Immediate vs. delayed stenting in acute myocardial infarction: a systematic review and meta-analysis

Aims: To conduct a meta-analysis of studies comparing immediate versus delayed stenting in populations where primary percutaneous coronary intervention (PCI) or early invasive revascularisation was the initial mode of reperfusion. Methods and results: We identified five non-randomised studies and one randomised trial for a total of 590 patients in studies comparing immediate to delayed stenting in populations where primary PCI or early invasive revascularisation was the initial mode of reperfusion. In non-randomised studies, delayed stenting was associated with a reduction of procedure-related angiographic events (OR=0.13, 95% credible interval [CrI]: 0.03-0.36). No differences were observed in the rates of major bleeding (OR=0.81, 95% CrI: 0.01-13.42) and major adverse cardiac events (OR=0.40, 95% CrI: 0.09-1.91), between delayed and immediate stenting. In one randomised trial, delayed stenting was associated with a reduction in myocardial infarction during hospitalisation (39% vs. 60%; relative risk [RR]=0.55, 95% confidence interval [CI]: 0.39-0.80). None of the patients assigned to delayed stenting experienced a major adverse cardiac event in the interval between the initial angiogram and the stenting. Conclusions: Delayed stent implantation is associated with better angiographic outcomes. Randomised trials are required to assess whether delayed stenting translates into better long-term cardiac outcomes.