Off-Pump Reduces Risk of Coronary Bypass Grafting in Patients with High MELD-XI Score

Abstract

Background: This study aimed to assess the influence of the model of end-stage liver disease without International Normalized Ratio (INR) (MELD-XI) score on outcomes after elective coronary artery bypass surgery (CABG) without (Off-Pump) or with (On-Pump) cardiopulmonary bypass.

Methods: We calculated MELD-XI (5.11 × ln serum bilirubin + 11.76 × ln serum creatinine in + 9.44) for 3,535 consecutive patients having undergone elective CABG between 2009 and 2020. A MELD-XI threshold was determined using the Youden Index based on receiver operating characteristics. Propensity score matching and logistic regression was performed to identify risk factors for inhospital mortality and Major Adverse Cardiac and Cerebrovascular Event (MACCE).

Results: Patients were 68 ± 10 years old (76% male). Average MELD-XI was 10.9 ± 3.25. The MELD-XI threshold was 11. Patients below this threshold had somewhat lower EuroSCORE II than those above (3.5 ± 4 vs. 4.1 ± 4.7, p < 0.01), but mortality was almost four times higher above the threshold (below 1.5% vs. above 6.2%, p < 0.001). Two-thirds of patients received Off-Pump CABG. There was a trend towards higher risk in Off-Pump patients. Mortality was numerically but not statistically different to On-Pump below the MELD XI threshold (1.3 vs. 2.2%, p = 0.34) and was significantly lower above the threshold (4.9 vs. 8.9%, p < 0.02). Off-Pump above the threshold was also associated with less low-output syndrome and fewer strokes. Equalizing baseline differences by propensity matching verified the significant mortality difference above the threshold. Multivariable regression analysis revealed MELD-XI, On-Pump, atrial fibrillation, and the De Ritis quotient (Aspartate aminotransferase (ASAT)/Alanine Aminotransferase (ALAT)) as independent predictors of mortality.

Conclusion: Elective CABG patients with elevated MELD-XI scores are at increased risk for perioperative mortality and morbidity. This risk can be significantly mitigated by performing CABG Off-Pump.