New scoring model may predict liver graft failure after transplant

Last Updated: 2017-12-29

By Marilynn Larkin

NEW YORK (Reuters Health) - The Liver Graft Assessment Following Transplantation (L-GrAFT) risk score may be more accurate than currently available tools for predicting post-transplant graft failure at three months, researchers say.

Early allograft dysfunction (EAD) after a liver transplant is a harbinger of adverse graft and patient outcomes, but a widely accepted classification or grading system is lacking, according to Dr. Vatche Agopian of the University of California, Los Angeles, and colleagues.

The team developed L-GrAFT and compared it with the Model for Early Allograft Function (MEAF) score and with the binary EAD definition: bilirubin level of at least 10 mg/dL on postoperative day 7; international normalized ratio (INR) of at least 1.6 on postoperative day 7; or aspartate aminotransferase or alanine aminotransferase level >2000 U/liter within the first 7 days.

The retrospective single-center analysis included 2,008 patients (median age, 56; 64% male) who underwent primary liver transplant from 2002 to 2015.

As reported online December 20 in JAMA Surgery, rates of overall survival and graft-failure-free survival, respectively, were 83% and 81% at 1 year post-transplant, 74% and 71% at 3 years, and 69% and 65% at 5 years.

The incidence of graft failure or death at three months was 11.1%.

Factors associated with 3-month graft failure-free survival included platelet count, INR, and levels of post-transplant aspartate aminotransferase and bilirubin. These measures were used to calculate the L-GrAFT risk score.

The L-GrAFT model discriminated graft failure-free survival at three months significantly better than the EAD definition and the MEAF score, according to the authors.

Compared to patients with lower L-GrAFT scores, transplant recipients in the highest decile had significantly higher median Model for End-Stage Liver Disease scores (34 vs. 31); greater need for pretransplant hospitalization (56.8% vs. 44.8%), renal replacement therapy (42.9% vs. 30.5%), mechanical ventilation (35.8% vs. 18.1%), and vasopressors (22.9% vs. 11.0%); longer median cold ischemia times (436 vs. 401 minutes); more intraoperative blood transfusions (median, 17 vs. 10 units of packed red blood cells); and older donors (median age, 47 vs. 41).

Dr. Agopian told Reuters Health in an email, "We anticipate this will be an excellent and accurate tool clinicians may utilize for prognosticating the need for liver retransplantation, standardizing the evaluation of allograft function to make it comparable across transplant centers and practice environments and - perhaps most importantly - as a clinical endpoint in the growing number of translational studies that aim to mitigate ischemia-reperfusion injury and optimize graft function."

"One such example is the growing field of machine perfusion of liver allografts prior to transplantation," he said. "A critical need exists to be able to measure and compare the efficacy of these interventions across the various modalities and practice environments. The L-GrAFT may be an excellent tool to do this."

"However," he acknowledged, "the L-GrAFT has yet to be validated in an external cohort to determine its generalizability."

"To this end," he added, "we have now analyzed its performance in an external validation cohort of greater than 3,000 transplant recipients from three transplant centers in three different UNOS (United Network for Organ Sharing) regions. The early results are promising, and we plan to report these shortly."

Dr. William Chapman, Chief, Section of Transplantation, at Washington University in St. Louis, commented, "The value of the L-GrAFT risk score is that it appears to provide a more accurate determination of the risk of the transplanted liver failing in the post-transplant period."

"This becomes an issue when a liver transplant has been performed and the new liver is functioning suboptimally," he explained. "The transplant team wants to know if the just transplanted liver will likely recover, or if they should just proceed to re-listing (and re-transplanting) the patient, which is something no team wants to do if it is not necessary."

"On the other hand, if a transplanted liver is not going to recover, then the patient is better off having that re-transplant performed earlier," he said, "and avoiding potential risks of infection or other complications by waiting too long for the re-transplant."

"The main caveat," he added, "is that transplant physician care and decision making will remain critically important, especially in decisions for patients in the moderate-risk category, who will potentially have livers that could recover without re-transplant, but also could go on to liver failure and require re-transplant."

Dr. Milan Kinkhabwala, Chief of Transplant Surgery at Montefiore Einstein Center for Transplantation in New York City, said in an email, "The main problem is that the data is all post-transplant, so we can't use this formula to, say, advise patients before transplant about what their actual risk of post-transplant survival might be based on their condition and other factors. This is much more complicated and has not been done yet."

SOURCES: http://bit.ly/2BHgpRx and http://bit.ly/2pH5upG

JAMA Surg 2017.