Frequency and Predictors of Stroke After Acute Myocardial Infarction: Specific Aspects of In-Hospital and Postdischarge Events
What are the incidence, predictors, and prognosis of in-hospital and post-discharge (1-year follow-up) ischemic stroke (IS) and hemorrhagic stroke (HS) in patients with acute myocardial infarction (AMI)?
This was an analysis of data from RICO (obseRvatoire des Infarctus de Cote-d’Or), in which consecutive patients admitted with AMI were enrolled between January 2001 and July 2010. Follow-up was performed at 30 days and 1 year. Logistic regression analysis was used to determine predictors of in-hospital ischemic stroke (IH-IS), in-hospital hemorrhagic stroke (IH-HS), and postdischarge stroke (PDS).
The study sample included 8,485 patients. Of these participants, 168 (1.98%) experienced a stroke during the first year after AMI. Two thirds (n = 123) were in-hospital strokes, mostly occurring in the first 5 days after admission (87%) and mostly IH-IS (86.2%; incidence rate, 1.25%). The leading subtype of IH-HS was cardioembolic (n = 64, 60%). The following were independent predictors of IH-IS in multivariable backward regression analysis: female sex, previous transient ischemic attack (TIA)/stroke, new-onset atrial fibrillation, left ventricular ejection fraction, and C-reactive protein. Antiplatelet and anticoagulant therapies were protective against in-hospital stroke. In analyses adjusted for prognostic factors after AMI, IH-IS was associated with a significant increase in mortality (odds ratio, 1.82; 95% confidence interval, 1.05-3.15; p = 0.031). Only 45 patients experienced PDS, the vast majority of which were IS (43 patients, 95.6%; incidence rate, 0.64%).
The authors concluded that IH-IS after AMI is common, often related to cardioembolism, and associated with increase in mortality. The use of antiplatelet and anticoagulant therapies is associated with a lower risk for IH-IS. PDS is generally infrequent.
This is an important study that draws attention to the different subtypes of stroke following AMI. The authors demonstrated that cardioembolism is the primary mechanism of IH-HS. This observation, as the authors opine, emphasizes ‘that not only chronic but also transient cardiac disorders are responsible for emboli migrating from the heart.’ That said, the limitations of the study should be kept in mind. In particular, the annual rate of stroke after AMI remained stable throughout a 10-year study period. And, a relatively small number of postdischarge strokes were recorded.
Keywords: Myocardial Infarction, Stroke, C-Reactive Protein, Follow-Up Studies, Ischemic Attack, Transient, Anticoagulants, Stroke Volume, Atrial Fibrillation, Confidence Intervals, Patient Discharge
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