ObjectiveTo compare the ability of five established risk scores to identify patients with suspected acute coronary syndromes (ACS) suitable for discharge after a single presentation highsensitivity troponin (hs-cTn) result.
MethodsProspective observational study conducted in a U.K. District General Hospital Emergency Department. Consecutive adults recruited with suspected ACS whom attending physicians determined evaluation with serial troponin testing was required. Index tests were definitions of low risk applied to Goldman, TIMI, GRACE, HEART and Vancouver risk scores, incorporating either hs-cTnT or hs-cTnI results. The endpoint was acute myocardial infarction (AMI) within 30 days. A test sensitivity threshold for AMI of 98% was chosen.Clinical utility was defined as a negative predictive value (NPV) ≥99.5% and identification of >30% suitable for discharge.
Results959 patients underwent hs-cTnT and 867 hs-cTnI analysis. In the hs-cTnT group, 79/959 (8.2%) had an AMI and 66/867 (7.6%) in the hs-cTnI group. Two risk scores (GRACE<80, HEART≤3) did not have the potential to achieve a sensitivity of 98% with hs-cTnT and three 2 scores (Goldman≤1, TIMI≤1, GRACE<80) with hs-cTnI. TIMI 0 or ≤1 and m-Goldman≤1 with hs-cTnT, and TIMI 0 and HEART≤3, with hs-cTnI have the potential to achieve an NPV ≥99.5% while identifying >30% for discharge.
ConclusionUsing established risk scores, it may be possible to identify >30% of patients suitable for discharge with an NPV ≥99.5% for the diagnosis of AMI using a single hs-cTn result taken at presentation. There is variation in hs-cTn assays which may have implications in introducing rapid rule-out protocols.