Transplantation Direct最新文献

Background: Transplant centers have traditionally relied upon procurement teams from their own programs (transplant program procurement team [TPT]) to recover donation after circulatory death (DCD) livers and rarely use surgical procurement teams not affiliated with the recipient center (nontransplant program procurement team [NTPT]). However, in the era of wider geographic organ sharing, greater reliance on NTPTs is often necessary.

Methods: We used national data to study the association between the origin of the donor procurement team (NTPT versus TPT) and the risk of DCD liver allograft failure.

Results: Five hundred NTPT and 2257 TPT DCD transplants were identified: 1-y graft survival was 88.9 and 88.6%, respectively (P = 0.962). In a multivariable model, the origin of the procurement team was not associated with graft failure NTPT versus TPT (hazard ratio, 0.92; 95% confidence interval, 0.71-1.22; P = 0.57) but rather with known risks for DCD graft loss including donor age, degree of recipient illness, cold ischemic time, and retransplantation. The overall incidence of retransplantation and ischemic cholangiopathy as an indication for retransplantation were similar between NTPT and TPT.

Conclusions: This data suggests that transplant centers may be able to safely use DCD livers recovered by local surgical teams.

Background: Endomyocardial biopsy (EMB) is considered the gold-standard method to diagnose rejection after heart transplantation. However, the many disadvantages and potential complications of this test restrict its routine application, particularly in pediatric patients. Donor-derived cell-free DNA (dd-cfDNA), released by the transplanted heart as result of cellular injury, is emerging as a biomarker of tissue damage involved in ischemia/reperfusion injury and posttransplant rejection. In the present study, we systematically evaluated dd-cfDNA levels in pediatric heart transplant patients coming for follow-up visits to our clinic for 12 mo, with the aim of determining whether dd-cfDNA monitoring could be efficiently applied and integrated into the posttransplant management of rejection in pediatric recipients.

Methods: Twenty-nine patients were enrolled, and cfDNA was obtained from 158 blood samples collected during posttransplant follow-up. dd-cfDNA% was determined with a droplet-digital polymerase chain reaction assay. EMB scores, donor-specific antibody measurements, and distress marker quantification were correlated with dd-cfDNA, together with echocardiogram information.

Results: The percentage of dd-cfDNA increased when EMBs scored positive for rejection (P = 0.0002) and donor-specific antibodies were present (P = 0.0010). N-terminal pro-B-type natriuretic peptide and high-sensitive troponin I elevation were significantly associated with dd-cfDNA release (P = 0.02 and P < 0.0001, respectively), as were reduced isovolumetric relaxation time (P = 0.0031), signs of heart failure (P = 0.0018), and treatment for rejection (P = 0.0017). By determining a positive threshold for rejection at 0.55%, the test had a negative predictive value maximized at 100%.

Conclusions: Collectively, results indicate that dd-cfDNA monitoring has a high negative prognostic value, suggesting that in heart transplanted children with dd-cfDNA levels of <0.55% threshold, protocol EMBs may be postponed.

Background: Although COVID-19 is no longer a declared global health emergency, data remain limited on the impact of COVID-19 in lung transplant recipients.

Methods: We identified lung transplant recipients who were diagnosed with COVID-19 from March 2020 through August 2022 in our institutional database and investigated clinical outcomes. We then analyzed outcomes based on date of COVID-19 diagnosis (first wave March 2020-October 2020; second wave November 2020-2021; third wave December 2021-September 2022) and compared these results.

Results: Of the 210 lung transplant recipients (median age 67; 67% men) enrolled, 140 (67%) required hospital admission. Among admitted recipients, 35 (25%) were intubated and 7 (5%) were placed on extracorporeal membrane oxygenation. Overall survival was 67.1% at 1 y and 59.0% at 2 y post-COVID-19 diagnosis. COVID-19 led to mortality in all 5 patients diagnosed during their index admission for lung transplantation. Although overall survival was significantly better in recipients with COVID-19 during the third wave, in-hospital mortality remained high (first wave 28%, second wave 38%, and 28% third wave). Vaccination (partially vaccinated versus none and fully vaccinated versus none) was the only significant protective factor for hospital admission, and age 70 y and older and partially vaccinated (versus none or fully vaccinated) were independent risk factors for in-hospital mortality.

