Stress cardiac magnetic resonance imaging with observation unit care reduces cost for patients with emergent chest pain: a randomized trial

Abstract

Study objective: We determine whether imaging with cardiac magnetic resonance imaging (MRI) in an observation unit would reduce medical costs among patients with emergent non-low-risk chest pain who otherwise would be managed with an inpatient care strategy.

Methods: Emergency department patients (n=110) at intermediate or high probability for acute coronary syndrome without electrocardiographic or biomarker evidence of a myocardial infarction provided consent and were randomized to stress cardiac MRI in an observation unit versus standard inpatient care. The primary outcome was direct hospital cost calculated as the sum of hospital and provider costs. Estimated median cost differences (Hodges-Lehmann) and distribution-free 95% confidence intervals (Moses) were used to compare groups.

Results: There were 110 participants with 53 randomized to cardiac MRI and 57 to inpatient care; 8 of 110 (7%) experienced acute coronary syndrome. In the MRI pathway, 49 of 53 underwent stress cardiac MRI, 11 of 53 were admitted, 1 left against medical advice, 41 were discharged, and 2 had acute coronary syndrome. In the inpatient care pathway, 39 of 57 patients initially received stress testing, 54 of 57 were admitted, 3 left against medical advice, and 6 had acute coronary syndrome. At 30 days, no subjects in either group experienced acute coronary syndrome after discharge. The cardiac MRI group had a reduced median hospitalization cost (Hodges-Lehmann estimate $588; 95% confidence interval $336 to $811); 79% were managed without hospital admission.

Conclusion: Compared with inpatient care, an observation unit strategy involving stress cardiac MRI reduced incident cost without any cases of missed acute coronary syndrome in patients with emergent chest pain.

Figure 1

Screening, enrollment, randomization, and followup of patients in the trial.

Figure 2

Distributions of cost for study participants in the inpatient care group (INPAT) (n=57) and observation unit–cardiac MRI (OUCMR) group (n=53). All participants have some reported cost for each category unless otherwise noted. A, ED facility cost. B, Laboratory testing cost. C, Catheterization and revascularization cost, no cost n=48 INPAT, n=45 OUCMR. D, Noninvasive imaging cost. E, Pharmacy-associated cost, no cost n=1 INPAT, n=0 OUCMR. F, Inpatient facility cost, no cost n=3 INPAT, n=30 OUCMR. G, Total nonprovider cost representing the sum of cost in A to F. H, Total provider cost. I, Total cost of care, representing the sum of cost in G and H.

Figure 2

Distributions of cost for study participants in the inpatient care group (INPAT) (n=57) and observation unit–cardiac MRI (OUCMR) group (n=53). All participants have some reported cost for each category unless otherwise noted. A, ED facility cost. B, Laboratory testing cost. C, Catheterization and revascularization cost, no cost n=48 INPAT, n=45 OUCMR. D, Noninvasive imaging cost. E, Pharmacy-associated cost, no cost n=1 INPAT, n=0 OUCMR. F, Inpatient facility cost, no cost n=3 INPAT, n=30 OUCMR. G, Total nonprovider cost representing the sum of cost in A to F. H, Total provider cost. I, Total cost of care, representing the sum of cost in G and H.

Figure 3

Total cost by TIMI risk score, inpatient care, n=57, and observation unit–cardiac MRI (OUCMR), n=53.

Figure 4

Distributions of revenue from participants by study group, inpatient care, n=57, and observation unit–cardiac MRI (OUCMR), n=53. A, Provider revenue. B, Nonprovider revenue. C, Total revenue, representing the sum of A and B.