BACKGROUND: Major liver resection for perihilar cholangiocarcinoma (PHC) is associated with a 22% to 33% postoperative liver failure incidence. The aim of this study was analyze the predictive value of future liver remnant (FLR) volume for postoperative liver failure after resection for PHC and to develop a risk score to improve patient selection for portal vein embolization. STUDY DESIGN: A consecutive series of 217 patients underwent major liver resection for PHC between 1997 and 2014 at 2 Western centers; FLR volumes were calculated with CT volumetry; other variables included jaundice at presentation, immediate preoperative bilirubin, and preoperative cholangitis. The FLR volume was categorized as 45%. A risk score for postoperative liver failure (grade B/C according to the International Study Group of Liver Surgery criteria) was developed using multivariable logistic regression with 5 predefined variables. RESULTS: Postoperative liver failure incidence was 24% and liver failure-related mortality was 12%. Risk factors for liver failure were FLR volume 50 μmol/L (>2.9 mg/dL) (odds ratio 4.3; 95% CI 1.7 to 10.7), and preoperative cholangitis (odds ratio 3.4; 95% CI 1.6 to 7.4) were risk factors for liver failure. These variables were included in a risk score that showed good discrimination (area under the curve 0.79; 95% CI 0.72 to 0.86) and ranking patients in 3 risk sub-groups with predicted liver failure incidence of 4%, 14%, and 44%. CONCLUSIONS: The selection of patients for portal vein embolization using only liver volume is insufficient, considering the other predictors of liver failure in PHC patients. The proposed risk score can be used for selection of patients for portal vein embolization, for adequate patient counseling, and identification of other modifiable risk factors besides liver volume.

Significance: Hepatic ischemia/reperfusion (I/R) injury is an inevitable side effect of major liver surgery that can culminate in liver failure. The bulk of I/R-induced liver injury results from an overproduction of reactive oxygen and nitrogen species (ROS/RNS), which inflict both parenchymal and microcirculatory damage. A structure that is particularly prone to oxidative attack and modification is the glycocalyx (GCX), a meshwork of proteoglycans and glycosaminoglycans (GAGs) that covers the lumenal endothelial surface and safeguards microvascular homeostasis. ROS/RNS-mediated degradation of the GCX may exacerbate I/R injury by, for example, inducing vasoconstriction, facilitating leukocyte adherence, and directly activating innate immune cells. Recent Advances: Preliminary experiments revealed that hepatic sinusoids contain a functional GCX that is damaged during murine hepatic I/R and major liver surgery in patients. There are three ROS that mediate GCX degradation: hydroxyl radicals, carbonate radical anions, and hypochlorous acid (HOCl). HOCl converts GAGs in the GCX to GAG chloramides that become site-specific targets for oxidizing and reducing species and are more efficiently fragmented than the parent molecules. In addition to ROS/RNS, the GAG-degrading enzyme heparanase acts at the endothelial surface to shed the GCX. Critical Issues: The GCX seems to be degraded during major liver surgery, but the underlying cause remains ill-defined. Future Directions: The relative contribution of the different ROS and RNS intermediates to GCX degradation in vivo , the immunogenic potential of the shed GCX fragments, and the role of heparanase in liver I/R injury all warrant further investigation. Antioxid. Redox Signal. 21, 1098–1118.