Yield of Cardiac Magnetic Resonance Imaging in Patients With Acute Coronary Syndrome and No Obstructive Coronary Artery Disease.

PURPOSE

Ten percent to 25% of women and 6%-10% of men with acute coronary syndrome (ACS) are found to have no obstructive coronary artery disease (CAD) on coronary computed tomography angiogram or invasive coronary angiography. The etiology of presentation is often unclear. We examined the diagnostic yield of cardiac magnetic resonance imaging (CMR) in patients with signs and symptoms suggestive of an ACS and no obstructive CAD.

METHODS

We retrospectively studied patients with signs and symptoms suggestive of an ACS and no obstructive CAD on coronary computed tomography angiogram or invasive coronary angiography who had CMR performed at St. Paul's Hospital, British Columbia, Canada, from 2013 to 2015. No obstructive CAD was defined as <50% stenosis in any epicardial artery. We compared CMR diagnostic yield in troponin-positive and troponin-negative patients and determined the etiology of presentation in each category. We also examined gender differences.

RESULTS

Ninety-eight patients met inclusion criteria. The average age was 55.8 years, 70% were female, and 60% were troponin positive upon presentation. Abnormal CMR was observed in 35.7% of patients, yielding a diagnosis in 27.9% of females and 53.5% of males (P = 0.02). Troponin-positive patients had a significantly higher prevalence of an abnormal CMR than did troponin-negative patients (44.1% vs. 23.1%; P = 0.03). Myocarditis was more common in troponin-positive patients (25.4% vs. 2.6%; P = 0.002).

CONCLUSIONS

Forty-four percent of patients with positive troponin and with signs and symptoms suggestive of an ACS, no obstructive CAD on invasive coronary angiography or coronary computed tomography angiogram, and unclear diagnosis had abnormalities on CMR that identified the diagnosis. CMR should be considered in patients with positive troponin values when the etiology for their presentation is unclear.