Protocols using sensitive troponin assays can accelerate the rule out of acute myocardial infarction in patients with low-risk (suspected) acute coronary syndrome (ACS).
This study evaluated 2 prospective cohorts of patients in the emergency department with ACS in an accelerated diagnostic pathway integrating 0- and 2-h hs-TnI results, Thrombolysis In Myocardial Infarction (TIMI) risk scores, and electrocardiography. Strategies to identify low-risk patients incorporated TIMI risk scores?= 0 or?¡Ü1. The primary endpoint was a major adverse cardiac event (MACE) within 30 days.
In the primary cohort, 1,635 patients were recruited and had 30-day follow-up. A total of 247 patients (15.1 % ) had a MACE. The finding of no ischemic electrocardiogram and hs-TnI?¡Ü26.2 ng/l with the TIMI?= 0 and TIMI?¡Ü1 pathways, respectively, classified 19.6 % (n = 320) and 41.5 % (n = 678) of these patients as low risk; 0 % (n = 0) and 0.8 % (n = 2) had a MACE, respectively. In the secondary cohort, 909 patients were recruited. A total of 156 patients (17.2 % ) had a MACE. The TIMI?= 0 and TIMI?¡Ü1 pathways classified 25.3 % (n = 230) and 38.6 % (n = 351), respectively, of these patients as low risk; 0 % (n = 0) and 0.8 % (n = 1) had a MACE, respectively. Sensitivity, specificity, and negative predictive value for TIMI?= 0 in the primary cohort were 100 % (95 % confidence interval [CI]: 98.5 % to 100 % ), 23.1 % (95 % CI: 20.9 % to 25.3 % ), and 100 % (95 % CI: 98.8 % to 100 % ), respectively. Sensitivity, specificity, and negative predictive value for TIMI?¡Ü1 in the primary cohort were 99.2 (95 % CI: 97.1 to 99.8), 48.7 (95 % CI: 46.1 to 51.3), and 99.7 (95 % CI: 98.9 to 99.9), respectively. Sensitivity, specificity, and negative value for TIMI?¡Ü1 in the secondary cohort were 99.4 % (95 % CI: 96.5 to 100), 46.5 % (95 % CI: 42.9 to 50.1), and 99.7 % (95 % ?CI: 98.4 to 100), respectively.
An early-discharge strategy using an hs-TnI assay and TIMI score?¡Ü1 had similar safety as previously reported, with the potential to decrease the observation periods and admissions for approximately 40 % of patients with suspected ACS. (Advantageous Predictors of Acute Coronary Syndromes Evaluation [APACE] Study, ; A 2hr Accelerated Diagnostic Protocol to Assess patients with chest Pain symptoms using contemporary Troponins as the only biomarker [ADAPT]: a prospective observational validation study, )