complex coronary artery lesions , such as bifurcation , diffuse , and calcified tortuous lesions , constitute one of the most challenging lesion subsets in the field of interventional cardiology . compared with treating simple coronary artery disease ( cad ) , treatment of complex coronary lesions requires the use of more complicated procedures , has lower procedural success rates and higher rates of clinical adverse events . thus , making the proper decision on whether to clinically intervene when a complex lesion is detected is of critical importance . while coronary angiography has limited value in determination of the physiologic significance of a coronary stenosis , intracoronary measurement of myocardial fractional flow reserve ( ffr ) has been introduced and proven to be a reliable physiology parameter for determining the need for intervention . however , in practice , the pressure guidewire used in obtaining ffr data is difficult to manipulate in certain complex coronary artery , leading to increased fluoroscopy time and contrast dye usage . we propose the use of a workhorse guidewire for easier engagement in the complex lesion with subsequent broken balloon and ffr wire through the lesion , and then final withdrawal of the workhorse guidewire and balloon . we performed this study to compare the novel ( nov ) technique with the conventional ( con ) technique used for obtaining measurements of ffr in complex coronary artery lesions . this prospective randomized control study was conducted from december 1 , 2012 to may 1 , 2014 in 56 consecutive patients ( mean age , 71.5  8.2 years ; 32 males and 24 females ) with complex coronary artery lesions at the second affiliated hospital of zhejiang university . among the 56 patients , 32 had hypertension , 24 had diabetes , 23 had hyperlipidemia , and 35 were smokers . the patient exclusion criteria were as follows : acute myocardial infarction ; left ventricle hypertrophy ; simple coronary artery lesions . the 56 enrolled patients were assigned into two groups based on the technique selected for measuring ffr . the con ffr measurement technique and nov measurement technique were used in the con group ( n = 26 patients ) , and nov group ( n = 30 patients ) , respectively . the device used for measuring ffr with the new technique figure 2 illustrates how the novel ( nov ) technique is employed for measuring ffr in a patient with a bifurcation lesion . in this case , percutaneous coronary intervention ( pci ) was performed while using provisional stenting with a 6f - coronary - guiding catheter . the novel technique for measuring fractional flow reserve in complex coronary artery lesions , such as bifurcation lesion : ( 1 ) routine placement of the side branch ( sb ) workhorse guidewire and main branch pressure guidewire after stent implantation . the workhorse and pressure guidewires were fixed in vitro , and the broken balloon was then pushed to the distal end of the pressure guidewire in a state of negative pressure ; ( 2 ) the pressure guidewire and broken balloon were then advanced along the fixed workhorse guidewire to a location past the sb ostial lesion ; ( 3 ) the two guidewires were fixed once again , the broken balloon was further advanced until it exited from the pressure guidewire ; ( 4 ) finally , the broken balloon and workhorse guidewire were withdrawn , and the pressure guidewire was retained within the sb . in this study , when side branch ( sb ) ffr was measured using the con method , the jailed sb was re - crossed through the stent strut using a pressure wire . when using the nov technique , a stent was implanted into the main branch , and the main wire was withdrawn . next , the jailed wire in the sb was used to guide insertion of the workhorse guidewire into the sb . the previously jailed sb wire was then withdrawn , and the pressure guidewire was inserted into the main branch . a balloon previously dilated to a low pressure ( 68 atm ) in vitro , and then punctured with a fine needle . the broken balloon was then passed through by external tips of the pressure and workhorse guidewires respectively [ figure 1 ] . next , the external tips of the two guidewires were fixed in position , and the broken balloon was advanced to the distal end of the pressure guidewire in a state of negative pressure . the workhorse guidewire remained fixed in place while the pressure guidewire was advanced past the sb ostial lesion with the broken balloon . the two guidewires were then fixed once again , and the broken balloon was further advanced until it exited from the pressure guidewire . finally , the broken balloon and workhorse guidewire were both withdrawn while the pressure guidewire retained within the sb . after obtaining an accurate ffr measurement , the operators were able to make an informed decision regarding treatment of the sb lesion . after performing ffr measurements using the con and nov techniques , the fluoroscopy time , contrast dye usage , and ffr - related complications associated with each method were assessed . the ffr - related complications included coronary spasm , dissection , perforation and intra - stent thrombosis . values for continuous variables are expressed as the mean  standard deviation or a range while values for categorical variables are expressed as frequencies or percentages . comparisons of parametric and categorical values between the two groups were performed using the independent sample t - test and chi - square test , respectively . this prospective randomized control study was conducted from december 1 , 2012 to may 1 , 2014 in 56 consecutive patients ( mean age , 71.5  8.2 years ; 32 males and 24 females ) with complex coronary artery lesions at the second affiliated hospital of zhejiang university . among the 56 patients , 32 had hypertension , 24 had diabetes , 23 had hyperlipidemia , and 35 were smokers . the patient exclusion criteria were as follows : acute myocardial infarction ; left ventricle hypertrophy ; simple coronary artery lesions . the 56 enrolled patients were assigned into two groups based on the technique