The results of this study appear in the April 2006 issue of Liver Transplantation, the official journal of the American Association for the Study of Liver Diseases (AASLD) and the International Liver Transplantation Society (ILTS). The journal is published on behalf of the societies by John Wiley & Sons, Inc. and is available online via Wiley InterScience at http://www.interscience.wiley.com/journal/livertransplantation.
Monitoring liver function following LDLT is crucial and identifying poor function as early as possible would be a step in the right direction toward achieving better outcomes. Since tests traditionally used to measure liver function are not always conclusive, researchers led by Tomohide Hori of Mie University in Tsu City, Japan analyzed how indocyanine green (ICG), a non-toxic dye, was processed by the liver, assessed a non-invasive method of measuring its levels, and determined whether such a test would be a reliable indicator of outcome.
The study involved 30 adult recipients who underwent LDLT between June 2003 and February 2005 at Mie University Hospital. The patients were divided into two groups based on liver function and outcome following the transplant (as measured by traditional methods such as bilirubin concentration). Group I consisted of 24 recipients who had good clinical outcomes while group II consisted of 6 recipients who needed intensive clinical management and had poor clin ical outcomes. ICG was injected into the patients and its disappearance was monitored by a non-invasive photometric device. This was done for the first 14 days following transplant (including every 12 hours in the first 72 hours) and again at 21 and 28 days following surgery.
The results showed that immediately following transplant, elimination of ICG improved for all patients in the study when compared to pre-operative tests, but within 24 hours ICG elimination was significantly better in Group I than in Group II. The test correlated well with more traditional methods of measuring liver function, specifically liver biopsies that were performed in 17 of the patients and liver scintigraphy (an imaging technique using a radioactive substance that is swallowed) performed on 18 patients. The ICG test however, had certain benefits. "This novel noninvasive method has advantages in its simplicity, its real-time presentation of results without consuming a lot of time, and its cost-effectiveness," the researchers note. They conclude that being able to predict poor outcomes based on ICG elimination immediately following liver transplants should have a large impact on further improving LDLT outcomes, since appropriate clinical management can then be instituted if necessary.
In another study in the same issue, researchers led by Christoph Jochum, M.D. of the University Duisberg-Essen in Essen, Germany investigated ICG elimination, galactose elimination capacity (GEC), and lidocaine elimination as markers for the quality of liver regeneration in 22 donors and their recipients in the first 3 months following LDLT. They found that ICG elimination and GEC remained significantly altered in donors and improved significantly in recipients during that period, while lidocaine elimination showed no significant changes. "In this study we evaluated only a small group of patients, however the results indicate a longer and more profound change in the quality of the liver of d onors and recipients after LDLT than conventional liver function tests indicate," the authors conclude.
In an accompanying editorial, Jürg Reichen, M.D., of the University Hospital, University of Berne in Switzerland notes that ICG clearance as measured in the first study can predict poor outcomes and might be useful for LDLT recipients, while the second study points out that liver regeneration might not be complete for donors, even though the liver achieves its full size within four weeks of transplant. "Whether the about 10 percent loss of function compared to preoperative values will translate into clinically relevant impairment of liver function ?in particular with respect to drug metabolism as suggested by the authors ?has yet to be determined," he states. He also notes that the multiple blood sampling used by the second study is quite labor intensive when compared to the device used in the first study, which is more apt to make its way into clinical practice. He concludes: "Before clinical decisions are based upon any of these tests, however, confirmation of the findings in larger patient populations in prospective studies are needed."