Comparison of Vascular Response After Sirolimus-Eluting Stent Implantation Between Patients With Unstable and Stable Angina Pectoris: A Serial Optical Coherence Tomography Study

Abstract

The aim of the present study was to compare lesion morphologies after sirolimus-eluting stent (SES) implantation between patients with unstable angina pectoris (UAP) and stable angina pectoris (SAP) with the use of optical coherence tomography (OCT). The lesion morphologies before and after coronary stenting have been proposed as important predictors of clinical outcome. The high resolution of OCT provides detailed information of coronary vessel wall. We enrolled 55 patients (UAP: n = 24, SAP: n = 31), and examined lesion morphologies by using OCT at pre- and post-SES implantation and 9 months' follow-up. The incidence of plaque rupture (42% vs. 3%, p < 0.001), intracoronary thrombus (67% vs. 3%, p < or = 0.001) and thin-capped fibroatheroma (cap thickness <65 microm; 46% vs. 3%, p < 0.001) at pre-intervention was significantly greater in UAP than that in SAP. Although stent profiles and procedural characteristics were not different between the 2 groups, inadequate stent apposition (67% vs. 32%, p = 0.038) and tissue protrusion (79% vs. 42%, p = 0.005) after percutaneous coronary intervention were observed more frequently in patients with UAP. Plaque rupture was significantly increased after percutaneous coronary intervention in patients with UAP (42% to 75%, p = 0.018), and the persistence of core cavity after plaque rupture (28% vs. 4%, p = 0.031) at 9 months' follow-up was observed more frequently in UAP patients compared with SAP patients. At 9 months' follow-up, the incidence of inadequately apposed stent (33% vs. 4%, p = 0.012) and partially uncovered stent by neointima (72% vs. 37%, p = 0.019) was significantly greater in UAP patients than that in SAP patients. All patients took aspirin and ticlopidine during follow-up period, and no patients had stent thrombosis or adverse coronary events. Serial OCT examinations demonstrated markedly different vascular response up to 9 months after SES implantation between UAP and SAP patients. Although the inadequate lesion morphologies after stenting were observed more frequently in UAP patients, these findings were not associated with adverse outcomes in patients with antiplatelet therapy.