Immediate vs Delayed Stenting in ST-Elevation Myocardial Infarction: Rationale and Design of the International
E Marc Jolicoeur1, Nandini Dendukuri2, Patrick Belisle3
1Montreal Heart Institute, Université de Montréal, Montréal, Québec, Canada.
Insights
Delayed stenting may improve outcomes for ST-elevation myocardial infarction (STEMI) patients by reducing cardiovascular events. This strategy contrasts with immediate stenting, aiming to prevent complications from thrombus-laden arteries.
Area of Science:
- Cardiology
- Interventional Cardiology
- Clinical Trials
Background:
- Primary percutaneous coronary intervention (PCI) restores blood flow but immediate stenting in thrombus-laden arteries can cause embolization, impairing reperfusion.
- The benefit of delayed stenting versus immediate stenting in ST-elevation myocardial infarction (STEMI) remains uncertain.
Purpose of the Study:
- To compare outcomes of delayed versus immediate stenting in STEMI patients.
- To assess the prevention of cardiovascular death, myocardial infarction, heart failure, or revascularization at 9 months.
Main Methods:
- The Primary Reperfusion Secondary Stenting (PRIMACY) trial is a Bayesian prospective, randomized, open-label, blinded endpoint study.
- Participants with STEMI were randomized to immediate stenting or delayed stenting (24-48 hours) bridged with antithrombin therapy.
- Bayesian analysis will combine PRIMACY data with existing trials (DEFER, MIMI, DANAMI-3, INNOVATION) for robust efficacy assessment.
Main Results:
- 305 participants were randomized across 15 centers in France and Canada (April 2014-September 2017).
- Baseline characteristics included a median age of 59 years, 81% male, and 3% prior PCI history.
- Results will be updated with patient-level data from 1568 participants in four prior trials.
Conclusions:
- The study aims to determine if delayed stenting safely reduces adverse cardiovascular endpoints compared to immediate stenting in STEMI patients.
- Clarifying the optimal stenting strategy is crucial for improving STEMI patient outcomes.
Background:
Primary percutaneous coronary intervention is used to restore blood flow in the infarct-related coronary artery, followed by immediate stenting to prevent reocclusion. Stents implanted in thrombus-laden arteries cause distal embolization, which paradoxically impairs myocardial reperfusion and ventricular function. Whether a strategy of delayed stenting improves outcomes in patients with acute ST-elevation myocardial infarction (STEMI) is uncertain.
Methods:
The Primary Reperfusion Secondary Stenting (PRIMACY) is a Bayesian prospective, randomized, open-label, blinded end point trial in which delayed vs immediate stenting in patients with STEMI were compared for prevention of cardiovascular death, nonfatal myocardial infarction, heart failure, or unplanned target vessel revascularization at 9 months. All participants were immediately reperfused, but those assigned to the delayed arm underwent stenting after an interval of 24 to 48 hours. This interval was bridged with antithrombin therapy to reduce thrombus burden. In the principal Bayesian hierarchical random effects analysis, data from exchangeable trials will be combined into a study prior and updated with PRIMACY into a posterior probability of efficacy.
Results:
A total of 305 participants were randomized across 15 centres in France and Canada between April 2014 and September 2017. At baseline, the median age of participants was 59 years, 81% were male, and 3% had a history of percutaneous coronary intervention. Results from PRIMACY will be updated from the patient-level data of 1568 participants enrolled in the Deferred Stent Trial in STEMI (DEFER; United Kingdom), Minimalist Immediate Mechanical Intervention (MIMI; France), Danish Trial in Acute Myocardial Infarction-3 (DANAMI-3; Denmark), and Impact of Immediate Stent Implantation Versus Deferred Stent Implantation on Infarct Size and Microvascular Perfusion in Patients With ST Segment-Elevation Myocardial Infarction (INNOVATION, South Korea) trials.
Conclusions:
We expect to clarify whether delayed stenting can safely reduce the occurrence of adverse cardiovascular end points compared with immediate stenting in patients with STEMI.
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