Heart attacks much more likely after a tiny stroke (TIA)

Evidence supporting the expectation that the underlying causal factors resulting in a TIA (transient ischemic attack) also increase the risk of heart attacks was  just published in the journal Stroke. The authors first observe that although...

"Coronary artery disease is the leading cause of death after TIA. Reliable estimates of the risk of MI [myocardial infarction = heart attack] after TIA, however, are lacking...Our purpose was to determine the incidence of and risk factors for MI after TIA."

They cross-referenced data from the Rochester Epidemiology Project for TIA (1985–1994) and MI (1979–2006) to identify all community residents with incident MI after incident TIA. They then compared it to the age-, sex-, and period-specific MI incidences in the general population. What did the data show?

"Relative risk for incident MI in the TIA cohort compared to the general population was 2.09. This was highest in patients younger than 60 years old. "

In other words, having had a TIA doubles the risk of having a heart attack. And very interestingly...

"Increasing age, male sex, and the use of lipid-lowering therapy at the time of TIA were independent risk factors for MI after TIA."

The hazard ratio for using lipid-lowering therapy (statins) was 3.10, meaning that this tripled the incidence of myocardial infarction.This study alerts clinicians to think comprehensively and cautiously when considering lipid-lowering agents in cardiovascular prophylaxis after a TIA. Patients who consider a TIA to be a relatively minor event should understand that the underlying causal factors can be a 'ticking time bomb' if not addressed. The authors conclude:

"Average annual incidence of MI after TIA is...approximately double that of the general population. The relative risk increase is especially high in patients younger than 60 years old. These data are useful for identifying subgroups of patients with TIA at highest risk for subsequent MI."