Determining Predictors of Actual Living Kidney Donation Based on Potential Donor Characteristics.

BACKGROUND: Living donor kidney transplantation is the optimal treatment for end-stage kidney disease; however, few living donor candidates (LDCs) who begin evaluation actually donate. While some LDCs are deemed medically ineligible, others discontinue for potentially modifiable reasons. METHODS: At five transplant centers, we conducted a prospective cohort study measuring LDCs' clinical and psychosocial characteristics, educational preparation, readiness to donate, and social determinants of health. We followed LDCs for 12 months after evaluation to determine whether they donated a kidney, opted to discontinue, had modifiable reasons for discontinuing, were medically ineligible, or had other recipient-related reasons for discontinuing. RESULTS: Among 2184 LDCs, 18.6% donated, 38.2% opted to or had modifiable reasons for discontinuing, and 43.2% were deemed ineligible due to medical or recipient-related reasons. Multivariable analyses comparing successful LDCs with those who did not complete donation for modifiable reasons (N = 1241) found that LDCs who discussed donation with the recipient before evaluation (OR, 2.31; 95% CI, 1.54-3.46), had completed high school (OR, 2.01; 95% CI, 1.21-3.35), or were a "close relation" to their recipient (OR, 1.89; 95% CI, 1.33-2.69) were more likely to donate. Conversely, LDCs who reported religion as important (OR, 0.55; 95% CI, 0.38-0.80), were Non-White (OR, 0.70; 95% CI, 0.49-1.00), or had overall higher anxiety scores (OR, 0.92; 95% CI, 0.86-0.99) were less likely to donate. CONCLUSION: With fewer than a fifth of LDCs donating, developing programs to provide greater emotional support and facilitate open discussions between LDCs and recipients earlier may increase living donation rates.

Qualifying a novel clinical trial endpoint (iBOX) predictive of long-term kidney transplant outcomes.

New immunosuppressive therapies that improve long-term graft survival are needed in kidney transplant. Critical Path Institute's Transplant Therapeutics Consortium received a qualification opinion for the iBOX Scoring System as a novel secondary efficacy endpoint for kidney transplant clinical trials through European Medicines Agency's qualification of novel methodologies for drug development. This is the first qualified endpoint for any transplant indication and is now available for use in kidney transplant clinical trials. Although the current efficacy failure endpoint has typically shown the noninferiority of therapeutic regimens, the iBOX Scoring System can be used to demonstrate the superiority of a new immunosuppressive therapy compared to the standard of care from 6 months to 24 months posttransplant in pivotal or exploratory drug therapeutic studies.

Qualifying a Novel Clinical Trial Endpoint (iBOX) Predictive of Long-Term Kidney Transplant Outcomes.

New immunosuppressive therapies that improve long-term graft survival are needed in kidney transplant. Critical Path Institute's Transplant Therapeutics Consortium received a qualification opinion for the iBOX Scoring System as a novel secondary efficacy endpoint for kidney transplant clinical trials through European Medicines Agency's qualification of novel methodologies for drug development. This is the first qualified endpoint for any transplant indication and is now available for use in kidney transplant clinical trials. Although the current efficacy failure endpoint has typically shown the noninferiority of therapeutic regimens, the iBOX Scoring System can be used to demonstrate the superiority of a new immunosuppressive therapy compared to the standard of care from 6 months to 24 months posttransplant in pivotal or exploratory drug therapeutic studies.

Ciprofloxacin for BK viremia prophylaxis in kidney transplant recipients: Results of a prospective, double-blind, randomized, placebo-controlled trial.

In kidney transplantation, BK virus infection has historically resulted in high rates of graft dysfunction and graft loss. Unlike other opportunistic infections, no therapies have been shown to prevent BK. The purpose of the current study was to evaluate the safety and efficacy of ciprofloxacin for the prevention of BK viremia in kidney transplant recipients. Two hundred kidney transplant recipients were enrolled in a prospective, randomized, double-blind, placebo-controlled trial comparing a 3-month course of ciprofloxacin (n = 133) vs placebo (n = 67) for the prevention of BK viremia. The primary endpoint of BK viremia at month 6 posttransplant occurred in 25 (18.8%) patients in the ciprofloxacin group and 5 (7.5%) in the placebo group (P = .03). Higher rates of BK viremia (23.3% vs 11.9%; P = .06) and BK nephropathy (5.8% vs 1.5%; P = .26) remained at 12 months in the ciprofloxacin group. Ciprofloxacin use was associated with a significantly higher rate of fluoroquinolone-resistant gram-negative infections (83.3% vs 50%; P = .04). A 3-month course of ciprofloxacin was ineffective at preventing BK viremia in kidney transplant recipients and was associated with an increased risk of fluoroquinolone-resistant infections. Clinical trial registration number: NCT01789203.

Cross-sectional and case-control analyses of the association of kidney function staging with adverse postoperative outcomes in general and vascular surgery.

