EuroSCORE overestimates the risk of cardiac surgery: results from the national registry of the German Society of Thoracic and Cardiovascular Surgery

The EuroSCORE risk stratification model has been developed in 1995 and is still widely used to assess individual patient risk prior to cardiac surgery. Furthermore, the score advanced to a decision tool to determine so-called "high-risk patients" and in consequence serves as an important selection criterion in new technologies, such as the catheter-based aortic valve replacement. Several studies with relatively small patient numbers showed a substantial overestimation of risk by the EuroSCORE. The aim of our study was to evaluate whether the nationwide data support this finding. A subgroup of the registry of the German Society of Thoracic and Cardiovascular Surgery from 2006 and 2007, with 32,806 patients undergoing isolated coronary surgery and isolated aortic valve replacement was investigated. The overall hospital mortality in isolated coronary surgery in this patient cohort (n = 26,501 patients) was 2.6% (n = 695). The overall hospital mortality in isolated aortic valve replacement in this patient cohort (n = 6,305 patients) was 3.9% (n = 245). The logistic EuroSCORE predicted a proportion of 5.2% for patients with isolated CABG and 7.3% for patients with isolated aortic valve replacement. The area under the receiver operating characteristic curve was 0.77 for isolated CABG procedures and 0.69 for isolated valve procedures, supporting the substantial lack of predictive value of the EuroSCORE. The logistic EuroSCORE insufficiently evaluates the risk of the current patient population and therefore should be carefully used as a tool for important therapeutic decision-making.