PURPOSE: We evaluated surface modification effects of micro-incision and debulking preparation technologies on complex porcine peripheral in-stent restenosis lesions (ISRL).

METHODS: Bilateral ISRL were created in 7 Yorkshire pigs at Day -30. On Day 0, ISRL (53-73% stenosis) received either six treatment passes by a retractable catheter with a self-sizing treatment element made of three radially positioned surgical blades (FLEX Vessel Prep System [FLEX VP]) or four debulking passes (HawkOne Directional Atherectomy [DA]). Vessels were imaged by OCT at baseline and post treatment and compared manually offline in 5mm intervals along 30mm of the MLD encompassing stenosis (6 frames/ISRL). Surface modification engagement was recorded on an overlaid 8-sector circular image filter, and cut depths measured.

RESULTS: Similar stenotic characteristics of baseline ISRLs facilitated comparison of the two technologies. Debulking effects with DA were large and 380±320µm deep, but only circumferentially engaged 15±17% of proximal vs 41±20% of distal sectors (P<0.0001). FLEX VP preparation resulted in 180±30µm deep micro-incisions, with consistently high circumferential engagement along the stenosed lesion (80±14% vs 28±23% by DA, P<0.0001).

CONCLUSION: OCT imaging differentiated vessel preparation technologies in porcine peripheral artery ISR lesions. Debulking effects with DA were uncontrolled in location and depth, posing potential safety concerns. By contrast, FLEX VP enabled continuous controlled depth longitudinal micro-incisions along the entire lesion, offering a more predictable vessel preparation.