OBJECTIVE: This study aimed to assess kidney dysfunction in general surgical patients and examine the effect on postoperative mortality and morbidity. BACKGROUND: An estimated 13% of the US population has chronic kidney disease (CKD), but awareness among patients and caregivers is lacking. METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) data sets for 2005-2007 were analyzed. Preoperative kidney function was assessed by the Modification of Diet in Renal Disease formula for estimated glomerular filtration rate (eGFR) and staged according to National Kidney Foundation. Cross-sectional analyses were performed for 30-day mortality (Cox proportional hazard) and incidence of major complications (nominal logistic regression). A case-control cohort of colectomy cases was analyzed comparing patients in the stage 4 CKD group and the no CKD group (no-CKD). RESULTS: Sixty-four percent of evaluable patients had reduced eGFR, but eGFR was not evaluable in 28% of the surgical cases. In the 260,352 evaluable cases, adjusted hazard ratio for 30-day mortality was 2.30 [95% confidence interval (CI), 2.11-2.51] for stage 3 CKD; 3.37 (95% CI, 3.01-3.76) for stage 4 CKD; and 3.05 (95% CI, 2.68-3.47) for stage 5 CKD compared with no-CKD (P < 0.0001). CKD was an independent risk factor for having major complications postsurgery [stage 3, odds ratio (OR) = 1.24 (95% CI, 1.19-1.29); stage 4, OR = 1.65 (95% CI, 1.52-1.78); and stage 5 CKD, OR = 1.40 (95% CI, 1.30-1.51); P < 0.0001]. The case-control for colectomy was confirmatory: increased 30-day mortality in stage 4 CKD versus no-CKD (hazard ratio = 2.58, 95% CI, 1.13-5.92; P = 0.025). CONCLUSIONS: Renal insufficiency may be underrecognized in the general and vascular (noncardiac) surgery population, is a leading independent predictor of poor early postoperative outcomes, and should be routinely assessed in the preoperative setting.

Clinical Outcomes of Heart Transplant Recipients Admitted with COVID-19 Infection in 2020: A Nationwide Analysis.

The COVID-19 pandemic, caused by infection of the SARS-CoV-2 virus, has impacted morbidity and mortality through widespread cytokine release and aberrant immunity; the mainstay of management has been immunosuppression. The aim of our retrospective study is to determine the effects of solid-organ transplantation (SOT) on COVID-19 admissions using data from the 2020 nationwide inpatient sample (NIS). After multivariate adjustment, we found COVID-19 admission with SOT had no difference in mortality (11.5% vs 11.1%, adjusted OR: 0.99 [95% CI 0.84-1.19, P = 0.99], no difference in need for vasopressor use (2.6% vs 1.8%, adjusted OR: 1.02 [95% CI 0.73-1.44, P = 0.88]), lower odds of requiring mechanical ventilation (MV) (13.7% vs 14.8%, adjusted OR: 0.83 [95% CI 0.71-0.97, P = 0.02]), lower odds of MV within 24 hours of admission (adjusted OR: 0.60 [95% CI 0.47-0.78, P < 0.01]), increased odds of mechanical circulatory support needs (adjusted OR 3.7 [95% CI 1.2-11.7, P = 0.025]), increased odds of acute renal failure requiring renal replacement therapy (adjusted OR 1.66 [95% CI 1.29-2.15, P < 0.01]), decreased mean length of stay (7.45 days vs 7.48 days, adjusted difference: 0.8 days less, P <0.01), and no difference in mean total hospitalization charges ($91,316 vs $79,100, adjusted difference: -$2,667, P = 0.57) compared to COVID-19 admissions without SOT.

Longitudinal estimated glomerular filtration rate (eGFR) modeling in long-term renal function to inform clinical trial design in kidney transplantation.

Kidney transplantation is the preferred treatment for individuals with end-stage kidney disease. From a modeling perspective, our understanding of kidney function trajectories after transplantation remains limited. Current modeling of kidney function post-transplantation is focused on linear slopes or percent decline and often excludes the highly variable early timepoints post-transplantation, where kidney function recovers and then stabilizes. Using estimated glomerular filtration rate (eGFR), a well-known biomarker of kidney function, from an aggregated dataset of 4904 kidney transplant patients including both observational studies and clinical trials, we developed a longitudinal model of kidney function trajectories from time of transplant to 6 years post-transplant. Our model is a nonlinear, mixed-effects model built in NONMEM that captured both the recovery phase after kidney transplantation, where the graft recovers function, and the long-term phase of stabilization and slow decline. Model fit was assessed using diagnostic plots and individual fits. Model performance, assessed via visual predictive checks, suggests accurate model predictions of eGFR at the median and lower 95% quantiles of eGFR, ranges which are of critical clinical importance for assessing loss of kidney function. Various clinically relevant covariates were also explored and found to improve the model. For example, transplant recipients of deceased donors recover function more slowly after transplantation and calcineurin inhibitor use promotes faster long-term decay. Our work provides a generalizable, nonlinear model of kidney allograft function that will be useful for estimating eGFR up to 6 years post-transplant in various clinically relevant populations.

Factors affecting survival after liver retransplantation: a systematic review and meta-analysis.

