Natremia and liver transplantation: The right amount of salt for a good recipe

Abstract

An adequate balance between electrolytes and clear water is of paramount importance to maintaining physiologic homeostasis. Natremia imbalance and, in particular, hyponatremia is the most frequent electrolyte abnormality observed in hospitalized subjects, involving approximately one-fourth of them. Pathological changes occurring during liver cirrhosis predispose patients to an increased risk of sodium imbalance, and hypervolemic hyponatremia has been reported in nearly 50% of subjects with severe liver disease and ascites. Splanchnic vasodilatation, portal-systemic collaterals’ opening and increased excretion of vasoactive modulators are all factors impairing clear water handling during liver cirrhosis. Of concern, sodium imbalance has been consistently reported to be associated with increased risk of complications and reduced survival in liver disease patients. In the last decades clinical interest in sodium levels has been also extended in the field of liver transplantation. Evidence that [Na⁺] in blood is an independent risk factor for in-list mortality led to the incorporation of sodium value in prognostic scores employed for transplant priority, such as model for end-stage liver disease-Na and UKELD. On the other hand, severe hyponatremic cirrhotic patients are frequently delisted by transplant centers due to the elevated risk of mortality after grafting. In this review, we describe in detail the relationship between sodium imbalance and liver cirrhosis, focusing on its impact on peritransplant phases. The possible therapeutic approaches, in order to improve transplant outcome, are also discussed. 

Keywords: Sodium imbalance, Liver transplant, Cirrhosis, Vaptan, Transplant list, Hypervolemic hyponatremia

Core Tip: Sodium imbalance represents an important issue in cirrhotic patients. In the last decades, the impact of altered sodium levels in the peritransplant phases has also gained a relevant clinical interest. In this review, we examined: (1) The determinants of an impaired sodium balance in the course of severe liver diseases; (2) The consequences of sodium imbalance on liver transplant; and (3) The possible corrective measures for this condition.