Prospective Validation of a New Priority Allocation Model for Liver Transplant Candidates: An Interim Analysis

Background

The system that controls the waiting list (WL) and organ allocation for liver transplantation (OLT) seeks to achieve 3 main goals: objectivity, low dropout risks and good post-OLT results. We sought to prospectively validate a priority allocation model that is believed to achieve objectivity without penalizing dropout risk and post-OLT results.

Methods

We evaluated a study group of 272 patients enrolled in 2006-2007. WL candidates were divided into 2 categories: cirrhotic patients classified according to Model for End-Stage Liver Disease (MELD) score (MELD list and patients with hepatocellular carcinoma (HCC) organized according to a specific score (non-MELD list). The allocation algorithm for donor-recipient match assigned an optimal graft to the first MELD candidate with a MELD score of ≥20; a suboptimal graft, to the first non-MELD patient. A respective control group of 327 patients transplanted from 2003-2006 was characterized by a unique WL with a free allocation policy. We performed an interim analysis of this prospectively controlled study.

Results

Although the study group showed a lower percentage of OLT (P < .05) than the control group (37% vs 45%), it selected patients for OLT based on a higher MELD score (P < .05), thus obtaining similar dropout, post-OLT survivals, and intention-to-treat (ITT) survival probabilities as the controls. Among MELD patients, we observed a significantly reduced dropout and better ITT survival profiles than those of the control group (P = .02), whereas the similar results were delivered among non-MELD patients (P > .05). Among patients with a MELD score of ≥20, the prevalences of suboptimal grafts (0% vs 48%) and of early graft losses (0% vs 21%) were lower in the study than in the control group (P < .05).

Conclusions

We prospectively validated a priority allocation model based on objective criteria that achieved high ITT survival rates.