Technical Failure in Pancreas Transplantation: A Composite Model for Predicting Risk in the Current Era

Abstract

Purpose: Define the incidence of technical failure (TF) in pancreas transplants performed during the current era, examine risk factors, and develop a predictive composite risk model. Methods: Retrospective review of 1,115 pancreas transplants performed between 1998 and 2011 at a single center. TF is defined as graft loss within 90 days of transplant due to thrombosis, anastomotic leak, intra-abdominal infection, bleeding, or graft pancreatitis. The association of donor and recipient factors with TF was assessed by univariate and multivariate analyses. Recipient factors were age, gender, retransplant, pretransplant vascular disease, and pretransplant dialysis. Donor factors were age, gender, race, DCD, mechanism of death, BMI, preservation time, Creatinine, Amylase, and history of pancreatitis, drug, or alcohol abuse. Immune factors were HLA mismatches and PRA. Immunsuppression compared induction and maintenance agents as well as immunosuppressive era. Surgical factors were type of transplant (SPK/PTA/PAK) and bladder v. enteric drainage. Results: TF occurred in 10.2% of patients (5.6% thrombosis, 2.6% pancreatitis, 1.3% infection, 0.5% leak, and 0.2% bleeding). Risk factors in univariate analysis were SPK transplants (HR1.52, p=0.031), donor history of pancreatitis (HR7.39, p=< 0.001), donor Cr≥2.5 (HR3.06, p=0.002), preservation time >20 hours (HR1.82, p=0.002), donor age>50 (HR2.08, p=0.010), donor BMI≥30 (HR1.75, p=0.007), donor history of alcohol abuse (HR1.69, p=0.058), and donor mechanism of death other than head trauma (HR1.45, p=0.049). Bladder drainage (HR0.69, p=0.052) and alemtuzumab induction (HR0.63, p=0.093) were protective. Significant factors were included in the full Cox multivariate model. Of these, alcohol abuse, donor cause of death, alemtuzumab induction, and SPK transplant were not significant (all p >0.2). In the reduced Cox model, predictors of TF included donor pancreatitis (HR15.69, CI4.59-53.65, p< 0.001); preservation time>20 hours (HR2.14, CI1.41-3.23, p< 0.001); donor age>50 (HR1.75, CI0.94-3.24, p=0.077); donor BMI>30 (HR1.95, CI1.26-3.03, p=0.003); and Cr≥2.5 (HR3.12, CI1.39-7.03, p=0.006). Bladder drainage was protective (HR0.54, CI0.34-0.81, p=0.003) We compiled a composite risk model for transplants with one or more risk factors (donor Cr≥2.5, preservation time>20 hours, donor age>50, donor BMI≥30). Donor pancreatitis and bladder drainage were included as confounding factors but were not included in the composite score. Transplants with a single risk factor were insignificant (HR1.267, CI0.80-2.00, p=0.309). Two risk factors resulted in a 3.8-fold risk of TF (HR3.81, CI2.24-6.48, p< 0.001). Three risk factors increased the rate of TF greater than 8-fold (HR8.04, CI3.40-19.04, p< 0.001). Conclusion: TF remains a considerable risk in pancreas transplantation. A composite risk model incorporating donor age, BMI, Cr, and preservation time can predict TF following transplant. One risk factor is likely acceptable, but two or more results in a significantly increased risk for TF.Figure: [Composite Model]