Preoperative hepatic dysfunction could predict postoperative mortality and morbidity in patients undergoing cardiac surgery: Utilization of the MELD scoring system

BACKGROUND: According to recent advances in operative techniques, an increasing number of patients with liver dysfunction have been subjected to cardiac surgery. Model of End-Stage Liver Disease (MELD and MELD-XI) scores allow risk stratification of patients undergoing cardiac and non-cardiac surgeries. METHODS: We retrospectively analyzed 1856 consecutive patients (69.3% male, mean 66.8 ± 12.2 years) undergoing cardiac surgery between 2008 and 2013 at our institution. RESULTS: The mean values of MELD/MELD-XI scores obtained from the total cohort were 9.7 ± 4.6/11.9 ± 4.8. Patients with high MELD/MELD-XI scores (>12) were older, more anemic, and had lower left ventricular ejection fraction than those with low scores (all p<0.0001). High scores were associated with longer hospitalization (36.8 ± 33.0 vs. 23.6 ± 21.5 days for MELD, 36.7 ± 34.0 vs. 23.5 ± 21.0 days for MELD-XI, both p<0.0001) and higher in-hospital all-cause mortality (6.6% vs. 1.0% for MELD, 7.7% vs. 0.7% for MELD-XI). Atrial fibrillation occurred more frequently in the high MELD group, but this difference was not found for MELD-XI. MELD/MELD-XI could predict mortality with a sensitivity of 64.3%/60.0% and specificity of 79.1%/85.3%. Comparison of AUC values among MELD scores, individual MELD components, and Child-Turcotte-Pugh (CTP) classification showed that the predictive strength of MELD scores for mortality was stronger than individual parameters or CTP classification (AUC: 0.7702 for MELD, 0.7655 for MELD-XI, 0.5799 for CTP classification with pairwise p<0.0001 and p=0.0002 vs. MELD and MELD-XI, respectively). CONCLUSIONS: Assessment of liver dysfunction using the MELD scores can be useful for predicting postoperative morbidity and mortality, which may allow additional risk stratification in patients undergoing cardiac surgery.