Abstract 410: Stress Cardiac MRI in an Observation Unit Setting Reduces Index Hospitalization Cost in ED Patients With Chest Pain at Intermediate Risk for Acute Coronary Syndromes
Introduction Emergency department (ED) patients with chest pain at intermediate risk for acute coronary syndrome (ACS) often receive relatively expensive inpatient care involving 23 hours of observation and stress testing with echo or radioistotope imaging.
Hypothesis Compared to inpatient care, observation unit (OU) stress cardiac magnetic resonance (CMR) will reduce index hospitalization cost in ED patients at intermediate risk for ACS.
Methods A single center clinical trial randomized 110 ED patients with intermediate risk chest pain (TIMI ≥2 or clinical impression) with a non-diagnostic ECG and a non-elevated initial troponin to OU CMR (OU care, serial cardiac markers and stress CMR) or inpatient care (admission, care determined by the admitting provider). Participant outcomes at 30 days were adjudicated by consensus of 2 blinded reviewers. Index hospitalization cost included hospital and physician costs. Hospital cost was calculated from itemized charges converted to cost using departmental-specific cost-to-charge ratios. Physician cost was calculated from work-RVUs using a Medicare conversion factor. A Wilcoxon-rank sum test and Cox PH modeling were used to conduct unadjusted and adjusted cost comparisons. The secondary outcome was correct cardiac disposition decision (excluding subjects leaving against medical advice (AMA)) based on the occurrence of ACS.
Results 53 subjects were randomized to OU-CMR and 57 to usual care; 8/110 (7%) experienced ACS. In the OU CMR group, 49/53 underwent stress CMR. 11/53 were admitted, 1 left AMA, 41 were discharged, and 2 experienced ACS (MI=1, CABG=1) in association with the index visit. In the usual care group, 39/57 subjects initially received stress testing. 54/57 were admitted, 3 left AMA, and 6 experienced ACS (MI=2, angioplasty=4). At 30 days no subjects in either group experienced ACS after discharge. OU CMR was associated with reduced median index hospitalization cost before ($2062 vs $2680, p<0.001) and after adjusting for covariates (p=0.014). OU CMR improved correct cardiac disposition decisions (83% vs 11%, p<0.001).
Conclusion In ED patients with intermediate risk chest pain, an OU CMR strategy reduces cost and improves cardiac disposition decisions with similar patient outcomes at 30 days.