Incidence, trends, and predictors of ischemic stroke 30 days after an acute myocardial infarction

Abstract

Background and purpose: Ischemic stroke is a known complication of acute myocardial infarction (AMI). Treatment of AMI has undergone great changes in recent years. We aimed to investigate whether changes in treatment corresponded to a lower incidence of ischemic stroke and which factors predicted ischemic stroke after AMI.

Methods: Data were taken from the Swedish Register of Information and Knowledge about Swedish Heart Intensive Care Admissions. Patients with their first registered AMI between 1998 and 2008 were included. To identify ischemic strokes, we used the Swedish national patient register. To study a potential trend in the incidence of ischemic stroke after AMI over time, we divided the patient population into 5 time periods. Event-free survival was studied by Kaplan-Meier analysis. Cox proportional hazards regression model was used to identify stroke predictors.

Results: Of 173,233 patients with AMI, 3571 (2.1%) developed ischemic stroke within 30 days. The incidence of ischemic stroke was significantly lower during the years 2007 to 2008 compared with 1998 to 2000, with respective rates of 2.0% and 2.2% (P=0.02). Independent predictors of an increased risk of stroke were age, female sex, prior stroke, diabetes mellitus, atrial fibrillation, clinical signs of heart failure in hospital, ST-segment-elevation myocardial infarction, coronary artery bypass grafting, and angiotensin-converting enzyme inhibitor treatment at discharge. Percutaneous coronary intervention, fibrinolysis, acetylsalicylic acid, statins, and P2Y12 inhibitors were predictors of reduced risk of stroke.

Conclusions: The incidence of ischemic stroke within 30 days of an AMI has decreased during the period 1998 to 2008. This decrease is associated with increased use of acetylsalicylic acid, P2Y12 inhibitors, statins, and percutaneous coronary intervention.

Keywords: epidemiology; myocardial infarction; risk factors; stroke.