Role of Cardiac MRI in Patients Presenting with Acute Coronary Syndromes (ACS) with Normal or Minor Coronary Artery Disease

Abstract

Background: Increased sensitivity of cardiac biomarkers has increased the number of troponin positive patients with subsequent normal coronary arteries. We evaluated the use of Cardiac MRI (CMR) in this setting from March 2008 to January 2012. Methods: Retrospective and prospective analysis was performed on patients with ACS with normal or minor coronary disease on angiography whom had CMR performed. Results: The total of 36 patients had an average age of 55(SD = 13). Patient demographics revealed that 42% patients were smokers, 40% hypertensive and 36% dyslipidaemic. One patient had a prior stroke whilst another patient had a TIA. One patient was diabetic. Only one patient did not present with chest pain syndrome. Thirty-one patients were troponin positive. Five patients without a troponin rise had an abnormal ECG. Angiography revealed normal coronaries in the majority (75%) and minor coronary artery disease in 19%. One patient did not undergo coronary angiography due to pregnancy. Average ejection fraction (EF) on CMR was 59% (SD 0.09). Eighteen patients normal EF, 16 had mild LV-impairment, two patients had an EF < 45%. CMR was scar positive in 13 patients with a final diagnosis as follows: 7 = myocarditis, 4 = ischaemic infarct, 1 = dilated cardiomyopathy, 1 = sarcoid. The remaining 23 patients who were CMR scar negative; 7 = TakoTsubo, 3 = vasospasm, 10 = myocarditis, 2 = pericarditis, 1 = thrombus Conclusion: CMR is useful to establish a diagnosis in patients presenting with ACS with normal coronary arteries. In this study, findings of an alternative diagnosis was useful in longterm planning and management of these patients.