Evaluation of Liver Grafts With FibroScan® Before Organ Retrieval in Patients With Brain Death

Overview

According to the French Biomedicine Agency annual report on retrieval activities and transplants, 1,164 liver transplants were performed in 2011 and 1,161 in 2012. If the amount of brain death donors and retrieved liver grafts appears relatively stable, it remains clearly insufficient compared to the increasing number of patients on the waiting list for liver transplantation (2,462 in 2011). The median time on the waiting list before liver transplantation which was established from the cohort of patients registered between 2007 and 2011 (excluding patients registered for emergency transplantation and for living related-donor transplantation) increased significantly from 4.4 months between 2007 and 2009 to 6.6 months between 2010 and 2011. In order to compensate for the lack of liver grafts, donors acceptance criteria were broadened. For example, alternative transplantation lists were created with liver grafts coming from so-called "marginal" donors. However, despite these efforts, livers were retrieved on only two out of three brain death donors, i.e. in 1,572 and 1,589 organ donors in 2011 and 2012, respectively. This is unfortunately not enough to meet the increasing needs in liver grafts and a growing number of patients wait each year for transplant. Strategic lines of improvement were defined in order to meet the "2012-2016 transplant perspective" which targets 5,700 transplants carried out in 2015 (+5% every year, all transplants included, with 5,023 transplants in 2012). According to the last consensus conference on liver transplantation of the HAS (French High Authority of Health) the assessment of the degree of macrovacuolar and microvacuolar steatosis determines the possibility to retrieve the graft or not. Liver steatosis consists in an accumulation of fatty droplets in hepatocytes. Its prevalence is high, ranging from 16% to 31% in the general population, and increases up to 46% in heavy drinkers and to 50-80% in the obese population. Steatosis results mostly from alcohol consumption and from metabolic syndrome (obesity, type 2 diabetes, hypertriglyceridemia) called non-alcoholic fatty liver disease (NAFLD), and is more rarely secondary to viral hepatitis or exposure to certain medications. NAFLD involves up to 30% of the population in Western countries and its prevalence is increasing. NAFLD may lead to asymptomatic steatosis, but also to steatohepatitis or advanced fibrosis including cirrhosis and its complications Accordingly, the improvement of liver grafts selection based on objective quantitative criteria which takes into account the degree of liver steatosis appears crucial to increase the number of hepatic transplants.

Medical procedure: Fibroscan® based on vibration control transient elastography (VCTETM) with evaluation of controlled attenuation parameter (CAP™) by ultrasounds (Echosens, Paris, France).