Sequential Proximal Optimizing Technique in Provisional Bifurcation Stenting With Everolimus-Eluting Bioresorbable Vascular Scaffold: Fractal Coronary Bifurcation Bench for Comparative Test Between Absorb and XIENCE Xpedition

Objectives The aim of this fractal bifurcation bench study was to compare provisional bifurcation stenting with a “re-POT” sequence, comprising a proximal optimizing technique (POT), side branch inflation, and final POT, between a bioresorbable vascular scaffold (BVS) and a metallic stent. Background Re-POT proved significantly better than kissing balloon inflation in maintaining circular geometry without overstretch in metal stents, while significantly reducing side branch ostium strut obstruction and global strut malapposition. This should be useful for BVSs, which are more easily breakable. Methods Twenty left main–like and 20 left anterior descending–like fractal coronary bifurcation bench models used 10 each 2.5 × 24 mm and 3.5 × 24 mm Absorb (Ab) BVSs and 10 each 2.5 × 24 mm and 3.5 × 24 mm XIENCE Xpedition (XX) metal stents, implanted by re-POT, with optical coherence tomographic analysis at each step and micro–computed tomographic analysis of Ab devices to detect strut fracture. Results With Ab devices, re-POT reduced percentage strut malapposition close to XX rates (0.8 ± 0.7% vs. 0.0 ± 0.0%, p < 0.05; 3.5 ± 1.7% vs. 0.3 ± 0.6%, p < 0.05), conserving proximal circularity (elliptical ratio, 1.04 vs. 1.03 and 1.04 vs. 1.04; p = NS). Mean post-re-POT proximal expansion was 0.6 ± 0.1 mm (+21.6 ± 2.1%) for 2.5-mm and 1.0 ± 0.1 mm (+23.6 ± 2.2%) for 3.5-mm Ab devices, with only 1 strut fracture (left anterior descending–like bench). Side branch ostium strut obstruction was greater with Ab scaffolds than XX stents: 41.1 ± 9.4% versus 16.4 ± 8.1% (p < 0.05) and 31.8 ± 3.2% versus 10.0 ± 5.3% (p < 0.05), respectively, for 2.5- and 3.5-mm scaffolds and stents. Ab scaffolds showed 2 ± 1% moderate but significant late recoil as of 1 h, reaching 4 ± 2% by 24 h (p < 0.05). Conclusions Re-POT optimized most Ab provisional bifurcation treatments, without fracture, respecting fractal geometry, and without exceeding 1.0-mm proximal differential diameter.