Major risk stratification models do not predict perioperative outcome after coronary artery bypass grafting in patients with previous percutaneous intervention.

OBJECTIVE To investigate whether common risk stratification models in cardiac surgery predict perioperative outcome of coronary artery bypass grafting (CABG) in patients with previous percutaneous coronary interventions (PCIs). METHODS We retrospectively analyzed the perioperative mortality and morbidity of 367 patients with prior elective PCI versus 2361 patients without prior PCI, who underwent first-time isolated CABG between 2001 and 2009 at our institution. Receiver operating characteristics (ROC) were used to describe the performance and accuracy of the European System for Cardiac Operative Risk Evaluation (EuroSCORE) and the Society of Thoracic Surgeons (STS) risk model in predicting mortality and morbidity. RESULTS Both groups were comparable concerning preoperative logistic EuroSCORE (PCI: 4.9 ± 6.57, non-PCI: 4.60 ± 5.45, p=0.51). Patients with previous elective PCI had increased perioperative mortality (PCI: 3.8% vs non-PCI: 2.1%, p=0.01) and higher rates of major adverse cardiac events (8.4% vs 4.5% respectively, p=0.003). Discriminatory power for 30-day mortality was higher in the non-PCI group (EuroSCORE area under the curve (AUC): 0.875 vs 0.552 in the PCI group). Logistic EuroSCORE predicted 30-day mortality in the non-PCI group (confidence interval (CI)=0.806-0.934, p=0.0004) but not in the PCI group (CI=0.301-0.765, p=0.8). Discriminatory power for morbidity or mortality (M&M) was lower in the PCI group (AUC: 0.980 vs 0.713 for the non-PCI group). The STS risk model had a lower discriminatory power for predicting M&M in PCI patients (AUC: 0.611 vs 0.686 for the non-PCI group, p<0.001). CONCLUSIONS The EuroSCORE and the STS risk model were inaccurate in predicting perioperative mortality after CABG in patients with history of elective PCI. There is a need for modification of risk models to improve risk assessment for surgical candidates with prior PCI.