Computed Tomography Coronary Angiography in Patients With Acute Myocardial Infarction Without Significant Coronary Stenosis

Abstract

Background— It is known that a significant number of patients experiencing an acute myocardial infarction have normal coronary arteries or nonsignificant coronary disease at coronary angiography (CA). Computed tomography coronary angiography (CTCA) can identify the presence of plaques, even in the absence of significant coronary stenosis. This study evaluated the role of 64-slice CTCA in detecting and characterizing coronary atherosclerosis in these patients. Methods and Results— Consecutive patients with documented acute myocardial infarction but without significant coronary stenosis at CA underwent late gadolinium-enhanced magnetic resonance and CTCA. Only the 50 patients with an area of myocardial infarction identified by late gadolinium-enhanced magnetic resonance were included in the study. All of the coronary segments were assessed for the presence of 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 noncalcified, 17 mixed, and 22 calcified; in the non-IRAs, 5 plaques were noncalcified, 8 mixed, and 27 calcified ( P =0.005). Mean plaque area was greater in the IRAs than in the non-IRAs (6.1±5.4 mm 2 versus 4.2±2.1 mm 2 ; P =0.03); there was no significant difference in mean percentage stenosis (33.5%±14.6 versus 31.7%±12.2; P =0.59), but the mean remodeling index was significantly different (1.25±0.41 versus 1.08±0.21; P =0.01). Conclusions— CTCA detects coronary plaques in nonstenotic 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 acute myocardial infarction patients without significant coronary stenosis.

Prognosis of Patients With Non–ST-Segment–Elevation Myocardial Infarction and Nonobstructive Coronary Artery Disease

“…Coronary spasm provocation tests should be considered during the initial angiogram. 10,19 Imaging modalities such as intravascular ultrasound, optical coherence tomography, CT angiography, 23 and MRI should also be considered to differentiate between plaque rupture, plaque erosion, type-2 MI, myocarditis, cardiomyopathy, and Tako-Tsubo syndrome. Further studies are needed to confirm our findings and guide clinical practice.…”

Letter by Opolski et al Regarding Article, “Computed Tomography Coronary Angiography in Patients With Acute Myocardial Infarction Without Significant Coronary Stenosis”

“…Although this area of research is attractive and merits future exploration, the main conclusions of the study by Aldrovandi et al 1 should be accepted with caution. In our opinion, the practical application of CCTA in patients with angiographically benign MI remains to be determined.…”

“…We read with interest the article by Aldrovandi et al 1 evaluating the characteristics of coronary lesions using coronary computed tomography angiography (CCTA) in patients with acute myocardial infarction (MI) and angiographically nonobstructive coronary artery disease. We congratulate the authors on their elegant study fitting comfortably with the vulnerable plaque paradigm.…”

Combined Computed Tomography Angiography (CTA) and Single Photon Emission Computed Tomography Is Not Superior to CTA Plus High-Risk Plaque Assessment in Predicting Future Cardiac Events

“…However, CTA can identify HRP even in the absence of significant coronary artery stenosis. 15 SPECT cannot identify the patients in this category. Therefore, it is expected that SPECT and CTA supplement each other in the combined assessment of CAD.…”