Normal coronary arteries are rare in young patients with acute myocardial infarction

To delineate the angiographic extent of coronary atherosclerosis in young patients (<45 years) with acute myocardial infarction (MI).

Prior studies suggest 20% of young patients with acute MI have normal coronary arteries. However, most such studies defined "normal" as absence of stenoses >50% luminal diameter, ignoring the presence of nonflow limiting disease that may harbor culprit plaques.

We retrospectively analyzed 131 patients <45 years old with ST-segment elevation MI undergoing emergency catheterization. Angiograms were analyzed for the presence and extent of disease, including lesion "complexity" indicative of plaque instability. "Normal" vessels were defined as absence of any disease.

Mean patient age was 40 +/- 7 years. The infarct related artery and an obvious complex culprit lesion was identified in all (100%) cases (left anterior descending 44%, right coronary 38%, and circumflex 18%). Single vessel disease involving the culprit vessel only was identified in 60% of cases, whereas additional disease was found in 40% of others (two-vessel in 29% and three-vessel disease in 11% of patients).

These findings demonstrate that young patients with acute MI typically manifest an identifiable complex culprit atherosclerotic coronary lesion. Furthermore, they often have multivessel atherosclerosis.