Clinical Significance of Pre-interventional Optical Coherence Tomography in Bioresorbable Vascular Scaffold Implantation

It is well-known that non-optimal stent implantation associated with under-expansion or incomplete strut apposition during percutaneous coronary intervention (PCI) leads to a higher incidence of restenosis and stent thrombosis. OCT-guided PCI with metallic stent has previously been shown to be safe and feasible, resulting in better clinical outcomes compared with angiography-only guided PCI. Everolimus-eluting bioabsorbable vascular scaffold (BVS; Abbott Vascular, Santa Clara, CA, USA) was made from a bioabsorbable polylactic acid backbone which is coated with a more rapidly absorbed polylactic acid layer that contains and controls the release of the antiproliferative drug, everolimus. BVS has a number of proposed advantages over current metallic stent technology. These include elimination of chronic sources of vessel irritation and inflammation, which can reduce the potential risk of late scaffold thrombosis after complete scaffold bioresorption. Although the current generation of the Absorb BVS have larger strut thickness of 150 μm compared with 80 μm of strut of Xience stent, the acute recoil of the polymeric device was similar to that of metallic stent. However, operators tented to use dilating devices less aggressively because of the concerns about limitation in elongation-at-break of polylactide.

Previous studies reported 20-30% of under-expansion or malapposition with BVS, which would increase the risk of adverse events including late stent thrombosis. OCT-guidance may improve more optimized scaffold placement and also better outcomes. However, there is still no sufficient evidence that OCT has an inevitable role in optimal implantation of BVS and it should be more evaluated in real practice. In the study, the investigators will evaluate an incidence of OCT-defined BVS sub-optimization requiring additional PCI+A1.