Coronary atherosclerotic burden assessed by SYNTAX scores and outcomes in surgical, percutaneous or medical strategies: a retrospective cohort study

Introduction Coronary atherosclerotic burden and SYNTAX Score (SS) are predictors of cardiovascular events. Objectives To investigate the value of SYNTAX scores (SS, SYNTAX Score II (SSII) and residual SYNTAX Score (rSS)) for predicting cardiovascular events in patients with coronary artery disease (CAD). Design Retrospective cohort study. Setting Single tertiary centre. Participants Medicine, Angioplasty or Surgery Study database patients with stable multivessel CAD and preserved ejection fraction. Interventions Patients with CAD undergoing coronary artery bypass graft (CABG), percutaneous coronary intervention (PCI) or medical treatment (MT) alone from January 2002 to December 2015. Primary and secondary outcomes Primary: 5-year allcause mortality. Secondary: composite of all-cause death, myocardial infarction, stroke and subsequent coronary revascularisation at 5 years. Results A total of 1719 patients underwent PCI (n=573), CABG (n=572) or MT (n=574) alone. The SS was not considered an independent predictor of 5-year mortality in the PCI (low, intermediate and high SS at 6.5%, 6.8% and 4.3%, respectively, p=0.745), CABG (low, intermediate and high SS at 5.7%, 8.0% and 12.1%, respectively, p=0.194) and MT (low, intermediate and high SS at 6.8%, 6.9% and 6.5%, respectively, p=0.993) cohorts. The SSII (low, intermediate and high SSII at 3.6% vs 7.9% vs 10.5%, respectively, p<0.001) was associated with a higher mortality risk in the overall population. Within each treatment strategy, SSII was associated with a significant 5-year mortality rate, especially in CABG patients with higher SSII (low, intermediate and high SSII at 1.8%, 9.7% and 10.0%, respectively, p=0.004) and in MT patients with high SSII (low, intermediate and high SSII at 5.0%, 4.7% and 10.8%, respectively, p=0.031). SSII demonstrated a better predictive accuracy for mortality compared with SS and rSS (c-index=0.62). Conclusions Coronary atherosclerotic burden alone was not associated with significantly increased risk of all-cause mortality. The SSII better discriminates the risk of death.