Abstract 18461: Myocardial Infarction With Normal Coronary Angiography and Computed Tomography Angiography
Background: Three to five percent of patients, who fulfil the criteria for AMI, have angiographically normal coronary arteries. The mechanisms that cause AMI in the patient with no visible coronary atherosclerosis on the invasive coronary angiography (ICA) are still debatable. The aim of this study was to assess the presence and characteristics of atherosclerotic plaques on computed tomography coronary angiography (CTCA) in patients with AMI who have no visible coronary plaques on ICA.
Methods and Results: Patients with AMI without visible coronary plaques on ICA underwent CTCA within three days after ICA. 30 patients were enrolled in the study. According to local routine, echocardiography was performed in the majority (26/30) of patients. Twenty-eight patients presented with NSTEMI and two with STEMI. Mean age of the study population was 60.2 years and 23/30 were women. A total number of 452 coronary segments were analysed. A total of 24/30 (80%) patients had normal coronary arteries and 6 patients had coronary atherosclerosis on CTCA. In case of atherosclerosis, the median number of segments with plaque per patient was one. 12/26 patients had completely normal echocardiography results, 11/26 patients had only wall motion abnormalities (WMA), 2/26 patients had WMA with minimal pericardial effusion and 1 patient had only minimal pericardial effusion.
Conclusions: Despite a diagnosis of AMI, the majority of patients (80%) with a completely normal ICA showed no coronary plaques on CTCA. The remaining 20% of patients had only minimal non-obstructive atherosclerosis. The previously proposed mechanism of AMI due to rupture of a non-obstructive-, invisible on ICA-, plaque could only account for a minority (20%) of this study population. Our data suggest that most patients either had AMI caused by a mechanism not involving plaque rupture or did not have an infarction at all. Having in mind what consequences a diagnosis of AMI confers to the patient it is reasonable to extend the diagnostic evaluation of these patients to cardiac MRI for excluding myocarditis and/or intravascular imaging (optical coherence tomography or intravascular ultrasound) to provide information about some mechanisms of coronary damage (i.e. dissection).
- © 2013 by American Heart Association, Inc.