Introduction: Prolonged intensive care unit (ICU) stay contributes to increased cost and resource utilization in cardiac surgery [1,2]. The aim of this study was to evaluate prediction of outcome, i.e. 30 day mortality, and postoperative duration of ICU stay in patients undergoing off-pump coronary artery bypass grafting (OPCABG) using the European System of Cardiac Operative Risk Evaluation (EuroSCORE) .
Method: From Jan 1st, 2001 to Dec 31st, 2002 398 patients underwent OPCABG in our institution (78% of all isolated CABG procedures performed during this period). Patients were scored using the simple additive EuroSCORE. 30-day mortality and duration of ICU stay were recorded. The discriminative power of the score was assessed by calculating the area under the receiver operating characteristic curve (ROC). P < 0.05 was considered significant.
Results: EuroSCORE was 4.6 ± 3.6 for these patients (age = 64.3 ± 9.7 years, female/male ratio = 89/309, ejection fraction = 58.1 ± 15.3%). The preoperative risk profile was equally distributed (low risk [EuroSCORE 0-2] = 30.4%, medium risk [EuroSCORE 3-5] = 33.4% and high risk group [EuroSCORE > 6] = 36.2%). Predicted 30-day mortality was 5.3%, observed 30-day mortality was 1.5% (6 death during follow-up period). ROC for EuroSCORE to predict mortality was 66% (P = 0.17; i.e. no significant difference from 0-hypothesis: ROC area = 50%). Duration of ICU stay was 1.7 ± 1.4dy. ICU stay and EuroSCORE correlated positively (Pearson correlation coefficient [r] = 0.48, P < 0.001). ROC to predict ICU stay >1 dy was 66.3% (P < 0.001). For ICU stay >2dy ROC was 74.8% (P < 0.001), for >3dy, >4dy and >5dy 80.2%, 90.4%, and 91.7% (P < 0.01).
Discussion: The power of EuroSCORE to predict mortality in this sample of patients undergoing OPCABG was weak. By contrast, discriminative power to predict prolonged postoperative ICU stay was good. Use of the score might allow for more efficient allocation and thus cost reduction.
1 Hamilton A, Norris C, Wensel R, et al. Cost reduction in cardiac surgery. Can J Cardiol
2 Pinna Pintor P, Bobbio M, Colangelo S, et al. Can EuroSCORE predict direct costs of cardiac surgery? Eur J Cardiothorac Surg
3 Nashef SA, Roques F, Michel P, et al. European system for cardiac operative risk evaluation (EuroSCORE). Eur J Cardiothorac Surg