Jacqueline M. Smits

Listing for lung transplantation: life expectancy and transplant effect, stratified by type of end-stage lung disease, the Eurotransplant experience

BACKGROUND Increased referral for lung transplantation, persistent shortage of donor lungs, and moderate transplant outcome call not only for adequate listing criteria, but also for an optimal allocation scheme. We used global cohort survival after listing and survival benefit from transplantation to study the effect of a lung allocation scheme, primarily driven by waiting time, on the different types of end-stage lung disease. METHODS We followed all adult patients consecutively listed for first, lung-only transplantation between 1990 and 1996 (n = 1,208) for at least 2 years, with an additional 2-year follow-up after transplantation (n = 744). We used the competing risk method, the Kaplan-Meier method, and a time-dependent non-proportional hazards model to analyze waiting-list outcome and global mortality after listing, post-transplant survival, and transplant effect, respectively. Each analysis was stratified for type of end-stage lung disease. RESULTS At 2 years, 57% of the total cohort had received lung transplants, whereas 25% had died on the waiting list. The 2-year survival post-transplant was 55%. The global mortality of the cohort, since listing, amounted to 46% at 2 years. Compared with continued waiting, patients experienced benefit from transplantation by Day 100, which lasted until the end of the 2-year analysis period. We noticed the highest global mortality rates for patients with pulmonary fibrosis and pulmonary hypertension (54% and 52%); emphysema patients had the lowest (38%). Patients with pulmonary fibrosis and cystic fibrosis had much earlier benefit from transplantation, 55 and 90 days, respectively. Transplantation also benefited emphysema patients by Day 260. CONCLUSIONS Lung transplantation conferred transplant benefit in a Western European cohort of adults, in particular for patients with pulmonary fibrosis and cystic fibrosis, but also for patients with emphysema. The global survival rate, reflecting the real life expectancy for a newly listed transplant candidate, is poor for patients with pulmonary fibrosis and pulmonary hypertension. Allocation algorithms that lessen the impact of waiting time and take into account the type of end-stage lung disease should be developed.

Machine Perfusion Versus Cold Storage for the Preservation of Kidneys Donated After Cardiac Death A Multicenter, Randomized, Controlled Trial

Objective:Hypothermic machine perfusion may improve outcome after transplantation of kidneys donated after cardiac death (DCD), but no sufficiently powered prospective studies have been reported. Because organ shortage has led to an increased use of DCD kidneys, we aimed to compare hypothermic machine perfusion with the current standard of static cold storage preservation. Methods:Eighty-two kidney pairs from consecutive, controlled DCD donors 16 years or older were included in this randomized controlled trial in Eurotransplant. One kidney was randomly assigned to machine perfusion and the contralateral kidney to static cold storage according to computer-generated lists created by the permuted block method. Kidneys were allocated according to standard rules, with concealment of the preservation method. Primary endpoint was delayed graft function (DGF), defined as dialysis requirement in the first week after transplantation. All 164 recipients were followed until 1 year after transplantation. Results:Machine perfusion reduced the incidence of DGF from 69.5% to 53.7% (adjusted odds ratio: 0.43; 95% confidence interval 0.20–0.89; P = 0.025). DGF was 4 days shorter in recipients of machine-perfused kidneys (P = 0.082). Machine-perfused kidneys had a higher creatinine clearance up to 1 month after transplantation (P = 0.027). One-year graft and patient survival was similar in both groups (93.9% vs 95.1%). Conclusions:Hypothermic machine perfusion was associated with a reduced risk of DGF and better early graft function up to 1 month after transplantation. Routine preservation of DCD kidneys by hypothermic machine perfusion is therefore advisable.

Effect of receiving a heart transplant: analysis of a national cohort entered on to a waiting list, stratified by heart failure severity

Abstract Objective: To determine whether there is a survival benefit associated with cardiac transplantation in Germany. Design: Prospective observational cohort study. Setting: All 889 adult patients listed for a first heart transplant in Germany in 1997. Main outcome measure: Mortality, stratified by heart failure severity. Results: Within 1 year after listing, patients with a predicted high risk had the highest global death rate (51% v 32% and 29% for medium and low risk patients respectively; P<0.0001), had the highest risk of dying on the waiting list (32% v 20% and 20%; P=0.0003), and were more likely to receive a transplant (48% v 45% and 41%; P=0.01). Differences between the risk groups in outcome after transplantation did not reach significance (P=0.2). Transplantation was not associated with a reduction in mortality risk for the total cohort, but it did provide a survival benefit for the high risk group. Conclusion: Cardiac transplantation in Germany is currently associated with a survival benefit only in patients with a predicted high risk of dying on the waiting list. Patients with a predicted low or medium risk have no reduction in mortality risk associated with transplantation; they should be managed with organ saving approaches rather than transplantation.

