Comparison of neointimal coverage between durable-polymer everolimus-eluting stents and bioresorbable-polymer everolimus-eluting stents 1 year after implantation using high-resolution coronary angioscopy

Objectives We aimed to compare the coronary angioscopic appearance of neointimal coverage (NIC) over durable-polymer everolimus-eluting stents (XIENCE-EES) and bioresorbable-polymer everolimus-eluting stents (SYNERGY-EES) 1 year after implantation. Background XIENCE-EES and SYNERGY-EES have been developed to prevent delayed arterial healing associated with first generation drug-eluting stents. However, the process of arterial healing after XIENCE-EES and SYNERGY-EES implantation has not been clarified. Methods Patients who underwent implantation of XIENCE-EES (n = 20) or SYNERGY-EES (n = 20) were enrolled in this study. Coronary angiography and coronary angioscopy were performed 12 +/- 1 months after stent implantation. The NIC over the stent was classified into four grades: grade 0, stent struts fully exposed; grade 1, stent struts bulging into the lumen and, still visible; grade 2, stent struts embedded in neointima but still visible; and grade 3, stent struts fully embedded and invisible. Stents exhibiting more than one NIC grade was defined as heterogeneous. Moreover, presence of thrombi was investigated. Results The distribution of dominant NIC grade (XIENCE-EES: grade 0, 0%; grade 1, 25%; grade 2, 50%; grade 3, 25%; SYNERGY-EES: grade 0, 0%; grade 1, 5%; grade 2, 15%; grade 3, 80%; P = 0.002) and NIC heterogeneity was significantly different (P = 0.004). Thrombi were more frequent in XIENCE-EES than in SYNERGY-EES (40 versus 10%, respectively; P = 0.03). Conclusion Compared with XIENCE-EES, SYNERGY-EES were well covered by neointima and accompanied by fewer thrombi. These findings implied arterial healing of SYNERGY-EES was better than that of XIENCE-EES.