Stress cardiovascular magnetic resonance imaging in intermediate-risk emergency department patients with abnormal high-sensitivity troponin.

backgroundPatients presenting to the emergency department (ED) with chest pain often have abnormal high-sensitivity troponin (hsTn). However, only about 5% have an acute coronary syndrome. We aimed to assess the safety, feasibility, and utility of a clinical disposition protocol, including outpatient observation with stress cardiovascular magnetic resonance (CMR) in intermediate-risk patients with abnormal hsTn of unclear etiology.

methodsPatients with abnormal hsTn and modified HEART-score ≤6 underwent CMR to inform diagnosis, risk stratification, and ED disposition. Patients were followed at 30 and 90 days for all-cause mortality, readmission for myocardial infarction, and unplanned coronary revascularization.

resultsCMR was completed in 50 patients (64 years, 56% male) at a median of 23.2 h after presentation to the ED. CMR findings of coronary artery disease (CAD) were present in 19 (38%, 19/50) of patients, of which 13 had known CAD and 6 received a new diagnosis of CAD. In 12 (24%, 12/50) patients, cardiac noncoronary artery disease was diagnosed [cardiomyopathy (8), valvular disease (3), and myocarditis/pericarditis (1)], of which the majority (83%) (10/12) were new diagnoses. CMR was normal in 19 (38%, 19/50) patients. After CMR results were reported, the decision to admit was made in 10 (20%, 10/50) patients, while 40 (80%, 40/50) were discharged from the ED without further cardiac testing. Follow-up was completed in 96% (48/50) of patients, of which no patients experienced an adverse event.

conclusionA disposition protocol with outpatient observation and stress CMR is feasible and useful for determining the etiology of myocardial injury and risk stratification in patients presenting to the ED with chest pain, abnormal hsTn, and intermediate risk.