Null CTA results reinforce the need for RCTs over observational hunches
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Safety and efficacy of the 0/1 h pathway for myocardial infarction in the emergency department: an international, pragmatic, stepped-wedge, cluster-randomised, controlled trial
Christian Eugen MuellerJasper BoeddinghausPaolo BimaLuca CrisantiDagmar I KellerKsenija SlankamenacMichael ChristPhilipp SchüetzAndrea WiencierzIvo StrebelJulia ReinhardtIryna VyshnevskaTe Hung TsaoMaria Pia RuggieriStephan SteuerÓscar MiróVeli-Pekka HarjolaFulvio MorelloPeiman NazerianDominik RothJosé L ZamoranoDeborah GannonJason PottBen BloomRafique ZubaidRichina BicetteAndreea CuculiciHéctor BuenoJuan SanchisFelix MahfoudMohammed O A AbubakrHyun Suk YangDoris EisStefan VenturiniSebastian HaubitzAngelika Hammerer-LercherLaurent HaegeliBoris AdjibodouLukas AltweggSimone WeisskopfGemma Martínez-NadalBeatriz LópezJohan LassusKimmo SuojanenTomi MäkiahoEnrico LupiaSilvia TarditiGiulia LabarileSilvia RauleGiuliano De StefanoEduardo GaisGianni MecocciMaximilian NiedererLarissa BernertPaloma Remior PérezMarcelo Sanmartín FernándClemencia de Rueda PanaderoVanesa Santos PoloKim HansenVirginia GehrkeSharyl DwyerJulie GoofruitRaine Astin-ChamberlainNoemi CaponiEmily CampellFatma MohammedNimca OmerAlison QuinnJaqueline SearGrace TunesiCristina ThiebaudKaren HopkinsKatie MorganElamein YousifHein ZawAlex JamesNeha KasaravalliMohamed ElbouhiWessam AndrawesStephanos GhobrialMark JadavKyeong Ryong LeeMina HurJoe YoungFrank W PeacockPhong HuynhAdriana CovaliovOvidiu ChioncelGabriele ValliFrancesca De MarcoM. Lorena Castro AriasRodrigo Pacheco PuigGuillermo MorenoBerk Mehmet FeyziJorge Vélez GarcíaAgustín Fernández-CisnalJosé NocedaAura WinterhalderBeate HartmannLu Cheng
What happened
Rapid 0/1-hour troponin pathway achieves non-inferior 30-day safety compared with the standard 0/3-hour protocol.
- OR 0.93
- 95% CI 0.77-1.13
- n=67,624
Does this change practice?
Where experts agree
Multiple experts note that the 0/1-hour pathway met noninferiority for safety but failed to reduce ED length of stay, framing this as a disconnect between faster testing and real-world throughput.
What this trial adds
Experts see the 0/1-hour troponin pathway as safely noninferior to the 0/3-hour pathway, but the failure to shorten ED length of stay surprised many and raises questions about real-world implementation barriers.
Published field read
Cardiologists broadly accept that the faster troponin pathway is safe, but the headline surprise is that it did not get patients out of the ED any sooner. The trial's lead investigator points to systemic bottlenecks like specialist review, admissions workflow, and bed availability as the likely culprits. The open question is whether the 0/1-hour pathway can deliver on its efficiency promise if hospitals redesign the surrounding processes.
Still open
Questions raised in published commentaryWhether redesigning hospital workflows around specialist review, admissions, and bed availability could unlock the ED throughput benefit the 0/1-hour pathway was expected to deliver.
It also remains uncertain how the new 2026 ESC Fifth Universal Definition of MI guidelines will position the 0/1-hour pathway given these results.
Context from published commentary. Source summaries are not a new guideline recommendation.
Who says what
Author asks
Jasper Boeddinghaus57d ago
Interventional · University of Basel
What should clinicians watch for when these results land?
PRESC1SE-MI co-author
Safety was noninferior but the implementation challenge is the real story
X post ↗Jasper Boeddinghaus
Results readoutEmergency medicine researcher, University of BaselFaster troponin alone does not fix ED throughput because bottlenecks lie elsewhere
Original post ↗Show 5 more perspectivesShow fewer perspectives
Martha Gulati
ContextCardiologistThe 0/1-hour algorithm has huge implications for ruling out heart attacks faster
X post ↗
Notes the 0/1-hour pathway was noninferior for safety but did not reduce ED length of stay.
X post ↗
Framed PRESC1SE-MI as a test of whether diagnostic pathways for suspected MI can become faster and more selective.
