she had had dyspnea on exertion ( nyha class iii ) for 10 years , and this had aggravated recently . her past history included hypertension , pulmonary tuberculosis when younger , and percutaneous coronary stent insertion in the left anterior descending artery ( lad ) , left circumflex artery ( lcx ) , and right coronary artery ( rca ) 5 months ago . she has taken aspirin 100 mg , clopidogrel 75 mg , and diltiazem 90 mg daily , and all of these medications were continued . transthoracic echocardiography showed severe as with an aortic valve area ( ava ) of 0.8 cm , a mean pressure gradient of 41 mmhg and an aortic annulus diameter of 21 mm . mild mitral regurgitation ( mr ) was present and the left ventricular ejection fraction was 62% . coronary angiography ( cag ) showed that all stents were patent . computed tomography ( ct ) showed diffuse calcification in the abdominal aorta and no tortuosity in either common iliac artery . the right iliac artery was 13.2 mm and the right femoral artery was 8.9 mm in diameter . a 5-lead electrocardiograph , pulse oximeter , bis sensor , and two cerebral oxymetry sensors were applied . anesthesia was induced with etomidate 12 mg , rocuronium 50 mg , and continuous infusion of remifentanil ( target effect site concentration 10 ng / ml ) and propofol ( target effect site concentration 1.0 g / ml ) using a target controlled infusion system ( orchestra , fresenius vial , brezims , france ) . an intra - arterial catheter was inserted into the left radial artery and endotracheal intubation was performed . a central venous catheter ( mac two - lumen central venous access set , arrow , reading , pa , usa ) with a swan - ganz catheter ( swan - ganz ccombo , cco / svo2/cedv , edwards lifesciences llc , irvine , ca , usa ) was inserted into the right internal jugular vein for continuous monitoring of cardiac output and mixed venous oxygen saturation using continuous cardiac output monitoring ( vigilance , edwards lifesciences llc , irvine , ca , usa ) . during the procedure , anesthesia was maintained with oxygen ( 2 l / min ) , and continuous infusion of remifentanil ( target effect site concentration 10 - 20 ng / ml ) , propofol ( target effect site concentration 1.0 - 1.5 g / ml ) and rocuronium 0.5 g / ml / min . transesophageal echocardiography ( tee ) ( live 3d tee , ie33 , philips ultrasound , bothell , wa , usa ) was performed to confirm the aortic annulus diameter and to provide images for correct valve positioning during the procedure . heparin ( 1 mg / kg ) was given to achieve an activated coagulation time > 250 seconds . the left femoral vein was used for the placement of a pacing wire ( electrophysiology catheter , st . paul , mn , usa ) in the right ventricular apex and the left femoral artery was used for insertion of a pigtail catheter in the aortic root . surgical exposure of the right femoral artery was performed and a 12 french introducer was inserted . balloon valvuloplasty was successfully performed under rapid ventricular pacing ( rvp ) of 200 beats / min ( dual chamber temporary pacemaker , medtronic , minneapolis , mn , usa ) ( fig . systolic blood pressure was 110 - 140 mmhg and diastolic blood pressure was 50 - 60 mmhg before and after rvp . althought preoperative ct indicated that the right femoral artery was large enough for a 24 french introducer , it was a tight fit during the procedure , and insertion required the cardiologist to exert more force than anticipated . a 23 mm edward - sapien valve ( edwards lifesciences llc , irvine , ca , usa ) crimped onto a balloon was then advanced into the aortic annulus . however , the prosthetic valve was ejected into the ascending aorta and moved down to the descending thoracic aorta . tee was performed immediately and showed that the valve was packed in the descending thoracic aorta . however , there was no flow disturbance around the valve and the vital signs were stable . the cardiologist made a decision to leave the valve in place and insert another valve . rvp was repeated several times to enable correct positioning and intermittent bolus injections of phenylephrine ( 100 g / ml ) were used without continuous infusion of a vasopressor . a root aortogram showed patent coronary arteries and no paravalvular leakage or aortic regurgitation ( ar ) ( fig . , the cardiac surgeon tried to remove the 24 french introducer , but initially found that it would not move in any direction . after approximately 30 minutes of manipulation , the surgeon was able to move the introducer backward . at that time a vascular surgeon performed an emergecy laparotomy and clamped the proximal side of the