Evaluation of the Eurotransplant Senior Program. The Results of the First Year

On 4 January 1999, the Eurotransplant Senior Program (ESP) was implemented within the Eurotransplant kidney allocation scheme.

Machine perfusion versus cold storage for preservation of kidneys from expanded criteria donors after brain death.

The purpose of this study was to analyze the possible effects of machine perfusion (MP) versus cold storage (CS) on delayed graft function (DGF) and early graft survival in expanded criteria donor kidneys (ECD). As part of the previously reported international randomized controlled trial 91 consecutive heart‐beating deceased ECDs – defined according to the United Network of Organ Sharing definition – were included in the study. From each donor one kidney was randomized to MP and the contralateral kidney to CS. All recipients were followed for 1 year. The primary endpoint was DGF. Secondary endpoints included primary nonfunction and graft survival. DGF occurred in 27 patients in the CS group (29.7%) and in 20 patients in the MP group (22%). Using the logistic regression model MP significantly reduced the risk of DGF compared with CS (OR 0.460, P = 0.047). The incidence of nonfunction in the CS group (12%) was four times higher than in the MP group (3%) (P = 0.04). One‐year graft survival was significantly higher in machine perfused kidneys compared with cold stored kidneys (92.3% vs. 80.2%, P = 0.02). In the present study, MP preservation clearly reduced the risk of DGF and improved 1‐year graft survival and function in ECD kidneys.

Reexposure of cord blood to noninherited maternal HLA antigens improves transplant outcome in hematological malignancies

Cord blood (CB) hematopoietic stem cell transplantation can be successful even if donor and recipient are not fully matched for human leukocyte antigens (HLA). This may result from tolerance-inducing events during pregnancy but to date this concept has not been tested in CB transplantation. Hence we analyzed the impact of fetal exposure to noninherited maternal antigens (NIMA) of the HLA-A, -B antigens, or -DRB1 alleles on the outcome of CB transplants. The 1,121 patients studied were transplanted for hematological malignancy with a single CB unit: 1,059 received grafts mismatched for one or two HLA antigens. Of these patients, 79 patients had a mismatched antigen that was identical to a donor NIMA, 25 with one HLA mismatch (MM), and 54 with two. If there was a NIMA match, transplant-related mortality (TRM) was improved, especially in patients ≥10 years (P = 0.012) as were overall mortality and treatment failure (P = 0.022 and 0.020, respectively, in the older subset), perhaps related to improved neutrophil recovery, especially in patients who received a low total nucleated cell (TNC) dose (P = 0.031). Posttransplant relapse rate also tended to be reduced, especially in patients with myelogenous malignancies given units with a single HLA mismatch (P = 0.074). These findings represent unique evidence that donor exposure to NIMA can improve survival in unrelated CB transplantation and might reduce relapse, indicating that cord blood cells can mount an antileukemic effect. By matching for donor NIMAs in search algorithms of CB inventories, the probability of selecting a graft with an optimal outcome will increase significantly.

Association between specific HLA combinations and probability of kidney allograft loss: the taboo concept

