Background: Implementation of an early rule-out pathway for myocardial infarction using high-sensitivity cardiac troponin to risk stratify patients reduces length of stay and hospital admission. Whether gains are similar in low- and intermediate-risk patients, and those discharged were correctly identified as being at lower risk of future cardiovascular events is uncertain.
Objectives: To evaluate the effectiveness and safety of risk stratification with high-sensitivity cardiac troponin in patients with suspected acute coronary syndrome stratified as low and intermediate risk.
Methods: In this secondary analysis of a stepped-wedge cluster-randomised controlled trial, we evaluated the effectiveness and safety of risk stratification with high-sensitivity cardiac troponin in 31,492 consecutive patients presented with suspected acute coronary syndrome, identified as low (<5 ng/L) or intermediate (5 ng/L to 99th percentile) risk at presentation. The primary effectiveness outcome was length of hospital stay. The primary safety outcome was subsequent myocardial infarction or cardiac death at 1 year.
Results: Of 31,492 patients (59±17 years, 45% women), 17,299 (54.9%) and 14,193 (45.1%) were low and intermediate risk, respectively. Following implementation, length of stay was reduced in low- (6.9±3.2 versus 4.7±2.8 hours: difference 2.2, 95% confidence interval 0.7 to 3.7 hours) and intermediate- (15.8±4.7 versus 11.0±4.9 hours: difference 4.8, 3.8 to 5.8 hours) risk patients (P<0.001 for both). Discharge from the Emergency Department increased in low- (62%[4,962/7,941] versus 83%[7,747/9,358], adjusted odds ratio [aOR] 3.31, 95% confidence interval 3.06 to 3.57) and intermediate- (36%[2,445/6,759] versus 55%[4,095/7,434], aOR 2.06, 1.92 to 2.21) risk patients. Following implementation, patients discharged were at lower risk of myocardial infarction or cardiac death at 1 year (1.5%[112/7,407] versus 1.0%[124/11,842], adjusted hazard ratio [aHR] 0.65, 0.50 to 0.86), whether stratified as low (0.6% versus 0.3%, aHR 0.46, 0.26 to 0.83) or intermediate (3.4% versus 2.4%, aHR 0.74, 0.55 to 0.99) risk at presentation.
Conclusions: Risk stratification with high-sensitivity cardiac troponin reduced length of stay and increased discharge from the Emergency Department in both low- and intermediate-risk patients with suspected acute coronary syndrome. Patients discharged from the Emergency Department were at lower risk of subsequent myocardial infarction or cardiac death at 1 year.
Editors
Editor-in-Chief
Harlan M. Krumholz, MD, SM, FACC
CME Editor
Ragavendra R. Baliga, MD
Author
Ioannis Dimarakis, MD, PhD
Important Dates
Date of Release: November 3, 2025
Term of Approval/Date of CME/MOC Expiration: November 2, 2026