Grant: Operating Grant: Industry-partnered Collaborative Research

Stenting during STEMI has become a standard of care in industrialized countries. A primary percutaneous coronary intervention (PCI) typically consists of restoring flow in the occluded coronary artery, after which the culprit lesion is immediately sealed with a stent to prevent a reocclusion of the artery. However, a growing body of evidence suggests that delaying stent implantation may be superior to traditional immediate stenting. During a STEMI, stents are implanted in a thrombotic environment which paradoxically impairs myocardial reperfusion because of distal embolization. The potential drawbacks of immediate stenting should be considered in the context of improved anti-platelet agents and safer systemic anticoagulation which have virtually eliminated the risk of an acute coronary reocclusion. Ideally, stents should be withheld until adjunctive anticoagulation has been administered long enough to reduce the thrombus burden. The primary objective of the PRIMACY trial is to assess whether delayed stenting is superior to immediate stenting at improving cardiovascular outcomes in patients with ST elevation myocardial infarction. We hypothesize that delayed stenting will reduce the combined occurrence of cardiac death, non-fatal myocardial infarction, congestive heart failure, and target vessel revascularization at 9 months. Patients with STEMI successfully reperfused will be randomized to either immediate stenting or to delayed stenting where anticoagulation will be administered for 24 hours before stenting is allowed. The PRIMACY trial will be ran using Bayesian assumptions; an independent board of experts will determine the prior probability of efficacy and will supervise the evolution of the Bayesian monitoring. This trial is critically important because delayed stenting carries the potential to improve survival and quality of life in the large and vulnerable population of Canadian with STEMI who are in the greatest need of more effective therapy.