By Matthew E. Fink, MD
Louis and Gertrude Feil Professor and Chairman, Department of Neurology, and Assistant Dean of Clinical Affairs, Weill Cornell Medical College; Neurologist-in-Chief, New York Presbyterian Hospital
Dr. Fink reports no financial relationships relevant to this field of study.
SOURCE: Merkler AE, Diaz I, Murthy SB, et al. Duration of heightened stroke risk after acute myocardial infarction. Stroke 2018;49:A172.
Merkler et al performed a retrospective cohort study using inpatient and outpatient claims data from 2008 through 2015 from a nationally representative 5% sample of Medicare beneficiaries ≥ 66 years of age. Diagnosis of acute myocardial infarction (MI) and ischemic stroke were ascertained using validated ICD-9 diagnosis codes. Strokes were included only if they occurred after discharge from the acute MI hospitalization to make sure that periprocedural strokes related to coronary interventions were excluded. Cox regression models were used to sort the groups and perform the analyses, and risk of ischemic stroke was adjusted for demographics, stroke risk factors, and other comorbidities. Survival probabilities were used to compute a hazard ratio for each four-week interval after discharge from the hospital following acute MI. Among 1,746,476 beneficiaries, 46,182 were hospitalized for acute MI and 80,466 were hospitalized for ischemic stroke. Compared to patients without acute MI, patients with stroke and acute MI were older and carried more stroke risk factors. After adjusting for demographics, risk factors, and comorbidities, the risk of ischemic stroke was highest in the first four weeks after discharge from the MI hospitalization (hazard ratio [HR] = 2.7) and remained elevated substantially during weeks five to eight (HR = 2.0) and weeks nine to 12 (HR = 1.6) and no longer was elevated significantly after 12 weeks. Established stroke classification systems categorize MI-associated stroke as occurring in the 30-day period following MI. This study establishes that the elevated short-term risk of stroke extends beyond 30 days and remains elevated for up to 12 weeks following acute MI.