Prognostic Impact of Peritransplant Serum Sodium Concentrations in Liver Transplantation

Early neurologic complications after liver transplant are associated with reduced long-term survival and increased rates of rejection

Neurologic complications (NCs) are common following liver transplantation (LT) and have been associated with impaired short-term survival. The impact of NC on long-term survival is less defined. We aimed to characterize these outcomes and assess for risk factors for post-LT NC. We performed a single-center, retrospective review of 521 patients with LT from 2016 to 2020. Baseline clinical and laboratory factors, intraoperative events, and outcomes were compared between patients with and without NC. The 5-year overall and rejection-free survival was estimated using the Kaplan-Meier analysis. Multivariable logistic regression assessed for an independent relationship between risk factors and the development of NC. Among 521 LT recipients, 24% experienced post-LT NC. Overall and rejection-free survival at 5 years was, respectively, 69% and 75% among those with NC versus 87% and 88% among those without NC (log-rank < 0.001). Among those who survived the first 3 months after LT, overall survival but not rejection-free survival was reduced among patients with NC. Risk factors for developing NC included peri-LT serum sodium (ΔSNa) ≥ 6 (29.4% vs. 20.5%, p = 0.04), grade 3 or 4 HE pre-LT, SNa < 125 pre-LT, and more intraoperative transfusions. In a multivariable logistic regression model controlling for described variables, SNa < 125 (or 0.21, 95% CI, 0.06-0.74) at LT and pre-LT HE grade 3 or 4 (or 0.45, 95% CI, 0.26-0.76) was independently associated with NC. Long-term survival was reduced among patients who developed NC in the immediate post-transplant period, even when censoring those who died in the first 3 months. Post-LT NC was associated with perioperative ΔSNa ≥ 6. Optimization of SNa pre-LT > 125 and limiting perioperative ΔSNa <6 mEq/L might have a beneficial impact in decreasing NC post-LT, which may improve long-term post-LT survival.

Hyponatremia and Liver Transplantation: A Narrative Review

Hyponatremia is a common electrolyte disorder in patients with end-stage liver disease (ESLD) and is associated with increased mortality on the liver transplantation (LT) waiting list. The impact of hyponatremia on outcomes after LT is unclear. Ninety-day and one-year mortality may be increased, but the data are conflicting. Hyponatremic patients have an increased rate of complications and longer hospital stays after transplant. Although rare, osmotic demyelination syndrome (ODS) is a feared complication after LT in the hyponatremic patient. The condition may occur when the serum sodium (sNa) concentration increases excessively during or after LT. This increase in sNa concentration correlates with the degree of preoperative hyponatremia, the amount of intraoperative blood loss, and the volume of intravenous fluid administration. The risk of developing ODS after LT can be mitigated by avoiding large perioperative increases in sNa concentration . This can be achieved through measures such as carefully increasing the sNa pretransplant, and by limiting the intravenous intra- and postoperative amounts of sodium infused. SNa concentrations should be monitored regularly throughout the entire perioperative period.

Perioperative Delta Sodium and Post-Liver Transplant Neurological Complications in Liver Transplant Recipients

BACKGROUND

Hyponatremia before liver transplant (LT) increases risk of post-LT neurological complications in patients with decompensated cirrhosis, but it is unknown to what extent change in sodium from pre- to post-LT influences risk of central nervous system (CNS) sequelae. We assessed the relationship between pre- to post-LT delta sodium and prevalence of CNS complications during LT hospitalization.

METHODS

We performed retrospective single-center chart review of 1265 adults with cirrhosis who underwent LT (2011-2020). Delta sodium is defined as the difference between maximum sodium within 48 h post-LT and lowest sodium within 7 d pre-LT. Primary outcomes are post-LT CNS events during same hospitalization-encephalopathy, delirium, seizure, coma, osmotic demyelination syndrome, or other altered mental status, determined by International Classification of Diseases codes. Secondary outcome is length of hospital stay post-LT (LOS). Logistic regression modeled association between delta sodium and post-LT CNS outcomes; negative binomial regression modeled LOS.

RESULTS

Median age was 59 y, 36% were female, and median MELD was 20. Median delta sodium was 8 mmol/L (interquartile range, 5-11). 194 (15%) experienced post-LT CNS complications. In multivariable analysis, controlling for confounders including pre-LT hyponatremia, every 5 mmol/L increase in delta sodium associated with 47% greater odds of CNS complication (95% confidence interval, 22%-77%). Delta sodium also associated with 7% increased LOS in adjusted regression (95% confidence interval, 3%-12%).

CONCLUSIONS

Adult LT recipients with higher perioperative delta sodium shifts displayed a higher risk of post-LT CNS complications, even after adjusting for pre-LT sodium. LT recipients, even those with pre-LT hyponatremia, may benefit from maintenance of stable serum sodium levels to minimize post-LT CNS complications.

Perioperative Evolution of Sodium Levels in Cirrhotic Patients Undergoing Liver Transplantation: An Observational Cohort and Literature Review

Background & Aims

Hyponatremia is an important predictor of early death among cirrhotic patients in the orthotopic liver transplantation (OLT) waiting list. Evidence exists that prioritizing OLT waiting list according to the MELD score combined with plasma sodium concentration might prevent pre transplantation death. However, the evolution of plasma sodium concentrations during the perioperative period of OLT is not well known. We aimed to describe the evolution of perioperative sodium concentration during OLT and its relation to perioperative neurohormonal responses.

Methods

Twenty-seven consecutive cirrhotic patients who underwent OLT were prospectively included in the study over a period of 27 months. We studied the evolution of plasma sodium levels, the hemodynamics, the neurohormonal response and other biological markers during the perioperative period of OLT.

Results

Among study's population, four patients had hyponatremia before OLT, all with Child cirrhosis. In patients with hyponatremia, plasmatic sodium reached normal levels during surgery, and sodium levels remained within normal ranges 1 day, 7 days, as well as 6 months after surgery for all patients. Creatinine clearance was decreased significantly during the perioperative period, while creatinine and cystatin C levels increased significantly. Neutrophil gelatinase-associated lipocalin (NGAL) and vasopressin levels did not change significantly in this period. Plasma renin activity, concentrations of norepinephrine and brain natriuretic peptide varied significantly during the perioperative period.

Conclusion

In our study, plasmatic sodium concentrations among hyponatremic cirrhotic patients undergoing OLT seem to reach normal levels after OLT and remain stable six months after surgery providing more evidence for the importance of sodium levels in prioritization of liver transplant candidates. Further investigation of rapid correction and stabilization of sodium levels after OLT, as observed in our study, would be of interest in order to fully understand the mechanisms involved in cirrhosis-related hyponatremia, its prognostic value and clinical implications.

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

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.