshold for noise.
Recommendations r elating to specific clinical uses
1. Flow measurements a. PW Doppler technique Flow is derived as the product of CSA and the average velocity of the blood cells passing through the blood vessel or valve orifice during the flow period (Figure 3), while stroke volume (SV) represents the product of CSA and VTI. When PW Doppler is used, the velocities recorded within the sample volume will be affected by the flow profile. With current instrumentation, assessing flow profile or measuring the average velocity of the blood cells is difficult. Consequently, volume-flow measurements are most accurate when flow is laminar (i.e., all blood cells are moving in the same direction) and the profile is flat. The most important technical factor to ensure accuracy of measurements is to properly match the site of velocity recording with the anatomic measurement of the CSA.1 For this reason, it is preferable to use sites where the CSA does not change significantly during the flow period and can be determined accurately from the 2D image and where the flow profile is likely to be flat. When tracing the velocity to derive a VTI, it is best to trace the outer edge of the most dense (or brightest) portion of the spectral tracing (i.e., the modal velocity) and ignore the dispersion that occurs near peak velocity. For patients in sinus rhythm, data from 3-5 cardiac cycles may be averaged. However, in patients with irregular rhythms such as atrial fibrillation, 5-10 cycles may be required to insure accuracy of results. The preferred sites for determining SV and cardiac output (in descending order of preference) are:
Page 7
The LVOT tract or aortic annulus
The mitral annulus
The pulmonic annulus
The LVOT is the most widely used site.2 SV is derived as: SV = CSA x VTI
The CSA of the aortic annulus is circular, with little variability during systole. Because the area of a circle = πr2, the area of the aortic annulus is derived from the annulus diameter (D) measured in the parasternal long axis view as: CSA = D2 x π/4 = D2 x 0.785
Image the LV outflow with the expanded or zoom option and place 1 or 2 beats in a cineloop (Figure 4).
This imaging allows a more precise measurement of the annulus
diameter during early systole from the junction of the aortic leaflets with the septal endocardium, to the junction of the leaflet with the mitral valve posteriorly, using inner edge to inner edge. The largest of 3 to 5 measurements should be taken because the inherent error of the tomographic plane is to underestimate the annulus diameter. When serial measurements of SV and CO are being performed, use the baseline annulus measurement for the repeated studies because little change in annulus size occurs in adults over time. The LV outflow velocity is recorded from the apical 5-chamber or long-axis view, with the sample volume positioned about 5 mm proximal to the aortic valve (Figure 4). The opening click of the aortic valve or spectral broadening of the signal should not be viewed in mid-systole because this means the sample volume is into the region of proximal acceleration. The closing click of the aortic valve is often seen when the sample volume is correctly positioned. The LVOT method should not be applied when the landmarks needed to measure the annulus diameter cannot be properly visualized or if evidence of LV outflow obstruction exists because the velocities recorded will not be matched to the CSA of the aortic annulus. Flow across the mitral annulus is measured in the apical 4-chamber view with equation 4 (Figure 5). Although the mitral annulus is not perfectly circular, applying a
Page 8
circular geometry (equation 5) gives similar or better results than attempting to derive an elliptical CSA with measurements taken from multiple views.2,3 The diameter of the mitral annulus should be measured from the base of the posterior and anterior leaflets during early to mid-diastole, one frame after the leaflets begin to close after its initial opening. The sample volume is positioned so that in diastole it is at the level of the annulus. The pulmonic annulus is probably the most difficult of the three sites, mostly because the poor visualization of the annulus diameter limits its accuracy and the right ventricular (RV) outflow tract contracts during systole. Measure the annulus during early ejection (2 to 3 frames after the R wave on the electrocardiogram) from the anterior corner to the junction of the posterior pulmonic leaflet with the aortic root (Figure 6).4,5 Equations 4 and 5 are used to derive SV and CSA, respectively. When
learning to measure flow volumes across the above sites, make
measurements in all three sites inpatients without regurgitant lesions or intracardiac shunts because the flow through these sites should be equal. Doing this will develop expertise needed to apply these methods accurately. In regurgitant valve lesions, the forward flow through the regurgitant valve is greater than through the other valves, and the difference between them is equivalent to the regurgitant flow. Regurgitant fraction, an index of severity of regurgitation, is derived as regurgitant flow (in milliliters) divided by the forward flow across the regurgitant valve. In the presence of significant left-toright intracardiac shunts, flow measurements can calculate the pulmonic to systemic (Qp:Qs) flow ratio. For example, in a patient with an atrial-septal defect, pulmonic flow will be much higher than aortic flow; the ratio of the two is equivalent to the Qp:Qs ratio. In the best of hands, these calculations may have up to a 20% error. b.
Flow measurements with CW Doppler Recordings of flow velocity through the above sites are also possible with CW
Doppler. In addition, flow velocity can be recorded in the ascending aorta from the suprasternal notch.6 The main difficulty with CW Doppler is that the velocity envelope reflects the highest velocity of the moving blood cells. This, in turn, is affected by the flow profile and the smallest CSA of flow. For example, when recording the LV outflow
Page 9
velocity from the apical window by CW, the velocity integral is related to the CSA of the aortic valve rather than the annulus.7 The area of the valve is more difficult to derive with 2D imaging. A primary application of Doppler is in the serial evaluation of SV and CO. Given that the CSA is relatively stable in the same patient, the VTI can accurately track changes in SV. The day-to-day variability of velocity measurements appears to be less with CW than with PW Doppler. 8 2.
Application of flow measurements in the evaluation of diastolic function
Left ventricle PW Doppler recordings of the mitral and pulmonary vein velocities can provide
insight into the dynamics of left ventricular filling and help evaluate diastolic function (Figure 7).9-11 Importantly, changes in these velocities occur with alterations in left atrial and LV diastolic pressures.12-18
In addition, the transmitral velocity, together with
tricuspid and hepatic vein velocities, is useful when evaluating cardiac tamponade and constrictive pericarditis.19-23 (1) Mitral inflow velocity Parameters of diastolic function that reflect changes in flow should be measured from recordings of the inflow velocity at the mitral annulus, where the CSA is more stable. On the other hand, parameters that relate to the transmitral gradient are best obtained at the tips of the valve leaflets. The measurements obtained are divided into three categories: (1) absolute velocities such as E and A velocities, (2) time intervals such as acceleration and deceleration times, and (3) time-velocity integrals such as the integrals of the E and A velocities, respectively. The ratio of these integrals to the total integral of flow velocity is used as an index of the respective filling fractions. The first two categories are best measured at the tips of the valve leaflets, whereas the third is more accurate from the mitral annulus site. An additional index of diastolic function is the isovolumic relaxation time (IVRT), defined as the interval from the closure of the aortic valve to the opening of the mitral valve. This interval can be accurately measured by Doppler with either PW or CW Doppler. With PW Doppler, the transducer is angulated into the apical 5-chamber or
Page 10
long-axis view and the sample volume placed within the LVOT, but in proximity to the anterior MV leaflet to record both inflow and outflow signals. With CW Doppler, IVRT is measured by aiming the Doppler beam at an intermediate position between inflow and outflow to record both velocities (Figure 8). IVRT is measured as the interval between the end of ejection and the onset of mitral inflow. As a rule, CW recordings provide a more reproducible measure of IVRT than PW. Three to five cardiac cycles should be averaged when measuring transmitral velocities and IVRT. One exception to this rule is made in conditions in which these velocities change with respiration, such as in pericardial constriction or tamponade. In these cases the velocities should be recorded with a respiratory tracing and averaged separately. Certain patterns have been associated with changes in left atrial pressures in patients with LV disease, particularly those with depressed systolic function (Figure 9). With normal pressures, the transmitral velocity, as a rule, has a lower E than A velocity with a prolonged IVRT and deceleration time, reflecting the impaired relaxation of the left ventricle. On the other hand, with higher left atrial pressures, the E velocity increases while the IVRT and deceleration time shorten. This resembles the pattern seen in normal young individuals and thus it is referred to as pseudonormal. (2) Pulmonary vein velocity Analysis of the pulmonary vein velocities can provide insight into the diastolic properties of the LV and the function of the left atrium. Certain patterns have been associated with increased left atrial pressures in patients with LV disease, particularly those with depressed systolic function, that complement the information derived from the mitral inflow velocity (Figure 9).16,17 With current technology, the velocity of flow within the pulmonary veins can be recorded from the transthoracic apical view in 80% of patients. The most common vein accessible from this window is the right upper pulmonary vein. The flow within the vein can be visualized with color Doppler using a lower velocity scale (<40 cm/s) and the PW sample volume can be placed inside the vein. Without attention to proper sample volume location, two errors commonly occur. The sample volume can be placed near the opening of the pulmonary vein but still within the
Page 11
left atrium, or the low-velocity motion of the posterior atrial wall can be recorded. When recording the pulmonary veins, keep the wall filters at a low level. The flow velocity measurements currently recommended in the pulmonary veins are the peak systolic (S), peak diastolic (D), and atrial reversal (A) velocities, the S/D ratio, and the duration of the A velocity (Figures 7 and 9). (3) Myocardial and annular velocities Longitudinal velocities within the myocardium can be recorded with tissue Doppler from the apical window with the PW mode. A small (<5 mm) sample volume is placed within a myocardial segment and a spectral recording of velocities within the segment obtained (Figure 10). For optimal recording of tissue velocity, both gains and filter settings should be set low. Myocardial velocities are highest at the base and lowest toward the apex. Consequently, the velocities at the basilar segments are commonly used to assess the function of the corresponding wall. The sample volume is usually placed at the junction of the LV wall with the mitral annulus. The spectral longitudinal velocity of the myocardium normally consists of a positive systolic wave and two diastolic peaks, one during early diastole and a second during atrial contraction (Figure 10). The early diastolic velocity (Em; also referred to as Ea for annular velocity) has been demonstrated to be an index of LV relaxation that is relatively insensitive to left atrial pressure.24-26 Although Em can be measured in any ventricular wall, the lateral wall and septum have been more commonly used in the evaluation of diastolic function. The ratio of transmitral E velocity to Em has been recently demonstrated to relate well with mean left atrial (or pulmonary capillary wedge) pressure in multiple clinical scenarios, such as depressed or normal systolic LV function, hypertrophic cardiomyopathy, sinus tachycardia, and atrial fibrillation. 26-30 (4) Flow propagation velocity Color Doppler can record an early inflow velocity across the mitral valve from the apical 4-chamber view (Figure 11). An M-mode cursor placed in the center of the brightest inflow velocity can record a color M-mode of the inflow jet as it moves from the mitral inflow area toward the apex. Adjusting the color Doppler baseline can highlight a color edge, the slope of which represents the propagation velocity of blood flowing
Page 12
toward the apex. This flow propagation velocity has been shown to relate inversely with the time constant of LV relaxation and to be fairly insensitive to changes in left atrial pressures. 31,32
In a manner analogous to the Em velocity, the ratio of transmitral E to
flow propagation velocity relates to mean left atrial (or pulmonary capillary wedge) pressure. 33,34 b.
