Hyponatremia Is Protective Against the Development of Portal Vein Thrombosis in Patients Undergoing Liver Transplant

Background: Both hyponatremia and portal vein thrombosis (PVT) reflect the severity of liver dysfunction and are independently associated with increased morbidity in cirrhotic patients. In this study, we analyzed effects of hyponatremia on PVT development. Methods: Data on adult liver transplants (LTs) in the Model for End-Stage Liver Disease era through September 2016 were obtained. Receiver operating curves and multivariable logistic regression models were constructed to evaluate the association between serum sodium level and PVT. Based on the receiver operating curves, hyponatremia was defined as a sodium level below 125 mEq/L. Results: Of the 49,155 recipients included, 16% had hyponatremia (n = 7828) and 9% had PVT (n = 4414) at transplant. Subjects with hyponatremia had lower rates of PVT at the time of LT (4.4% vs 10.1%, P < .001), incidence of nonalcoholic steatohepatitis (10.8% vs 16.5%, P < .001), diabetes (19.7% vs 24.3%, P < .001), and need for dialysis (8.8% vs 16.0%, P < .001) as well as higher rates of chronic hepatitis C and B (37.6% vs 29.1%, P < .001 and 2.9% vs 1.7%, P < .001). Multivariable regression analysis confirmed that hyponatremia was independently associated with a decreased likelihood of PVT (odds ratio [OR], 0.44, P < .001). African American patients had a lower incidence of PVT (OR, 0.70; P < .001). Variables associated with a higher incidence of PVT were: nonalcoholic steatohepatitis (OR, 1.15; P = .005), moderate-to-severe ascites (OR, 1.10; P = .008), and Hispanic ethnicity (OR, 1.2; P < .001). Conclusion: Hyponatremia is associated with a lower rate of PVT independent of severity of liver disease and other thrombotic risk factors. This protective effect should be taken into consideration during the perioperative management of hyponatremia in patients undergoing LT.