Short-term independent mortality risk factors in patients with cirrhosis undergoing cardiac surgery

Cirrhosis represents a serious risk in patients undergoing cardiac surgery. Several preoperative factors identify cirrhotic patients as high risk for cardiac surgery; however, a patient's preoperative status may be modified by surgical intervention and, as yet, no independent postoperative mortality risk factors have been identified in this setting. The objective of this study was to identify preoperative and postoperative mortality risk factors and the scores that are the best predictors of short-term risk.

Fifty-eight consecutive cirrhotic patients requiring cardiac surgery between January 2004 and January 2009 were prospectively studied at our institution. Forty-two (72%) patients were operated on for valve replacement, 9 (16%) for a CABG and 7 (12%) for both (CABG and valve replacement). Thirty-four (58%) patients were classified as Child-Turcotte-Pugh class A, 21 (36%) as class B and 3 (5%) as class C. We evaluated the variables that are usually measured on admission and during the first 24 h of the postoperative period together with potential operative predictors of outcome, such as cardiac surgery scores (Parsonnet, EuroSCORE), liver scores (Child-Turcotte-Pugh, model for end-stage liver disease, United Kingdom end-stage liver disease score) and ICU scores (acute physiology and chronic health evaluation II and III, simplified acute physiology score II and III, sequential organ failure assessment).

Seven patients (12%) died in-hospital, of whom 5 were Child-Turcotte-Pugh class B and 2 class C. Comparing survivors vs non-survivors, univariate analysis revealed that variables associated with short-term outcome were international normalized ratio (1.5 ± 0.24 vs 2.2 ± 0.11, P < 0.0001), presurgery platelet count (171 ± 87 vs 113 ± 52 l nl(-1), P = 0.031), presurgery haemoglobin count (11.8 ± 1.8 vs 10.2 ± 1.4 g dl(-1), P = 0.021), total need for erythrocyte concentrates (2 ± 3.4 vs 8.5 ± 8 units, P < 0.0001), PaO(2)/FiO(2) at 12 h after ICU admission (327 ± 84 vs 257 ± 78, P = 0.04), initial central venous pressure (11 ± 3 vs 16 ± 4 mmHg, P = 0.02) and arterial blood lactate concentration 24 h after admission (1.8 ± 0.5 vs 2.5 ± 1.3 mmol l(-1), P = 0.019). Multivariate analysis identified initial central venous pressure as the only independent factor associated with short-term outcome (P = 0.027). The receiver operating characteristic curve showed that the model for end-stage Liver disease score had a better predictive value for short-term outcome than other scores (AUC: 90.5 ± 4.4%; sensitivity: 85.7%; specificity: 83.7%), although simplified acute physiology score III was acceptable.

We conclude that central venous pressure could be a valuable predictor of short-term outcome in patients with cirrhosis undergoing cardiac surgery. The model for end-stage liver disease score is the best predictor of cirrhotic patients who are at high risk for cardiac surgery. Sequential organ failure assessment and simplified acute physiology score III are also valuable predictors.