Right ventricle (1) Tricuspid inflow velocity As with the mitral inflow, the tricuspid inflow velocity reflects the atrioventricular
diastolic pressure-flow interactions on the right side of the heart.
Tricuspid flow
velocities, however, are also affected by respiration; thus all measurements taken must be averaged throughout the respiratory cycle or recorded at end-expiratory apnea. The tricuspid inflow velocity is best recorded from either a low parasternal RV inflow view or from the apical 4-chamber view. The same measurements derived from the mitral inflow velocity can be measured in the tricuspid.
However, to date, there are fewer investigations available on the
application of these measurements in the evaluation of RV diastolic function. RV IVRT has not been used as an index of diastolic function because it is significantly altered by pulmonary hypertension and difficult to measure with Doppler alone. (2) Hepatic vein flow velocity The velocity of flow in the hepatic veins can be recorded from the subcostal window with the flow oriented parallel to the sound waves (Figure 12). The normal pattern of flow velocity consists of systolic and diastolic antegrade flow velocities (S and D waves, respectively) and a retrograde A velocity. Each of these waves being profoundly altered by the two phases of respiration. The influence of respiration differs between disease states. These variations may be used to differentiate between restrictive and constrictive pericardial disorders.22 3.
Estimation of right-sided pressures
When TR is present, application of the 4V2 equation to the peak TR velocity provides a close estimate of the peak pressure gradient between RV and right atrium (RA).35 Consequently, RV systolic pressure can be derived by adding an estimate of mean RA
Page 13
pressure to the peak RV-RA gradient. The mean RA pressure is estimated with the magnitude of the inferior vena cava collapse, with inspiration and variations in the hepatic vein velocities.36-38 In the absence of pulmonic stenosis, the peak RV pressure is equivalent to the PA systolic pressure. In the presence of pulmonic stenosis, the PA systolic pressure is estimated by subtracting the maximal pulmonic valve pressure gradient, derived from the velocity across the valve by CW Doppler, from the peak RV systolic pressure. The accuracy of these pressure estimates depends on recording a clear envelope of the TR velocity by CW Doppler. If the signal is incomplete, significant underestimation of the peak TR velocity will occur. The quality of the TR velocity recording may be enhanced with contrast echocardiography by injecting agitated saline or other contrast echo agents intravenously.39 Varying degrees of pulmonic regurgitation (PR) are common, particularly in cardiac patients. The velocity of PR reflects the instantaneous gradient between PA and RV.
Thus the PR velocity at end diastole may be used to derive the PA diastolic
pressure with the 4V2 equation and adding to the pressure gradient an estimate of mean RA pressure. The RV outflow and pulmonic flow velocities are often altered in the presence of significant pulmonary hypertension. The acceleration time is shortened, and a midsystolic notch in the flow velocity envelope is often present. An inverse curvilinear relation exists between the acceleration time and mean PA pressure from which regression equations have been developed. The 95% confidence limits of the estimate of PA pressure with these equations are, however, too wide for accurate clinical use and are therefore not recommended. 4.
Pressure gradients and valve areas Recommendations on the use of CW Doppler for recording high-velocity jets have
been previously discussed. The modified Bernoulli equation, 4V2, is very accurate in estimating the pressure gradient across a restrictive orifice under most physiologic conditions.40-43 The exceptions are: (1) a velocity proximal to the stenosis greater than 1.5 m/s, (2) the presence of two stenotic areas proximal to each other, for example,
Page 14
subpulmonic stenosis combined with valvular stenosis, and (3) the presence of a long tunnel-like stenotic lesion. In stenotic lesions, the jet velocity can derive the peak instantaneous and the mean pressure gradient across the stenosis. The mean gradient is obtained by averaging the instantaneous gradients. Current ultrasound systems contain software to derive the peak velocity, VTI, and mean gradients from a tracing of the velocity envelope. It is important to include both heart rate and rhythm when reporting valve gradients. The Doppler equation is fairly accurate in deriving the pressure gradient across a tight stenosis. However, in AS the phenomenon of pressure recovery may result in a higher gradient by Doppler than the gradient measured by catheter, particularly if the distal pressure is recorded several centimeters away from the stenotic valve. In practice, the error is small and of minimal clinical significance. a.
Valve area measurements with the continuity equation The continuity equation states that the flow passing through a stenotic valve is
equal to the flow proximal to the stenosis (Figure 13). Given that flow equals velocity multiplied by CSA, if flow is known the area of stenosis can be derived as: Stenotic area = Flow / Velocity across stenosis
AS is the most common lesion for which the continuity equation is used.
The flow volume represents the SV across the aortic valve, determined at the LV outflow. In AS, however, the sample volume must be positioned carefully to not be within the prestenotic flow acceleration region. Place the sample volume 1 cm proximal to the aortic valve while recording the velocity. Then, slowly move the sample volume is toward the valve until an increase in velocity and spectral broadening is seen.
Thereafter, the
sample volume is moved back until a narrow band of flow velocities is obtained. The denominator of the continuity equation is the integral of the stenotic jet. Consequently, the maximal AS velocity must be recorded by aligning the CW beam as parallel as possible to the stenotic jet. This is best accomplished with a non-imaging CW transducer using multiple windows of interrogation. In mitral stenosis, the continuity equation is useful in situations for which the pressure half-time method is limited. However, in this lesion accurately determining flow
Page 15
across the mitral annulus is difficult. SV is therefore measured at the aortic annulus and used in the numerator of the equation; the denominator is the integral of the mitral stenosis jet.
The method is quite accurate in the absence of associated mitral
regurgitation (MR).5 b.
Mitral valve area with the pressure half-time method The pressure half time (P1/2t) method is a simple and accurate method of
determining valve area in mitral stenosis (Figure 14). Pressure half time represents the time that the maximal pressure gradient takes to decrease by one half. When expressed in terms of velocity, this time is equivalent to the time that the peak stenotic velocity takes to drop by 30%. Early studies established an inverse relation between P1/2t and mitral valve area (MVA),46 and from this relation the following empirical equation was derived: MVA = 220 / P1/2t
This formula works surprisingly well in most patients and can be reliably used in clinical decision making.47,48 Potential sources of errors must be considered, such as rapid heart rate, the presence of significant aortic regurgitation, and conditions that alter left atrial or LV compliance and/or LV relaxation.49-51 In some patients the early velocity descent is curvilinear rather than linear, resembling a ski slope. In these instances, derive a pressure half time by extrapolating the mid-diastolic linear descent backwards, as illustrated in Figure 15. Although there are similarities between mitral and tricuspid stenosis, the P1/2t method has not been as extensively validated for the calculation of tricuspid valve area. 5.
Application of Doppler in regurgitant valve lesions Doppler echocardiography is the most commonly used diagnostic technique for
detecting and evaluating valvular regurgitation. Multiple indexes have been developed to assess severity of regurgitation with PW, CW, and color Doppler. Although techniques for measuring these indexes are described in this document, recommendations concerning their clinical application will be discussed in an upcoming document dedicated to the evaluation of regurgitant valve lesions.
Regurgitant volume, regurgitant fraction, and effective regurgitant orifice area
Page 16
In the presence of valvular regurgitation, the flow through the affected valve is greater than through other competent valves. For example, in MR more volume will pass through the mitral valve than through the aortic or pulmonic valves. The difference between the two represents the regurgitant volume. Regurgitant fraction is derived from the regurgitant volume divided by the flow through the regurgitant valve.3,52 Careful measurement of flow volumes through the annular sites described can determine the calculation of regurgitant volume and regurgitant fraction.
Effective regurgitant orifice area (EROA) is a new index of regurgitation derived with the continuity equation: EORA = Regurgitant volume / Regurgitant VTI
where the regurgitant VTI is the integral of the regurgitant velocity recorded by CW Doppler.53 b.
Application of pressure half time in aortic regurgitation Recording of aortic regurgitation jet by CW Doppler reflects the instantaneous
pressure differential between the aorta and left ventricle. Thus the rate of velocity decline from its early peak to late diastole is an index of severity of aortic regurgitation. Although this rate of decline may be measured as a slope, it is more commonly assessed by measuring pressure half time in a manner analogous to mitral stenosis; that is, the time taken for the peak velocity to decline by 30% (Figure 16).54 To accurately measure this index, a complete envelope of the regurgitant jet must be recorded by CW and the peak velocity should be ≼4 m/s. In addition to severity of regurgitation, other hemodynamic factors such as LV diastolic compliance and systemic vascular resistance can alter the rate of decline of the regurgitant velocity. c.