right external iliac artery . the total infused fluid volume was 14 units of packed red blood cells , 10 units of fresh frozen plasma , 10 units of platelets , 1,500 ml of cell saver blood , 4,400 ml of crystalloid solutions and 1,000 ml of colloid solutions . on post - operative day 1 , the patient was mentally alert , had good motor and sensory nerve function , and a normal pulse in her right lower extremity . echocardiography showed a well - functioning prosthetic aortic valve , a mean pressure gradient of 16 mmhg , mild paravalvular leakage and mild ar . the prosthetic aortic valve was functioning stable , however , the patient had ileus till post - operative day 30 . her past history included hypertension , pulmonary tuberculosis when younger , and intermediate stenosis of lad and lcx . she has taken aspirin 100 mg , isosorbide dinitrate 40 mg , and atenolol 50 mg daily , and all of these medications were continued . transthoracic echocardiography showed severe as with an ava of 0.8 cm , a mean pressure gradient of 40 mmhg and an aortic annulus diameter of 21.5 mm . the left ventricular ejection fraction was 66% and mild to moderate atherosclerosis was present in the descending thoracic aorta and aortic arch . ct showed patent non - tortuous iliac and femoral arteries ( the right iliac artery was 8.5 mm and right femoral artery was 7.3 mm in diameter ) . heparin ( 1 g / kg ) was given to achieve an activated coagulation time > 250 seconds . systolic blood pressure was 90 - 120 mmhg and diastolic blood pressure was 50 - 60 mmhg before and after rvp . however , st segment elevation was observed in lead ii and v , and worsened after repeated rvp . the infusion rate of isosorbide dinitrate was therefore increased and intermittent bolus injections of phenylephrine ( 100 g / ml ) were used . prosthetic aortic valve implantation was successfully performed and st segment elevation improved to the normal range . after confirmation of valve function , a new - onset left bundle branch block was observed . although she occasionally complained of chest discomfort without pain , electrocardiography and cardiac enzymes findings remained normal , and the symptoms resolved within 3 hours . the isosorbide dinitrate infusion was ceased , and she continued on her pre - operative oral medications with the addition of clopidogrel 75 mg . the patient was sent to the general ward on post - operative day 1 , and showed no signs of complications . echocardiography showed a satisfactorily functioning prosthetic aortic valve , a mean pressure gradient of 21 mmhg and mild ar . she had had dyspnea on exertion ( nyha class iii ) for 10 years , and this had aggravated recently . her past history included hypertension , pulmonary tuberculosis when younger , and percutaneous coronary stent insertion in the left anterior descending artery ( lad ) , left circumflex artery ( lcx ) , and right coronary artery ( rca ) 5 months ago . she has taken aspirin 100 mg , clopidogrel 75 mg , and diltiazem 90 mg daily , and all of these medications were continued . transthoracic echocardiography showed severe as with an aortic valve area ( ava ) of 0.8 cm , a mean pressure gradient of 41 mmhg and an aortic annulus diameter of 21 mm . mild mitral regurgitation ( mr ) was present and the left ventricular ejection fraction was 62% . coronary angiography ( cag ) showed that all stents were patent . computed tomography ( ct ) showed diffuse calcification in the abdominal aorta and no tortuosity in either common iliac artery . the right iliac artery was 13.2 mm and the right femoral artery was 8.9 mm in diameter . a 5-lead electrocardiograph , pulse oximeter , bis sensor , and two cerebral oxymetry sensors were applied . anesthesia was induced with etomidate 12 mg , rocuronium 50 mg , and continuous infusion of remifentanil ( target effect site concentration 10 ng / ml ) and propofol ( target effect site concentration 1.0 g / ml ) using a target controlled infusion system ( orchestra , fresenius vial , brezims , france ) . an intra - arterial catheter was inserted into the left radial artery and endotracheal intubation was performed . a central venous catheter ( mac two - lumen central venous access set , arrow , reading , pa , usa ) with a swan - ganz catheter ( swan - ganz ccombo , cco / svo2/cedv , edwards lifesciences llc , irvine , ca , usa ) was inserted into the right internal jugular vein for continuous monitoring of cardiac output and mixed venous oxygen saturation using continuous cardiac output monitoring ( vigilance , edwards lifesciences llc , irvine , ca , usa ) . during the procedure , anesthesia was maintained