A review with meta-analysis of observational studies for survival following off-pump coronary artery bypass versus drug-eluting stent implantation

Abstract

To determine whether off-pump coronary artery bypass (OPCAB) improves survival over drug-eluting stent (DES) implantation, we performed a review with meta-analysis of exclusive OPCAB versus DES. Databases including MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials were searched through October 2013 using Web-based search engines (PubMed and OVID). Studies that met the following criteria were considered for inclusion: the design was a randomized controlled trial or observational comparative study; the study population was patients with any coronary artery disease; patients were assigned to OPCAB versus DES and outcomes included all-cause mortality at ≥1 years. Our exhaustive search identified no randomized trial and 10 observational studies of OPCAB versus DES. A pooled analysis demonstrated no statistically significant difference in all-cause mortality between OPCAB and DES (hazard ratio, 0.94; 95% confidence interval, 0.76-1.15; P = 0.55). In general, exclusion of any single study from the analysis did not substantially alter the overall result of our analysis. There was no evidence of significant publication bias. In conclusion, OPCAB may not improve survival over DES despite greater number of treated vessels in OPCAB than in DES or greater number of distal anastomosis in OPCAB than that of implanted stents in DES.

Response to the comment letter about adjustment

“…A meta-analysis of randomized and nonrandomized studies" [1].In the comment letter [2], the authors proposed that our cumulative rate of all-cause death at 3 years from only 3 nonrandomized observational cohort studies [3][4][5] (enrolling a total of 2417 patients) was lower in the off-pump coronary bypass grafting (OPCAB) group than the drug-eluting stent (DES) group (relative risk (RR), 0.56; 95% confidence interval (CI), 0.33 to 0.96; P = 0.03) [1], which seemed discrepant from their results that OPCAB was not associated with improved survival during ≧1 year (range from 1 to 5.5 years) follow-up over DES (hazard ratio (HR), 0.72; 95% CI, 0.45 to 1.17; P = 0.19) in their recent metaanalysis [6]. It was pointed out by the authors that our results were vulnerable to bias because of the crude data extracted from observational studies without any adjustment for significant differences in the baseline characteristics of patients.…”