selected for measuring ffr . the con ffr measurement technique and nov measurement technique were used in the con group ( n = 26 patients ) , and nov group ( n = 30 patients ) , respectively . the device used for measuring ffr with the new technique is shown in figure 1 . figure 2 illustrates how the novel ( nov ) technique is employed for measuring ffr in a patient with a bifurcation lesion . in this case , percutaneous coronary intervention ( pci ) was performed while using provisional stenting with a 6f - coronary - guiding catheter . the novel technique for measuring fractional flow reserve in complex coronary artery lesions , such as bifurcation lesion : ( 1 ) routine placement of the side branch ( sb ) workhorse guidewire and main branch pressure guidewire after stent implantation . the workhorse and pressure guidewires were fixed in vitro , and the broken balloon was then pushed to the distal end of the pressure guidewire in a state of negative pressure ; ( 2 ) the pressure guidewire and broken balloon were then advanced along the fixed workhorse guidewire to a location past the sb ostial lesion ; ( 3 ) the two guidewires were fixed once again , the broken balloon was further advanced until it exited from the pressure guidewire ; ( 4 ) finally , the broken balloon and workhorse guidewire were withdrawn , and the pressure guidewire was retained within the sb . in this study , when side branch ( sb ) ffr was measured using the con method , the jailed sb was re - crossed through the stent strut using a pressure wire . when using the nov technique , a stent was implanted into the main branch , and the main wire was withdrawn . next , the jailed wire in the sb was used to guide insertion of the workhorse guidewire into the sb . the previously jailed sb wire was then withdrawn , and the pressure guidewire was inserted into the main branch . a balloon previously dilated to a low pressure ( 68 atm ) in vitro , and then punctured with a fine needle . the broken balloon was then passed through by external tips of the pressure and workhorse guidewires respectively [ figure 1 ] . next , the external tips of the two guidewires were fixed in position , and the broken balloon was advanced to the distal end of the pressure guidewire in a state of negative pressure . the workhorse guidewire remained fixed in place while the pressure guidewire was advanced past the sb ostial lesion with the broken balloon . the two guidewires were then fixed once again , and the broken balloon was further advanced until it exited from the pressure guidewire . finally , the broken balloon and workhorse guidewire were both withdrawn while the pressure guidewire retained within the sb . after obtaining an accurate ffr measurement , the operators were able to make an informed decision regarding treatment of the sb lesion . after performing ffr measurements using the con and nov techniques , the fluoroscopy time , contrast dye usage , and ffr - related complications associated with each method were assessed . the ffr - related complications included coronary spasm , dissection , perforation and intra - stent thrombosis . values for continuous variables are expressed as the mean  standard deviation or a range while values for categorical variables are expressed as frequencies or percentages . comparisons of parametric and categorical values between the two groups were performed using the independent sample t - test and chi - square test , respectively . as shown in table 1 , there were no significant differences in either the age or sex of the patients or the lesion characteristics in the two groups . patient and lesion characteristics lad : left anterior descending coronary ; lcx : left circumflex coronary artery ; rca : right coronary artery ; con : conventional ; nov : novel . as shown in table 2 , both the mean time required for fluoroscopy and the amount of contrast dye used were significantly greater in the con group compared to the nov group ( 10.1  2.1 s vs. 5.7  1.0 s and 64.7  9.2 ml vs. 38.9  5.0 ml , respectively ) ( both p < 0.05 ) . however , as shown in table 3 , there is no significant difference between the two groups regarding their rates of ffr - related complications , including spasm , dissection , perforation and intra - stent thrombosis ( p > 0.05 ) . additionally , three patients in the con group experienced a failed ffr procedure while there were no failures in the nov group ( p > 0.05 ) . comparisons of fluoroscopy time and contrast dye usage for con and nov ffr measurement procedures ( mean  sd ) compared with con group , * p < 0.05 . sd : standard deviation ; ffr : fractional flow reserve ; con : conventional ; nov : novel . comparisons of complication and success rates between two groups , n ( % ) compared with nov group , * p > 0.05 . as shown in table 1 , there were no significant differences in either the age or sex of the patients or the lesion characteristics in the two groups . patient and lesion characteristics lad : left anterior descending coronary ; lcx : left circumflex coronary artery ; rca : right coronary artery ; con : conventional ; nov : novel . as shown in table 2 , both the mean time required for fluoroscopy and the amount of contrast dye used were significantly greater in the con group compared to the nov group ( 10.1  2.1 s vs. 5.7  1.0 s and 64.7  9.2 ml vs. 38.9  5.0 ml , respectively ) ( both p < 0.05 ) . however , as shown in table 3 , there is no significant difference between the two groups regarding their rates of ffr - related complications , including spasm , dissection , perforation and intra - stent thrombosis ( p > 0.05 ) . additionally , three patients in the con group experienced a failed ffr procedure while there were no failures in the nov group ( p > 0.05 ) . comparisons of fluoroscopy time and contrast dye usage for con and nov ffr measurement procedures ( mean  sd ) compared with con group , * p < 0.05 . sd : standard deviation ; ffr : fractional flow reserve ; con : conventional ; nov : novel . comparisons of complication and success rates between two groups , n ( % ) compared with nov