Application of color Doppler Color flow Doppler imaging is widely used to detect regurgitant valve lesions.
The area of color Doppler flow velocity disturbance in the receiving chamber provides a semiquantitative evaluation of regurgitant severity. Trivial and mild degrees of regurgitation, as a rule, have thin jets that travel short distances into the receiving chamber; more severe lesions have broader jets covering larger areas within the receiving
Page 17
chamber. However, the regurgitant jet area is seriously limited by numerous technical and physiologic variables that affect the length and width of the regurgitant jet. Jets that are centrally directed into a receiving chamber tend to have a larger color jet area for a given flow because of entrainment of blood cells inside the receiving chamber (Figure 17). On the other hand, eccentric jets traveling along a wall will lose energy and have a smaller color area for a given flow.55 Regurgitant jet area should therefore be used with caution when assessing severity of regurgitant lesions. Furthermore, when assessing valve regurgitation, set the aliasing threshold in the color scale to the highest possible level to limit the effect of entrainment on the regurgitant jet area. Parameters derived from the color flow velocities within the regurgitant orifice appear to be more accurate than the color jet area in evaluating severity of regurgitation.56-58 To assess these parameters well, image the regurgitant site in multiple longitudinal and cross-sectional planes, paying meticulous attention to imaging the velocities within the regurgitant orifice. Both the width and the area of the regurgitant jet at the valve orifice (i.e., near the vena contracta) or immediately distal to the orifice relate well with other independent measurements of severity of regurgitation (Figure 18).56-58 Examination of the flow velocity pattern proximal to the regurgitant orifice provides insight into the severity of regurgitation. Proximal flow acceleration occurs with the isovelocity "surfaces" assuming a hemispherical shape adjacent to the regurgitant orifice that can be visualized with color Doppler (Figure 19). 59-62 The velocity in this proximal isovelocity surface area (PISA) is equal to the aliasing velocity (Va). Regurgitant flow (in milliliters per second) can be derived from the PISA radius (r) as 2Ď€r2 x Va. Assuming the maximal PISA radius occurs simultaneously with the peak regurgitant flow and the peak regurgitant velocity (PkVreg), the EORA is derived as: EORA = (2Ď€r2 x Va) / PkVreg
Regurgitant volume can be estimated as EORA multiplied by regurgitant VTI. 63 The above calculations can be accurately performed only if the region of PISA appears hemispherical. To ensure this, the sound waves should be oriented parallel to
Page 18
flow and the color Doppler baseline shifted toward the direction of regurgitant flow until a semicircular area of PISA is well visualized. This method is therefore easier to apply to regurgitant lesions involving the mitral valve particularly those with centrally directed jets.. 6.
Evaluating prosthetic valves The general principles for evaluating prosthetic valve function are similar to those
of native valve stenosis. Because a prosthetic valve in general has a smaller effective area than the corresponding normal native valve, higher velocities, and therefore pressure gradients, are recorded through the prosthesis compared with a native valve. Velocities and gradients through prosthetic valves depend on valve type and size, flow, and heart rate.64,65 Thus reporting heart rate in addition to other parameters should be part of the routine assessment of prosthetic valve function. Overall, pressure gradients by Doppler and by catheter measurements correlate well.66 However, in certain valve prostheses, specifically bileaflet valves, overestimation of gradients by Doppler has been demonstrated, particularly for smaller sized prostheses. 67,68 The technique of recording adequate velocities through prosthetic valves is similar to that of native valves, with special attention directed toward minimizing the angle of incidence between the Doppler beam and flow velocity. For prostheses in the mitral or tricuspid position, this is performed from the apical or low parasternal window and can be guided with color flow imaging. However, some cases, because of an unusual position of the valve or presence of obstruction, have an eccentric inflow jet (or jets). In these cases the window of examination should be modified accordingly. For aortic valve prostheses, recording from all available windows, including apical, right sternal border, suprasternal, and subcostal, is encouraged to avoid an error in flow angulation and underestimation of gradients. This recording is particularly important in stenotic prosthetic valves, for which the stenotic jet may be eccentric, similar to native AS. a.
Prosthetic aortic valve function Because gradients depend on flow (among other factors), the continuity equation
is also applied to prosthetic valves. For prosthetic aortic valves, measurement of flow is usually performed with the apical 5-chamber or long-axis view, with the sample volume
Page 19
positioned within 1 cm proximal to the valve. By the continuity equation, effective aortic valve area can be derived as SV divided by the time-velocity integral of the jet. For determination of SV, measure the diameter of the LVOT; but in difficult cases, the sewing ring diameter can be substituted for the LVOT diameter, recognizing that it may yield a higher value for the effective valve area. 65,69 Doppler -derived effective valve areas have been shown to relate to valve size and have been reported for few prostheses. A Doppler velocity index, derived as the ratio of peak velocity in the LVOT to the peak velocity through the prosthesis, is less dependent on valve size. This index is especially useful if the valve size is not known at the time of the study 65,68 b.
Prosthetic mitral and tricuspid valve function Mean gradients for several types of mitral prostheses and more recently for
tricuspid prostheses, have been reported. Effective valve area has been derived for prosthetic mitral valves with the P1/2t formula. However, the constant of 220 has been derived for native mitral valves, not for prosthetic mitral valves.70 As with native valves, the P1/2t method has limitations similar to those previously discussed but is useful in detecting prosthetic valve obstruction.71 In cases in which discordance between gradients and effective area is apparent, application of the continuity equation may be beneficial.72 No data are available for the application of the continuity equation in tricuspid valves. c.
Prosthetic valve regurgitation For the most part, all the currently used mechanical valves have a minimal degree
of functional ("built-in") regurgitation that, at times, is detected with Doppler ultrasound and should not be confused with pathologic regurgitation.73,74 Regurgitation of prosthetic aortic valves is readily detected by transthoracic Doppler echocardiography, and its severity is assessed by several modalities in a manner analogous to native aortic insufficiency. Because of the position of the prosthetic mitral valve in relation to the transducer and the regurgitant chamber, considerable ultrasound shadowing and Doppler flow masking occurs during transthoracic studies in these patients. This scenario is more severe in mechanical valves compared with bioprosthetic valves. Thus transthoracic color and conventional Doppler are less sensitive for the detection of prosthetic mitral
Page 20
valve regurgitation.75,76 A nonimaging CW transducer should be used in all patients with prosthetic mitral valves because the lower frequency sound wave has better penetration and can often record a regurgitant jet that has not been detected with the imaging transducer. In patients with a mechanical St. Jude's mitral prosthesis, a peak early velocity ≼1.9 m/s without other signs of obstruction is 90% sensitive and 89% specific for significant valve regurgitation.77 Transesophageal echocardiography is often needed to confirm this lesion and assess the severity of regurgitation. For the most part, prosthetic tricuspid valve regurgitation is easier to detect than MR. D. Summar y and conclusions Doppler echocardiography provides an accurate assessment of the severity of many cardiac disorders and has therefore assumed an integral role in the clinical evaluation of cardiac patients. This document emphasizes the appropriate methods to properly record and quantify Doppler velocities. However, expertise in the performance of Doppler echocardiography can only be obtained by appropriate training, practice, and experience. Lastly, the field of echocardiography is dynamic and continues to evolve rapidly. Therefore future modifications of these recommendations will be created as newer methods and applications of Doppler echocardiography emerge.
Page 21
Refer ences 1. 2.
Zoghbi WA, Quiñones MA: Determination of cardiac output by Doppler echocardiography: a critical appraisal. Herz 1986;11:258-268. Lewis JF, Kuo LC, Nelson JG, Limacher MC, Quiñones MA: Pulsed Doppler echocardiographic determination of stroke volume and cardiac output: clinical validation of two new methods using the apical window. Circulation 1984;70:425-431. Enriquez-Sarano M, Bailey KR, Seward JB, Tajik AJ, Krohn MJ, Mays JM: Quantitative Doppler assessment of valvular regurgitation. Circulation 1993;87:841-848. Zoghbi WA, Farmer KL, Soto JG, Nelson JG, Quiñones MA: Accurate noninvasive quantification of stenotic aortic valve area by Doppler echocardiography. Circulation 1986;73:452-459. Nakatani S, Masuyama T, Kodama K, Kitabatake A, Fujii K, Kamada T: Value and limitations of Doppler echocardiography in the quantification of stenotic mitral valve area: comparison of the pressure half-time and the continuity equation methods. Circulation 1988;77:78-85. Huntsman LL, Stewart DK, Barnes SR, Franklin SB, Colocousis JS, Hessel EA: Noninvasive Doppler determination of cardiac output in man. Clinical validation. Circulation 1983;67:593-602. Bouchard A, Blumlein S, Schiller NB, Schlitt S, Byrd BF 3d, Ports T, Chatterjee K: Measurement of left ventricular stroke volume using continuous wave Doppler echocardiography of the ascending aorta and M-mode echocardiography of the aortic valve. J Am Coll Cardiol 1987;9:75-83. Moulinier L, Venet T, Schiller NB, Kurtz TW, Morris RC Jr, Sebastian A: Measurement of aortic blood flow by Doppler echocardiography: day to day variability in normal subjects and applicability in clinical research. J Am Coll Cardiol 1991;17:1326-1333. Rokey R, Kuo LC, Zoghbi WA, Limacher MC, Quiñones MA: Determination of parameters of left ventricular diastolic filling with pulsed Doppler echocardiography: comparison with cineangiography. Circulation 1985;71:543550. Stoddard MF, Pearson AC, Kern MJ, Ratcliff J, Mrosek DG, Labovitz AJ: Left ventricular diastolic function: comparison of pulsed Doppler echocardiographic and hemodynamic indexes in subjects with and without coronary artery disease. J Am Coll Cardiol 1989;13:327-336. Nishimura RA, Abel MD, Hatle LK, Tajik AJ: Assessment of diastolic function of the heart: background and current applications of Doppler echocardiography. Part II. Clinical studies [Review]. Mayo Clin Proc 1989;64:181-204. Appleton CP, Hatle LK, Popp RL: Relation of transmitral flow velocity patterns to left ventricular diastolic function: new insights from a combined hemodynamic and Doppler echocardiographic study. J Am Coll Cardiol 1988;12:426-440. Mulvagh S, Quiñones MA, Kleiman NS, Cheirif J, Zoghbi WA: Estimation of left ventricular end-diastolic pressure from Doppler transmitral flow velocity in
Page 22
19. 20. 21.