Conclusions: Overall survival after COVID-19 infection in lung transplant recipients continues to improve; however, in-hospital mortality remains remarkably high. Vaccination appears to have been impactful in preventing hospital admission, but its impact on in-hospital mortality is still unclear. Further research is needed to better identify lung transplant recipients at high risk for mortality from COVID-19.

Background: In HLA-incompatible kidney transplantation, the efficacy of desensitization in terms of anti-HLA antibody kinetics is not well characterized. We present an overview of the course of anti-HLA antibodies throughout plasma exchange (PE) desensitization in a series of crossmatch-positive patients.

Methods: All consecutive candidates in the Dutch HLA-incompatible kidney transplantation program between November 2012 and January 2022 were included. The eligibility criteria were a positive crossmatch with a living kidney donor and no options for compatible transplantation. Desensitization consisted of 5-10 PE with low-dose IVIg.

Results: A total of 16 patient-donor pairs were included. Patients had median virtual panel-reactive antibody of 99.58%. Cumulative donor-specific anti-HLA antibody (cumDSA) mean fluorescence intensity (MFI) was 31 399 median, and immunodominant DSA (iDSA) MFI was 18 677 for class I and 21 893 for class II. Median anti-HLA antibody MFI response to desensitization was worse in class II as compared with class I (P < 0.001), particularly for HLA-DQ. Class I cumDSA MFI decreased 68% after 4 PE versus 53% in class II. The decrease between the fifth and the 10th PE sessions was modest with 21% in class I versus 9% in class II. Antibody-mediated rejection occurred in 85% of patients, with the iDSA directed to the same mismatched HLA as before desensitization, except for 3 patients, of whom 2 had vigorous rebound of antibodies to repeated mismatches (RMMs). Rebound was highest (86%) in RMM-DSA with prior grafts removed (transplantectomy n = 7), lower (39%) in non-RMM-DSA (n = 30), and lowest (11%) for RMM-DSA with in situ grafts (n = 5; P = 0.018 for RMM-DSA transplantectomy versus RMM-DSA graft in situ). With a median follow-up of 59 mo, 1 patient had died resulting in a death-censored graft survival of 73%.

Conclusions: Patients with class II DSA, and particularly those directed against HLA-DQ locus, were difficult to desensitize.

Background: Organ transplantation is a well-established intervention but is reliant on the donation of organs and tissues, mostly from deceased donors. The proportion of Australians proceeding to organ donation (OD) has increased, but the proportion of Indigenous Australians proceeding remains two-thirds that of non-Indigenous Australians. We sought to explore perceived barriers and enablers for the involvement of Indigenous peoples in the OD process.

Methods: Qualitative methodology centered around focus groups was used to capture the experiences and perspectives of Indigenous people regarding OD. A purposively sampled group of Aboriginal Liaison Officers working within the Alice Springs Hospital Intensive Care Unit (ASH ICU) participated in up to 6 focus groups during 2021 with subsequent thematic analysis of the enablers and barriers to Indigenous participation in the OD process. The ASH ICU is the only ICU servicing Central Australia, and 70% of admissions are Indigenous patients.

Results: Four primary themes emerged: OD is a new and culturally taboo topic; conversations related to OD are confronting; education is needed (both about OD and cultural education for clinicians); and lack of trust in the healthcare system.

Conclusions: There are cultural barriers to engaging in the OD process and clinicians need more training on the delivery of culturally safe communication is needed. Despite this, there was a recognition that OD is important. Education about OD needs to be place based, culturally and linguistically appropriate, informed by local knowledge, delivered in community, and occur before a family member is admitted to ICU.

