Abstract 1715: Prognosis of Patients Under Chronic Clopidogrel Therapy while Suffering an Acute Coronary Syndrome

Abstract

Background: Chronic clopidogrel therapy (CCT) has been shown to be beneficial in decreasing the frequency of major adverse cardiovascular events (MACE) in coronary artery disease. However, some patients suffer an acute coronary syndrome (ACS) despite CCT. Objective : To assess the prognosis of patients suffering an ACS while on CCT compared to patients naive to clopidogrel. Method: Retrospective analysis of propensity matched cohorts of patients undergoing PCI for an ACS was performed. Patients under CCT before the ACS were matched 1:2 with patients not under CCT before the ACS. The primary endpoint was a composite of cardiac death and myocardial infarction (MI) at 1-year follow-up. A cohort of 2325 patients undergoing PCI for an ACS was studied. Among them, 256 patients were taking CCT for > 1 month at the time of the ACS and 2069 weren’t taking clopidogrel prior to the ACS. After propensity score matching 1:2, the 2 groups included, respectively, 84 and 168 patients. Results: Patients in both groups had similar rates of previous MI (no CCT vs CCT 47.6 vs 48.8%; p = 0.86) or PCI (40.5 vs 40.5%; p = 1). There was no difference in drug use on discharge between the 2 groups; in particular for thienopyridines (94 vs 96.4%; p = 0.6). At 1-year follow-up, patients under CCT before the ACS exhibited a worse prognosis than patients who were not under CCT prior to the ACS, with a higher rate of cardiac death and MI (14.2 vs 5.5%; p = 0.015). Conclusions: This study suggests that patients suffering an ACS while under CCT have a poor long-term prognosis, which could be linked to clopidogrel low response.