Femoropopliteal Arterial Dissections Post Flex Vessel Prep and Adjunctive Angioplasty: Results of the Flex iDissection Study.

Background: Luminal gain post balloon angioplasty (PTA) is in part due to the occurrence of dissections. The depth and extent of dissections, however, can influence the short- and long-term outcomes of a procedure. Focal force and scoring balloons have been used to reduce angiographic dissections post PTA. The role of the Flex Vessel Prep (VP) system (VentureMed Group), a dynamic, microincision, non-balloon based system, prior to PTA in reducing and/or limiting severe dissections has not been fully characterized.

Methods: In this prospective pilot study, a total of 15 patients were evaluated by angiography and intravascular ultrasound (IVUS) following treatment of femoropopliteal de novo or no-stent restenosis with the Flex VP system and PTA. Eagle Eye Platinum ST IVUS catheters were used in this study. No atherectomy devices were allowed. Cine and IVUS images were obtained at baseline, after Flex, and following adjunctive PTA. Angiographic and IVUS core labs analyzed the images.

Results: Mean patient age was 74.6 ± 11.7 years. Diabetes and claudication were present in 40% and 73.3%, respectively. Median baseline, post-Flex, and postadjunctive PTA stenosis severities were 77.0%, 60.0%, and 34.0%, respectively (P=.07 and P<.001 for baseline vs post Flex and post Flex vs post PTA, respectively). Lesion length was 63.6 ± 32.5 mm. Using PACSS classification for calcium grading, grades 3 and 4 were 6.7% and 40.0%, respectively. Total dissections identified on IVUS post-Flex microincisions were 14 compared with 3 dissections on angiogram (P=.35) (ratio, 4.7 to 1). Post adjunctive angioplasty, there were 49 dissections on IVUS vs 6 on angiogram (P<.01) (ratio, 8.2 to 1). Of these dissections and when compared with baseline, 3 and 37 dissections were new on IVUS post Flex and PTA, respectively. Of these dissections, 2/3 and 7/37 were ≥180° in circumference post Flex and post PTA, respectively. Also, 1/3 and 8/37 dissections involved the media and/or adventitia as seen on IVUS post Flex and PTA, respectively. The majority of dissections post PTA following Flex VP involved mostly the intima (71.4%) and were <180° in circumference (77.6%).

Conclusion: Dissections are grossly under-appreciated on angiogram when compared with IVUS. Dissections on IVUS post PTA following the Flex VP system involved mostly the intima, with <180° in width. The clinical significance of these findings needs to be further explored.