Background: The number of patients waiting for heart transplant far exceeds the number of hearts available. Donation after circulatory death (DCD) combined with machine perfusion can increase the number of transplantable hearts by as much as 48%. Emerging studies also suggest machine perfusion could enable allograft "reconditioning" to optimize outcomes. However, a detailed understanding of the energetic substrates and metabolic changes during perfusion is lacking.

Methods: Metabolites were analyzed using 1-dimensional ¹H and 2-dimensional ¹³C-¹H heteronuclear spectrum quantum correlation nuclear magnetic resonance spectroscopy on serial perfusate samples (N = 98) from 32 DCD hearts that were successfully transplanted. Wilcoxon signed-rank and Kruskal-Wallis tests were used to test for significant differences in metabolite resonances during perfusion and network analysis was used to uncover altered metabolic pathways.

Results: Metabolite differences were observed comparing baseline perfusate to samples from hearts at time points 1-2, 3-4, and 5-6 h of perfusion and all pairwise combinations. Among the most significant changes observed were a steady decrease in fatty acids and succinate and an increase in amino acids, especially alanine, glutamine, and glycine. This core set of metabolites was also altered in a DCD porcine model perfused with a nonblood-based perfusate.

Conclusions: Temporal metabolic changes were identified during ex vivo perfusion of DCD hearts. Fatty acids, which are normally the predominant myocardial energy source, are rapidly depleted, while amino acids such as alanine, glutamine, and glycine increase. We also noted depletion of ketone, β-hydroxybutyric acid, which is known to have cardioprotective properties. Collectively, these results suggest a shift in energy substrates and provide a basis to design optimal preservation techniques during perfusion.

Background: The effect of donor body mass index (BMI) on liver transplantation (LT) outcomes remains unclear.

Methods: A systematic search of the MEDLINE, CENTRAL, Web of Science, and bibliographic reference lists was conducted. All comparative studies evaluating the outcomes of LT in obese (BMI > 30 kg/m²) and nonobese donors (BMI < 30 kg/m²) were included, and their risk of bias was assessed using the ROBINS-I assessment tool. Patient and graft survival, acute rejection, and graft failure requiring retransplantation were evaluated as outcome parameters. A random-effects model was used for outcome synthesis.

Results: We included 6 comparative studies reporting a total of 5071 liver transplant recipients from 708 obese and 4363 nonobese donors. There was no significant difference in 1-y (89.1% versus 84.0%, odds ratio [OR] 1.58; 95% CI 0.63-3.94, P = 0.33), 5-y (74.2%% versus 73.5%, OR 1.12; 95% CI 0.45-2.80, P = 0.81) graft survival, and 1-y (87.1% versus 90.3%, OR 0.71; 95% CI 0.43-1.15, P = 0.17) and 5-y (64.5% versus 71.6%, OR 0.71; 95% CI 0.49-1.05, P = 0.08) patient survival between 2 groups. Furthermore, recipients from obese and nonobese donors had a comparable risk of graft failure requiring retransplantation (OR 0.92; 95% CI 0.33-2.60, P = 0.88) or acute graft rejection (OR 0.70; 95% CI 0.45-1.11, P = 0.13).

Conclusions: A meta-analysis of the best available evidence (level 2a) demonstrates that donor obesity does not seem to have a negative impact on graft or patient outcomes. The available studies might be subject to selection bias as the grafts from obese donors are usually subject to biopsy to exclude steatosis and the recipients usually belong to the low-risk group. Future research is needed to evaluate the impact of donors subgrouped by various higher BMI on graft and patient-related outcomes as well as to capture data of the discarded grafts from obese donors; hence, selection criteria for the grafts that could be used for transplantation from obese donors is identified.

