Eur J Cardiothorac Surg 2000 Apr;17(4):400-6 Free
Full Text Reprint (Adobe PDF, 191kb)
Risk stratification in heart surgery: comparison of six
score systems.
Geissler HJ, Holzl P, Marohl S, Kuhn-Regnier F, Mehlhorn U, Sudkamp M, de
Vivie ER.
Department of Cardiothoracic Surgery, University of Cologne, Joseph-Stelzmann-Strasse
9, 50924, Cologne, Germany. hans.geissler@medizin.uni-koeln.de
OBJECTIVE: Risk scores have become an important tool in patient assessment, as
age, severity of heart disease, and comorbidity in patients undergoing heart
surgery have considerably increased. Various risk scores have been developed
to predict mortality after heart surgery. However, there are significant
differences between scores with regard to score design and the initial patient
population on which score development was based. It was the purpose of our
study to compare six commonly used risk scores with regard to their validity
in our patient population. METHODS: Between September 1, 1998 and February 28,
1999, all adult patients undergoing heart surgery with cardiopulmonary bypass
in our institution were preoperatively scored using the initial Parsonnet,
Cleveland Clinic, French, Euro, Pons, and Ontario Province Risk (OPR) scores.
Postoperatively, we registered 30-day mortality, use of mechanical assist
devices, renal failure requiring hemodialysis or hemofiltration, stroke,
myocardial infarction, and duration of ventilation and intensive care stay.
Score validity was assessed by calculating the area under the ROC curve. Odds
ratios were calculated to investigate the predictive relevance of risk
factors. RESULTS: Follow-up was able to be completed in 504 prospectively
scored patients. Receiver operating characteristics (ROC) curve analysis for
mortality showed the best predictive value for the Euro score. Predictive
values for morbidity were considerably lower than predictive values for
mortality in all of the investigated score systems. For most risk factors,
odds ratios for mortality were substantially different from ratios for
morbidity. CONCLUSIONS: Among the investigated scores, the Euro score yielded
the highest predictive value in our patient population. For most risk factors,
predictive values for morbidity were substantially different from predictive
values for mortality. Therefore, development of specific morbidity risk scores
may improve prediction of outcome and hospital cost. Due to the heterogeneity
of morbidity events, future score systems may have to generate separate
predictions for mortality and major morbidity events.