# The HEART-GP strategy for ruling out acute coronary syndrome in out-of-hours primary care: a diagnostic accuracy trial protocol

## TL;DR

This study tests a new strategy to quickly rule out heart attacks in out-of-hours primary care using a simple blood test and clinical assessment.

## Contribution

The HEART-GP strategy combines high-sensitivity troponin testing with clinical evaluation to safely and efficiently rule out acute coronary syndrome in primary care.

## Key findings

- The HEART-GP strategy aims to improve diagnostic safety and reduce emergency department referrals.
- The study will compare the strategy's performance against standard care in out-of-hours primary care.
- Blinded adjudication ensures unbiased outcome assessment.

## Abstract

Acute coronary syndrome (ACS) is a life-threatening condition that requires rapid identification to prevent morbidity and mortality. Differentiating ACS from benign conditions remains difficult in out-of-hours primary care (OOH-PC) settings due to non-specific and overlapping symptom profiles, and limited diagnostic resources. Current guidelines promote a low threshold for emergency department (ED) referral. Despite this cautious approach, ACS cases are still missed. The arrival of high-sensitivity troponin (hs-troponin) point-of-care testing (POCT) may enable safer, faster, and more efficient diagnosis.

This multicenter prospective diagnostic accuracy trial evaluates the HEART-GP strategy, combining a single fingerstick hs-troponin test with clinical assessment and optional ECG. Adults (≥18 years) presenting with acute chest pain or discomfort to one of four participating Dutch OOH-PC centers are eligible. The primary outcome is the occurrence of major adverse cardiovascular events a composite of death, ACS, or urgent revascularization within six weeks. Diagnostic safety (sensitivity, negative predictive value) and efficiency (ED referral reduction) will be compared against standard care. Secondary analyses will assess the value of sex-specific cut-offs and integration with existing risk scores.

We anticipate that the HEART-GP strategy will demonstrate improved diagnostic safety along with efficiency gains in OOH-PC. Our straightforward rapid rule-out strategy holds promise to be widely implemented in primary care settings to advance the evaluation of acute chest pain.

The study was approved by the Medical Research Ethics Committee of the Amsterdam UMC (NL82428.000.22, 02-03-2023) and registered in the ISRCTN-registry (ISRCTN11954040 https://doi.org/10.1186/ISRCTN11954040).

•An innovative, pragmatic strategy for rapid rule-out of ACS.•High external validity due to prospective, multi-center, real-world OOH-primary care design.•Identification of the optimal strategy of various risk stratification approaches using hs-troponin testing.•Blinded, independent adjudication of clinical outcomes.

An innovative, pragmatic strategy for rapid rule-out of ACS.

High external validity due to prospective, multi-center, real-world OOH-primary care design.

Identification of the optimal strategy of various risk stratification approaches using hs-troponin testing.

Blinded, independent adjudication of clinical outcomes.