X post ↗
C. Michael GibsonResults readoutInterventional / Structural Cardiology · Beth Israel Deaconess Medical Center
Summarized the trial as meeting noninferiority for 30-day safety but not shortening ED length of stay, and discussed findings alongside the IPD meta-analysis.
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Tomasz GuzikEuropean Society of Cardiology
“This year, ESC Congress received a record number of submissions of late-breaking clinical trials, reflecting the remarkable pace of innovation across cardiology. We rigorously selected the studies with the greatest scientific quality and potential clinical impact.”
Conference Coverage ↗What should the author answer first?
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Full evidence
Why the trial, key points, tables, limitations, PICO, abstract, media & sources
Full evidence
Why the trial, key points, tables, limitations, PICO, abstract, media & sources
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Why the trial?
The ESC 0/1-hour high-sensitivity troponin algorithm entered guidelines from observational studies, without randomised evidence that implementing it is as safe as the 0/3-hour pathway or that it actually shortens emergency department stays.
Does the 0/1 h pathway reduce emergency department length of stay and prevent 30-day death or new myocardial infarction in adults with suspected myocardial infarction compared to the 0/3 h pathway?
Key Points
- To evaluate the safety and efficacy of implementing a guideline-recommended 0/1 h high-sensitivity cardiac troponin pathway compared with a standard 0/3 h pathway in emergency departments.
- Pragmatic, stepped-wedge, cluster-randomised, controlled, masked-endpoint trial (PRESC1SE-MI; NCT05649384) conducted across 19 hospitals in ten countries.
- Hospitals using standard 0/3 h blood draws transitioned to 0/1 h blood draws at 6 or 12 months, with non-inferiority safety set at an odds ratio margin of 1·3.
- Implementation of the 0/1 h pathway did not shorten emergency department length of stay compared with the 0/3 h pathway.
Evidence details
What drove the result?
| Outcome | 0/1 h pathway | 0/3 h pathway |
|---|---|---|
| Death or new type 1 MI at 30 days | 341/31,160 (1.1%) | 454/36,464 (1.2%) |
| Coprimary safety outcome · noninferior (aOR 0.93, 95% CI 0.77-1.13) | ||
| ED length of stay (median) | 309 min | 309 min |
| Coprimary efficacy outcome · not shortened (p=0.65) | ||
Limitations & tradeoffs
Representation
conducted only in hospitals that had not yet adopted the 0/1 h pathway, and only 8.7% of presentations had an adjudicated index diagnosis of MI, so results reflect a low-prevalence ED population.
Design limitations
pragmatic cluster design with unblinded treating clinicians (only endpoint adjudication was masked); the in-world abstract is truncated, so ED length-of-stay medians come from the trial summary record.
Structured PICO
Does the 0/1 h pathway reduce emergency department length of stay and prevent 30-day death or new myocardial infarction in adults with suspected myocardial infarction compared to the 0/3 h pathway?
P
Population
67,624 adults presenting to the emergency department with suspected myocardial infarction, evaluated for 30-day outcomes.
I
Intervention
0/1 h pathway (blood draws for high-sensitivity cardiac troponin at 0 h and 1 h)
C
Comparator
0/3 h pathway (blood draws at 0 h and 3 h) as standard care
O
Outcome
Coprimary safety outcome: composite of death from any cause or new type 1 myocardial infarction within 30 days. Coprimary efficacy outcome: emergency department length of stay.composite
Main Result
Odds Ratio: 0.93 (95% CI 0.77–1.13)
Absolute Event Rate: 1.1% vs 1.2%
The guideline-recommended 0/1 h troponin pathway is safe but does not reduce emergency department length of stay compared to the 0/3 h pathway.
Discussion
No takes yet. Share an insight, caveat, or question.
Expert reaction
What experts said about PRESC1SE-MI
The Lancet · ESC Congress 2026
What 4 experts said about this trial's result
1supportive2neutral1cautious
Expert labels are toward PRESC1SE-MI's result, from named public quotes (n=4). As of Aug 30, 2026.
Where experts stand
Experts see the 0/1-hour troponin pathway as safely noninferior to the 0/3-hour pathway, but the failure to shorten ED length of stay surprised many and raises questions about real-world implementation barriers.
Cardiologists broadly accept that the faster troponin pathway is safe, but the headline surprise is that it did not get patients out of the ED any sooner. The trial's lead investigator points to systemic bottlenecks like specialist review, admissions workflow, and bed availability as the likely culprits. The open question is whether the 0/1-hour pathway can deliver on its efficiency promise if hospitals redesign the surrounding processes.
Agreement
Multiple experts note that the 0/1-hour pathway met noninferiority for safety but failed to reduce ED length of stay, framing this as a disconnect between faster testing and real-world throughput.
