performance of care rule in ruling out acute coronary syndrome in non-traumatic chest pain: an external validation study

Objective: about one out of every 10 patients with chest pain in the emergency department (ed) are finally diagnosed with acute coronary syndrome (acs). a heart score of · 3 has been shown to rule out acs with a low risk of major adverse cardiac events (mace) occurrence. it has been proposed that a negative care rule (·1), which stands for the first four elements of the heart score and excludes the troponin assay requirement, may have similar rule-out reliability. this study aimed to externally validate the care rule. methods: in this multicenter, observational study a convenience sample consisting of patients over the age of 15 who had at least one troponin study were included. the performance of the care rule at the cut-off ·1 for mace prediction was assessed and compared to a heart score of ·3 and physicians’ gestalt. macewas defined as myocardial infarction, coronary angioplasty, coronary artery bypass graft, and all-cause mortality in 6 weeks. results: the data of 154 patients was analyzed. of these, 121 patients had a negative care score of ·1 and 33 individuals had a positive care score. of those with a negative care score, only 1 (3%) experienced an adverse cardiac event while in those with a positive care score, 26 individuals (16.88 %) experienced mace. the sensitivity of the care rule was 96.15% and the specificity was 25% with a negative likelihood ratio (lr-) of 0.15. the indices for heart score were 88%, 59.69%, and 0.2, respectively. in comparison, physicians’ gestalt had a sensitivity of 96%, specificity of 49.22%, and a lr- of 0.08. of note, utilizing the care rule with a cut-off of <3 showed sensitivity of 96%, specificity of 41.86%, and a lr- of 0.1. conclusion: the care rule miss rate inmace was more than 2% and while its performance was better than the heart score, physicians’ gestalt outperformed both rules for ruling outmace