Post-dilatation after implantation of bioresorbable everolimus- and novolimus-eluting scaffolds: an observational optical coherence tomography study of acute mechanical effects

The objective was to investigate the acute mechanical effects of post-dilatation on bioresorbable scaffolds (BRS) as determined by optical coherence tomography (OCT). Post-dilatation with high-pressure balloons is regarded as a key component of BRS implantation for treatment of coronary artery stenoses. However, the impact of post-dilatation on BRS in vivo has not been thoroughly investigated. OCT was performed after the implantation procedure of 51 everolimus-eluting or novolimus-eluting polylactic acid-based BRS with (n = 27) or without non-compliant balloon post-dilatation (n = 24). The number of malapposed struts, strut fractures, edge dissections, residual in-scaffold area stenosis, and incomplete scaffold apposition area was analyzed over the complete length of each BRS with a spacing of 1 mm. OCT revealed a significantly lower incomplete scaffold apposition area if post-dilatation was performed (0.16 +/- 0.49 mm(2) with post-dilatation vs. 2.65 +/- 2.78 mm(2) without post-dilatation, p < 0.001), as well as a significantly lower absolute number of malapposed struts (1 +/- 2 with post-dilatation vs. 13 +/- 13 without post-dilatation, p < 0.001). No significant differences regarding residual in-scaffold area stenosis, strut fracture, edge dissection, symmetry index, or eccentricity index were observed in patients with vs. without post-dilatation. Post-dilatation of BRS with non-compliant balloons significantly reduces the number of malapposed struts and incomplete scaffold apposition area without inducing higher rates of edge dissection or strut fracture.