# Utilization and outcomes of single-troponin discharge from the emergency department in a low-risk population

## TL;DR

The study examines the safety and effectiveness of discharging low-risk chest pain patients from the emergency department based on a single undetectable troponin test.

## Contribution

It evaluates a real-world implementation of an accelerated rule-out strategy for acute coronary syndrome using high sensitivity troponin assays.

## Key findings

- No patients with undetectable troponin were diagnosed with acute coronary syndrome.
- Patients following the protocol had shorter emergency department stays and fewer hospital admissions.
- Protocol adherence was only 50%, limiting the overall impact of the strategy.

## Abstract

Objectives: There is emerging data supporting rapid triage of low-risk chest pain patients to help facilitate Emergency Department (ED) throughput. We assessed an algorithm for accelerated rule-out of acute coronary syndrome in low-risk patients with an undetectable initial high sensitivity cardiac troponin (hs-cTn assays; Roche Diagnostics) in a real-world clinical setting.

Methods: All adults presenting with chief complaint of non-traumatic chest pain to our tertiary care ED with HEART score ≤3 with at least one hs-cTn and EKG obtained were included in our study. Data and outcomes were compared three months before and after implementation of our updated Acute Chest Pain Optimal Care Pathway that allowed discharge of patients with an initial troponin below detectable range (<6ng/L). The primary outcome was acute coronary syndrome at presentation or major adverse cardiovascular events within 30 days. Secondary outcomes included ED length of stay, cardiology consultations, and hospital admissions.

Results: Of the 229 patients fitting our criteria with a low-risk heart score (≤3) and undetectable initial troponin, zero patients were diagnosed with ACS and one major adverse cardiac event occurred post-implementation (0.8%). There were no significant differences in median ED length of stay pre- (4.5 h, IQR 3.8–6.6) versus post-implementation (4.6 h, IQR 3.5–5.7; p = 0.448), number of cardiology consults (p = 0.305) and hospital admissions (p = 0.261). However, protocol adherence was poor (50%). In a subgroup analysis post-implementation, patients whose care aligned with the algorithm (n = 64, 50.0%) had significantly shorter ED stays (median 4.1 h, IQR 3.3-4.9 vs 5.2 h, IQR 4.4-6.9, p¡0.001), fewer admissions (p = 0.001) but not fewer cardiology consults (p = 0.440).

Conclusions: Our study supports current data regarding the safety of accelerated rule out strategy with hs-cTn. However, our conclusions are limited due to its small sample size and retrospective design.