Computed tomography coronary angiography in patients with acute myocardial infarction without significant coronary stenosis

Background It is known that 9-31% of women and 4-14% of men experiencing an acute myocardial infarction(AMI) have normal coronary arteries or non-significant coronary disease at angiography.Computed tomography coronary angiography(CTCA) can non-invasively identify the presence of coronary plaques even in the absence of significant coronary artery stenosis.This study evaluated the role of 64-slice CTCA in detecting and characterising coronary atherosclerosis in patients with a documented AMI but without significant coronary artery stenosis.Methods and Results Consecutive patients with AMI but without significant coronary stenosis at coronary angiography(CA) underwent late gadolinium-enhanced magnetic resonance(LGE-CMR) and CTCA.Only the 50 patients with an area of MI identified by LGE-CMR were included in the study.All of the coronary segments were assessed for the presence of coronary plaques.CTCA identified 101 plaques against the 41 identified by CA:61(60.4%) located in infarct-related arteries(IRAs) and 40(39.6%) in non-IRAs.In the IRAs,22 plaques were non-calcified,17 mixed,and 22 calcified;in the non-IRAs,five plaques were non-calcified,eight mixed,and 27 calcified(P = 0.005).Mean plaque area was significantly greater in the IRAs than in the non-IRAs(6.1 ± 5.4 mm 2 vs 4.2 ± 2.1 mm 2,P = 0.03);there was no significant difference in mean percentage stenosis(33.5% ± 14.6 vs 31.7% ± 12.2,P = 0.59),but the mean remodelling index was significantly different(1.25 ± 0.41 vs 1.08 ± 0.21,P = 0.01).Conclusions CTCA detects coronary atherosclerotic plaques in segments of non-stenotic coronary arteries that are underestimated by CA,and identifies a different distribution of plaque types in IRAs and non-IRAs.It may therefore be valuable for diagnosing coronary atherosclerosis in AMI patients without any significant coronary stenosis.