Coronary surgery in Europe: comparison of the national subsets of the European System for Cardiac Operative Risk Evaluation database

OBJECTIVE: To compare the national samples of patients who underwent isolated coronary artery bypass grafting (CABG) during the European System for Cardiac Operative Risk Evaluation (EuroSCORE) trial in order to evaluate national differences in epidemiology, patient risk profile and surgical methods. METHODS: From September to November 1995, 11731 patients had CABG in the six largest contributing nations to the EuroSCORE project: Germany, UK, Spain, Finland, France and Italy. The Chi-square and Kruskal-Wallis tests were applied to obtain an international comparison of patient general status, including pre-operative risk factors, cardiac status, critical pre-operative states, rare conditions, urgency of surgery, angina status, coronary lesions, procedures and EuroSCORE risk assessment. RESULTS: Large national samples (from 984 patients in Finland to 3138 in Germany) identified significant differences in epidemiology, risk profile and surgical practice. Regarding epidemiology, CABG accounted for 62.8% of adult cardiac surgery, with a range of 46.2 in Spain to 77.7% in Finland (P<0.001). The mean age was 62.9 years (61.4 in Britain to 64.4 in France, P<0.001). The mean body mass index was 26.8 (26 in France to 27.5 in Finland, P<0.001). With regard to risk profile, diabetes was present in 20.3% of patients (11.8% in Britain to 27.7% in Spain, P<0.001). Chronic renal failure was present in 8.3% (6.8% in Germany to 10.6% in Spain, P<0.001). Chronic airway disease affected 3.8% (1.9% in Italy to 5. 1% in Germany, P<0.001). The mean ejection fraction was 0.56 (0.48 in Britain to 0.58 in Finland, P<0.001). The mean predicted mortality (according to EuroSCORE) was 3.3% (2.8% in Finland to 3.6% in France, P<0.001). The prevalence of chronic congestive heart failure, unstable angina and recent myocardial infarction also showed statistically significant differences. No differences were found for some critical preoperative states (such as immediate preoperative cardiac massage and pre-operative intubation), or for surgery for catheter laboratory complication. Regarding surgical practice, major differences were noted in preoperative intra-aortic balloon use (mean 1%, Finland 0%, Spain 2.3%, P<0.001), the number of mammary artery conduits used (mean 0.9, Spain 0.7, France 1.1, P=0.0001) and the number of distal anastomoses (mean 3, France 2.7, Finland 3.8, P=0.001). CONCLUSION: There are important epidemiological differences in the national cohorts of CABG patients in the EuroSCORE database. Any international comparison of European surgical results must therefore take into account the risk profile of patients by using a compatible risk stratification system.