Objectives: Patients sustaining Acute Coronary Syndromes (ACS) despite chronic aspirin treatment, suffer from worse prognosis as compared to aspirin naïve patients. Despite growing use of clopidogrel, data regarding the characteristics and prognostic significance of patients with chronic use of clopidogrel sustaining ACS is limited.
Methods: 3505 consecutive ACS patients who were drawn from the 2008-2010 ACS Israeli (ACSIS) survey were characterized and followed-up for 30 days. For the purpose of this study major adverse cardiac and cerebrovascular event (MACCE) was defined as death, re-myocardial infarction (MI), stroke, unstable angina and urgent revascularization.
Results: Out of 3505 patients, 423 (12%) were treated with clopidogrel prior to the index ACS. They were older (66±12 vs. 63±13 p< 0.01) and suffered more from diabetes, hypertension, dyslipidemia as well as prior cardiovascular history, including prior MI, revascularization, coronary artery bypass graft and stroke. Nevertheless, They were less likely to present with ST elevation MI (21% vs. 46%; p < 0.001) and had smaller infarct size as manifested by lower peak creatine kinase level (401 ± 601 u/l vs. 679 ± 1007 u/l p < 0.01). On the contrary they had 3 fold higher incidence of sub-acute stent thrombosis (2.1% vs. 0.7%; p =0.005) but their prognosis as was manifested by MACCE rates at 30 days was similar to clopidogrel naïve patients (9.93% vs. 8.47%; p = 0.31).
Conclusions: Although patients with chronic use of clopidogrel sustaining ACS were less likely to present with ST elevation MI and did not show worse prognosis at 30 days, they were at increased risk of sub-acute stent thrombosis.
