Immediate versus deferred percutaneous coronary intervention for patients with acute coronary syndrome: A meta-analysis of randomized controlled trials

Inconsistent results exist regarding the treatment effectiveness of immediate versus deferred percutaneous coronary intervention (PCI) in patients with acute coronary syndrome (ACS). This meta-analysis aimed to evaluate the efficacy and safety of immediate versus deferred PCI in ACS patients. PubMed, EMBASE, and Cochrane Library electronic databases were systematically searched from their inception up to August 2019. Random-effects models were employed to calculate pooled relative risks (RRs) and weight mean differences (WMDs) with 95% confidence intervals (CIs). A total of 10 randomized controlled trials (RCTs) that recruited 3350 patients were selected for inclusion in the final meta-analysis. Four trials included patients with non-ST elevation ACS (NSTEACS), whereas the remaining six trials included patients with ST elevation myocardial infarction (STEMI). There were no significant differences between immediate versus deferred PCI for the risk of major adverse cardiovascular events (NSTEACS patients: RR, 0.76, 95%CI, 0.33-1.75, P = 0.513; STEMI patients: RR, 1.24, 95%CI, 0.80-1.92, P = 0.335), myocardial infarction (NSTEACS patients: RR, 0.88, 95%CI, 0.27-2.81, P = 0.826; STEMI patients: RR, 0.86, 95%CI, 0.43-1.74, P = 0.678), all-cause mortality (NSTEACS patients: RR, 0.85, 95%CI, 0.38-1.88, P = 0.686; STEMI patients: RR, 1.16, 95%CI, 0.82-1.66, P = 0.407), target vessel revascularisation (NSTEACS patients: RR, 1.26, 95%CI, 0.29-5.43, P = 0.756; STEMI patients: RR, 1.01, 95%CI, 0.51-1.97, P = 0.988), or major bleeding (NSTEACS patients: RR, 0.99, 95%CI, 0.64-1.54, P = 0.972; STEMI patients: RR, 0.90, 95%CI, 0.45-1.77, P = 0.753). Although patients who underwent immediate PCI may experience increased incidences of cardiac death (RR, 1.19, 95%CI, 0.69-2.07, P = 0.525) and no or slow reflow (RR, 1.60, 95%CI, 0.91-2.84, P = 0.105), these increases were not statistically significant. We noted that immediate versus deferred PCI was associated with a reduced incidence of myocardial brush grade 3 (RR, 0.70, 95%CI, 0.56-0.88, P = 0.002); however, no significant differences were observed between immediate and deferred PCI for TIMI III flow (RR, 0.98, 95%CI, 0.93-1.03, P = 0.453), complete ST-segment resolution (RR, 0.93, 95%CI, 0.75-1.17, P = 0.548), and ejection fraction (WMD, -1.05, 95%CI, -2.58 to 0.49, P = 0.182). The findings of this study suggested that deferred PCI did not yield significant benefits for clinical endpoints. Further large-scale RCTs should be conducted to verify the findings of this study.