with oxygen ( 2 l / min ) , and continuous infusion of remifentanil ( target effect site concentration 10 - 20 ng / ml ) , propofol ( target effect site concentration 1.0 - 1.5 g / ml ) and rocuronium 0.5 g / ml / min . transesophageal echocardiography ( tee ) ( live 3d tee , ie33 , philips ultrasound , bothell , wa , usa ) was performed to confirm the aortic annulus diameter and to provide images for correct valve positioning during the procedure . heparin ( 1 mg / kg ) was given to achieve an activated coagulation time > 250 seconds . the left femoral vein was used for the placement of a pacing wire ( electrophysiology catheter , st . paul , mn , usa ) in the right ventricular apex and the left femoral artery was used for insertion of a pigtail catheter in the aortic root . surgical exposure of the right femoral artery was performed and a 12 french introducer was inserted . balloon valvuloplasty was successfully performed under rapid ventricular pacing ( rvp ) of 200 beats / min ( dual chamber temporary pacemaker , medtronic , minneapolis , mn , usa ) ( fig . systolic blood pressure was 110 - 140 mmhg and diastolic blood pressure was 50 - 60 mmhg before and after rvp . althought preoperative ct indicated that the right femoral artery was large enough for a 24 french introducer , it was a tight fit during the procedure , and insertion required the cardiologist to exert more force than anticipated . a 23 mm edward - sapien valve ( edwards lifesciences llc , irvine , ca , usa ) crimped onto a balloon was then advanced into the aortic annulus . however , the prosthetic valve was ejected into the ascending aorta and moved down to the descending thoracic aorta . tee was performed immediately and showed that the valve was packed in the descending thoracic aorta . however , there was no flow disturbance around the valve and the vital signs were stable . the cardiologist made a decision to leave the valve in place and insert another valve . rvp was repeated several times to enable correct positioning and intermittent bolus injections of phenylephrine ( 100 g / ml ) were used without continuous infusion of a vasopressor . a root aortogram showed patent coronary arteries and no paravalvular leakage or aortic regurgitation ( ar ) ( fig . , the cardiac surgeon tried to remove the 24 french introducer , but initially found that it would not move in any direction . after approximately 30 minutes of manipulation , the surgeon was able to move the introducer backward . at that time a vascular surgeon performed an emergecy laparotomy and clamped the proximal side of the right external iliac artery . the total infused fluid volume was 14 units of packed red blood cells , 10 units of fresh frozen plasma , 10 units of platelets , 1,500 ml of cell saver blood , 4,400 ml of crystalloid solutions and 1,000 ml of colloid solutions . on post - operative day 1 , the patient was mentally alert , had good motor and sensory nerve function , and a normal pulse in her right lower extremity . echocardiography showed a well - functioning prosthetic aortic valve , a mean pressure gradient of 16 mmhg , mild paravalvular leakage and mild ar . the prosthetic aortic valve was functioning stable , however , the patient had ileus till post - operative day 30 . her past history included hypertension , pulmonary tuberculosis when younger , and intermediate stenosis of lad and lcx . she has taken aspirin 100 mg , isosorbide dinitrate 40 mg , and atenolol 50 mg daily , and all of these medications were continued . transthoracic echocardiography showed severe as with an ava of 0.8 cm , a mean pressure gradient of 40 mmhg and an aortic annulus diameter of 21.5 mm . ct showed patent non - tortuous iliac and femoral arteries ( the right iliac artery was 8.5 mm and right femoral artery was 7.3 mm in diameter ) . heparin ( 1 g / kg ) was given to achieve an activated coagulation time > 250 seconds . systolic blood pressure was 90 - 120 mmhg and diastolic blood pressure was 50 - 60 mmhg before and after rvp . however , st segment elevation was observed in lead ii and v , and worsened after repeated rvp . the infusion rate of isosorbide dinitrate was therefore increased and intermittent bolus injections of phenylephrine ( 100 g / ml ) were used . prosthetic aortic valve implantation was successfully performed and st segment elevation improved to the normal range . after confirmation of valve function , a new - onset left bundle branch block was observed . although she occasionally complained of chest discomfort without pain , electrocardiography and cardiac enzymes findings remained normal , and the symptoms resolved within 3 