Geographic disparity in 10-year mortality after coronary artery revascularization in the SYNTAXES trial

Abstract Aims To investigate geographic disparity in long-term mortality following revascularization in patients with complex coronary artery disease (CAD). Methods and results The SYNTAXES trial randomized 1800 patients with three-vessel and/or left main CAD to percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) and assessed their survival at 10-years. Patients were stratified according to the region of recruitment: North America (N-A, n=245), Eastern Europe (E-E: Poland, Hungary, Czech, n=189), Northern Europe (N-E: United Kingdom, Sweden, Norway, Latvia, Finland, and Denmark, n=425), Southern Europe (S-E: Spain, Portugal, and Italy, n=263), and Western Europe (W-E: Netherlands, Germany, France, Belgium, and Austria, n=678), which also served as the reference group. Compared to W-E, patients were younger in E-E (62 vs 65 years, p<0.001), and less frequently male in N-A (65.3% vs 79.6%, p<0.001). Diabetes (16.0% vs 25.4%, p<0.001) and peripheral vascular disease (6.8% vs 10.9%, p=0.025) were less frequent in N-E than W-E. Ejection fraction was highest in W-E (62% vs 56%, p<0.001). Compared to W-E, the mean anatomic SYNTAX score was higher in S-E (29 vs 31, p=0.008) and lower in N-A (26, p<0.001). Crude ten-year mortality was similar in N-A (31.6%), and W-E (30.7%), and significantly lower in E-E (22.5%, p=0.041), N-E (21.9%, p=0.003) and S-E (22.0%, p=0.014) as presented in left-middle lower of the graphical abstract. We adjusted the survival curves by following factors based on previous report; age, sex, medically treated diabetes, current smokers, peripheral vascular disease, chronic obstructive pulmonary disease, chronic kidney disease, left ventricular ejection fraction, disease type, and anatomical SYNTAX score [1]. When the differences in baseline characteristics were adjusted, mortality was still significantly lower in N-E (HR 0.85, 95% CI [0.74–0.97], p=0.019) and trended lower in S-E (HR 0.72 95% CI [0.52–0.99] p=0.043) compared to W-E (right middle-lower of the graphical abstract). However, no significant interaction (P interaction = 0.728) between region and modality of revascularization was seen. Discussion and conclusions The main findings of this study are: 1. Rates of crude 10-year mortality were significantly lower in E-E, N-E, and S-E compared to W-E and N-A. 2. The differences in 10-year mortality remained significantly lower with N-E and S-E even after adjustment for confounding factors. 3. However, when comparing PCI to CABG in the five geographic regions, there were no statistically significant interactions between the geographic disparity in pre- and peri-procedural characteristics and all-cause mortality. In the era of globalization, knowledge and understanding of geographic disparity are of paramount importance for the correct interpretation of global studies. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): The German Foundation of Heart Research (Frankfurt am Main, Germany)