3 clinicians say this directly
2 takes classified by contention axis so far — the map appears as more land.
Still unclear
Whether redesigning hospital workflows around specialist review, admissions, and bed availability could unlock the ED throughput benefit the 0/1-hour pathway was expected to deliver. It also remains uncertain how the new 2026 ESC Fifth Universal Definition of MI guidelines will position the 0/1-hour pathway given these results.
Key expert perspectives
“At 30 days, a primary safety event occurred in 1.1% of presentations in the 0/1-hour group versus 1.2% in the 0/3-hour group (adjusted OR 0.93, 95% CI 0.77-1.13, P=0.0004 for noninferiority).”
Null CTA results reinforce the need for RCTs over observational hunches
Fonarow uses the trial setting to underscore that the role of imaging cannot be defined by hunches or observational findings, noting that the CTA results in this context were null and calling for rigorous RCT evidence.
Distilled from their postX post
Safety was noninferior but the implementation challenge is the real story
Van Spall highlights that noninferiority was met for safety and ED length of stay was similar across arms. She flags the discussion around trial methods and challenges of implementation trials as particularly notable.
Distilled from their postX post
Implication
0/1 h pathway is noninferior for 30-day safety versus 0/3 h in suspected MI; confirms guideline use without shortening emergency department length of stay.
Abstract
BACKGROUND: The evaluation of patients with suspected myocardial infarction relies on serial measurements of high-sensitivity cardiac troponin. We aimed to evaluate the safety and efficacy of implementing the guideline-recommended 0/1 h pathway, compared with a 0/3 h pathway, in hospitals that had not yet adopted the newer strategy. METHODS: PRESC1SE-MI was an international, pragmatic, stepped-wedge, cluster-randomised, controlled, masked-endpoint trial at 19 hospitals in ten countries. The study included consecutive adults presenting to the emergency department with acute non-traumatic chest discomfort and suspected myocardial infarction. Hospitals using a 0/3 h pathway (blood draws at 0 h and 3 h) as standard care were randomly allocated to implement the 0/1 h pathway (blood draws at 0 h and 1 h) after 6 months (early implementation) or 12 months (late implementation). The trial was designed to test the non-inferiority of the 0/1 h pathway for safety and its superiority for efficacy. The non-inferiority margin was set at an odds ratio of 1·3. Analyses were done in the full analysis set. The coprimary safety outcome was a composite of death from any cause or new type 1 myocardial infarction within 30 days, and the coprimary efficacy outcome was emergency department length of stay. This trial is registered with ClinicalTrials.gov, NCT05649384, and is active but no longer enrolling. FINDINGS: Between Dec 1, 2020, and Dec 31, 2024, 71 983 consecutive patient presentations were screened, of which 67 624 (93·9%) met the eligibility criteria and comprised the full analysis set. Median age was 59 years (IQR 46-73); 29 954 (44·3%) patient presentations were in female patients and 37 670 (55·7%) were in male patients. 13 753 (22·2%) of 62 060 patient presentations with available data were in patients with known coronary artery disease, and 5855 (8·7%) patient presentations had an adjudicated index diagnosis of myocardial infarction. Overall, 36 464 patient presentations were managed with a 0/3 h pathway and 31 160 with the 0/1 h pathway. Death from any cause or new type 1 myocardial infarction occurred in 454 (1·2%) patient presentations in the 0/3 h group and in 341 (1·1%) patient presentations in the 0/1 h group (adjusted odds ratio 0·93 [95% CI 0·77-1·13]; p INTERPRETATION: Implementation of the 0/1 h pathway met the prespecified non-inferiority criterion for the 30-day composite safety outcome but did not shorten emergency department length of stay compared with the 0/3 h pathway. In this setting, implementation of the 0/1 h pathway alone should therefore not be expected to improve emergency department throughput. FUNDING: Swiss National Science Foundation, Swiss Heart Foundation, University Hospital Basel, University of Basel, Foundation for Cardiovascular Research Basel, Fondazione Ricerca Molinette, Idorsia, and Roche.
Coverage & sources
Journal, society, and media accounts. Useful signal, not independent expert judgment.
Cite This Study
Boeddinghaus et al. (2026) conducted an RCT in Suspected myocardial infarction (n=67,624). 0/1 h pathway (blood draws at 0 h and 1 h) vs. 0/3 h pathway (blood draws at 0 h and 3 h) was evaluated on Composite of death from any cause or new type 1 myocardial infarction within 30 days (OR 0.93, 95% CI 0.77-1.13). The 0/1 h pathway met the prespecified non-inferiority criterion for the 30-day composite safety outcome of death or new myocardial infarction compared with the 0/3 h pathway (OR 0.93).