Comprehensive Summary
This prospective, stepped-wedge, randomized trial compared an accelerated 0/1-hour myocardial (MI) exclusion protocol with the 0/3-hour standard approach in patients presenting to the emergency department (ED) with suspected MI. In the accelerated protocol, high-sensitivity cardiac troponin I (hs-cTnI) was measured at 0 and 1 hours. Standard care involved hs-cTnI testing at 0 and 3 hours, combined with a modified HEART score for risk assessment. Across nine U.S. EDs, 32,609 patients with suspected MI were randomized to either protocol to assess eligibility for safe discharge. The primary endpoint was the proportion of patients safely discharged from the ED without death or MI within 30 days. Secondary endpoints included 30-day death, MI, or coronary revascularization among patients discharged from the ED or observation unit. The study found no significant difference in safe discharges between standard care (59.5%) and the accelerated protocol (57.8%) (adjusted odds ratio [aOR] = 1.05, 95% CI 0.95-1.16). At 30 days, deaths or MIs occurred in 38patients (0.4%) in the standard care group and 52patients (0.4%) in the accelerated protocol group (aOR = 0.84, 95% CI 0.43-1.68).
Outcomes and Implications
Rapid MI evaluation has the potential to improve early and safe patient discharges, thereby reducing ED crowding and healthcare costs. However, the real-world effectiveness of such rapid troponin-based MI evaluation protocols remains unclear. This trial demonstrated that the 0/1-hour hs-cTn1 accelerated protocol was noninferior to standard care in safety, but did not result in more safe ED discharges. Beyond failing to meet its primary endpoint, the trial was limited by its conduct within a single U.S. healthcare system during the COVID-19 pandemic and by the absence of clinical risk scoring in the accelerated protocol. Future pragmatic studies should evaluate site-specific performance of accelerated 0/1-hour hs-cTn1 protocols that integrate clinical risk scoring.