group , * p > 0.05 . it has become increasingly apparent that revascularization of ischemia - associated lesions is the superior treatment in the patients with cad . however , if a coronary stenosis is not associated with inducible ischemia , medical treatment is indicated better than pci . therefore , it is important to determine whether such an association exists when selecting therapy for cad . since the introduction of coronary angiography , various methods have been introduced to assess the severity and clinical significance of the stenosis in coronary arteries . measurements of ffr , rather than visual estimations of coronary obstruction have demonstrated the greatest accuracy for determining the functional significance of coronary artery stenosis . additionally , the fame trial revealed that outcomes achieved following pci performed based on ffr measurements were better than those achieved following pci performed based on angiographic results alone . however , the pressure wire used in taking coronary ffr measurements is very flimsy and difficult to maneuver . thus , in practice , it has been difficult to insert the pressure guidewire and manipulate it to determine the functional significance of complex coronary artery lesions , such as bifurcation lesions , diffuse lesions , and calcified tortuous lesions . , the interventional physicians must repeatedly remodel the shape of the pressure guidewire , and make repeated attempts to push it through the target lesion . this process can damage the pressure sensors in the wire , and affect the accuracy of ffr measurements . presently , there are numerous different types of workhorse guidewires available ; many of which are preferred by different interventional cardiologists . due to their good tensile strength , and increased maneuver ability , lubrication , and tactile feedback additionally , their low traumatic effects and high ease of use have made them excellent wires for engaging complex lesions during postprovisional stenting . in our new technique , a workhorse guidewire was used to initially engage a complex lesion , and then insert a broken balloon carried by a pressure guidewire through the lesion along the workhorse guidewire . next , the broken balloon and workhorse guidewire were withdrawn following separation of the balloon from the pressure guidewire . the profile of the balloon used in an actual operation should be as small as possible , ( e.g. , 1.52.0 mm ) , to reduce its effects on the lesion or the structure of the stent . although the new ffr measurement technique required puncturing the balloon , this did not appear to increase the operation risk or the probability of failure ( p > 0.05 ) . our new method reduced the technical difficulty of using pressure wire , and also decreases the fluoroscopy time , and volume of contrast medium required for a ffr procedure . ffr measurements are crucial for evaluating the physiologic significance of complex coronary artery lesions , which can help determine whether certain coronary interventions are feasible and thus prevent unnecessary complex interventions and their related complications . our nov technique will facilitate making timely and economically sound decisions related to treatment of complex lesions such as bifurcation , diffuse and calcified tortuous lesions . however , both our new technique and study results also have limitations that should be mentioned . the new technique has a possible drawback in that it may increase the financial cost of an ffr measurement procedure by requiring an additional workhorse guidewire and a balloon . however , the balloon and workhorse guidewire used in a pci procedure can be re - used in a subsequent ffr measurement procedure performed immediately afterward . also , any interpretation of our study results is limited by the small sample size , which might have influenced the negative result found when comparing procedural success rates in the two groups of patients . due to the difficulties encountered when evaluating the physiologic significance of complex coronary artery lesions , we proposed a nov technique for obtaining measurements of ffr . compared with the con technique used to measure ffr , the new technique has advantages of reduced fluoroscopy time and contrast dye usage , without increasing the risk of operation or decreasing the success rate .
background : fractional flow reserve ( ffr ) has become an increasingly important index when making decisions with respect to revascularization of coronary artery stenosis . however , the pressure guidewire used in obtaining ffr measurements is difficult to control and manipulate in certain complex coronary artery lesions , resulting in increased fluoroscopy time and contrast dye usage . 
 this study examined a novel ( nov ) technique for obtaining ffr measurements in hope of easing the difficulties associated with evaluating and treating complex coronary artery lesions.methods:fifty-six patients with complex coronary artery lesions were assigned to a conventional ( con ) ffr technique group or a nov ffr technique group . 
 the nov technique involved the use of a balloon and wire exchange within the coronary artery . 
 the fluoroscopy time , contrast dye usage , and ffr - related complications were assessed after completing the ffr measurement procedure for each patient.results:the median time required for fluoroscopy in the nov technique group was significantly less than that in the con technique group ; additionally , lesser amounts of contrast dye were used in the nov technique group ( both p < 0.05 ) . 
 the nov technique was successfully performed in thirty patients , without any ffr - related complications . however , the con technique failed in three patients , including two who experienced coronary artery spasms ( p > 0.05).conclusions : compared to the con technique used for measuring ffr , the new technique reduced the fluoroscopy time and amount of contrast dye used when evaluating complex coronary artery lesions . 
 the new technique did not increase the risk of operation or decrease the success rate .