Vol. 10 Issue S1
On the cover: Official Journal of the Mexican Association of Hepatology and the Latin-American Association for the Study of the Liver
During the course of cirrhosis, a progressive reduction of splanchnic vascular resistance takes place in parallel with a deterioration of cardiac function manifested by the disappearance of the hyperdynamic circulation due to a fall in cardiac output. This compromises arterial pressure and determines a homeostatic activation of endogenous vasoconstrictor systems. Cirrhotic patients are prone to developing renal vasoconstriction, decreased renal perfusion and renal failure in response to insults that impairs the effective arterial blood volume such as severe bacterial infections or other clinical events that produce hypovolemia. Although circulatory dysfunction in cirrhosis predominantly affects the kidney, it has also effects on other organs and systems: brain edema and encephalopathy, increased portal pressure and decreased intestinal motility. Albumin infusion is effective in the prevention of circulatory dysfunction after therapeutic paracentesis or acute bacterial infections and in in the treatment of hepatorenal syndrome. This effectiveness may be related to the dual effect of albumin on the cardio-circulatory function, the increase in the cardiac output and in the systemic vascular resistance. The administration of intravenous albumin not only expands the plasma volume and increases cardiac preload and cardiac output but also induces arterial vasoconstriction at the level of splanchnic microcirculation. Moreover, albumin is a powerful antioxidant as well as plays a crucial role in the transport of physiologic substances and disposal of toxic substances. Impairment of albumin function is one of the most characteristic traits of cirrhosis. Administration of exogenous albumin could be beneficial because of its positive effects on microcirculation.
The role of proteins in the maintenance of colloid osmotic pressure has been described by Starling since 1896. For many decades, the importance of albumin was associated exclusively to its colloid osmotic function. More recently, other properties of albumin have been demonstrated, such as: carrying different substances, anti-inflammatory activity, preserving capillaries permeability, anti-oxidant role. It is noteworthy that, in decompensated cirrhosis, there is qualitative and quantitative decrease in albumin function. This is why, when we use it, we must have in mind its pharmacological role, as well as its colloid osmotic function. Currently, albumin has three major indications in the treatment of cirrhosis. The first would be in the treatment of tense or refractory ascites, when large-volume paracentesis are accomplished, maily when more than 4-5L of ascites are drained, in order to avoid post-paracentesis dysfunction. The second would be in cases of spontaneous bacterial peritonitis, avoiding renal impairment and increasing survival; it is formally indicated when bilirubin is greater than 4 mg/dL or creatinine is greater than 1 mg/dL. Finally, we understand its use associated to terlipressin seems to be the best treatment strategy for type I hepatorenal syndrome. Hence, its judicial use is of great relevance and benefit in the treatment of these complications of the cirrhotic patient.
Extracorporeal liver support has been a much studied topic throughout the last 50 years. Albumin dialysis as a therapeutic option for patients with acute liver failure or acute decompensation of chronic liver disease was introduced in the mid-nineties. The Molecular Adsorbent Recirculating System (MARS) is based on the concept of albumin dialysis and allows for the removal of protein-bound as well as water-soluble toxins. Besides its role as a sufficient volume expander human serum albumin is an important scavenger for molecules with pathophysiological relevance in liver failure. Albumin dialysis enables the selective regeneration of patient´s albumin resulting in an increase of albumin binding capacity. Clinically, an improvement of central and local hemodynamics as well as liver-, brain-, and kidney-functions were observed. Thus, the treatment can contribute to liver regeneration and stabilization of vital organ functions and thus help to bridge patients to liver transplantation or to recovery of native liver function. Proper patient selection is critical for clinical success. Aggressive treatment of infections and sepsis seems to be a decisive pre-requisite for its safe and efficient use. Cautious anticoagulation with heparin is the common standard. Citrate use is recommended for patients prone to bleeding. Today, albumin dialysis MARS is among the best studied liver support methods. It appears as a valuable therapeutic tool for the treatment of various complications of of liver failure, especially hemodynamic instability and hepatic encephalopathy. Further studies will need to help defining the optimal patient selection and technical process parameters such as sessionlength and frequency of treatment.