Safety of Using Risk Stratification Along With High-Sensitivity Cardiac Troponin in the Emergency Department: A Secondary Analysis.

Abstract

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. This study sought 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. In this secondary analysis of a stepped-wedge cluster-randomized controlled trial, we evaluated the effectiveness and safety of risk stratification with high-sensitivity cardiac troponin in 31,492 consecutive patients who presented with suspected acute coronary syndrome and 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. 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-risk (6.9 ± 3.2 vs 4.7 ± 2.8 hours: difference 2.2; 95% CI: 0.7-3.7 hours) and intermediate-risk (15.8 ± 4.7 vs 11.0 ± 4.9 hours: difference 4.8; 95% CI: 3.8-5.8 hours) patients (P < 0.001 for both). Discharge from the emergency department increased in low-risk (62% [4,962 of 7,941] vs 83% [7,747 of 9,358]; adjusted OR: 3.31; 95% CI: 3.06-3.57) and intermediate-risk (36% [2,445 of 6,759] vs 55% [4,095 of 7,434]; adjusted OR: 2.06; 95% CI: 1.92-2.21) patients. Following implementation, patients discharged were at lower risk of myocardial infarction or cardiac death at 1 year (1.5% [112 of 7,407] vs 1.0% [124 of 11,842]; adjusted HR [aHR]: 0.65; 95% CI: 0.50-0.86), whether stratified as low (0.6% vs 0.3%; aHR: 0.46; 95% CI: 0.26-0.83) or intermediate (3.4% vs 2.4%; aHR: 0.74; 95% CI: 0.55-0.99) risk at presentation. 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. (High-Sensitivity Cardiac Troponin on Presentation to Rule Out Myocardial Infarction [HiSTORIC]; NCT03005158).