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J De Meester

Publications and source records attributed to J De Meester.

At least 19 recordsLinked to original sources
PubMed2003

Mortality rates after heart transplantation: how to compare center-specific outcome data?

BACKGROUND: Studies of outcome in cardiac transplantation have focused primarily on identifying patient- and donor-related factors associated with patient mortality. Less consideration has been given to the impact of the transplant center. This study was undertaken to assess variability in heart transplantation outcome in Eurotransplant centers to provide a framework for auditing. METHODS AND RESULTS: In a 2-year period, 1,401 adult patients underwent heart transplantation in 45 centers. The 1-year patient survival rate was 76% (95% CI, 74%-78%) with a range of 0% to 100% at the center level. The risk-adjusted center effect on mortality was estimated by calculating a standardized difference between the observed number of deaths 1 year after transplantation and the expected number of deaths based on the case mix. By assessing within- and between-center variations with empirical Bayes (EB) methods, after adjustment for all registered prognostic factors, an improved estimate of the true center effect was obtained. Compared with the standard risk-adjusted center effect method, fewer outlying centers were identified with the EB method. CONCLUSION: EB methods, because they are known to incorporate more information from the data, enable a more precise and realistic portrayal of heart transplant centers' performances, compared with other risk-adjusted center effect methods. In the context of auditing procedures, EB methods should preferably be used for the identification of centers that deviate significantly from quality standards.

Adolescent↗
PubMed2001

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.

Adolescent↗
PubMed2001

Renal retransplantation of children: is a policy 'first cadaver donor, then live donor' an acceptable option?

Retransplantation is often a necessity for children with end-stage renal disease (ESRD), as kidney graft survival is still not infinite. If a suitable live donor is present, the current policy is to use the live donor first, in order to obtain excellent long-term outcome and to prevent human leucocyte antigen (HLA) sensitization. Data from the Eurotransplant International Foundation were analyzed to determine whether the sequence, first a cadaveric donor then a live donor, is acceptable. Between January 1 1983 and December 31 1995, 1305 children received a first renal transplant; 269 of them had a second transplant during the same period. Follow-up of at least 1 yr was available. Categories were made according to the sequence of renal donor source: 217 patients were classified as first cadaver and second cadaver (1cad-2cad) transplant, 26 as first cadaver and second live (1cad-2liv) donor transplant, 23 as first live donor and second cadaver (1liv-2cad) transplant and three patients had two subsequent live donor transplants (1liv-2liv). When a live donor transplant was carried out, either first or second, the donor age was always higher, and the chance of a pre-emptive transplantation or short stay on dialysis was higher, compared with a cadaver transplant. The re-graft survival rate of the '1cad-2liv' was better than the '1cad-2cad' and '1liv-2cad' transplants. At 5 yr, the survival was 76%, 49%, and 61%, respectively. These data suggest that, when a suitable live donor is not available for a first transplantation owing to medical and/or familial reservations, a policy of 'first a cadaver donor then a live donor' transplantation is a viable option and should even be promoted. The pre-emptive stage of the second transplant, probably with a live donor, is additionally advantageous.

Adolescent↗
PubMed2001

Heart transplantation indicated only in the most severely ill patient: perspectives from the German heart transplant experience.

The COCPIT study, performed in a complete national cohort of adult patients consecutively listed for cardiac transplantation in Germany in 1997, found a beneficial effect only in the group that was at high risk of dying from heart failure without transplantation. If these results can be reproduced in other countries, the discussion on the respective roles of pharmacological and organ-saving surgical therapies for advanced heart failure, medical urgency and waiting time as heart transplantation allocation criteria, and the feasibility of a randomized clinical trial testing the survival benefit of transplantation must be reopened.

Adult↗
PubMed2001

Cardioscopy and robotic assistance for the diagnosis of intraventricular endocarditis.

A 44-year-old male patient with an undefined mass in the left ventricular endocardium was scheduled for minimally invasive cardiac surgery. Ventricular investigation and tissue biopsies were completed with the help of a voice-controlled robotic arm. Pathologic examination revealed non-bacterial thrombotic endocarditis. In addition to videoscopy, robotic assistance allows an easier diagnostic and therapeutic approach of intraventricular pathologies.

Adult↗
PubMed2000

Permanent detrimental effect of nonimmunological factors on long-term renal graft survival: a parsimonious model of time-dependency.

