Rapid or Ultra-rapid Diagnosis of Myocardial Infarction Using High-Sensitivity Cardiac Troponin on Hospital Presentation

Each year, approximately 80,000 individuals present to the Danish healthcare system with chest pain. Of these, around 25,000 are admitted to hospital and approximately 8,000 are diagnosed with acute myocardial infarction. High-sensitivity cardiac troponin (hs-cTn) is the cornerstone biomarker for the diagnosis of myocardial infarction and is essential for the rapid rule-in and rule-out of acute coronary syndromes. Because the diagnosis of myocardial infarction relies not only on troponin concentration but also on changes in troponin levels over time, serial blood sampling is required to distinguish acute myocardial injury from chronic elevations.

Advances in hs-cTn assay sensitivity have enabled progressively shorter intervals between serial blood sampling. Traditionally, most emergency departments have used a 0/3-hour algorithm, in which hs-cTn is measured at presentation and again after 3 hours. However, contemporary European guidelines recommend accelerated diagnostic pathways using a 0/1-hour or 0/2-hour algorithm.

The primary purpose of the DanRUSH trial is to determine whether shortening the interval between serial hs-cTn measurements from 3 hours to 1 hour is both safe and effective in adults presenting with suspected acute coronary syndrome.

The primary safety endpoint is defined as the risk of new (missed or recurrent) myocardial infarction or cardiovascular death after dischage from the index hospitalization -of the 0/1-hour algorithm compared with the 0/3-hour algorithm. Efficacy will be assessed as hospital length of stay, defined as the time from presentation to discharge. The study aims to demonstrate that the 0/1-hour algorithm is non-inferior to the 0/3-hour algorithm with respect to safety while improving efficiency through shorter hospital stays.

The study is designed as a nationwide, pragmatic, open-label, stepped-wedge cluster randomized trial. Participating emergency- and cardiology departments in Denmark will sequentially and randomly transition from the conventional 0/3-hour hs-cTn algorithm to the 0/1-hour hs-cTn algorithm until all sites are exposed to the intervention. A study-specific order set in the electronic medical record will ensure the correct timing of serial blood sampling and facilitate identification of study participants. Relevant baseline and outcome information will be obtained from routinely collected data in the electronic medical record and Danish nationwide health registries.

The results of DanRUSH are expected to provide definitive randomized evidence regarding the safety and effectiveness of the 0/1-hour hs-cTn algorithm. If the accelerated diagnostic strategy is shown to be safe, it may support broader implementation and improve patient flow by reducing unnecessary hospital stays. Conversely, if safety cannot be confirmed, the study may prevent widespread adoption of an insufficiently validated diagnostic strategy.

• 0/3-hour high-sensitivity cardiac troponin algorithm (Diagnostic test): High-sensitivity cardiac troponin measurements obtained at presentation and 3 hours after the initial sample as part of the conventional diagnostic strategy for suspected acute coronary syndrome.
• 0/1-hour high-sensitivity cardiac troponin algorithm (Diagnostic test): High-sensitivity cardiac troponin measurements obtained at presentation and 1 hour after the initial sample as part of the accelerated diagnostic strategy for suspected acute coronary syndrome.

Primary outcomes

• Safety outcome: New myocardial infarction or cardiovascular death [From discharge from the index hospitalization until 30 days after discharge.]: The risk of new (missed or recurrent) myocardial infarction or cardiovascular death after dischage -of the 0/1-hour algorithm compared with the 0/3-hour algorithm.
• Efficacy outcome: Length of hospital stay [During the index hospitalization (from emergency department presentation until hospital discharge)]: Length of stay, defined as the time from presentation to the emergency department until discharge from hospital.

Secondary outcomes

• New myocardial infarction at 12 months [From discharge from the index hospitalization until 12 months after discharge.]: New myocardial infarction within 12 months following discharge from the index hospitalization, excluding myocardial infarction diagnosed during the index hospitalization.
• All-cause mortality [30 days and 12 months following discharge]: Death from any cause following discharge from the index hospitalization
• Overall myocardial infarction rate [30 days and 12 months following discharge]: Occurrence of myocardial infarction during follow-up
• Diagnostic coronary angiography [During the index hospitalization, at 30 days, and at 12 months after the index presentation]: Performance of diagnostic coronary angiography following the index presentation
• Invasive treatment [During the index hospitalization, at 30 days, and at 12 months after the index presentation]: Invasive coronary treatment, including percutaneous coronary intervention or coronary artery bypass grafting.
• Re-presentation to hospital [30 days and 12 months following discharge]: Presentation to the emergency department or hospital following discharge from the index hospitalization
• Re-hospitalization [30 days and 12 months following discharge]: Hospital admission following discharge from the index hospitalization
• Time to treatment initiation [From emergency department presentation until initiation of treatment, assessed during the index hospitalization (up to 7 days)]: Time from presentation to initiation of relevant treatment for acute coronary syndrome

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Adults (≥18 years) presenting with suspected acute coronary syndrome (ACS) with a clinical indication for high-sensitivity cardiac troponin testing

Exclusion Criteria:

* Age <18 years.
* ST-segment elevation myocardial infarction (STEMI) identified on the presenting electrocardiogram and requiring immediate reperfusion therapy.

• Manan Pareek, MD, MSc PhD, FAHA, FESC, FACC, Principal investigator, Center for Translational Cardiology and Pragmatic Randomized Trials and Department of Cardiology, Herlev and Gentofte Hospital