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.
Keywords
coronary artery bypass grafts surgery - CABG - Off-Pump surgery - cardiac
