Therapy insight: Management of hepatorenal syndrome

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.

Outcomes of liver transplantation in patients with hepatorenal syndrome

Hepatorenal syndrome (HRS) plays an important role in patients with liver cirrhosis on the wait list for liver transplantation (LT). The 1 and 5-year probability of developing HRS in cirrhotic with ascites is 20% and 40%, respectively. In this article, we reviewed current concepts in HRS pathophysiology, guidelines for HRS diagnosis, effective treatment options presently available, and controversies surrounding liver alone vs simultaneous liver kidney transplant (SLKT) in transplant candidates. Many treatment options including albumin, vasoconstrictors, renal replacement therapy, and eventual LT have remained a mainstay in the treatment of HRS. Unfortunately, even after aggressive measures such as terlipressin use, the rate of recovery is less than 50% of patients. Moreover, current SLKT guidelines include: (1) estimation of glomerular filtration rate of 30 mL/min or less for 4-8 wk; (2) proteinuria > 2 g/d; or (3) biopsy proven interstitial fibrosis or glomerulosclerosis. Even with these updated criteria there is a lack of consistency regarding long-term benefits for SLKT vs LT alone. Finally, in regards to kidney dysfunction in the post-transplant setting, an estimation of glomerular filtration rate < 60 mL/min per 1.73 m² may be associated with an increased risk of patients having long-term end stage renal disease. HRS is common in patients with cirrhosis and those on liver transplant waitlist. Prompt identification and therapy initiation in transplant candidates with HRS may improve post-transplantation outcomes. Future studies identifying optimal vasoconstrictor regimens, alternative therapies, and factors predictive of response to therapy are needed. The appropriate use of SLKT in patients with HRS remains controversial and requires further evidence by the transplant community.

Hypoalbuminemia

Hypoalbuminemia is frequently observed in hospitalized patients and it can be associated with several different diseases, including cirrhosis, malnutrition, nephrotic syndrome and sepsis. Regardless of its cause, hypoalbuminemia has a strong predictive value on mortality and morbidity. Over the years, the rationale for the use of albumin has been extensively debated and the indications for human serum albumin supplementation have changed. As the knowledge of the pathophysiological mechanisms of the pertinent diseases has increased, the indications for intravenous albumin supplementation have progressively decreased. The purpose of this brief article is to review the causes of hypoalbuminemia and the current indications for intravenous administration of albumin. Based on the available data and considering the costs, albumin supplementation should be limited to well-defined clinical scenarios and to include patients with cirrhosis and spontaneous bacterial peritonitis, patients with cirrhosis undergoing large volume paracentesis, the treatment of type 1 hepatorenal syndrome, fluid resuscitation of patients with sepsis, and therapeutic plasmapheresis with exchange of large volumes of plasma. While albumin supplementation is accepted also in other clinical situations such as burns, nephrotic syndrome, hemorrhagic shock and prevention of hepatorenal syndrome, within these contexts it does not represent a first-choice treatment nor is its use supported by widely accepted guidelines.

Hot topics in liver intensive care

Liver dysfunction is an independent predictor of mortality among intensive care patients. Avoidance or early restoration of normal liver function should therefore be targeted in all critically ill patients. The present work seeks to provide an overview of the "hottest topics" among liver-related problems in intensive care. The management of increased intracranial pressure in severe hepatic encephalopathy is still not sufficiently documented. The promising results with regard to intracranial pressure control by the molecular adsorbent recycling system (MARS) in animal studies are only partially reproducible in patients. Intracranial pressure monitoring is inconsistently applied in various centers, mainly because of the lack of information about the risk benefit ratio. Further, we still do not know which coagulation management protocol reduces the risk of intracranial bleeding. Type I hepatorenal syndrome is a complication of liver failure that is strongly associated with bad outcomes. Only about the half of the patients will recover from dialysis-dependent hepatorenal syndrome after liver transplantation. The usefulness of combined liver and kidney transplantation has not been sufficiently clarified. Terlipressin together with fluid and albumin substitution appear to be the most promising therapeutic interventions. Extracorporeal liver support systems, such as single-pass albumin dialysis, MARS, and the dialysis- and plasmapheresis-based Prometheus, are still under investigation with regard to effectiveness of toxin elimination, appropriate indications, and number duration of treatments.

Development of hepatorenal syndrome in bile duct ligated rats

AIM

To evaluate in bile duct ligated rats whether there were progressive alterations of renal function without changes in histopathology.

METHODS

Male Wistar rats were submitted to sham-surgery or bile duct ligation (BDL) and divided according to the post-procedure time (2, 4 and 6-wk). To determine renal function parameters, rats were placed in metabolic cages and, at the end of the experiment, blood and urine samples were obtained. Histology and hydroxyproline content were analyzed in liver and renal tissue.

RESULTS

Rats with 2 wk of BDL increased free water clearance (P = 0.02), reduced urinary osmolality (P = 0.03) and serum creatinine (P = 0.01) in comparison to the sham group. In contrast, rats at 6 wk of BDL showed features of HRS, including significant increase in serum creatinine and reductions in creatinine clearance, water excretion and urinary sodium concentration. Rats with 4 wk of BDL exhibited an intermediate stage of renal dysfunction. Progressive hepatic fibrosis according to post-procedure time was confirmed by histology. The increased levels of liver hydroxyproline contrasted with the absence of structural changes in the kidney, as assessed by histology and unchanged hydroxyproline content in renal tissue.

CONCLUSION

Our data show that BDL produced progressive renal dysfunction without structural changes in the kidney, characterizing HRS. The present model will be useful to understand the pathophysiology of HRS.