Two thirds of patients who experience a myocardial infarction during or shortly after noncardiac surgery do not have ischemic symptoms, according to an Annals of Internal Medicine study.
Researchers followed a cohort of some 8350 patients who had, or were at risk for, atherosclerosis and were undergoing noncardiac surgery. ECGs were performed several times until day 30 after surgery, and troponin levels were measured daily through day 3.
Five percent of patients had a perioperative MI (usually within 2 days after surgery). Of these, only one third had ischemic symptoms, while nearly all (94%) had elevated troponin levels. Patients who had MIs, even without symptoms, were at increased risk for another cardiac event or death within 30 days.
The authors conclude that because most patients with perioperative MIs will not have symptoms, "physicians should ... require perioperative troponin monitoring to avoid missing these prognostically important MIs."
Annals of Internal Medicine article (Free abstract)