cardiac patients independent of systolic performance. J Am Coll Cardiol 1992;20:112-119. Pozzoli M, Capomolla S, Pinna G, Cobelli F, Tavazzi L: Doppler echocardiography reliably predicts pulmonary artery wedge pressure in patients with chronic heart failure with and without mitral regurgitation. J Am Coll Cardiol 1996;27:883-893. Nishimura RA, Abel MD, Hatle LK, Tajik AJ: Relation of pulmonary vein to mitral flow velocities by transesophageal Doppler echocardiography. Effect of different loading conditions. Circulation 1990;81:1488-1497. Kuecherer HF, Muhiudeen IA, Kusumoto FM, Lee E, Moulinier LE, Cahalan MK, Schiller NB: Estimation of mean left atrial pressure from transesophageal pulsed Doppler echocardiography of pulmonary venous flow. Circulation 1990;82:1127-1139. Appleton CP, Galloway JM, Gonzalez MS, Gaballa M, Basnight MA: Estimation of left ventricular filling pressures using two-dimensional and Doppler echocardiography in adult patients with cardiac disease. Additional value of analyzing left atrial size, left atrial ejection fraction and the difference in duration of pulmonary venous and mitral flow velocity at atrial contraction. J Am Coll Cardiol 1993;22:1972-1982. Nagueh SF, Kopelen HA, Zoghbi WA: Feasibility and accuracy of Doppler echocardiographic estimation of pulmonary artery occlusive pressure in the intensive care unit. Am J Cardiol 1995;75:1256-1262. Burstow DJ, Oh JK, Bailey KR, Seward JB, Tajik AJ: Cardiac tamponade: characteristic Doppler observations. Mayo Clin Proc 1989;64:312-324. Chandraratna PA: Echocardiography and Doppler ultrasound in the evaluation of pericardial disease. Circulation 1991;84:(Suppl I):I303-I310. Hatle LK, Appleton CP, Popp RL: Differentiation of constrictive pericarditis and restrictive cardiomyopathy by Doppler echocardiography [see comments]. Circulation 1989;79:357-370. Oh JK, Hatle LK, Seward JB, Danielson GK, Schaff HV, Reeder GS, Tajik AJ: Diagnostic role of Doppler echocardiography in constrictive pericarditis [see comments]. J Am Coll Cardiol 1994;23:154-162. Cohen GI, Pietrolungo JF, Thomas JD, Klein AL: A practical guide to assessment of ventricular diastolic function using Doppler echocardiography [Review]. Journal of the American College of Cardiology 1996;27:1753-1760. Oki T, Tabata T, Yamada H, Wakatsuki T, Shinohara H, Nishikado A, Iuchi A, Fukuda N, Ito S: Clinical application of pulsed Doppler tissue imaging for assessing abnormal left ventricular relaxation [see comments]. Am J Cardiol 1997;79:921-928. Sohn DW, Chai IH, Lee DJ, Kim HC, Kim HS, Oh BH, Lee MM, Park YB, Choi YS, Seo JD, Lee YW: Assessment of mitral annulus velocity by Doppler tissue imaging in the evaluation of left ventricular diastolic function. J Am Coll Cardiol 1997;30:474-480. Nagueh SF, Middleton KJ, Kopelen HA, Zoghbi WA, Qui単ones MA: Doppler tissue imaging: a noninvasive technique for evaluation of left ventricular
Page 23
relaxation and estimation of filling pressures. J Am Coll Cardiol 1997;30:15271533. Ommen SR, Nishimura RA, Appleton CP, Miller FA, Oh JK, Redfield MM, Tajik AJ: Clinical utility of doppler echocardiography and tissue doppler imaging in the estimation of left ventricular filling pressures: A comparative simultaneous doppler-catheterization study Circulation 2000;102:1788-1794. Nagueh SF, Lakkis NM, Middleton KJ, Spencer WH 3d, Zoghbi WA, Qui単ones MA: Doppler estimation of left ventricular filling pressures in patients with hypertrophic cardiomyopathy. Circulation 1999;99:254-261. Nagueh SF, Mikati I, Kopelen HA, Middleton KJ, Qui単ones MA, Zoghbi WA: Doppler estimation of left ventricular filling pressure in sinus tachycardia: A new application of tissue doppler imaging. Circulation 1998;98:1644-1650. Oki T, Iuchi A, Tabata T, Mishiro Y, Yamada H, Abe M, Onose Y, Wakatsuki T, Ito S: Left ventricular systolic wall motion velocities along the long and short axes measured by pulsed tissue Doppler imaging in patients with atrial fibrillation. J Am Soc Echocardiogr 1999;12:121-128. Brun P, Tribouilloy C, Duval AM, Iserin L, Meguira A, Pelle G, Dubois-Rande JL: Left ventricular flow propagation during early filling is related to wall relaxation: a color M-mode Doppler analysis. J Am Coll Cardiol 1992;20:420432. Garcia MJ, Smedira NG, Greenberg NL, Main M, Firstenberg MS, Odabashian J, Thomas JD: Color M-mode Doppler flow propagation velocity is a preload insensitive index of left ventricular relaxation: animal and human validation. J Am Coll Cardiol 2000;35:201-208. Garcia MJ, Ares MA, Asher C, Rodriguez L, Vandervoort P, Thomas JD: An index of early left ventricular filling that combined with pulsed Doppler peak E velocity may estimate capillary wedge pressure. J Am Coll Cardiol 1997;29:448454. Nagueh SF, Kopelen HA, Qui単ones MA: Assessment of left ventricular filling pressures by Doppler in the presence of atrial fibrillation. Circulation 1996;94:2138-2145. Currie PJ, Seward JB, Chan KL, Fyfe DA, Hagler DJ, Mair DD, Reeder GS, Nishimura RA, Tajik AJ: Continuous wave Doppler determination of right ventricular pressure: a simultaneous Doppler-catheterization study in 127 patients. J Am Coll Cardiol 1985;6:750-756. Kircher BJ, Himelman RB, Schiller NB: Noninvasive estimation of right atrial pressure from the inspiratory collapse of the inferior vena cava. Am J Cardiol 1990;66:493-496. Nagueh SF, Kopelen HA, Zoghbi WA: Relation of mean right atrial pressure to echocardiographic and Doppler parameters of right atrial and right ventricular function. Circulation 1996;93:1160-1169. Ommen SR, Nishimura RA, Hurrell DG, Klarich KW: Assessment of right atrial pressure with 2-dimensional and Doppler echocardiography: a simultaneous catheterization and echocardiographic study. Mayo Clin Proc 2000;75:24-29.
Page 24
41. 42.
46. 47. 48.
51. 52.
Himelman RB, Stulbarg MS, Lee E, Kuecherer HF, Schiller NB: Noninvasive evaluation of pulmonary artery systolic pressures during dynamic exercise by saline-enhanced Doppler echocardiography. Am Heart J 1990;119:685-8. Hatle L, Brubakk A, Tromsdal A, Angelsen B: Noninvasive assessment of pressure drop in mitral stenosis by Doppler ultrasound. Br Heart J 1978;40:131140. Hatle L, Angelsen BA, Tromsdal A: Non-invasive assessment of aortic stenosis by Doppler ultrasound. Br Heart J 1980;43:284-292. Currie PJ, Seward JB, Reeder GS, Vlietstra RE, Bresnahan DR, Bresnahan JF, Smith HC, Hagler DJ, Tajik AJ: Continuous-wave Doppler echocardiographic assessment of severity of calcific aortic stenosis: a simultaneous Doppler-catheter correlative study in 100 adult patients. Circulation 1985;71:1162-1169. Currie PJ, Hagler DJ, Seward JB, Reeder GS, Fyfe DA, Bove AA, Tajik AJ: Instantaneous pressure gradient: a simultaneous Doppler and dual catheter correlative study. J Am Coll Cardiol 1986;7:800-806. Skjaerpe T, Hegrenaes L, Hatle L: Noninvasive estimation of valve area in patients with aortic stenosis by Doppler ultrasound and two-dimensional echocardiography. Circulation 1985;72:810-818. Otto CM, Pearlman AS, Comess KA, Reamer RP, Janko CL, Huntsman LL: Determination of the stenotic aortic valve area in adults using Doppler echocardiography. J Am Coll Cardiol 1986;7:509-517. Hatle L, Angelsen B, Tromsdal A: Noninvasive assessment of atrioventricular pressure half-time by Doppler ultrasound. Circulation 1979;60:1096-1104. Stamm RB, Martin RP: Quantification of pressure gradients across stenotic valves by Doppler ultrasound. J Am Coll Cardiol 1983;2:707-718. Smith MD, Handshoe R, Handshoe S, Kwan OL, DeMaria AN: Comparative accuracy of two-dimensional echocardiography and Doppler pressure half-time methods in assessing severity of mitral stenosis in patients with and without prior commissurotomy. Circulation 1986;73:100-107. Flachskampf FA, Weyman AE, Gillam L, Liu CM, Abascal VM, Thomas JD: Aortic regurgitation shortens Doppler pressure half-time in mitral stenosis: clinical evidence, in vitro simulation and theoretic analysis. J Am Coll Cardiol 1990;16:396-404. Karp K, Teien D, Bjerle P, Eriksson P: Reassessment of valve area determinations in mitral stenosis by the pressure half-time method: impact of left ventricular stiffness and peak diastolic pressure difference. J Am Coll Cardiol 1989;13:594599. Loyd D, Ask P, Wranne B: Pressure half-time does not always predict mitral valve area correctly. J Am Soc Echocardiogr 1988;1:313-321. Rokey R, Sterling LL, Zoghbi WA, Sartori MP, Limacher MC, Kuo LC, Qui単ones MA: Determination of regurgitant fraction in isolated mitral or aortic regurgitation by pulsed Doppler two-dimensional echocardiography. J Am Coll Cardiol 1986;7:1273-1278.
