P2800Impact of plaque vulnerability on vascular response after implantation of two types of biodegradable-polymer drug-eluting stent: coronary angioscopic study

Abstract

Abstract Background Vascular response after drug-eluting stent (DES) implantation depends not only on stent design but also on vulnerability of target coronary lesions. In this study, non-obstructive coronary angioscopy (CAS) revealed vascular response after two types of biodegradable polymer (BP) DES implantation into patients with acute coronary syndrome (ACS) or stable angina pectoris (SAP). Methods Eighteen Nobori BP biolimus-eluting stents (BP-BES) were successfully implanted into 15 patients (9 ACS and 9 SAP lesions). Twenty-three Ultimaster BP sirolimus-eluting stents (BP-SES) were implanted into 16 patients (6 ACS and 17 SAP lesions). At one year after stenting, CAS semi-quantified degree of neointimal stent coverage (NSC) into 4 grades (0, no coverage; 1, thin coverage; 2, thick coverage; 3, embedded in thick neointima and invisible). When NSC through a stent was composed of plural grades, CAS determined dominant, maximum and minimum NSC grades. Heterogeneity index was defined as subtraction of minimum from maximum grade. CAS also semi-quantified degree of yellow plaques (YP) into 3 grades (0, light; 1, dense; 2, glittering yellow). CAS detected presence of in-stent mural thrombi (ISMT). Results At one year after BP-BES implantation: 1) There was no significant difference with regards to dominant NSC between ACS and SAP lesions (1.00±0.50 vs. 0.89±0.60); 2) Heterogeneity index was greater in ACS than in SAP (1.22±0.44 vs. 0.67±0.50, P=0.02); 3) YP grade was greater in ACS than in SAP (1.89±0.33 vs. 1.00±1.00, P=0.02); and 4) We found one ISMT in ACS lesions and two ISMT in SAP lesions. At one year after BP-SES implantation: 1) There was neither significant difference between ACS and SAP lesions with regards to dominant NSC (1.67±1.21 vs. 1.53±1.01), with regards to heterogeneity index (0.50±0.55 vs. 0.35±0.49), nor with regards to YP grade (1.33±1.51 vs. 0.88±0.99); and 2) We found ISMT neither in ACS nor in SAP lesions. Conclusions For BP-SES implantation, vascular response at ACS lesions was similar to SAP lesions. Even one year after BP-BES implantation, however, plaque vulnerability appeared to remain in ACS lesions.