Computed Tomography Coronary Angiography in Patients with Acute Myocardial Infarction without Significant Coronary Stenosis

Annachiara Aldrovandi; Filippo Cademartiri; Daniele Arduini; Daniela Lina; Fabrizio Ugo; Erica Maffei; Alberto Menozzi; Chiara Martini;
Alessandro Palumbo; Federico Bontardelli; Tiziano Gherli;Livia Ruffini; Diego Ardissino

Circulation

Received May 11, 2012. Accepted October 22, 2012.

Abstract

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 mm2 vs 4.2±2.1 mm2, 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.