P5751Comparison of side branch dilation techniques after resorbable magnesium scaffold implantation: a bench study

Abstract

Abstract Background Resorbable magnesium scaffolds (RMS) have demonstrated good safety profile to treat de novo lesions. Nevertheless, bifurcations lesions involving a side branch>2.0mm in diameter were excluded from these studies and such lesions remain technically challenging due to concerns of scaffold deformation or fracture. Purpose We sought to evaluate different side branch dilation strategies after provisional T stenting strategy with RMS. Methods Using RMS in bifurcations phantoms, three different side branch dilation strategies after provisional T stenting were compared: POT-side-rePOT (rePOT), Kissing-Balloon Inflation (KBI) and Mini Kissing-Balloon Inflation (MKBI) strategies. In vitro experiments were performed under fluoroscopy in the catheterization laboratory. Struts and connectors fractures were evaluated by micro computed-tomography and apposition by optical coherence tomography (OCT). In addition, step by step proximal over-expansion was carried out with different incremental NC balloons and scaffolds were then re-inspected on micro-CT after each over-expansion. Results Twelve RMS (n=4 in each group) were successfully implanted. There was no difference on struts and connectors fractures among the 3 techniques as no fracture was visualized. OCT demonstrated that MKBI sequence significantly decreased global malapposition following SB inflation as compared with rePOT or KBI strategies (95.3% vs 88.3% of perfectly apposed struts; p<0,0001 and 93.6%; p=0.004, respectively for MKBI vs. rePOT and KBI). After step by step overexpansion, no strut or connector fracture could be visualized. Stent strut apposition between in vitro models rePOT, n (%) KBI, n (%) MKBI, n (%) P value rePOT vs KBI P value rePOT vs MKBI P value KBI vs MKBI Overall bifurcation 1702/1928 (88.3%) 2062/2211 (93.6%) 1824/1913 (95.3%) p<0,0001 p<0,0001 p=0.004 MB proximal 376/390 (98.3%) 407/407 (100%) 398/398 (100%) p=0.0001 p=0.0001 p=NS MB bifurcation ostial 210/286 (77.5%) 326/391 (82%) 243/269 (89.8%) p=0.002 p<0,0001 p=0.01 MB bifurcation abostial 421/425 (99.3%) 421/421 (100%) 324/324 (100%) p=0.05 p=0.08 P=NS SB bifurcation ostial 147/227 (62.8%) 321/365 (88.3%) 256/306 (85%) p<0,0001 p<0,0001 p=NS SB bifurcation abostial 98/150 (70.3%) 128/168 (78%) 161/173 (95.5%) p=0.03 p<0,0001 p=0,0005 MB distal 450/450 (100%) 459/459 (100%) 442/443 (99.8%) p=NS p=NS p=NS Comparison between rePOT, KBI and MKBI. Abbreviations: POT, proximal optimization technique; MKBI, mini kissing balloon inflation; KBI, kissing balloon inflation. Bifurcation exemples Conclusion Provisional RMS one stent technique on a bifurcation lesion is technically feasible with these 3 different strategies without scaffold fracture. MKBI strategy resulted in better apposition rates as compared to KBI or rePOT strategies.