Page 25
58. 59.
64. 65.
Enriquez-Sarano M, Seward JB, Bailey KR, Tajik AJ: Effective regurgitant orifice area: a noninvasive Doppler development of an old hemodynamic concept. J Am Coll Cardiol 1994;23:443-451. Teague SM, Heinsimer JA, Anderson JL, Sublett K, Olson EG, Voyles WF, et al. Quantification of aortic regurgitation utilizing continuous wave Doppler ultrasound. J Am Coll Cardiol 1986;8:592-599. Chen CG, Thomas JD, Anconina J, Harrigan P, Mueller L, Picard MH, et al. Impact of impinging wall jet on color Doppler quantification of mitral regurgitation. Circulation 1991;84:712-720. Mele D, Vandervoort P, Palacios I, Rivera JM, Dinsmore RE, Schwammenthal E, et al. Proximal jet size by Doppler color flow mapping predicts severity of mitral regurgitation. Clinical studies. Circulation 1995;91:746-754. Hall SA, Brickner ME, Willett DL, Irani WN, Afridi I, Grayburn PA. Assessment of mitral regurgitation severity by Doppler color flow mapping of the vena contracta [see comments]. Circulation 1997;95:636-642. Perry GL, Helmcke F, Nanda NC, et al: Evaluation of aortic insufficiency by Doppler color flow mapping. J Am Coll Cardiol 1997;9:952-959. Pu M, Vandervoort PM, Griffin BP, Leung DY, Stewart WJ, Cosgrove DM, et al. Quantification of mitral regurgitation by the proximal convergence method using transesophageal echocardiography. Clinical validation of a geometric correction for proximal flow constraint. Circulation 1995;92:2169-2177. Schwammenthal E, Chen C, Benning F, Block M, Breithardt G, Levine RA. Dynamics of mitral regurgitant flow and orifice area. Physiologic application of the proximal flow convergence method: clinical data and experimental testing. Circulation 1994;90:307-322. Enriquez-Sarano M, Miller FA, Jr., Hayes SN, Bailey KR, Tajik AJ, Seward JB. Effective mitral regurgitant orifice area: clinical use and pitfalls of the proximal isovelocity surface area method. J Am Coll Cardiol 1995;25:703-709. Utsunomiya T, Doshi R, Patel D, Mehta K, Nguyen D, Henry WL, et al. Calculation of volume flow rate by the proximal isovelocity surface area method: simplified approach using color Doppler zero baseline shift. J Am Coll Cardiol 1993;22:277-282. Dujardin KS, Enriquez-Sarano M, Bailey KR, Nishimura RA, Seward JB, Tajik AJ. Grading of mitral regurgitation by quantitative Doppler echocardiography: calibration by left ventricular angiography in routine clinical practice. Circulation 1997;96:3409-3415 Reisner SA, Meltzer RS. Normal values of prosthetic valve Doppler echocardiographic parameters: a review. J Am Soc Echocardiogr 1988;1:201-210 Chafizadeh ER, Zoghbi WA. Doppler echocardiographic assessment of the St. Jude Medical prosthetic valve in the aortic position using the continuity equation. Circulation 1991;83:213-223. Burstow DJ, Nishimura RA, Bailey KR, Reeder GS, Holmes DR Jr, Seward JB, et al. Continuous wave Doppler echocardiographic measurement of prosthetic valve gradients. A simultaneous Doppler-catheter correlative study. Circulation 1989;80:504-514.
Page 26
70. 71.
Baumgartner H, Khan S, DeRobertis M, Czer L, Maurer G. Discrepancies between Doppler and catheter gradients in aortic prosthetic valves in vitro. A manifestation of localized gradients and pressure recovery. Circulation 1990;82:1467-1475. Baumgartner H, Khan S, DeRobertis M, Czer L, Maurer G. Effect of prosthetic aortic valve design on the Doppler-catheter gradient correlation: an in vitro study of normal St. Jude, Medtronic-Hall, Starr-Edwards and Hancock valves. J Am Coll Cardiol 1992;19:324-332. Pibarot P, Honos GN, Durand LG, Dumesnil JG. Substitution of left ventricular outflow tract diameter with prosthesis size is inadequate for calculation of the aortic prosthetic valve area by the continuity equation. J Am Soc Echocardiogr 1995;8:511-517. Chambers JB. Mitral pressure half-time: is it a valid measure of orifice area in artificial heart valves? [Review]. J Heart Valve Dis 1993;2:571-577. Dumesnil JG, Honos GN, Lemieux M, Beauchemin J. Validation and applications of mitral prosthetic valvular areas calculated by Doppler echocardiography. Am J Cardiol 1990;65:1443-1448. Bitar JN, Lechin ME, Salazar G, Zoghbi WA. Doppler echocardiographic assessment with the continuity equation of St. Jude Medical mechanical prostheses in the mitral valve position [published erratum appears in Am J Cardiol 1995;76(8):642]. Am J Cardiol 1995;76:287-293. Mohr-Kahaly S, Kupferwasser I, Erbel R, Oelert H, Meyer J. Regurgitant flow in apparently normal valve prostheses: improved detection and semiquantitative analysis by transesophageal two-dimensional color-coded Doppler echocardiography. J Am Soc Echocardiogr 1990;3:187-195. Flachskampf FA, O'Shea JP, Griffin BP, Guerrero L, Weyman AE, Thomas JD. Patterns of normal transvalvular regurgitation in mechanical valve prostheses. J Am Coll Cardiol 1991;18:1493-1498. Daniel LB, Grigg LE, Weisel RD, Rakowski H. Comparison of transthoracic and transesophageal assessment of prosthetic valve dysfunction. Echocardiography 1990;7:83-95. Khandheria BK, Seward JB, Oh JK, Freeman WK, Nichols BA, Sinak LJ, et al. Value and limitations of transesophageal echocardiography in assessment of mitral valve prostheses. Circulation 1991;83:1956-1968. Olmos L, Salazar G, Barbetseas J, Qui単ones MA, Zoghbi WA. Usefulness of transthoracic echocardiography in detecting significant prosthetic mitral valve regurgitation. Am J Cardiol 1999;83:199-205.
Page 27
PW Doppler recording of the left ventricular outflow track velocity obtained from the apical window. Because the flow is away from the transducer, the velocities are displayed below the baseline. Notice the narrow spectral pattern during flow acceleration and the deceleration and the wider dispersion seen during mid-systole. The degree of dispersion indicates the range of blood flow velocities detected within the sample volume.
CW Doppler recording of velocity through the aortic valve in a patient with AS. Transducer position is at the apex; thus the systolic velocities are displayed below the baseline.
In diastole, positive mitral inflow
velocities can be seen as the inflow moves toward the transducer. Note the wide spectral dispersion of velocities during systole and diastole indicating that the Doppler beam is detecting all the flow velocities encountered along its course.
Diagrammatic illustration of flow through a vessel showing two different flow profiles. A flat profile with all cells traveling at the same velocity and a parabolic profile with the cells at the center traveling faster than those on the side. At any given time, the flow through the vessel represents the product of the average velocity of all cells multiplied by the CSA of the vessel.
The method used in determining systolic flow volume through the left ventricular outflow.
The method used in determining diastolic flow volume through the mitral annulus.
Page 28
The method used in determining systolic flow volume through the pulmonic annulus.
Example of transmitral and pulmonary vein velocity recordings in a normal subject. The pulmonary vein velocity recording has been aligned in time with the mitral velocity for illustration purposes.
The method use for measuring IVRT from a recording of LV outflow and inflow velocities with CW Doppler. The transducer is at the cardiac apex, and the Doppler cursor is aligned in an intermediate position between the aortic and mitral valves.
Diagrammatic illustration of three common patterns of mitral and pulmonary vein velocities: normal, delayed relaxation, and pseudonormal.
FIGURE 10. Myocardial velocity recording obtained from the apical window with tissue Doppler using the PW mode. The diagram illustrates the Doppler cursor with sample volume positioned at the base of the lateral wall. The recording shows a systolic positive wav (S), an early diastolic wave (Em), and an atrial wave (Am).
FIGURE 11. Demonstration of method used to measure flow propagation velocity using color M-mode. In panel A a 2D color Doppler frame with the M-mode cursor aligned in the center of the red inflow velocities is shown. Panels B, C, and D illustrate the color M-mode tracing obtained through the cursor at three different aliasing velocities obtained by shifting the 0 baseline. This maneuver enhances the appreciation of the propagation velocity.
Page 29
FIGURE 12. A normal hepatic vein velocity recorded from the subcostal window. From this window, a negative velocity indicates antegrade flow moving toward the RA. Notice that the antegrade systolic velocity is larger than the antegrade diastolic velocity. A small retrograde atrial (A) velocity is also seen. These velocities are subject to variation with respiration.
