Meta-analysis: Effects of Percutaneous Coronary Intervention Versus Medical Therapy on Angina Relief

BACKGROUND: Several meta-analyses have evaluated the efficacy of percutaneous coronary intervention (PCI) compared with medical therapy, but none has focused on angina relief. PURPOSE: To summarize the evidence on the degree of angina relief from PCI compared with medical therapy in patients with stable coronary artery disease. DATA SOURCES: The Cochrane Library (1993 to June 2009), EMBASE (1980 to June 2009), and MEDLINE (1950 to June 2009), with no language restrictions. STUDY SELECTION: Two independent reviewers screened citations to identify randomized, controlled trials of PCI versus medical therapy in patients with stable coronary artery disease. DATA EXTRACTION: Two independent reviewers abstracted data on patient characteristics, study conduct, and outcomes. A random-effects model was used to combine data on freedom from angina and to perform stratified analyses based on duration of follow-up, inclusion of patients with recent myocardial infarction, coronary stent utilization, recruitment period, and utilization of evidence-based medications. DATA SYNTHESIS: A total of 14 trials, enrolling 7818 patients, met the inclusion criteria. Although PCI was associated with an overall benefit on angina relief (odds ratio, 1.69 95% CI, 1.24 to 2.30), important heterogeneity across trials was observed. The incremental benefit of PCI observed in older trials (odds ratio, 3.38 CI, 1.89 to 6.04) was substantially less and possibly absent in recent trials (odds ratio, 1.13 CI, 0.76 to 1.68). An inverse relationship between use of evidence-based therapies and the incremental benefit of PCI was observed. LIMITATIONS: Information about the long-term use of medication was incomplete in most trials. Few trials used drug-eluting stents. Meta-regression analyses used aggregated study-level data from few trials. CONCLUSION: Percutaneous coronary intervention was associated with greater freedom from angina compared with medical therapy, but this benefit was largely attenuated in contemporary studies. This observation may be related to greater use of evidence-based medications in contemporary trials. PRIMARY FUNDING SOURCE: Canadian Institutes of Health Research.