PURPOSE: We attempted to model and test the pattern of effects of prognostic factors on renal graft survival during the posttransplantation time course. PATIENTS AND METHODS: Patients who received a cadaveric kidney-only transplant between January 1990 and December 1995 in Eurotransplant, who received cyclosporine as induction therapy, and who had a complete follow-up at the time of analysis were included in the study (n= 10614). An index summarizing all covariate information was calculated and used for modeling the time-dependent effects with relation to graft failure. RESULTS: The immunological factors (HLA mismatch and % panel-reactive antibody) were seen to have a slowly decreasing negative effect on renal graft survival. The cold ischemic trauma (>24 hr) exerted a permanent detrimental effect on the grafts. The use of organs obtained from old donors was associated with a constant higher risk of graft loss. CONCLUSIONS: An analysis of determinants of human allograft dysfunction should also study the interaction between the effects and time. Nonimmunological factors had a constant detrimental effect on graft failure, whereas the impact of the immunological factors--although remaining important for late graft loss--very slowly decreased. In the context of marginal transplants, clustering of unfavorable factors should be avoided to prevent late graft losses.

Adolescent↗
PubMed2000

Cross-reactive group matching does not lead to a better allocation and survival of donor kidneys.

BACKGROUND: In cadaveric renal transplantation HLA-A, -B, -DR matching of donor and recipient is beneficial for graft survival. However, allocation based on HLA matching seems to favor recipients with more frequently occurring HLA antigens. In this study we investigated whether matching on the basis of cross-reactive groups (CREGs), defined according to the United Network for Organ Sharing (UNOS), would be a good alternative for the allocation of kidneys without negatively influencing graft survival. Theoretically, this approach would provide more recipients with an immunologically well-matched donor organ. METHODS: The influence of CREG matching on graft survival was studied in univariate analyses using the Eurotransplant database. RESULTS: No beneficial effect of CREG matching was observed, whereas a significant HLA matching effect was observed in the 0 CREG mismatched donor/ recipient combinations. Only in the small subgroup with 1 MM for HLA-A, -B and 0 MM for HLA-DR, a significantly better survival was observed, when this mismatch belonged to the 0 or 1 MM CREG group versus two or more MM CREG group. However, this subgroup concerns only 8% of the transplants performed. CONCLUSIONS: In contrast to other reports, our study showed that HLA matching is by far more beneficial than CREG matching. In the homogenous Eurotransplant population, adjusting the matching criteria toward CREG matching would not lead to an improved graft survival.

Cross Reactions↗
PubMed1999

Eurotransplant randomized multicenter kidney graft preservation study comparing HTK with UW and Euro-Collins.

The aim was to evaluate the effect of HTK compared to UW and Euro-Collins (EC) on the initial graft function and long term graft survival in two prospective randomized studies. Only kidneys from heart-beating, kidney-only or kidney + heart donors were eligible for entry. Initial non-function (INF) was defined as the absence of life-sustaining renal function, requiring dialysis treatment on two or more occasions, during the first week after transplantation. To evaluate the contribution of the preservation solutions on INF in relation to other factors, a multivariate, 2-step logistic regression model was used. Randomization was performed between July 1990 and September 1992. The UW-HTK study comprised 342 donors and 611 transplants (UW: 168 donors and 297 transplants, HTK: 174 donors and 314 transplants). In the EC-HTK study 317 donors and 569 transplants were included (EC: 155 donors and 277 transplants, HTK: 162 donors and 292 transplants). INF occurred in 33% of either HTK-(n = 105) or UW-(n = 99) preserved kidneys (P = NS), and in 29% of the HTK-(n = 85) and in 43% of the EC-(n = 119) preserved kidneys (P = 0.001). Multivariate analysis showed no significant influence of the preservation solution on the incidence of INF in the UW-HTK study, but factors contributing to INF were donor age, cause of death, retransplantation, and cold ischemic period. The EC-HTK study showed a significantly higher risk of INF, using EC as preservation, in addition to cold ischemic period and donor quality. The 3-year graft survival of HTK-preserved kidneys was 73%, compared to 68% for UW-preserved kidneys in the UW-HTK study (P = NS); while the 3-year graft survival of HTK preserved kidneys was 70% compared to 67% for EC-preserved kidneys in the EC-HTK study (P = NS). We can conclude that HTK is comparable to UW in its preservative abilities, using kidneys from heart-beating kidney-only donors, whereas EC as renal preservation solution should be avoided.

