Early vessel healing after implantation of biodegradable-polymer and durable-polymer drug-eluting stent: 3-month angioscopic evaluation of the RESTORE registry

The purpose of this study was to evaluate the vessel healing status 3months after stent implantation of bioresorbable-polymer drug-eluting stents (BP-DESs) in comparison with durable-polymer DESs (DP-DESs) by angioscopy. Study design was a single-center all-comer prospective cohort study: the RESTORE registry (UMIN000033009). All patients who received successful angioscopic examination at planned 3-month follow-up after the DES implantation in the native coronary artery were enrolled. We evaluated main, maximum, minimum strut coverage grades and coverage heterogeneity score defined as a difference between maximum and minimum coverage grades. All lesions were divided into three segments: proximal, mid, and distal segments. A total of 108 patients (66.6 +/- 10years) with 124 lesions were analyzed (BP-DES 57 patients 61 lesions 226 segments vs. DP-DES 57 patients 63 lesions 203 segments; six patients had both BP-DES and DP-DES). Patient and lesion demographics, procedural characteristics were well balanced. Main coverage grade (mean +/- standard error; 1.08 +/- 0.02 vs. 1.05 +/- 0.03, p=0.354) and minimum coverage grade (1.00 +/- 0.00 vs. 1.00 +/- 0.00, p>0.999) were not significantly different between BP-DES and DP-DES groups. Maximum coverage grade was significantly higher in the BP-DES than in the DP-DES (1.45 +/- 0.04 vs. 1.35 +/- 0.04, p=0.049). Coverage heterogeneity score did not differ between BP-DES and DP-DES groups (1.05 +/- 0.07 vs. 0.90 +/- 0.07, p=0.162). At 3-month follow-up, the current BP-DES had higher maximum stent coverage than the contemporary DP-DES, while main and minimum coverage grades and heterogeneity of the neointimal coverage were comparable. Further prospective randomized trials should be conducted to evaluate the clinical significance of the present imaging results.