Excerpt from Clinical Transplants 2012
Liver Transplantation in the MELD Era — Analysis of the OPTN /UNOS Registry
Michiko Taniguchi Terasaki Foundation Laboratory, Los Angeles, California Corresponding
The standardization and refinement of operative techniques since the first human orthotopic liver transplantation (OLT) in 1963— combined with progress in immunosuppression and perioperative management —led to improvement in OLT outcomes, with OLT becoming standard treatment for end -stage liver disease. Although the number of OLTs naturally rose, the limited availability of donor livers limited the number of liver transplants possible. To counter that limit, physicians began to accept extended- criteria donor grafts. Yet the supply of organs would always remain inadequate to meet the need for OLTs, so reform of allocation policies was necessary to achieve a fair, transparent, and more recipient- orientated distribution, the then - extant allocation system being inefficient and failing to accurately stratify patients according to their level of sickness, instead basing the award of grafts mainly on waiting time. To overcome these deficiencies, the Model for End -stage Liver Disease (MELD) system was implemented in February 2002. The aim of MELD was to prioritize organ allocation based on the severity of the chronic liver diseases of patients on the waiting list by scoring the laboratory values of their serum bilirubin, serum creatinine, and the international normalized ratio (INR) of prothrombin time. The implementation of MELD resulted in a significant reduction of patient mortality, number of patients on the transplant waiting list, and their time on the list (1). However, MELD had a limitation in its ability to rate the urgency of need for transplantation: its scoring system does not truly reflect the severity of all liver diseases (2). So MELD was adjusted to offer priority MELD score exceptions for certain disease categories (3). Since the rationale for MELD was to reduce pre - transplant mortality by allocating livers to the sickest patients first, the resultant shift to a sicker transplantation population may have compromised post - transplant survival. This report investigates that question, exploring the dynamics in liver transplantation during the MELD era and the impact of MELD on graft survival based on the data of the Organ Procurement and Transplant Network (OPTN) / United Network for Organ Sharing (UNOS) Registry.