Adenosine↗
PubMed1999

Lung transplant waiting list: differential outcome of type of end-stage lung disease, one year after registration.

BACKGROUND: Donor lung scarcity, distinct natural courses of the different types of end-stage lung diseases, and lung allocation schemes demand appropriate candidate acceptance for a lung transplant and time of listing. This study was undertaken to investigate the association between type of end-stage lung disease and outcome, 1 year after a lung transplant candidate was put on the waiting list. METHODS: From 1990 to 1995, 1376 adult patients were registered for a first lung (n = 1006) or heart-lung (n = 370) transplantation in Eurotransplant. All patients were followed for at least 1 year. For each type of end-stage lung disease (cystic fibrosis, pulmonary fibrosis, emphysema, pulmonary hypertension, congenital heart disease, and other), chances of transplantation, of death on the waiting list, and of removal for other reasons, 1 year after listing, were calculated with the competing risks method. A multivariate Cox regression model was used to assess the influence of the type of end-stage lung disease on the waiting list outflow among other prognostic variables. RESULTS: Lung transplant candidates with emphysema and with pulmonary fibrosis had the highest chance of a transplant; however, patients with pulmonary fibrosis had also the highest probability of dying while waiting, while the emphysema patients and those with the type "other" had the lowest probability. In the multivariate analysis, the type of end-stage lung disease appeared as an independent prognostic factor for both outcomes. Compared to the patients with cystic fibrosis (reference group), only patients with pulmonary fibrosis had a significantly higher chance of a transplant (RR = 1.50); the lowest chance of death for the emphysema and the "other" patients was confirmed (RR = 0.53 and RR = 0.51, respectively). Recipient size, ABO blood group, country and epoch of listing also had a significant impact on the transplant chance, while country of listing and recipient age were the other factors independently influencing the chance of dying on the waiting list. On the heart-lung waiting list, the type of end-stage lung disease solely affected the chance of death prior to transplant. Compared with cystic fibrosis, pulmonary fibrosis had a significantly higher risk (RR = 2.93), closely followed by pulmonary hypertension (RR = 2.57). Factors crucial for the chance of a heart-lung transplant were recipient size, ABO blood group and country of listing. CONCLUSIONS: The type of end-stage lung disease is a distinctive factor for predicting survival on the lung and heart-lung transplant waiting list, and should be taken into account whenever assessing waiting list outcomes. When developing lung allocation schemes, it is medically justified to incorporate the type of end-stage lung disease.

Adolescent↗
PubMed1999

Acceptable HLA mismatches for highly immunized patients.

Highly sensitized patients have developed antibodies against many different HLA antigens due to previous pregnancies, blood transfusions or failed transplants. These antibodies cause a positive crossmatch with almost all potential organ donors. As a positive crossmatch is a contra-indication for transplantation, highly sensitized patients have a low chance of transplantation unless special strategies are introduced. One such strategy is the acceptable mismatch program, which has led to transplantation of more than 300 of these highly sensitized patients within Eurotransplant. Centers are participating in the program on a voluntary basis. Before a patient can be included in this program, extensive antibody screening is necessary to define those HLA-A and -B antigens towards which the patient has never formed antibodies. Organ donor selection is based on complete compatibility with the patients own HLA antigens in combination with the acceptable mismatches. If such a combination is identified, mandatory exchange takes place. Despite the success of the acceptable mismatch program, about 25% of the patients will never receive a donor offer. These are patients with rare HLA antigens or rare combinations of HLA antigens. In the last few years, this group of patients has had the advantage of two additional programs running within Eurotransplant. In the HIT (highly immunized tray) program, sera of highly sensitized patients are sent to the different centers and crossmatched with all ABO compatible donors. In the case of a negative crossmatch, mandatory exchange takes place. Secondly, these patients can benefit from the extra points they receive for their waiting time, high antibody reactivity and rare HLA type in the standard Eurotransplant allocation system. We conclude that the application of these three strategies will lead to a significantly increased transplantation rate of highly sensitized patients.

Cross Reactions↗
PubMed1998

Analysis of the renal transplant waiting list: application of a parametric competing risk method.

