Deferred versus conventional stent implantation in patients with acute ST-segment elevation myocardial infarction: An updated meta-analysis of 10 studies.

Background: We sought to evaluate safety and efficacy of the deferred stenting versus immediate stent implantation of infarct-related arteries in patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI).

Methods: A meta-analysis using random-effects models were conducted. The primary outcome, major adverse cardiac events (MACE), was a composite of all-cause mortality, myocardial infarction (MI), any unplanned target vessel revascularization (TVR), and hospitalization due to cardiac cause. Periprocedural composite events were composed of acute re-occlusion, no-reflow/slow flow, or distal embolization.

Results: Seven non-randomized registries and three randomized trials comparing outcomes of deferred versus immediate stenting in infarct-related arteries of 2281 STEMI patients were selected. Risk of MACE between deferred or immediate stenting did not differ significantly (rates, 12.8% vs 15.0%; pooled RR=0.68, 95% CI: 0.43-1.06; p=0.087; I=26.8%). Deferred stenting was associated with significantly reduced risk of periprocedural composite events (rates, 5.3% vs 10.2%; pooled RR=0.36, 95% CI: 0.18-0.69; p=0.002; I=68.0%) and flow abnormality in infarct-related arteries (rates, 3.8% vs 8.4%; pooled RR=0.29, 95% CI: 0.14-0.61; p=0.001; I=58.1%). However, clinical outcomes including all-cause mortality, MI, or any unplanned TVR, were unaffected. Meta-regression indicated a significant relationship between prolonged total ischemic and reduced risk of MACE after deferred stenting (OR=0.994, 95% CI: 0.990-0.998; p=0.027; I residual 0.0%, adjusted R=100.0%).

Conclusions: Although deferred stenting carried significantly lower risk of periprocedural composite events and abnormal flow in patients undergoing primary PCI for STEMI, such benefits had no impact on MACE, which did not differ significantly by timing of stent placement.