Comparative application of multivariate models developed in Italy and Europe to predict early (28 days) and late (1 year) postoperative death after on- or off-pump coronary artery bypass grafting.

ABSTRACT

OBJECTIVES: The aim of this study was to compare the risk of death predictive performances of the OP-RISK, EuroSCORE, and Italian coronary artery bypass grafting (CABG) Outcome studies' functions when applied to a southern Italian cardiac surgery center (Sant'Anna hospital in Catanzaro [SAHCZ]), which contributed data to the Italian CABG Outcome study, and to see if this predictive index may be applied to on- and off-pump interventions. METHODS: The OP-RISK study data set was used to derive Weibull and logistic functions to predict early (28 days) and late (1 year) death rates following CABG based on ejection fraction, heart rate, age, and aortic cross-clamping time. Then the data of 385 CABG patients who underwent operations in 2003 in SAHCZ were collected with 1-year follow-up data, which also included data used to obtain EuroSCORE and Italian CABG Outcome study risk indices. RESULTS: Short- and long-term observed mortality rates after CABG were 2.59% and 5.88% in the SAHCZ series, largely dependent on whether CABG was alone (1.26% and 3.55%) or associated with ventriculoplasty (4.87% and 10.81%) or valve surgery (15.38% and 28.57%). There was a significant increasing trend (P = .002) of observed death rates in equinumeric tertiles of either OP-RISK (both Weibull and logistic) or EuroSCORE in the short term, whereas the trend was not significant for the Italian CABG Outcome study index. OP-RISK functions were significantly predictive for the long term (P < .005), as well as when only ejection fraction, heart rate, and age were considered (P < .011). CONCLUSIONS: It is essential to use clinical data following CABG when outcome prediction is concerned. OP-RISK and EuroSCORE indices are equally predictive in our experience, and a statistically significant (P = 0.02) difference was observed with the Italian CABG Outcome study index, whose trend in tertiles of calculated risk was not apparent, which is unexpected and unexplained. OP-RISK functions were adequate for long-term prediction. Since aortic cross-clamping time may be absent from tested predictive functions (for both short and long term), off-pump CABG mortality may also be predicted as similar to on-pump intervention mortality.