BACKGROUND: The strong competition for scarce renal graft resources jeopardizes an individual patient's chances of a transplantation within a reasonable time scale. This study was undertaken to quantify these chances of receiving a transplant. METHODS: All patients registered for their first renal allograft between January 1980 and December 1993 (n=40,636) in Eurotransplant were selected. The influence of patient characteristics, such as age, HLA phenotype frequency, % panel-reactive antibodies, period of registration, and ABO blood group, on the waiting list outflow was studied. The competing risk method was applied, and Poisson models were built to estimate the risk factor effects. RESULTS: The chance of transplantation within 10 years after registration was overestimated by Kaplan-Meier (84%); using the competing risk method it was only 74%. The predicted chance for death on the waiting list was overestimated by 33% (45% Kaplan-Meier vs. 12% competing risk). A time-varying covariate effect on the chances of waiting list outflow was observed. Favorable factors for quick transplantation, such as blood group AB or a common HLA phenotype, were no longer seen to be driving forces for transplantation once 5 to 6 years of waiting time had been accrued. CONCLUSION: When multiple outcomes exist, Kaplan-Meier estimates should not be interpreted as survival rates, while competing risk estimates yield appropriate chances. A significantly decaying effect of the usual allocation parameters is observed with ongoing waiting time. This phenomenon is the statistical basis for redesigning allocation strategies. Organ exchange algorithms should have the potential to adapt to these time-varying effects.

Analysis of Variance↗
PubMed1998

The new Eurotransplant Kidney Allocation System: report one year after implementation. Eurotransplant International Foundation.

BACKGROUND: Upon the availability of a cadaveric donor kidney, a delicate allocation process precedes every transplantation. A remodeled Eurotransplant Kidney Allocation System (ETKAS)-derived from simulation studies-was installed in March 1996. The purpose was to adjust long waiting times and international exchange balances, while aiming at an optimal HLA-mismatch distribution. The new ETKAS consisted of a point-score system that was 100% patient oriented. METHODS: The impact of the new ETKAS on the composition of the waiting list, and the outcome of the allocation procedures during its first year, were evaluated and compared with the results obtained in 1995. RESULTS: The percentage of long-waiting patients and of patients with poorly matchable HLA phenotype increased significantly, from 9% to 19% and from 19% to 29%, respectively. Zero HLA-A-, HLA-B-, HLA-DR-mismatched patients still comprised 23% of the kidney transplant activity. The kidney exchange of the different Eurotransplant countries became balanced within 4 months; this persisted during the rest of the year. Pediatric patients had a high transplantation rate due to an assignment of extra points. The composition of the waiting list showed, after 1 year, fewer long-waiting patients and fewer patients with rare HLA phenotypes. CONCLUSIONS: The new ETKAS was able in its first year to meet the goals set at its introduction. In comparison with the old ETKAS, there was a better trade-off between HLA matching and waiting time. The value of computer simulation studies has been demonstrated impressively in the context of organ allocation.

Cadaver↗
PubMed1998

Outcome of machine-perfused non-heart-beating donor kidneys, not allocated within the Eurotransplant area.

UNLABELLED: Eleven non-heart-beating (NHB) donor kidneys considered vital during machine perfusion (MP), could not be allocated inside Eurotransplant (ET). With the help of ET, five kidneys were transplanted in Karachi and six in Basel. Our goal was to prove that NHB kidneys successfully passing MP viability tests can be transplanted safely. METHODS: Donor age, serum creatinine (some post-mortem) and warm ischaemic time were, respectively, (mean and range): 44 (14-70) years, 137 mumol/l, and 44 (9-80) min. Reasons for refusal were: bold ureter (one), suboptimal flush (one), relatively long hypotensive phase (seven), and donor age of 70 years (two). After 8 h of MP, mean lactate dehydrogenase, intrarenal resistance and alpha glutathione S-transferase were (including range): 556 U/l (range 366-819 U/l), 0.86 mmHg/ml per min (0.41-1.15 mmHg/ml per min) and 1188 micrograms/l (575-2677 micrograms/l), respectively. Mean cold ischaemic time was 45 (range 28-72) h. RESULTS: Two kidneys showed immediate function, and nine showed delayed function. Mean creatinine levels after 1, 3 and 6 months were 295, 200 and 206 mumol/l, respectively. Four patients died for reasons not related to their kidney transplantation. CONCLUSIONS: We claim that MP can successfully assess viability of NHB donor kidneys. The reluctance to accept MP, and judged vital, NHB donor kidneys is not longer justified.

Adolescent↗