Background: There are no high-quality data to guide long-term mycophenolate mofetil (MMF) dosing in kidney transplant recipients (KTRs) to balance the long-term risks of allograft rejection with that of infections and malignancy. At our center, KTRs are managed with either a "preemptive" dose reduction strategy, where the MMF dose is reduced after the first year before the development of adverse events, or with a "reactive" dosing strategy, where they are maintained on the same MMF dose and only reduced if they develop an adverse event. We hypothesized that a preemptive MMF dosing strategy after the first year of transplantation is associated with decreased infections without increasing alloimmune complications.

Methods: We conducted a retrospective cohort study of all KTRs receiving MMF from January 1, 2015, to December 31, 2020. The primary outcome was the incidence of infections requiring hospitalization.

Results: One hundred forty-two KTRs met the inclusion criteria, of whom 44 (31%) were in the preemptive group and 98 (69%) were in the reactive group. The median follow-up was 4 y (interquartile range, 3.8-4.0). Multivariable analysis showed that a preemptive MMF dose reduction strategy was associated with a lower risk of infections requiring hospitalization (adjusted hazard ratio = 0.39; 95% confidence interval, 0.16-0.92). There was no difference in graft loss, rejection, or estimated glomerular filtration rate slope.

Conclusions: Preemptive MMF dose reduction in KTRs may be an effective strategy to prevent infections without increasing the risk of allograft rejection. Randomized clinical trials are needed to confirm these findings.

Background: To investigate the impact of intrapatient variability (IPV) in the levels of immunosuppressant drugs on health outcomes after liver transplantation.

Methods: A comprehensive systematic review and meta-analysis were conducted, examining literature from MEDLINE/PubMed, Embase, Web of Science, Cochrane Reviews, and Cochrane CENTRAL.

Results: The analysis focused on acute rejection, graft survival, acute kidney injury, and cancer risk as health outcomes. Of 2901 articles screened, 10 met the inclusion criteria. The results indicate a 19% reduction in the risk of acute rejection in patients with lower IPV (RR = 0.81; 95% confidence interval, 0.66-0.99), although 6 studies found no significant association between high IPV and acute rejection. Contrasting results were observed for graft survival, with 1 study indicating worse outcomes for high IPV, whereas another reported no significant difference. High IPV was consistently associated with acute kidney injury across 3 studies. One study suggested a link between high IPV and hepatocellular carcinoma, although a meta-analysis for these outcomes was not feasible.

Conclusions: These findings point to a marginal but statistically significant association between high IPV and an increased risk of acute rejection, highlighting the importance of precise management of immunosuppressive drugs in liver transplant recipients to enhance patient outcomes.

Background: Dialysis vintage is associated with worse outcomes after kidney transplantation. The reasons behind this observation include immunological and nonimmunological risk factors. To mitigate the influence of immunological factors, we examined the association between time on dialysis and clinical outcomes in a cohort of HLA-identical kidney transplant recipients.

Methods: This retrospective study included 13 321 kidney transplant recipients between 1999 and 2016, of whom 589 were HLA identical followed for at least 5 y. Patient and graft survivals were compared according to dialysis time (<12 or >12 mo) using the log-rank test and Cox regression analysis. We compared surgical complications, cytomegalovirus infection, acute rejection, disease recurrence, and the trajectories of estimated glomerular filtration rate (eGFR).

Results: Median time on dialysis was 15 mo; 9.2% of patients received preemptive transplants, and 55.3% of patients were on dialysis for >12 mo. After a median follow-up time of 154 mo, there were no differences in unadjusted and adjusted patient and graft survivals (1, 5, 10, and 15 y) between the 2 groups. There were no differences in the incidence of surgical complications (6.2% versus 3.1%), acute rejection (6.1% versus 7.7%), cytomegalovirus infection (7.6% versus 4.0%), and disease recurrence (4.2% versus 4.0%), respectively. There were no differences in mean eGFR during 5 y or in the proportion of patients with an eGFR <30 mL/min at 5 y (9.9% versus 9.2%).

Conclusions: In this low immunological risk cohort of HLA-identical kidney transplant recipients, we did not observe any association between dialysis vintage on patient survival and graft survival.