FIGURE 13. Diagrammatic representation of the continuity equation. When laminar flow encounters a small discrete stenosis, it must accelerate rapidly to pass through the small orifice. The flow proximal to the stenosis is the same as the flow passing through the stenosis. Because flow equals velocity times CSA, the area of the stenotic orifice can be solved if the velocity through the orifice and the flow is known.
FIGURE 14. CW Doppler tracing taken from a patient with mitral stenosis, illustrating the measurement of the pressure half time.
FIGURE 15. CW Doppler recording of transmitral velocity in a patient with mitral stenosis.
The velocity pattern shows a rapid early deceleration that
decelerates to mid-diastole, giving rise to a "ski slope� appearance. In these cases, estimating the pressure half time from the slower component of the velocity descent is better, as illustrated in the second cardiac cycle.
FIGURE 16. CW Doppler tracing of aortic regurgitation velocity illustrating the method for determining pressure half time.
FIGURE 17. Diagrammatic illustration explaining the concept of entrainment. Flow is passing from chamber A to chamber B through a discrete stenosis that generates a high-velocity jet. The initial high-velocity jet is depicted in black. As the high-velocity flow enters the receiving chamber, the blood that sits in that chamber is forced into motion. The blood cells will move
Page 30
in a circular fashion around the high velocity jet and will be encoded by the color Doppler. The jet in the receiving chamber becomes wider. In the case of mitral valve regurgitation, this phenomenon will make the regurgitant jet area appear larger that expected for a given volume of regurgitation.
FIGURE 18. A color Doppler recording of MR in a parasternal long (panel A) and a short axis (panel B) view. Measurement of the jet height and width is illustrated by the arrows in panel A and B, respectively.
FIGURE 19. Diagrammatic representation of the concept of PISA used to assess severity of MR.
Page 31
GLOSSARY OF TERMS A. Aliasing:
Ambiguous frequencies (or velocities) caused by frequencies exceeding the PRF sampling (Nyquist) limit with PW Doppler. The high velocities "wrap around� and are displayed as negative velocities. The intensity of the backscatter echoes reflected off the moving blood cells and displayed in gray scale. It reflects the number of red blood cells moving at a given velocity in a given time.
B. Baseline shift: Repositioning of the zero flow velocity line to the forward or reversed channels to overcome aliasing. Also referred as zero shift. Bernoulli Equation: An equation that relates the instantaneous pressure drop across a discrete stenosis to convective acceleration, viscous forces and early phasic acceleration. The latter two factors are usually neglected in the "modified" equation (4V2). C. Carrier Frequency: The frequency emitted by the transducer. Continuity Equation: Principle of the conservation of mass in which the flow volume proximally to a valve equals the distal flow volume. Because flow = area (A) x velocity (V), it follows that A1 x V1 = A2 x V2. Continuous-Wave (CW) Doppler: A method to measure Doppler velocity with a transducer incorporating two ultrasound crystals (or array of crystals). One constantly transmits a selected ultrasound frequency, and the other constantly receives frequency shifts backscattered from red blood cells in motion. High flow velocities can be recorded without aliasing, although depth localization is not possible. D. Deceleration Time: The time duration (in milliseconds) of the decrease from peak flow velocity to the zero baseline. Diameter: The maximal linear measurement (in centimeters) of a circle. Diastolic Filling Period: The duration of flow velocity from atrioventricular valve opening to closure.
Doppler Equation:
Page 32
A mathematical equation that relates the observed frequency shift (∆F) to the velocity of blood cells (V), the carrier frequency (Fo), the cosine of the angle theta (θ), and the speed of sound in soft tissue (c = 1540 m/s). The Doppler equation is ∆F = (V x 2 Fo x cos θ)/ c. E. Ejection Time:
The duration of flow from semilunar valve opening to closure.
F. Flow Convergence Region: The region proximal to a flow orifice in which flow streamlines converge, thereby creating "shells" of progressive flow acceleration. Isovelocity areas can be indicated by aliasing boundaries. Flow Profile: A spatial plot of velocity distribution across a vessel diameter that can be described as parabolic, flat, or irregular. Frequency Shift: The difference between transmitted and received ultrasound frequency. It is directly proportional to the velocity of blood flow as stated in the Doppler equation. G. Gradient:
The pressure drop or pressure difference across any restrictive orifice.
H. Hertz:
A unit of frequency equal to one cycle per second; kilohertz (KHz) = 1,000 hertz, and megahertz = 1 million hertz. High Pulse Repetition Frequency (PRF) Doppler: A method of achieving high sampling rates; multiple pulses and their return signals from within the heart are present at any one point in time, and Doppler shifts along the beam are summed along sample volume depths that are multiples of the initial sample volume depth to give a single output. I. Isovolumic Contraction: The time period (in milliseconds) between atrioventricular valve closure and semilunar valve opening. J. Jet:
High-velocity flow signal in or downstream from a restrictive orifice.
L. Laminar Flow:
Page 33
A flow state in which blood cells are moving in a uniform direction and with organized distribution of velocities across the flow area. M. Mean Velocity: The mean (average) of measured spectral shifts over a specific time period within a given sample site. Mirroring: An artifact of spectral display resulting in the inability of the spectrum analyzer to separate forward and reverse Doppler signals. The stronger signals are displayed in mirror-like fashion from the zero baseline in the opposite channel. Also called signal "cross talk." Modal Velocity: The mode in the frequency analysis of a signal is the frequency component that contains the most energy. In display of the Doppler frequency spectrum, the mode corresponds to the brightest (or darkest) display points of the individual spectra and represents the velocity component that is most commonly encountered among the various moving reflectors. N. Nyquist Limit: The highest Doppler shift frequency that can be measured. Equal to one half the pulse repetition frequency. P. Pressure Half Time: The time (in milliseconds) that it takes for the maximal pressure gradient to decrease by one half. Pulse repetition frequency (PRF): The rate at which pulses of ultrasound energy are transmitted. Pulsed-wave (PW) Doppler: A method of Doppler interrogation that utilizes specific time delays to assess the Doppler shifts within a discrete region along the path of the sound beam. S. Sample volume: The specific 3D site in which Doppler velocities are interrogated. Sample Volume Width: The lateral and azimuthal dimensions of the PW Doppler sample volume, which depends on beam characteristics. Sample Volume Length: The axial size of the PW Doppler sample volume. Spectral Analysis: A display of the Doppler shift frequency components over time. Frequency or velocity is displayed in the Y axis, time in the X axis, and amplitude in gray scale.
Page 34
Spectral Broadening: An increase in the number of frequency components in a PW Doppler signal; an indicator of a disorganized flow pattern or high velocity flow signal aliasing. T. Velocity-time integral (VTI): Integral of the velocity over time. Turbulent flow: Nonlaminar unstable blood flow in which the kinetic energy of flow creates vortices of differing velocities and direction. V. Vena contracta: W. Wall Filter:
Smallest area of flow in or downstream from a restrictive orifice.
A control that rejects echocardiographic information from low-velocity reflectors such as wall motion.
B. General principles recording and measurement of Doppler data. The document is not a comprehensive Doppler echocardiography is a noninvasi...


text:
Epsom Salt Bath - Views: 1998
Been working your body hard lately or just a little stressed out?? Here's a Stress Buster! Try an Epsom Salt Bath by relaxing in a warm bath with one to two cups of Epsom salt to relax your muscles and reduce inflammation. Epsom salt is a natural emollient, that will exfoliate your skin. A Lifestyle Tip that's good for your body and your budget.
Listing #39 posted in: Lifestyle Tips
Courtesy of Mara

subset: commoncrawl


text:
CIBC World Raises Estimates on Hotel Reservations
CIBC World raised estimates and maintains buy on Hotel Reservations (ROOM ).
Analyst Paul Keung says he's raising numbers following conversations with hotel suppliers suggesting online hotel bookings are exceeding the Q3 forecast. He notes, on the last conference call, that management indicated it is evaluating new distribution channels and affiliates, including supplier call centers and Web sites -- following the recent successful connections with Northwest Airlines and Cheap Tickets. He says the company could acquire another regional player, solidifying market share in a space with only a few scaled online hotel consolidators.
Kueng raised his $1.02 2001 EPS estimate to $1.05, and raised the $1.32 2002 estimate to $1.42. He has a $55 target.


text:
The Packers fullback will have an interview on 107.5 FM WDUZ in Green Bay at 9:20 a.m. CT.
Brian Carriveau joins 107.5 The Fan in Green Bay to discuss the upcoming NFL Draft and predicts the Packers first round draft choice.
Brian Carriveau joined WDUZ's SportsLine on 107.5 FM in Green Bay to talk about the NFL Draft. Listen in to find out what he had to say about the Missouri defensive lineman.


text:
New York Looks to Philadelphia for Ideas on Sewer Overflow Issues
When it comes to meeting federal clean water standards, New York and other older cities like Boston and Albany are decades behind. One reason is all the human waste that's discharged every time a storm overwhelms the capacity of 19th century combined sewer systems, which collect rain and sewage in the same pipes. Now New York is looking to another old East Coast city, Philadelphia, for new ideas.
Just a few years ago in South Philadelphia, Herron Playground looked like a lot of other city parks.
"Essentially this whole site was pavement before," says Glen Abrams from the Philadelphia Water Department. He says when the playground came up for a renovation in 2007, new guidelines required parks to manage stormwater runoff. But instead of just complying with those rules, city officials decided to go all the way and make Herron Playground into a showpiece of sustainability.
"All of this rubber safety surface is recycled ground up tires, so the water flows through it," Abrams says. "All of these drains, instead of going directly into the sewer system, first flow into the rain garden that's in the front here."
