Stress CMR reduces revascularization, hospital readmission, and recurrent cardiac testing in intermediate-risk patients with acute chest pain

Abstract

Objectives: The aim of this study was to determine the effect of stress cardiac magnetic resonance (CMR) imaging in an observation unit (OU) on revascularization, hospital readmission, and recurrent cardiac testing in intermediate-risk patients with possible acute coronary syndromes (ACS).

Background: Intermediate-risk patients commonly undergo hospital admission with high rates of coronary revascularization. It is unknown whether OU-based care with CMR is a more efficient alternative.

Methods: A total of 105 intermediate-risk participants with symptoms of ACS but without definite ACS on the basis of the first electrocardiogram and troponin were randomized to usual care provided by cardiologists and internists (n = 53) or to OU care with stress CMR (n = 52). The primary composite endpoint of coronary artery revascularization, hospital readmission, and recurrent cardiac testing at 90 days was determined. The secondary endpoint was length of stay from randomization to index visit discharge; safety was measured as ACS after discharge.

Results: The median age of participants was 56 years (range 35 to 91 years), 54% were men, and 20% had pre-existing coronary disease. Index hospital admission was avoided in 85% of the OU CMR participants. The primary outcome occurred in 20 usual care participants (38%) versus 7 OU CMR participants (13%) (hazard ratio: 3.4; 95% confidence interval: 1.4 to 8.0, p = 0.006). The OU CMR group experienced significant reductions in all components: revascularizations (15% vs. 2%, p = 0.03), hospital readmissions (23% vs. 8%, p = 0.03), and recurrent cardiac testing (17% vs. 4%, p = 0.03). Median length of stay was 26 h (interquartile range: 23 to 45 h) in the usual care group and 21 h (interquartile range: 15 to 25 h) in the OU CMR group (p < 0.001). ACS after discharge occurred in 3 usual care participants (6%) and no OU CMR participants.

Conclusions: In this single-center trial, management of intermediate-risk patients with possible ACS in an OU with stress CMR reduced coronary artery revascularization, hospital readmissions, and recurrent cardiac testing, without an increase in post-discharge ACS at 90 days. (Randomized Investigation of Chest Pain Diagnostic Strategies; NCT01035047).

Figure 1. Consort diagram

The study randomized 105 participants to OU-CMR (n=52) or usual care (n=53). All were analyzed based on intent to treat. OU, observation unit; CMR, cardiac magnetic resonance; ED, emergency department;

Figure 2. Cumulative incidence curves

Cumulative incidence curves demonstrate an early reduction in composite events that continued through 90 days in the OU-CMR group compared to the usual care group. OU, observation unit; CMR, cardiac magnetic resonance.