Liver dialysis is an artificial liver that employs hemodiabsorption (dialysis of blood against powdered sorbent) to remove the numerous small molecular weight toxins of hepatic failure 1). Liver dialysis is usually performed in the intensive care unit (ICU) using a non-biological liver dialysis devices known as the Molecular Adsorbent Recirculating System (MARS) often referred to as liver dialysis, the Single-Pass Albumin Dialysis (SPAD) system and the Fractionated Plasma Separation and Adsorption system – FPSA (Prometheus™). Liver dialysis is done when a person has severe liver disease, liver failure or poisoning that results in abnormal brain function or other problems. Liver failure is a severe life-threatening condition that can present acutely or chronically. Liver transplantation is expensive, requires a donor, and involves a major operation. As it takes at least one week to organize an appropriate liver transplant, liver dialysis is used as a bridge to liver transplantation for some patients with acute liver failure to support him/her through his/her liver failure until transplantation can be performed. Patients have been treated even up to one month while waiting for suitable living donors.
Liver dialysis similar to kidney dialysis allows your blood to be purified after liver failure. Your blood will be removed from your body and pumped through a set of filters to purify it. The procedure can last up to 6 hours, but you may need only one or two sessions because the treatment restarts the damaged liver.
These liver dialysis systems are based on the concept of albumin dialysis and therefore on the capacity to remove the albumin-bound toxins that accumulate in liver failure. These toxins are thought to be responsible for brain failure resulting from hepatic encephalopathy, renal failure due to hepatorenal syndrome, cardiovascular failure and/or an immunodepression state. These liver dialysis devices can also remove water-soluble substances, such as ammonia, creatinine or urea and smaller proteins such as some cytokines, by standard dialysis 2).
Some of the substances removed by the different artificial hepatic support systems include conjugate or unconjugated bilirubin or protoporphyrin, bile acids, glycoside derivatives, phenols, short- and medium-chain fatty acids, such as octanoate, or heterocyclic organic compounds 3). Removal of cytokines and other recognized inducers of hepatic encephalopathy, such as ammonia or amino acids (e.g. tryptophan or glutamine), may be a valuable tool for this major complication of liver failure 4). Some preclinical and clinical investigations also report the removal of plasmatic nitric oxide (NO) and some pro-inflammatory and anti-inflammatory cytokines, such as tumour necrosis factor alpha (TNF-α), interleukin-6 or interleukin-10 5), even though the final balance in the setting of acute liver failure or acute on chronic liver failure and its contribution to multiorgan failure are still unknown.
In the early years following the development of the different liver devices, some clinical trials demonstrated hemodynamic and neurological benefits in their use in patients with acute liver failure and in those with acute on chronic liver failure, but many of these studies were uncontrolled and included very few patients. Some randomized controlled trials showed an improvement in survival, but the small sample size, high heterogeneity of the included patients and high variability in disease severity prevented definitive conclusions from being reached 6). A randomized, prospectively controlled study of liver dialysis in treatment of liver failure was performed in 5 centers. Entry criteria were: decrease in hepatic function associated with Stage 2–4 encephalopathy, renal failure or respiratory failure allowed, but not already on dialysis or Continuous Veno-Venous Hemofiltration (CVVH). Another 28 patients were treated in crossover studies. Most patients had stage 4 encephalopathy, renal insufficiency, and respiratory insufficiency or failure. Of the 75 patients, 32 had fulminant hepatic failure and 43 had acute-on-chronic failure. Liver dialysis (6 hours, 3–5 days) significantly improved neurologic (70%) and physiologic status (72%) of all patients vs. control groups (27% and 10% respectively) 7). Liver dialysis significantly improved patient outcome (improvement of condition for transplant or recovery of liver function) for patients with A-on-C (57%) vs. control patients (36%), though not for fulminant hepatic failure patients. In 32 patients with hepatic and renal failure on entry, liver dialysis significantly improved patient outcome (41%) vs. control patients (0%). Since market introduction, more than 50 patients, mostly acute-on-chronic liver failure have been treated in many hospitals for hepatic failure, with 58% positive outcome, confirming the above studies.
MARS liver dialysis what to expect
MARS liver dialysis is the most commonly used device and it comes as an intermittent device or continuous device. Its charcoal-based system adsorbs the toxins, providing a detoxifying function without any contribution of the normal liver synthetic function. It may be coupled with a plasma separator and there may also be an albumin dialysis fluid (dialysate). The suspension is easily modified by adding dry powdered chemicals to the sorbent bag. Branched chain amino acids added to the sorbent result in a greater increase in Fischer’s ratio during treatment, and new ammonium sorbents increase the removal of ammonium. The system usually has some way of trying to renew the cartridges to prolong its lifespan. MARS liver dialysis may help restore some brain function by removing waste products or removing poisons that have built up in your body. MARS liver dialysis device has been utilized extensively for several years.
MARS liver dialysis treatment is not painful. Your will usually remain in intensive care unit (ICU) while having MARS therapy.
A specially trained nurse performs this treatment and will stay with your child the entire time.
The treatment may last up to eight hours and may need to be repeated.
First, a soft plastic tube, called a catheter, is placed in one of your large veins. Then, two machines are attached and connected to your catheter. The liver dialysis machines pull blood through the catheter, clean it and return the blood back to your body.
How quickly you get better may vary. Your doctor will decide when treatments can stop based on your improvement.
During MARS liver dialysis, you may experience:
- Infection in the catheter
- High or low heart rate
- Low blood pressure
- Trouble with the catheter, i.e., not working well and causing a delay in treatment
To prevent infection always washing your hands. Check to make sure everyone does the same − don’t be afraid to remind anyone who comes into your room to wash their hands.
You will need to rest quietly during this treatment. You may want to have books, videos and quiet activities available for your entertainment.
References [ + ]
|1, 2, 3.||↵||García Martínez, J.J., Bendjelid, K. Artificial liver support systems: what is new over the last decade?. Ann. Intensive Care 8, 109 (2018). https://doi.org/10.1186/s13613-018-0453-z|
|4.||↵||Koivusalo AM, Teikari T, Hockerstedt K, Isoniemi H. Albumin dialysis has a favorable effect on amino acid profile in hepatic encephalopathy. Metab Brain Dis. 2008;23(4):387–98.|
|5.||↵||Novelli G, Annesini MC, Morabito V, Cinti P, Pugliese F, Novelli S, et al. Cytokine level modifications: molecular adsorbent recirculating system versus standard medical therapy. Transpl Proc. 2009;41(4):1243–8.|
|6.||↵||Sgroi A, Serre-Beinier V, Morel P, Buhler L. What clinical alternatives to whole liver transplantation? Current status of artificial devices and hepatocyte transplantation. Transplantation. 2009;87(4):457–66.|
|7.||↵||Ash, S R1,2,3; Kuczek, T4; Blake, D E2; Gingrich, C H2 LIVER DIALYSIS IN TREATMENT OF HEPATIC FAILURE AND HEPATORENAL FAILURE: RANDOMIZED CLINICAL TRIALS AND CLINICAL EXPERIENCE, ASAIO Journal: March-April 2000 – Volume 46 – Issue 2 – p 223|