Personal view: current role of artificial liver support devices.

Enthusiasm for liver support devices, particularly cell-based biological systems and albumin dialysis, increased over the last decade and there has been considerable clinical activity both within and without the construct of clinical trials. Most data have been generated on patients with acute liver failure or in patients with decompensation of chronic liver disease, often referred to as acute-on-chronic liver failure. In acute liver failure liver, liver support devices are more realistically being used as a 'bridge' to liver transplantation rather than to transplant-free survival. In acute-on-chronic liver failure the clinical objective of attaining clinical stability with treatment appears more achievable. The so-called bioartificial liver device, based on porcine hepatocytes, is the most extensively evaluated biological device. A sizeable clinical trial failed to demonstrate efficacy, but secondary analyses suggest it would be unwise to assume futility had been established with this device. Molecular adsorbent recirculating system leads the way in the non-biological category in terms of the number of patients treated, but data from large clinical trials are not yet available. One of the strongest conclusions of this review is that the amount of high-quality data available on liver support devices dramatically understates the effort and money that have been expended in their assessment. It is very clear that randomized controlled trials are mandatory to establish clinical efficacy, but it is less clear how the ideal trial should be constructed.