Risk of Heart Attack Doubles After Transient Ischemic Attack

The risks for myocardial infarction (MI) among patients who have suffered a transient ischemic attack (TIA) is approximately double that of the general population, according to a new study.

Researchers at the Mayo Clinic (Rochester, MN, USA) used data from the Rochester Epidemiology Project to identify a cohort of residents who had had a TIA between 1985 and 1994, and then cross-referenced these with residents who had an MI between 1979 and 2006 to find all those who had had an MI after a TIA; follow-up ranged from 10 to as long as 20 years.

The researchers found that the average annual incidence of MI after TIA was 0.95%, which is twice the relative risk seen in the general population without TIA, and persisted over the long term. In addition, the researchers found that the risk was particularly high for those under 60 years of age (who faced a 15-fold risk), and that mortality associated with an MI after TIA was 3 times that of patients who did not have an MI. Increasing age, male sex, and the use of lipid-lowering therapy at the time of the initial TIA were all independent risk factors for MI after TIA. The study was published in the April 2011 issue of Stroke.

"Now that we've shown that the ultimate endpoint of coronary artery disease, MI, is clearly heightened over the long-term in patients with TIA, we need to step back and consider how we can prevent that outcome,” said corresponding author professor Robert Brown, Jr., MD, MPH, chair of the department of neurology. "And we will need to consider how to select which patients with TIA should have a screening study.”

Previous studies have shown that coronary artery disease is the leading cause of death in the first 5 to 10 years after TIA; it accounts for 24%-64% of deaths, compared with 12%-28% of deaths attributed to stroke.

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