hours . the isosorbide dinitrate infusion was ceased , and she continued on her pre - operative oral medications with the addition of clopidogrel 75 mg . the patient was sent to the general ward on post - operative day 1 , and showed no signs of complications . echocardiography showed a satisfactorily functioning prosthetic aortic valve , a mean pressure gradient of 21 mmhg and mild ar . although conventional avr is the gold standard treatment for symptomatic severe as , and operative mortality is low in ideal candidates , its use is limited in the elderly with comorbidities . hence , tavi was developed , and has been widely performed in selected high - risk patients , mainly in europe and north america . the advantages of tavi include avoidance of a sternotomy , cardiopulmonary bypass and cardiac arrest , along with a short hospital stay and fast return to functional status . recent national institute for health and clinical excellence ( nice ) guidelines and licensing regulations have restricted the use of tavi to selected patients not suitable for surgical avr due to high operative mortality and risk of severe complications . the euroscore is usually used as a predictive risk model   and tavi is recommended in patients with a logistic euroscore over 20% . comprehensive baseline examination and careful patient selection patients underwent transthoracic echocardiography , coronary and aortofemoral angiography , and a multidetector ct to confirm adequate vascular dimensions and lack of tortuosity or intravascular thrombus . these include bicuspid aortic valve ( because the altered anatomy makes secure placement of the transcatheter valve which are potentially unstable ) , previous mechanical avr , endocarditis , recent myocardial infarction or cerebrovascular accident , moderate to severe mitral or tricuspid valve regurgitation , left ventricular or atrial thrombus , an aortic annular diameter less than 18 mm or over 25 mm , an ascending aorta diameter over 45 mm , severe vascular calcification and aortic disease . a hybrid operation room ( a standard operation room with an additional angiography system equivalent to a standard catheterization laboratory ) is recommended for the tavi as a precaution for emergency such as device embolization , prolonged ventricular fibrillation , and massive hemorrhage . in our cases , the procedure was performed in the cardiac catheterization laboratory with operating room - like sterile precautions . a cardiac surgeon took active part in the procedure , and a vascular surgeon was on call and aware of the ongoing procedure . the anesthesiologist took a participatory role in monitoring and standards of care in the catheterization laboratory for this procedure . elective general anesthesia has many advantages , which includes facilitation of sheath placement , removal , and eventual surgical repair of the arterial access site , immobility during valve deployment , periprocedural tee , airway management , minimal patient movement , avoidance of breathing artifacts , and rapid cpb institution when necessary . short - acting anesthetics are used to facilitate emergence and extubation at the end of the procedure . reported complications include poor recovery of cardiac function after rvp , paravalvular leakage , ar , myocardial ischemia and device embolization , complete heart block , new - onset arrhythmia , neurological dysfunction or stroke , damage to the vascular access site , and radiocontrast induced acute renal failure . rvp and cessation of mechanical ventilation interrupt cardiac ejection and minimize cardiac motion , facilitating exact prosthesis positioning within the native annulus . after termination of rvp , heart rate , rhythm , and arterial blood pressure usually return to baseline , but a bolus injection of a vasopressor or defibrillation may be required to restore stable hemodynamics . intermittent bolus injections of phenylephrine ( 100 g / ml ) were used without continuous infusion of norepinephrine in both patients . catecholamines such as epinephrine may worsen hypotension when administered to patients with left ventricular hypertrophy   and should be used with caution . the second present patient with intermediate coronary artery disease showed aggravation of st segment elevation despite continuous isosorbide dinitrate infusion . therefore , it is necessary to consider the underlying coronary status and allow for sufficient rest periods of 1 - 2 minutes after rvp . paravalvular regurgitation is often present immediately after valve deployment , but improves after 24 - 48 hours as valve morphology alters at body temperature . reinflation of the deployment balloon within the prosthesis or further expansion of the valve within the annulus is often employed for treatment of paravalvular ar . significant ar suggests overexpansion of the prosthesis , which may require deployment of a second prosthetic valve within the first one . we assumed it was the result of the insufficient cardiac standstill . to prevent this , a few seconds of delay for non - pulsatile flow through the aortic valve previous reports documented that valve embolization has been experienced during initial attempts with the procedure . management of this complication requires repositioning of the prosthesis , implantation of an additional valve prosthesis , or an emergency sternotomy , cpb , aortic cross - clamping , and aortotomy to remove the embolized valve and perform open avr . vascular injury at the access site is the most common complication and causes sudden and significant hemorrhage . anesthesiologists should be alert to the possibility of a major vascular rupture , which requires urgent repair . to minimize the risk of this complication , careful evaluation of the arterial anatomy is necessary and the diameter of both the femoral and iliac arteries should be large enough for introducer sheath insertion . also , those arteries should be free of severe calcification and not be tortous . in the first present case , althought the femoral and iliac arteries were considered large enough , sheath insertion was found to be difficult due to intra - arterial calcification . we assumed that rupture of the common iliac artery occurred due to forceful insertion and removal of the sheath . the introducer sheath should be inserted and removed smoothly , and if it becomes stuck as our case , it should be removed in the operating room with preparation for emergency . systemic anticoagulation should be commence before tavi and continue postoperatively . usually , administering aspirin 300 mg and clopidogrel 300 mg before the procedure and starting regular dose of aspirin 100 mg and clopidogrel 75 mg , soon after the end of the procedure , are recommended . these are normally continued for 3 - 6 months . if a patient has been medicated as in our cases , loading dose of aspirin and clopidogrel are not necessary . patients who re - present after tavi for non - cardiac surgery can be managed similarly to patients after conventional avr . there is no evidence that discontinuing anti - platelet drugs increases the risk of valve thrombosis perioperatively , and full heparinization is not required . although the procedure is still in its infancy and long - term outcomes are not yet known , the results from the first generation have been encouraging , demonstrating satisfactory technical feasibility , substantial reduction of the transaortic pressure gradient , and fast left ventricular function recovery . previous reports demonstrated that perioperative mortality and in - hospital mortality were 0 - 6% and 6.7 - 12% , respectively , and that there was no evidence of structural device failure during 2 year follow - up . in conclusion , tavi has become an alternative to surgical avr for the elderly with comorbidities who have a high operative mortality rate or are deemed non - operable . however , judicious selection of patients is important because tavi can cause several serious complications . a multidisciplinary approach including a trained cardiac surgeon , interventional cardiologist , and cardiac anesthesiologist and a hybrid operation room is essential to provide safe and successful service . anesthesiologists must be aware of entire procedure and be prepared for sudden hemodynamic deterioration , which may require inotropic support , defibrillation , massive fluid infusion , or emergency surgery .
conventional aortic valve replacement for severe aortic stenosis is associated with a high operative mortality in the elderly patients with significant comorbidities , including severe respiratory dysfunction , renal insufficiency , and compromised cardiac function . 
 human transcatheter aortic valve implantation was first reported in 2002 and has become a valid alternative in selected high - risk patients in europe and north america . 
 this article describes the first attempt of transfemoral transcatheter aortic valve implantation in korea . 
 the procedure was applied in two consecutive patients with severe aortic stenosis . despite several intra - operative complications during procedure , the post - operative outcomes were good for both patients . at post - operative 
 30 days there was satisfactory prosthetic valve function and hemodynamic stability .