Background: The comparative effectiveness of coronary artery bypass grafting surgery (CABG) and percutaneous coronary interventions (PCI) is an open question for those patients in which both procedures are technically feasible and whose coronary artery disease (CAD) is neither too limited nor too extensive (e.g., single-vessel disease of the proximal left anterior descending (LAD) artery, most forms of double-vessel CAD, and less extensive forms of triple-vessel CAD). The purpose of this study is to evaluate the evidence for the comparative effectiveness of PCI and CABG in this group of patients.
Methods: We sought RCTs that compared survival and other health outcomes for PCI and CABG patients with angiographically-proven CAD. We performed individualized searches of relevant databases (Medline, Embase, and Cochrane from 1966 to 2006). We reviewed bibliographies of retrieved articles and relevant conference proceedings to obtain additional citations. We excluded trials that compared either PCI with medical therapy or CABG with medical therapy, unless the trial involved a three-way randomization to PCI, CABG, and medical therapy and reported a randomized comparison of PCI with CABG. We calculated weighted mean differences and odds ratios using random effects models.
Results: We identified 22 RCTs that enrolled a total of 9,640 patients. The baseline clinical characteristics of trial participants were typical of patients with CAD. The absolute risk difference in procedural mortality was not statistically significant ( 0.1%; 95% CI: -0.3% to +0.6%). There were no significant differences in procedural mortality when trials were sub-divided into balloon-era and stent-era studies, or into single-vessel disease and multivessel disease patient populations. Procedural strokes were significantly more common after CABG than after PCI (risk difference 0.6%; 95% CI: +0.2% to +1%; p=0.01). Long-term survival across all randomized trials between one and five years of follow-up was similar in CABG-assigned and PCI-assigned patients, with less than 1% absolute risk difference at each time point (not statistically significant). There was no difference in the comparative survival benefit when RCTs were sub-divided into those enrolling patients with single-vessel proximal LAD disease and those enrolling patients with multi-vessel disease. There was also no difference in comparative effectiveness between balloon-era trials or stent-era trials. Survival in patients with diabetes was reported by six trials: the pooled risk difference was 0.8% at five years (95%CI: +8.3% to -6.6%). Similarly, there was no evidence of an interaction with treatment assignment for hypertension, tobacco use, renal dysfunction or vascular disease. Angina relief was significantly greater after CABG than after PCI at all intervals post-procedure (risk difference ranges from 5% to 8%; p value
Conclusions: Although survival was not significantly different between procedures, CABG recipients had more procedural strokes, less angina, and fewer revascularization procedures. The extent to which these results vary according to patient characteristics has not been adequately addressed by RCTs.