# Implementation of the European Society of Cardiology Zero/Two-Hour High-Sensitivity Troponin Pathway for Non-ST-Elevation Myocardial Infarction Diagnosis: A Real-World Observational Study From a UK District Hospital

## TL;DR

A UK hospital improved its heart attack diagnosis process by implementing a new testing pathway, making it faster and safer without missing cases.

## Contribution

Demonstrates successful real-world implementation of the ESC zero/two-hour troponin pathway in a district hospital.

## Key findings

- Adherence to the ESC pathway increased from 74.2% to 94.4% after implementation.
- Unnecessary repeat testing dropped from 24.6% to 4.4%, and length of stay decreased by 313 minutes.
- No increase in missed heart attacks or adverse events was observed despite faster diagnosis.

## Abstract

Background

High-sensitivity cardiac troponin (hs-cTn) assays enable accelerated diagnostic pathways for non-ST-elevation myocardial infarction (NSTEMI). The 2023 European Society of Cardiology (ESC) guidelines recommend zero/one-hour or zero/two-hour protocols, but real-world adherence remains inconsistent. This study evaluated the impact of structured pathway implementation on diagnostic efficiency, test utilisation, and safety outcomes in a UK district general hospital.

Methodology

We conducted a retrospective, pre-post, observational study including adults presenting with chest pain who underwent hs-cTn testing. Data were collected during two periods: November 2024 (pre-implementation cohort, n = 595) and June 2025 (post-implementation cohort, n = 340). Between cohorts, interventions included targeted staff education, visual algorithm prompts, and collaboration with laboratory services. Outcomes included adherence to the ESC zero/two-hour pathway, unnecessary repeat testing, inappropriate testing in non-cardiac presentations, time to troponin sampling, length of stay, and documentation of risk stratification.

Results

Adherence to the ESC zero/two-hour pathway improved from 74.2% to 94.4% (p < 0.001). Unnecessary repeat testing in patients with very low initial troponin decreased from 24.6% to 4.4%. Efficiency improved significantly: time to first hs-cTn reduced by 13.5 minutes, zero to two-hour testing interval by 133.8 minutes, and length of stay by 313 minutes (all p < 0.001). Documentation of the ESC pathway (1.0% vs. 74.1%) and History, Electrocardiogram, Age, Risk factors, and Troponin (HEART) score use (1.0% vs. 62.8%) increased markedly. No rise in missed NSTEMI or 30-day major adverse cardiac events was observed. However, >70% of hs-cTn requests remained for non-cardiac presentations.

Conclusions

Structured implementation of the ESC zero/two-hour hs-cTn pathway substantially improved diagnostic efficiency, adherence, and safety without increasing adverse outcomes. Persistent overuse of hs-cTn in non-cardiac presentations highlights the need for system-level stewardship. The observed improvements in diagnostic speed and reduced length of stay also translate into significant operational benefits, including increased bed availability and improved patient flow, without compromising patient safety. Future efforts will focus on digital integration and continuous audit-feedback systems to reinforce adherence and address inappropriate troponin use in non-cardiac presentations.