11 High-Sensitivity Troponin T Identifies Patients at Very Low Risk of Adverse Events

Approximately 7 million patients present to US emergency departments (EDs) with suspected acute coronary syndrome (ACS) each year. Many undergo extensive, inconvenient, and expensive evaluation, the majority of which are negative. Our purpose was to determine if a negative high sensitivity troponin (hsTnT) at 0- and 3-hours following ED presentation could identify patients at <1% risk of 30-day adverse cardiac events (ACE). Eligible patients presented to 1 of 15 US EDs with ACS symptoms, and had 30-day follow up. ACE was defined as myocardial infarction, urgent revascularization or death. The upper reference level (the 99th %ile, established in a separate volunteer cohort) for the hsTnT assay (5th generation Roche Elecsys® hsTnT) was 19 ng/L and the FDA reportable level of detection (rLOD) was 6.0 ng/L. Patients were considered “ruled out” if hsTnT at 0 and 3 hours was <19 ng/L. In rule-out patients, one or both 0- and 3-hour hsTnT levels could be above or below the LOD and thus created 4 sub-cohorts, as in the figure. Gold standard diagnoses were determined by a clinical endpoint committee. In 1264 ED patients with suspected ACS, 30-day ACE occurred in 15 (1.2%). Of the 290 (22.9%) not “ruled out” (hsTnT >19 ng/L at 0 or 3 hours), ACE occurred in 8 (2.8%, 95% CI: -8.5 to 14.1). Of 974 (77.1%) with both 0- and 3-hour hsTnT<19 ng/L, negative predictive value for ACE was 99.3% (95% CI: 99.05 to 99.55), with 30-day ACE occurring in 7 (0.7%, 95% CI: -5.5 to 6.9). Patients with a 0- and 3-hour hsTnT < 19ng/L have a very low rate of 30-day ACE.