Prediction Models of Donor Arrest and Graft Utilization in Liver Transplantation From Maastricht-3 Donors After Circulatory Death

Abstract

Shortage of organs for transplantation has led to the renewed interest in donation after circulatorydetermination of death (DCDD).We conducted a retrospective analysis (2001-2009) and a subsequent prospective validation (2010) of liver MaastrichtCategory-3-DCDD and donation-after-brain-death (DBD) offers to our program. Accepted and declined offers were compared. Accepted DCDD offers were divided into donors who went on to cardiac arrest and those who did not. Donors who arrested were divided into those producing grafts that were transplanted or remained unused. Descriptive comparisons and regression analyses were performed to assess predictor models of donor cardiac arrest and graft utilization. Variables from the multivariate analysis were prospectively validated. Of 1579 DCDD offers, 621 were accepted, and of these, 400 experienced cardiac arrest after withdrawal of support. Of these, 173 livers were transplanted. In the DCDD group, donor age < 40 years, use of inotropes and absence of gag/cough reflexes were predictors of cardiac arrest. Donor age >50 years, BMI >30, warm ischemia time >25 minutes, ITU stay >7 days and ALT ≥ 4× normal rates were risk factors for not using the graft. These variables had excellent sensitivity and specificity for the prediction of cardiac arrest (AUROC = 0.835) and graft use (AUROC = 0.748) in the 2010 prospective validation. These models can feasibly predict cardiac arrest in potential DCDDs and graft usability, helping to avoid unnecessary recoveries and healthcare expenditure.

Predicting time to death after withdrawal of life-sustaining therapy

“…1). Fifteen observational studies fulfilled our inclusion criteria, 13 of which evaluated an adult population and two a pediatric population [1,[6][7][8][9][10][11][12][13][14][15][16][17][18][19]. In all studies, with one exception [2], time to death as an outcome was dichotomized.…”

“…In all studies, with one exception [2], time to death as an outcome was dichotomized. Time of death within 60 min was the primary outcome in 13 of the 15 included studies, with assessments of 5173 patients [6][7][8][9][10][11][12][13][14][15][16][17][18]. Three studies additionally evaluated time to death within 120 min [6,12,14].…”

“…Although most studies performed an exploratory analysis of risk factors of time to death, only a few studies derived prediction tools of time to death, and even a smaller subset validated previously derived prediction tools (Table 1). Seven studies evaluated DCD-like patients [6-9, 13, 14, 16], and one study evaluated identified actual DCD candidates [17]. The definition for a DCD-like patient varied with each study ( Table 1).…”

“…The majority of these studies focused specifically on time to death within 60 min [7,8,[10][11][12][13][14][15][16][17][18]. There was considerable variability between studies regarding key predictor risk factors associated with time to death.…”

A few realistic questions raised by organ retrieval in the intensive care unit

“…Removal of the endotracheal tube (extubation) is more often associated with progression to organ donation than terminal weaning without extubation (12). Death within one or two hour(s) of withdrawal usually correlates with severe brain injuries (low Glasgow Coma Scale, absence of brainstem reflexes) (30)(31)(32)(35)(36)(37)(38), high dependence on mechanical ventilation (non-triggered mode, high FiO 2 , high positive expiratory pressure) (28-32,36,38,39), use of inotrope drugs (29,30,35,39), young age (28,35,40), underlying diseases (37,39), and physiological anomalies (high severity index scores, low blood pressure, low pH on arterial blood gas analysis) (37,38,40,41). Under Maastricht III conditions, the removal of organs must be scheduled before withholding/ withdrawal implementation and starts as soon as death is certified.…”