Sequential techniques of provisional stenting in coronary bifurcation with the Xposition S™ self-apposing nitinol stent. A comparative bench study

Abstract

Coronary bifurcation revascularization needs to take account of the systematic diameter differential between vessels based on fractal geometry, and to limit side-branch obstruction (SBO). The mechanical properties of the Xposition S™ self-apposing stent seem interesting for provisional stenting of coronary bifurcations. The aim of this experimental fractal bifurcation bench study was to determine the best sequential provisional stenting technique with the Xposition S™ self-apposing nitinol stent (STENTYS, France). A fractal bifurcation bench test compared three Xposition S™ provisional stenting strategies: implantation alone, side-branch inflation (SBI) alone, and complete rePOT [initial proximal optimization technique (POT) + SBI + final POT]. Two dimensional- and 3D-OCT analyses and micro-scanner were performed to quantify the main mechanical results at each step. Of the 3 groups ( n = 5 each), SBI alone and complete rePOT provided better mechanical results than implantation alone for residual SBO (respectively, 24.6 ± 5.6% and 24.8 ± 5.0% vs. 46.5 ± 10.3%, P < 0.05) and for malapposition (respectively, 0.9 ± 0.6% and 0.8 ± 0.4% vs. 3.8 ± 1.9%, P < 0.05). Unlike SBI, the POTs did not improve the final rePOT result. SBI, alone or during rePOT, systematically led to only one connector disconnection, whereas implantation alone maintained stent integrity ( P > 0.05) ( Fig. 1 ). This experimental study justifies systematic SBI in clinical practice during provisional stenting with Xposition STM, but not post-dilatation specifically dedicated to bifurcation stenting (i.e., the two POTs in the rePOT sequence). However, global post-dilatation after implantation is still mandatory with Xposition STM stents, to prevent stent under-expansion due to untreated stenosis.