Increase in ticagrelor use over time is associated with lower rates of ischemic stroke following myocardial infarction

Abstract

Objectives: To evaluate the impact of a rapid change in preferred treatment from clopidogrel to ticagrelor on the risk of ischemic stroke following acute myocardial infarction (AMI). Methods: Data for AMI patients treated with either clopidogrel or ticagrelor were obtained from the Swedish Register of Information and Knowledge about Swedish Heart Intensive Care Admissions (RIKS-HIA). Patients were divided into two cohorts, each covering a two-year time period; the initial prescription of ticagrelor (20 Dec 2011) was used as a cut-off point. Patients in the early cohort (n = 23,447) were treated with clopidogrel, while those in the later cohort (n = 24,227), were treated with either clopidogrel (47.9%) or ticagrelor (52.1%). Kaplan-Meier analyses were used to assess the risk of ischemic stroke over time, with multivariable Cox regression analyses used to identify predictors of ischemic stroke. Results: Of 47,674 patients, there were 1203 cases of ischemic stroke. Cumulative Kaplan-Meier incidence estimates of ischemic stroke after one year were 2.8% vs. 2.4% for the early and late cohorts, respectively (p = 0.001). Older age, hypertension, diabetes, previous stroke, congestive heart failure, atrial fibrillation, and ST-elevation myocardial infarction were associated with an increased risk of ischemic stroke. Percutaneous coronary intervention and statins at discharge were associated with a decreased risk of ischemic stroke, as was higher estimated glomerular filtration rate. Membership of the late cohort correlated with a 13% reduction in the relative risk of ischemic stroke. Conclusions: The introduction of ticagrelor as well as an improved management of AMI was associated with a lower rate of ischemic stroke in a relatively unselected AMI population.