Retrospective Study
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World J Transplant. Sep 24, 2014; 4(3): 206-215
Published online Sep 24, 2014. doi: 10.5500/wjt.v4.i3.206
D-MELD risk capping improves post-transplant and overall mortality under markov microsimulation
Jeffrey B Halldorson, Robert L Carithers Jr, Renuka Bhattacharya, Ramasamy Bakthavatsalam, Iris W Liou, Andre A Dick, Jorge D Reyes, James D Perkins
Jeffrey B Halldorson, Division of Transplant Surgery, Department of Surgery, University of California, San Diego, CA 92103-8401, United States
Robert L Carithers Jr, Renuka Bhattacharya, Iris W Liou, Division of Transplantation, Department of Surgery, University of Washington, Seattle, WA 98195, United States
Ramasamy Bakthavatsalam, Andre A Dick, Jorge D Reyes, James D Perkins, Division of Gastroenterology, Department of Medicine, University of Washington, Seattle, WA 98195, United States
Author contributions: Halldorson JB, Carithers Jr RL, Reyes JD and Perkins JD designed the research; Halldorson JB and Perkins JD performed the research; Halldorson JB, Carithers Jr RL, Bhattacharya R, Bakthavatsalam R, Liou IW, Dick AA, Reyes JD and Perkins JD performed acquisition and interpretation of data; Halldorson JB wrote the manuscript; Carithers Jr RL, Bhattacharya R, Bakthavatsalam R, Liou IW, Dick AA, Reyes JD and Perkins JD provided assistance drafting the manuscript, provided critical reading leading to revisions of the manuscript and gave final approval of the version to be published.
Correspondence to: Jeffrey B Halldorson, MD, Division of Transplant Surgery, Department of Surgery, University of California, Suite 2-286, 200 West Arbor Drive, #8401, San Diego, CA 92103-8401, United States. jhalldorson@ucsd.edu
Telephone: +1-619-5433493 Fax: +1-619-5437785
Received: January 9, 2014
Revised: July 9, 2014
Accepted: July 18, 2014
Published online: September 24, 2014
Processing time: 288 Days and 8.3 Hours
Abstract

AIM: To hypothesize that the product of calculated Model for End-Stage Liver Disease score excluding exception points and donor age (D-MELD) risk capping ± Rule 14 could improve post liver transplant and overall survival after listing.

METHODS: Probabilities derived from the United Network for Organ Sharing database between 2002 and 2004 were used to simulate potential outcomes for all patients listed for transplantation. The Markov simulation was then modified by screening matches using a 1200 or 1600 D-MELD risk cap ± allowing transplants for Model for End-Stage Liver Disease (MELD) ≤ 14 (Rule 14). The differential impact of the rule changes was assessed.

RESULTS: The Markov simulation accurately reproduced overall and post transplant survival. A 1200 D-MELD risk cap improved post-transplant survival. Both the 1200 and 1600 risk caps improved overall survival for waitlisted patients. The addition of Rule 14 further improved post transplant and overall survival by redistribution of donor livers to recipients in higher MELD subgroups. The mechanism for improved overall and post-transplant survival after listing was due to shifting a larger percentage of transplants to the moderate MELD score subgroup (MELD 15-29) while also ensuring that high MELD recipients have livers of high quality to achieve excellent post transplant survival.

CONCLUSION: A 1200 D-MELD risk cap + Rule 14 provided the greatest overall benefit primarily by focusing liver transplantation towards the moderate MELD recipient.

Keywords: Liver transplantation; The product of calculated Model for End-Stage Liver Disease score excluding exception points and donor age; Donor/recipient matching; Markov microsimulation; Model for End-Stage Liver Disease; Donor age

Core tip: Optimal matching between donor livers and recipients balances recipient need with optimal utility. The product of calculated Model for End-Stage Liver Disease score excluding exception points and donor age (D-MELD) risk cap uniquely utilizes ethically neutral donor/recipient factors while maintaining predictive power, making it useful for donor/recipient matching paradigms aimed at improving utility. Described is a novel utilization of the D-MELD risk cap as an aid for donor/recipient matching. Markov modeling suggests that this paradigm improves outcomes both by decreasing futile transplantations but also by focusing the majority of transplantation on moderate Model for End-Stage Liver Disease (MELD) recipients while continuing to provide younger donor livers for the fewer number of patients transplanted at high MELD.