Ischemic stroke. Impact of a recent myocardial infarction.

Abstract

The risk of ischemic stroke is increased after a myocardial infarction. We quantified the stroke risk and evaluated ischemic stroke characteristics after an acute myocardial infarction. A case-control study including patients with first-ever stroke was undertaken. Cases (n=103) were recorded prospectively in the population-based Northern Sweden World Health Organization Multinational Monitoring of Trends and Determinants in Cardiovascular Disease (MONICA) study. Two controls per case with a stroke but without a recent myocardial infarction were matched for age, sex, and year of stroke onset. The sudden onset of neurological symptoms (76.7% versus 54.9%, P<0.001), impairment of consciousness (35.0% versus 18.4%, P<0.01), and a progression in neurological deficits (19.4% versus 8.7%, P<0.01) were more common in cases, while the onset of stroke during sleep was rarer in cases (6.8% versus 21.4%, P<0.01). In cases and controls, the clinical subclasses of stroke were as follows: total anterior circulation infarcts, 51.5% versus 37.9% (P<0.05); partial anterior circulation infarcts, 28.2% versus 26.7% (P=NS); lacunar infarcts, 4.8% versus 27.2% (P<0.001); and posterior circulation infarcts, 15.5% versus 8.2% (P=0.051). During the first 28 days after myocardial infarction, the daily rate of stroke declined rapidly from approximately 9 to 1 stroke per 10 000 myocardial infarction patients compared with an age-adjusted average daily stroke rate of 0.14 per 10 000 in the MONICA population. We conclude that the clinical characteristics of the stroke differ between patients with and without a recent myocardial infarction. The risk of a first-ever ischemic stroke is highest during the first few days after a myocardial infarction, but it then declines rapidly, and the absolute number of stroke events is low.