Comparison of SYNTAX score strata effects of percutaneous and surgical revascularization trials: A meta-analysis

Objectives: The evidence supporting the use of the Synergy Between Percutaneous Coronary Intervention With TAXUS and Cardiac Surgery (SYNTAX) score for risk stratification is controversial. We performed a systematic review and meta-analysis of all the randomized controlled trials comparing percutaneous coronary intervention versus coronary artery bypass grafting that reported their outcomes stratified by SYNTAX score, focusing on between-strata comparisons.

Methods: A systematic review of MEDLINE, EMBASE, Cochrane Library databases was performed. Incidence rate ratios were pooled with a random effect model. Between-group statistical heterogeneity according to accepted SYNTAX score tertiles was computed in the main analysis. Ratios of incidence rate ratios were computed to appraise between-strata effect, as sensitivity analysis. Primary and secondary outcomes were major adverse cardiac and cerebrovascular events and all-cause mortality, respectively. Separate sub-analyses were performed for left main and multivessel disease.

Results: From 425 citations, 6 trials were eventually included (8269 patients [4134 percutaneous coronary interventions, 4135 coronary artery bypass graftings]; mean follow-up: 6.2 years [range: 3.8-10]). Overall, percutaneous coronary intervention was associated with a significant increase in major adverse cardiac and cerebrovascular events (incidence rate ratio, 1.39, 95% confidence interval, 1.27-1.51) and nonsignificant increase in all-cause mortality (incidence rate ratio, 1.17, 95% confidence interval, 0.98-1.40). There was no significant statistical heterogeneity of treatment effect by SYNTAX score for major adverse cardiac and cerebrovascular events or mortality (P = .40 and P = .34, respectively). Results were consistent also for patients with left main and multivessel disease (major adverse cardiac and cerebrovascular events: P = .85 in left main, P = .78 in multivessel disease 0.78; mortality: P = .12 in left main; P = .34 in multivessel disease). Results of analysis based on ratios of incidence rate ratios were consistent with the main analysis.

Conclusions: No significant association was found between SYNTAX score and the comparative effectiveness of percutaneous coronary intervention and coronary artery bypass grafting. These findings have implications for clinical practice, future guidelines, and the design of percutaneous coronary intervention versus coronary artery bypass grafting trials.