Abrams says by capturing that initial inch -- known as the "first flush" -- and keeping it out of the drains for 24 hours, a little playground like this can do a lot to prevent the overflows that send pathogen-filled human waste into the Delaware River and other local waterways.
Philadelphia is relying more and more on green infrastructure: street trees, green roofs and restored wetlands around the city, and depending less and less on so-called "grey" infrastructure like expensive underground storage tanks. The water department has also changed the way it bills customers; non-residential building owners now have to pay for the amount of storm runoff they generate based on how much concrete or other impermeable surfaces they have on their properties.
"There are some real incentives for our customers over time, when they're thinking about redesigning or rebuilding their facilities, to start thinking about incorporating stormwater management," Abrams says.
Philadelphia's policy shift has been possible, in part, because federal regulators with the Environmental Protection Agency have become more flexible about how they measure compliance with the Clean Water Act.
"We are particularly interested in these sorts of innovative approaches because it's just not realistic that struggling communities are going to have the billions and billions of dollars necessary to upgrade every part of their sewage system," says Judith Enck, the regional director for EPA region 2, which covers New York and New Jersey.
Enck says the federal stimulus package included hundreds of millions of dollars for sewer upgrades, and 20 percent of that money has been set aside for green infrastructure projects.
"With that encouragement, cities are off to the races," says Carter Strickland, Mayor Michael Bloomberg's Deputy Commissioner for Sustainability. He says he's been to Philadelphia to check out their program, and he likes a lot of what he's seen. But he says New York is moving at a more deliberate pace in an attempt to get good data about which methods work best.
"We still, at the end of the day, have to prove that what we build will have an effect. We're holding ourselves to a high standard about what we build and the fact that it has to have a real water-quality benefit," Strickland says.
One project that is already underway is a limited version of Philadelphia's stormwater charge. It covers stand-alone parking lots that don't use drinking water, but generate a lot of runoff. Meanwhile, the Department of Environmental Protection has just awarded $2.5 million to fund five pilot projects in Brooklyn and Queens, but work on those hasn't started yet. When WNYC asked DEP officials if there are any sites we could see now, they sent us to see a single tree planter in Brooklyn.
That tree is at the corner of Autumn and Stanley Avenues in East New York and looks like your average street tree, only in a somewhat longer-than-average pit. It's actually one of 10 so-called swales in the Jamaica Bay watershed. DEP's Director of Ecological Services, John McLaughlin, says it may not look like much, but this black gum tree and the soil under it can hold 950 gallons from that crucial first inch of rainfall -- water that would ordinarily go into city sewers and contribute to overflows.
"While there's no silver bullet, every little piece helps, and placing these in many locations does have a cumulative effect that begins to make a difference," McLaughlin says.
The Jamaica Bay watershed trees are part of a pilot program, as is the stormwater charge for parking lots. That's the same stage the Parks Department is at with its green infrastructure projects, like the one under construction at the Pearly Gates structure in the Westchester Square neighborhood in the Bronx.
Pearly Gates is a small Robert Moses-era park that's currently getting a $1.5 million rehab. Landscape architect Stephen Koren created the rain garden, which is designed to receive runoff from the basketball court.
"All the surfaces actually drain into the surrounding planting bed," Koren says. "Whenever it rains it's actually watering the surrounding plants and any excess then goes into the catch basin, but the first flush is actually captured."
The project manager, Nette Compton, says landscape architects have been interested in stormwater management for a long time, but now it's easier to get approval for it.
"Basically, our bosses are into it now! So there's more of an environment to try new things, to experiment," Compton says.
Still, Koren concedes that it's not easy to transform the culture of a big agency like the Parks Department.
"There's a lot of tried and tested methods that I think we rely upon, and because we're such a large consumer of landscape materials, it's hard to just all of a sudden change course, so that's why we're taking baby steps," Koren says.
But that slow pace is a source of frustration for environmentalists like Michael Heimbinder with Stormwater Infrastructure Matters (SWIM coalition). He says the problem is built into Mayor Michael Bloomberg's sustainability goals for 2030, known as PlaNYC. He says the program provides a good blueprint for how different city agencies should work together to manage stormwater. "Unfortunately, it doesn't have any kind of enforcement mechanism. It doesn't have any kind of power to bring different stakeholders to the table and make them cooperate," Heimbinder says.
Heimbinder thinks the city should require the installation of green infrastructure any time crews renovate a park or tear up a street. He points out that every year that officials talk about these projects without implementing them, another 27 billion gallons of raw sewage and polluted rainwater spill into New York harbor.
More images of the proposed surface for the Pearly Gates Park:
Photos courtesy of NYC Department of Environmental Protection


text:
Obama Phones Lawmakers Seeking Ways to Recast Budget Cuts
President Barack Obama has begun contacting Republican and Democratic senators in search of a budget compromise even as each party blamed the other for across-the-board cuts in government spending.
The Democratic president worked the phones yesterday, calling senators "who he thinks could be part of a caucus of common sense to help move our country forward," National Economic Council Director Gene Sperling said today on NBC's "Meet the Press." He didn't identify the senators.
Slightly more than $85 billion in cuts, affecting agencies and programs that range from the Pentagon to the Smithsonian Institution, began March 1 amid a more than two-year-old impasse over raising taxes and cutting entitlements.
Even as lawmakers are deadlocked over what to do about the so-called sequestration, both sides signaled today they don't want a second confrontation over legislation that will be needed to keep federal agencies running beyond March 27.
"We should not have any talk of a government shutdown so I'm hopeful that the House and Senate will be able to work through this," said House Speaker John Boehner on "Meet the Press." The administration is amendable to legislation now being written in the House so long as it sticks to a $1.043 trillion spending level lawmakers previously agreed upon, said Sperling.
"The president doesn't believe in manufacturing another crisis," Sperling said.
Frank Meeting
Obama met with congressional leaders March 1 in what Boehner called a "polite" though "very frank" meeting on the across-the-board cuts. "There are big disagreements between the two parties" and "I don't think anyone quite understands how it gets resolved," said Boehner, an Ohio Republican.
Republicans will hold firm in their demands for entitlement cuts and "I've frankly made it my mission as speaker to address this problem because it is the greatest threat to our country," said Boehner. "It is going to be addressed."
Though sequestration would cut total federal spending this year by just 2 percent, the reductions are concentrated in a relatively small portion of the government's budget so they would have an outsize effect on many programs.
Defense Cuts
Defense programs will be cut by 7.8 percent, the White House budget office estimated last week, while non-defense "discretionary" programs will see about a 5 percent cut. The effective cuts will be even bigger, the agency said, because they come in the middle of the government's fiscal year.
In a report issued the evening of March 1, the administration itemized the impact on hundreds of programs. The National Endowment for the Arts was cut by a 5 percent, or $7 million. Medicare payments to health-care providers were pared by $11.3 billion, or 2 percent.
The budget of the Holocaust Memorial Museum in Washington D.C. shrunk by 5 percent, or $3 million. The Food and Drug Administration lost $209 million, while the Smithsonian Institution was cut by about 5 percent, or $51 million.
More than 150 budget accounts by law are immune from the cuts, including many of the government's biggest and most popular programs. Among them: Social Security, most of Medicare, Medicaid, veterans' benefits, the Children's Health Insurance Program, food stamps, Pell college tuition grants and the Supplemental Security Income program, which aids the disabled poor.
Republican Proposal
Sperling, also appearing on ABC's "This Week," rejected a Republican proposal that would make it easier for agencies to live with sequestration by giving them more power to decide how to make the cuts. While Republicans say that would allow departments to shift funding to higher-priority initiatives, Sperling said the cuts are so big as to be unworkable.
"When you have those type of harsh spending cuts in such a short, concentrated period of time, it's like saying to somebody, 'You can cut off three of your fingers but you can have the flexibility to choose which ones,'" Sperling said. Democrats say they want to replace the cuts with a combination of higher taxes on the wealthy and cuts in farm subsidies and defense spending.
Sperling also rejected complaints the administration has exaggerated the impact of sequestration.
Spreading Pain
"It's not going to hurt as much on day one," he told ABC. "As this pain starts to gradually spread to communities affected by military spending, to children who need mental health services, to people who care about our border security, I believe that more Republican colleagues who are concerned about this harm to their constituents will choose bipartisan compromise."
Appearing on the same program, New Hampshire Republican Kelly Ayotte said she's willing to consider tax increases though only as part of a major budget deal, not as a temporary fix to the automatic cuts.
"I am willing to say if we take the form of lowering rates so that we can focus on economic growth and then we take a portion of that, and apply it to the debt with real entitlement reform -- but it has to go to the debt," she said.
Senator Lindsey Graham agreed. "I'm not going to raise taxes to fix sequestration," he told CBS's "Face the Nation."
The South Carolina Republican did say he is willing to consider about $600 billion in tax increases as part of a sweeping budget deal that includes entitlement spending cuts and a rewrite of the tax code.
"The way forward is a big deal," said Graham. "a big deal, not a small deal."
To contact the reporters on this story: Jesse Hamilton in Washington at email@example.com Brian Faler in Washington at 1919 or firstname.lastname@example.com
To contact the editor responsible for this story: Steven Komarow at firstname.lastname@example.com


text:
Bibliographic Details
Title: Life and Letters, Vol. III, No. 15, August ...
Publisher: [London]
Publication Date: 1929
Binding: Paperback
Book Condition: Very Good
Edition: First UK Edition.
Wraps. Spine tanned, and chipped at tips; some light rubbing and tanning along edges of covers. Aside from a brief editorial, the entire issue of "Life and Letters" is given over to the first appearance of "High Wind" in the UK. Bookseller Inventory # D11599
Payment Methods
This bookseller accepts the following methods of payment:
AbeBooks Bookseller Since: July 15, 2002
Bookseller Rating:
Please reserve books by email or by phone. All items subject to prior
sale. NYS residents must include 8.875% sales tax. We accept checks,
money orders, online payment through paypal. Full refund within 15 days
provided book is returned in same condition as sent.
