Stent Thrombosis Risk Over Time on the Basis of Clinical Presentation and Platelet Reactivity: Analysis From ADAPT-DES.

ABSTRACT

OBJECTIVES: The aim of this study was to determine the risk period for increased stent thrombosis (ST) after percutaneous coronary intervention (PCI) in patients with acute coronary syndromes (ACS) and whether this increased risk is related to high platelet reactivity (HPR). BACKGROUND: ST risk after PCI is higher among patients with ACS than those with stable ischemic heart disease. When ST risk is highest in patients with ACS and how that is affected by HPR is unknown. METHODS: Using the ADAPT-DES (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents) registry, ST rates during 2-year follow-up post-PCI with drug-eluting stents were compared among patients presenting with ACS (myocardial infarction [MI] or unstable angina) or stable ischemic heart disease (non-ACS). Landmark analyses were done at 30 days and 1 year post-PCI. Platelet reactivity on aspirin and clopidogrel post-PCI was assessed using VerifyNow assays. RESULTS: Of 8,582 patients, 2,063 presented with MI, 2,370 with unstable angina, and 4,149 with non-ACS. Incidence rates of HPR were 48.0%, 43.3%, and 39.8%, respectively (p < 0.001). Within the first 30 days post-PCI, patients presenting with MI had increased ST risk compared with patients with non-ACS (hazard ratio [HR] 4.52; 95% confidence interval [CI] 2.01 to 10.14; p < 0.001). After 30 days, relative ST risks were progressively lower and no longer significant between groups (31 days to 1 year post-PCI HR 1.97; 95% CI 0.80 to 4.85; >1 year post-PCI HR 0.89; 95% CI 0.27 to 2.92). The elevated ST risk in patients with MI within 30 days was largely confined to those with HPR on clopidogrel (HR 5.77; 95% CI 2.13 to 15.63; p < 0.001). CONCLUSIONS: Among patients undergoing PCI, rates of ST during 2-year follow-up were highest in those with MI and lowest in those with non-ACS. Increased ST risk in patients with MI was greatest in the first 30 days post-PCI and was observed predominantly among those with increased HPR on clopidogrel. These findings emphasize the importance of adequate P2Y12 inhibition after MI, especially within the first 30 days after stent implantation.