Five-Year Optical Coherence Tomography in Patients With ST-Segment-Elevation Myocardial Infarction Treated With Bare-Metal Versus Everolimus-Eluting Stents.

BACKGROUND: The main causes of late (>1 month) stent thrombosis (ST) are stent uncoverage, malapposition, and neoatherosclerosis. First-generation drug-eluting stents were associated with higher rate of late ST compared with bare-metal stents (BMS), especially in patients with ST-segment-elevation myocardial infarction. Second-generation everolimus-eluting stents (EES) have shown similar rate of late ST than BMS. The aims of the study are to compare the ratio of uncovered to total struts per cross-section ≥30% and other optical coherence tomographic findings associated with ST between EES and BMS in patients with ST-segment-elevation myocardial infarction at 5 years.

METHODS AND RESULTS: One hundred and sixty-nine consecutive event-free patients of the randomized EXAMINATION study (A Clinical Evaluation of Everolimus Eluting Coronary Stents in the Treatment of Patients With ST-Segment Elevation Myocardial Infarction) were screened for optical coherence tomographic imaging at 5 years. Patients with target vessel-related events or life-threatening comorbidities were excluded. Finally, 64 patients (32 EES and 32 BMS) underwent optical coherence tomographic imaging. At 5 years, uncovered struts (4.1% versus 1.0%; P<0.01), length of uncoverage (3.4 versus 1.4 mm; P=0.02), and ratio of uncovered to total struts per cross-section ≥30% (35.5% versus 9.7%; P=0.02) were larger with EES than that with BMS. Malapposed struts (1.2% versus 0.3%; P=0.02) and malapposition length (1.3 versus 0.4 mm; P=0.06) were also larger with EES. Neoatherosclerotic plaques (16.1% versus 25.8%; P=0.35) and macrophage accumulations (19.4% versus 48.4%; P=0.02) were numerically more frequent with BMS.

CONCLUSIONS: Despite substantial dropout of patients, the healing pattern in event-free ST-segment-elevation myocardial infarction patients differs between EES and BMS at 5 years. EES presented with larger amount of uncovered and malapposed struts and similar rate of neoatherosclerosis as compared with BMS. The clinical relevance of these findings warrants longer follow-up.

CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00828087.