BACKGROUND HLA matching improves the outcome of cadaveric renal transplantation. However, many allografts function well even in the presence of one or more HLA mismatches, which raises the question of whether some mismatches are better recognised by the recipients immune system than others. We aimed to identify mismatched HLA donor-recipient combinations that were associated with increased graft loss. METHODS We selected 2877 first, unrelated renal transplants with a single HLA A, B, or DR mismatch, undertaken between 1982 and 1992, from the Eurotransplant database. To enhance statistical power the analysis was restricted to mismatches of an HLA antigen that occurred in 100 or more donors. 1342 transplants met this criterion and were grouped into a definition set (n = 873) and a validation set (n = 469). In the definition set, we studied further only those recipient HLA antigens that occurred in at least 30 cases within each donor antigen mismatch subset. By a Cox proportional hazards model, donor-recipient combinations that led to significantly higher graft loss than in the whole group were defined. Such combinations were classified as taboo; the remaining combinations were classified as indifferent. FINDINGS 106 individual recipient antigens were found at least 30 times with a corresponding donor mismatch in the definition set; 11 of the 106 had a significant effect on graft survival. Seven combinations were classified as taboo. Taboo combinations, confirmed as such in the validation set, were associated with graft survival of 81% at one year and 50% at 5 years, significantly lower than the rates in the group with indifferent combinations (89% and 69%; p = 0.04) or among 1190 recipients with no mismatches (89% and 72%; p = 0.03). The findings were substantiated by a multivariate analysis that included the effect of patient immunisation, cold ischaemia time, age, and sex. INTERPRETATION Mismatched donor antigens are differentially recognised depending on the HLA phenotype of the recipient. The findings may have important clinical consequences for graft survival after transplantation.

The Prognostic Value of Renal Resistance During Hypothermic Machine Perfusion of Deceased Donor Kidneys

Vascular renal resistance (RR) during hypothermic machine perfusion (HMP) is frequently used in kidney graft quality assessment. However, the association between RR and outcome has never been prospectively validated. Prospectively collected RR values of 302 machine‐perfused deceased donor kidneys of all types (standard and extended criteria donor kidneys and kidneys donated after cardiac death), transplanted without prior knowledge of these RR values, were studied. In this cohort, we determined the association between RR and delayed graft function (DGF) and 1‐year graft survival. The RR (mmHg/mL/min) at the end of HMP was an independent risk factor for DGF (odds ratio 21.12 [1.03–435.0]; p = 0.048) but the predictive value of RR was low, reflected by a c‐statistic of the receiver operator characteristic curve of 0.58. The RR was also found to be an independent risk factor for 1‐year graft failure (hazard ratio 12.33 [1.11–136.85]; p = 0.004). Determinants of transplant outcome are multifactorial in nature and this study identifies RR as an additional parameter to take into account when evaluating graft quality and estimating the likelihood of successful outcome. However, RR as a stand‐alone quality assessment tool cannot be used to predict outcome with sufficient precision.

Kidney Transplantation Without Prior Dialysis in Children: The Eurotransplant Experience

Kidney transplantation without prior dialysis may prevent dialysis‐associated morbidity. We analyzed the outcome of 1113 first kidney transplants in children performed between 1990 and 2000 in the Eurotransplant community. Enlistment for a deceased donor kidney before start of dialysis (127/895, 14%) made dialysis redundant in 55% of cases. Mean residual creatinine clearance at transplantation of these patients was 8 mL/min/1.73 m2. Pre‐emptive transplantations of deceased donor kidneys showed less acute rejections (52% vs. 37% rejection‐free at 3 years, p = 0.039), compared to transplantations following dialysis. The difference in graft survival between non‐dialyzed and dialyzed patients (82% vs. 69% at 6 year) did not reach statistical significance (p = 0.055). No differences were noted after living donor transplantation. Multivariate analysis showed that the period of transplantation was the strongest predictor of graft survival (p < 0.001). Congenital structural abnormalities such as primary kidney disease predominated in nondialyzed patients as compared to dialyzed patients (p < 0.001); this factor did not influence graft survival. Based on our conclusion that pre‐emptive transplantation is at least as good as post‐dialysis transplantation, as well as on quality of life arguments, we recommend to consider pre‐emptive transplantation in children with end‐stage renal failure.

Cost‐Effectiveness of Hypothermic Machine Preservation Versus Static Cold Storage in Renal Transplantation

Static cold storage (CS) is the most widely used organ preservation method for deceased donor kidney grafts but there is increasing evidence that hypothermic machine perfusion (MP) may result in better outcome after transplantation. We performed an economic evaluation of MP versus CS alongside a multicenter RCT investigating short‐ and long‐term cost‐effectiveness. Three hundred thirty‐six consecutive kidney pairs were included, one of which was assigned to MP and one to CS. The economic evaluation combined the short‐term results based on the empirical data from the study with a Markov model with a 10‐year time horizon. Direct medical costs of hospital stay, dialysis treatment, and complications were included. Data regarding long‐term survival, quality of life, and long‐term costs were derived from literature. The short‐term evaluation showed that MP reduced the risk of delayed graft function and graft failure at lower costs than CS. The Markov model revealed cost savings of