Can the HEART score safely reduce stress testing and cardiac imaging in patients at low risk for major adverse cardiac events?

BACKGROUND: Patients with low-risk chest pain have high utilization of stress testing and cardiac imaging, but low rates of acute coronary syndrome (ACS). The objective of this study was to determine whether the HEART score could safely reduce objective cardiac testing in patients with low-risk chest pain.
METHODS: A cohort of chest pain patients was identified from an emergency department-based observation unit registry. HEART scores were determined using registry data elements and blinded chart review. HEART scores were dichotomized into low (0-3) or high risk (>3). The outcome was major adverse cardiac events (MACE); a composite end point of all-cause mortality, myocardial infarction, or coronary revascularization during the index visit or within 30 days. Sensitivity, specificity, and potential reduction of cardiac testing were calculated.
RESULTS: In a span of 28 months, the registry included 1070 low-risk chest pain patients. MACE occurred in 0.6% (5/904) of patients with low-risk HEART scores compared with 4.2% (7/166) with a high-risk HEART scores (odds ratio = 7.92; 95% confidence interval [95% CI]: 2.48-25.25). A HEART score of >3 was 58% sensitive (95% CI: 32-81%) and 85% specific (95% CI: 83-87%) for MACE. The HEART score missed 5 cases of ACS among 1070 patients (0.5%) and could have reduced cardiac testing by 84.5% (904/1070). Combination of serial troponin >0.065 ng/mL or HEART score >3 resulted in sensitivity of 100% (95% CI: 72-100%), specificity of 83% (95% CI: 81-85%), and potential reduction in cardiac testing of 82% (879/1070).
CONCLUSIONS: If used to guide stress testing and cardiac imaging, the HEART score could substantially reduce cardiac testing in a population with low pretest probability of ACS.