Shipping costs are based on books weighing 2.2 LB, or 1 KG. If your book order is heavy or oversized, we may contact you to let you know extra shipping is required.


text:
The Rest of the Ivy Bridge Die Sizesby Anand Lal Shimpi on 5/31/2012 4:45 PM EST
- Posted in
- CPUs
- Intel
- Ivy Bridge
- GPUs
14 Comments
Back to Article
mavere - Thursday, May 31, 2012 - linkToo bad Intel and Apple couldn't work out a deal on a beefier Ivy Bridge; it would have a been a pretty good setup.
Apple would foot the bill on volume production because they sell so much of one SKU, while other companies would be able to use the chips on some high end units. Reply
JMS3072 - Thursday, May 31, 2012 - link"however only one customer was really asking for it and wasn't interested in paying a significant premium for it."
What's your source for that? Reply
CeriseCogburn - Friday, June 01, 2012 - linkAPPL standard operating prodecure Reply
iwod - Thursday, May 31, 2012 - linkThe most interesting fact is that they actually produce the die for each specification. And that is something new to me because we always thought GT 1/2 were only disabled die.
That would also means Intel has mastered another technique of yield and flexibility in its Fab. Reply
CeriseCogburn - Friday, June 01, 2012 - linkSo scowling "harvested" while blabbering binning and defective parts just won't do ?
I thank my lucky stars. Reply
fic2 - Friday, June 01, 2012 - linkI think that Grant's supposition on this was that there was a large enough die size difference between GT 1/2 that it made sense to Intel to have different die for each. They can probably get several more GT 1s per wafer than GT 2s. Also, since GT 1s are much smaller the number of defective chips/wafer is probably smaller.
Using http://mrhackerott.org/semiconductor-informatics/i...
and using 300mm wafer and default parameters since I don't know anything about wafer layout it looks like Intel can produce up to ~1400 more die per wafer for the M-2 GT1 than the H2 GT2. So, definitely worth it. Even at 75% yield that is over 1,000 die they can sell and probably $1-200,000 extra $$$. Reply
CeriseCogburn - Saturday, June 02, 2012 - linkWait, I thought it was all about not wasting precious resources, and bringing computers to the people of the world ?!!
If Intel can share this gift with 1,000 more people of the world, it would be selfish and evil if they did not. Reply
madooo12 - Saturday, June 02, 2012 - linkIntel is selfish and greedy, they won't share it for free you know Reply
seapeople - Sunday, June 03, 2012 - linkI think it would be better if Intel was taken over the by the government and forced to sell their CPUs to the world at just a hair above manufacturing cost. Then all their employees should share equally in the profits and receive free health care.
That would be much less selfish and greedy. Reply
CeriseCogburn - Monday, June 04, 2012 - linkBetter than getting a super gimped 25 different ways 5 year old brand new core hacked harvested mhz AMD core, isn't it madooo12 ?
Think of the bazillion wafers amd wastes as they constantly rebrand and gimp their completely harvested cpu line up.
No wonder they can't make dime one.
Maybe amd should rename itself to "Wasted Wafers !" Reply
JKflipflop98 - Saturday, June 02, 2012 - linkA lot of other places use defective parts with sections disabled as the lower-tiered parts. Intel doesn't mess up enough die to keep up with demand for the lower-price parts (which always do way more volume than the high-end parts). So instead of wasting die space on a part that you know you're going to purposely gimp in order to sell for less, we just make the smaller die with the low-end specifications.
You get the part you wanted at the price you wanted, and Intel gets to put extra die on a wafer. It's a win-win. Reply
stadisticado - Saturday, June 02, 2012 - linkOh there surely is still binning going on, we just haven't seen those products yet. Just think, we have four total die for desktop/mobile. I'm sure once the Core i3/Pentium/Celeron IVB variants get released you'll see that those are definitely downbinned versions of these four with defective EU units/cache/low speed etc. Reply
ajp_anton - Monday, June 04, 2012 - linkIntel rarely harvests dice. I talked to one of their representatives at a computer event once, and he said they just throw away non-functional chips as it's not worth the effort. If they disable parts, it's only for artificial market segmentation and not because of harvesting.
I don't know how much he's exaggerating, but I wouldn't be surprised considering how good their manufacturing is. Reply
CeriseCogburn - Monday, June 04, 2012 - linkWhereas AMD has a long running list of identical cores with disabled aka crippled parts belched out as standard operating procedure.
I wonder if there have been more than 3 AMD chips with a hundred different cpu's sometimes.
Talk about rebranding, AMD cpus are the absolute king of rebranding, for years running. Reply


text:
First time leaser looking for help
View Single Post
Registered User
Location: Kansas City, MO
Join Date: Jan 2013
Posts: 3
Mein Auto: 2009 GMC Yukon Denali
View My Garage
First time leaser looking for help
Long time lurker and first time poster. Good morning gentlemen (and ladies). I am in the market for a 2013 535xi currently and have a couple of different quotes from the local dealer. I have researched the lease threads on here, but still wanted to get opinions from the experts!
The first vehicle is one they have on the lot that I test drove. It was the May 2012 build according to bmwconfig. Alpine White, Black Dakota, Anthracite trim, M Sport, Cold Weather, Premium, Technology, & SAT. MSRP is 64945 and invoice is 59940 by bmwconfig. The dealer is offering this vehicle for a selling price of 61345 with a 297 doc fee and a 2.50 title fee. Zero down. 60% residual. .00170 money factor (even though ridewithg is stating .00130 right now). 36 mo lease/15K year miles. Monthly payment 931.21.
I would prefer to have the DG color but the dealer seems less willing to offer a lower price to have one built. I built this one out with the Sales Associate. Dark Graphite, Black Dakota, Anthracite trim, M Sport, Cold Weather, Premium, Technology, Driver Assistance, & SAT. MSRP on this one is 67695 with invoice at 62445. The dealer is offering this vehicle for a selling price of 66195 with same doc fees, residual, money factor, and lease terms as above. Monthly payment comes out to 1032.59 for this one.
I would like to build my own and don't believe I should have to pay a premium to do so. Also, I know that the money factor and selling price is high and want to offer the dealer 1K over invoice for the build out with a money factor of .00130. I am open to all suggestions from members on the board. Should I be asking for more? Less? All opinions are welcome and I look forward to becoming an active member on the board with a new car, but am also willing to walk away if the deal is not to my liking.
Have a great day everyone.
View Public Profile
Find all threads started by realdeal211
Find all posts by realdeal211
View My Garage
Add realdeal211 to Your Ignore List


text:
I am a humanitarian relief worker in Afghanistan. A keen photographer, trained as an architect, highly accident prone, and two-time malaria survivor, I've had my office broken into by monkeys, self-treated tonsillitis by gargling vodka and lost countless phones – the last one down an open sewer in India. While my greatest fear is flying, I've travelled to over 30 countries and called 9 of them 'home' at one time or another.
Bangladesh, Myanmar, Rwanda, Afghanistan, India, Zanzibar, London
the_goat hasn't logged any travels yet.
the_goat hasn't been active in the wiki travel guide yet. Have you?


text:
Page Not Found.
We could not find the page you requested.
This is either because:
- there's an error in the address or link,
- due to a technical fault it has not been properly published,
- it is an older article that has been removed from our site.
Welcome to The Sydney Morning Herald. Skip directly to: Search Box, Section Navigation, Content. Text Version.
|network map | member centre
Samoa's Head of State, his Majesty Malietoa Tanumafili II, has died in hospital aged 94.
He was one of the world's longest reigning monarchs.
Malietoa had sat on the Samoan throne since the country gained independence from New Zealand in 1962.
That made him the world's third longest reigning living monarch after Thailand's King Bhumibol Adulyadej, who has reigned since 1946 and Britain's Queen Elizabeth II, who ascended to the throne in 1952.
The king died on Friday night at Tupua Tamasese National Hospital in Apia where he had been staying for about a week. Details on the cause of death were not immediately available.
New Zealand prime minister Helen Clark expressed sorrow at his death.
Clark said it was a day of great sadness for Samoa.
"Through his long reign as Head of State, Malietoa represented Samoa with wisdom, humour and insight," she said.
"He was Head of State from the time of Samoa's independence from New Zealand 45 years ago, and at the time of his death, was understood to be the world's oldest national leader.
"He helped frame Samoa's Constitution prior to Samoa's independence from New Zealand in January 1962 and became joint Head of State at that time. From 1963, following the death of Tupua Tamasese Mea'ole, he became sole Head of State."
Malietoa was educated in Samoa at the government run Leififi School and attended St Stephens and Wesley College in New Zealand.
Vaasatia Poloma Komiti, chief executive officer of the prime minister's office, announced the king's passing on state-run television.
The prime minister was expected to address the nation later on Sunday, Komiti added.
The king succeeded the Malietoa title in 1940, when his father died. He was appointed an adviser to the New Zealand governor in Samoa the same year.
Malietoa held the post of head of state for life. His successor, however, will be elected by the legislature to a five-year term as stipulated in the Samoan constitution.
He was known to be an active sportsman from the time of his youth, playing rugby and cricket, and was reputed to be a good boxer.
Malietoa is survived by two sons and two daughters. His wife Lili Tunu died in 1986.
He was born on January 4, 1913.
© 2007
Brought to you by
When news happens: send photos, videos & tip-offs to 0424 SMS SMH (+61 424 767 764), or us.
Did you know you could pay less than $1 a day for a subscription to the Herald? Subscribe today.
Personalise your news, save articles to read later and customise settings
We could not find the page you requested.
This is either because: