Abstract WP182: Long Term Risk of Ischemic Stroke After Acute Coronary Syndrome

Background: Prior studies have shown an increased risk of ischemic stroke (IS) after myocardial infarction (MI), particularly in the first few days after the event. There is limited evidence, however, on the long-term risk and whether it is directly related to cardiac injury. We hypothesized that the risk of IS after acute coronary syndrome (ACS) is significantly higher when there is evidence of cardiac injury such as ST elevation MI (STEMI) or non-STEMI (NSTEMI) than when there is no evidence of cardiac injury such as Unstable Angina (UA). Methods: Administrative claims data were obtained from all emergency department encounters and hospitalizations at California’s nonfederal acute care hospitals between 2008 and 2011. Patients with STEMI, NSTEMI, and UA were identified using appropriate ICD-9 codes. Age and ICD-9 codes for sex, race-ethnicity, hypertension, diabetes, hyperlipidemia, congestive heart failure, and atrial fibrillation were analyzed. The outcome was IS during 2 years follow-up. Unadjusted and adjusted Cox proportional hazards models were used to determine the association between ACS subtype and ischemic stroke risk. Results: We identified 74,962 ACS patients: 35.9% STEMI, 54.8% NSTEMI, and 9.3% UA. The mean age in years was 66.7 ± 14.4 and 61.5% females; 3.2% of patients had IS during the two year follow-up. When compared to UA, the long term risk of IS was higher in patients with STEMI (adjusted HR 2.07 95% CI 1.67-2.56) and NSTEMI (adjusted HR 1.87, 95% CI 1.51-2.30), even after adjusting for stroke risk factors at baseline and incident atrial fibrillation (Figure). Other stroke risk factors after ACS are shown in the Figure. Conclusion: Analysis from a large administrative dataset revealed that both NSTEMI and STEMI confer an increased risk of ischemic stroke, independent of risk factors, which may be related to cardiac injury. Studies exploring ischemic stroke mechanisms in cardiac patients are needed to improve and tailor stroke prevention strategies.