Renal Replacement Therapy in Special Settings: Extracorporeal Support Devices in Liver Failure

Abstract

Hepatorenal syndrome (HRS) type I is a unique form of acute kidney injury resulting from renal vasoconstriction in the setting of systemic and splanchnic arterial vasodilation in patients with end-stage liver disease. The only definitive treatment currently available is liver or liver-kidney transplantation. The goal of extracorporeal support (ECS) systems in HRS is to bridge eligible liver failure patients to transplantation or functional recovery by means of detoxification, assistance with biosynthesis of key metabolic products, and regulation of inflammation. ECS systems in liver disease can be divided into two broad categories: cell-based and noncell-based systems. While cell-based systems aim to provide functions similar to those of normal hepatocytes, noncell-based systems do not incorporate tissue; they provide detoxification utilizing membranes and adsorbents. There are no standard guidelines for the application of ECS systems. Published studies are too small and show considerable differences in primary indication, primary endpoint, and treatment protocols for "intervention" and "standard" treatment groups. This article reviews the available evidence regarding the optimal use of ECS devices in HRS, makes evidence-based practice recommendations, and delineates key questions for future studies.

The Challenges of Providing Renal Replacement Therapy in Decompensated Liver Cirrhosis

“…These have been recently reviewed by Cerda et al [28]. These systems consist of membranes and adsorbent-based systems to provide detoxification and dialytic support as well as cell-based systems to provide the excretory, synthetic, and metabolic functions of the liver.…”

Should MARS and PROMETHEUS be Used in Patients with Liver Disease?

“…This paradoxical response of the kidney is often explained with the difficult to test concept of "arterial underfilling." Employing this concept, it follows that fluid removal in such a patient may worsen arterial underfilling and thus lead to worsening kidney function (3).…”

“…They also remove agents involved in the severe pruritus associated with a failing liver (particularly severe cholestatic disease) and have been utilized in its therapy. Intracranial pressure can be decreased by use of either method making them useful in treatment of the most acutely fatal consequences of hepatic encephalopathy .…”

Lactic Acidosis in a Patient with Type 2 Diabetes Mellitus

“…Third, RRT has the potential to maintain the plasma ionized calcium concentration while raising pH, thus potentially improving myocardial contractility (43). There are few studies of RRT relevant to the treatment of lactic acidosis, and most are in the setting of sepsis with hemodynamic instability (44). Almost all involve continuous RRT (CRRT).…”

“…Thus, metformin removal by dialysis has figured prominently in the management of patients with MALA (50). Metformin is readily dialyzable, owing to its low molecular weight and lack of protein binding (44). Because of its very high volume of distribution and two-compartment elimination kinetics (50), metformin's removal may be best accomplished with prolonged extracorporeal therapy, either intermittent (49) or continuous (51).…”