A TIA Is Also a Warning of an Increased Risk of MI

I recently blogged about the likelihood that a transient ischemic attack (TIA) will be followed by a full-blown stroke. There's another risk for patients who have had a TIA. The risk for a heart attack (myocardial infarction, M I) in patients who've already had a TIA but who have no known coronary artery disease is roughly double that of the general population, at about 1% per year. This has been shown in a study from the Mayo Clinic, Rochester, published in the journal Stroke.

Mario researchers obtained data from the Rochester Epidemiology Project, collecting data on TIAs from 1985 to 1994 and MIs from 1979 to 2006. They determined the average annual incidence of an MI in TIA patients over an average period of 10 years. The average age when the TIA occurred was 71; almost 60% of subjects were women. Risk factors in this group of patients were high blood pressure, current or former smoking, and diabetes. The average time between a TIA and a subsequent MIA was 4.6 years.

The average annual incidence of an MI after TIA was 0.95%. Compared to the general population, this risk was 2.1 times greater. However, in those subjects under 60, there was a 15-fold risk. For every 10 years the risk increased 1.5 times; in males it was 2.2 times that of females; and in those using lipid-lowering agents at the time of their TIA the risk was 3.1 times greater than they would have an MI subsequently.

This study shows that coronary artery disease is the most common cause of death in patients who've had a TIA – even more than a full-blown stroke. It can remind us of the importance of taking a TIA seriously.  Not only in the short term, but for at least the subsequent five years attention must be paid to the likely pathological changes (atherosclerosis) in the blood vessels, and attempts made to reverse them by lifestyle and dietary changes.