Background: Liver retransplantation (reLT) has historically had inferior survival relative to primary liver transplant (LT). To improve outcomes after reLT, researchers have identified factors predicting overall (OS) and/or graft survival (GS) after reLT. This systematic review and random effects meta-analysis sought to summarize this literature to elucidate the strongest independent predictors of post-reLT. Methods: A systematic review was conducted to identify manuscripts reporting factors affecting survival in multivariable Cox proportional hazards analyses. Papers with overlapping cohorts were excluded. Results: All 25 included studies were retrospective, and 15 (60%) were single-center studies. Patients on pre-transplant ventilation (HR, 3.11; 95% CI, 1.56-6.20; p = 0.001) and with high serum creatinine (HR, 1.46; 95% CI, 1.15-1.87; p = 0.002) had the highest mortality risk after reLT. Recipient age, Model for End-Stage Liver Disease score, donor age, and cold ischemia time >12 h also conferred a significant risk of post-reLT death (all p < 0.05). Factors affecting GS included donor age and retransplant interval (the time between LT and reLT; both p < 0.05). OS is significantly higher when the retransplant interval is ≤7 days relative to 8-30 days (p = 0.04). Conclusions: The meta-analysis was complicated by papers utilizing non-standardized cut-off values to group variables, which made between-study comparisons difficult. However, it did identify 7 variables that significantly impact survival after reLT, which could stimulate future research into improving post-reLT outcomes.

B-cell response in solid organ transplantation.

The transcriptional regulation of B-cell response to antigen stimulation is complex and involves an intricate network of dynamic signals from cytokines and transcription factors propagated from T-cell interaction. Long-term alloimmunity, in the setting of organ transplantation, is dependent on this B-cell response, which does not appear to be halted by current immunosuppressive regimens which are targeted at T cells. There is emerging evidence that shows that B cells have a diverse response to solid organ transplantation that extends beyond plasma cell antibody production. In this review, we discuss the mechanistic pathways of B-cell activation and differentiation as they relate to the transcriptional regulation of germinal center B cells, plasma cells, and memory B cells in the setting of solid organ transplantation.

The echocardiographic course of pretransplant pulmonary hypertension following kidney transplantation and associated outcomes.

The post 3 kidney transplant course of pretransplant echocardiographically-defined pulmonary hypertension (PH) was reviewed in 115 patients. Of these 61 patients (the largest cohort reported to date), underwent 160 "for indication" echocardiograms posttransplant (mean echocardiograms per patient: 2.6 ± 2.3). Patients undergoing posttransplant echocardiograms demonstrated greater risks for worse outcomes than those without posttransplant echocardiograms; however, there was no difference in mortality, death-censored graft failure or the composite of death or graft failure between these two groups. Of patients tested, 36 (59%) showed resolution of PH at a median of 37.5 months. Six patients (16.7%) in whom PH resolved (at a median of 29 months), experienced recurrence of PH after an interval of 48 months. No pretransplant demographic or echocardiographic characteristics distinguished those in whom PH persisted versus resolved. Though there was no difference in the risk for mortality or death-censored graft loss between the two groups at 3 and 5 years, there was a higher risk for the composite of mortality or graft loss at three but not at five years in the group with persistent PH. In conclusion, echocardiographically defined PH resolved in 59% of patients following kidney transplantation; but irrespective of resolution there was no clear association with worse outcome.

Utilization of Immunotherapy for the Treatment of Hepatocellular Carcinoma in the Peri-Transplant Setting: Transplant Oncology View.

Hepatocellular carcinoma (HCC) represents the second most common cause of cancer-related deaths and accounts for over eighty percent of primary liver cancers worldwide. Surgical resection and radiofrequency ablation in small tumors are included in the treatment options for HCC patients with good liver function profiles. According to the Milan Criteria, only a small portion of HCC patients are eligible for liver transplantation due to advanced-stage disease and large tumor size preventing/delaying organ allocation. Recently, the use of anti-programmed cell death protein 1 and programmed cell death ligand 1 (PD-1 and PD-L1) checkpoint inhibitors in the treatment of cancers have evolved rapidly and these therapies have been approved for the treatment of HCC. Immune checkpoint inhibitors have resulted in good clinical outcomes in pre-and post-transplant HCC patients, although, some reports showed that certain recipients may face rejection and graft loss. In this review, we aim to illustrate and summarize the utilization of immune checkpoint inhibitor therapies in pre-and post-liver transplants for HCC patients and discuss the assessment of immune checkpoint inhibitor regulators that might determine liver transplant outcomes.

Predicting a Positive Antibody Response After 2 SARS-CoV-2 mRNA Vaccines in Transplant Recipients: A Machine Learning Approach With External Validation.

BACKGROUND: Solid organ transplant recipients (SOTRs) are less likely to mount an antibody response to SARS-CoV-2 mRNA vaccines. Understanding risk factors for impaired vaccine response can guide strategies for antibody testing and additional vaccine dose recommendations. METHODS: Using a nationwide observational cohort of 1031 SOTRs, we created a machine learning model to explore, identify, rank, and quantify the association of 19 clinical factors with antibody responses to 2 doses of SARS-CoV-2 mRNA vaccines. External validation of the model was performed using a cohort of 512 SOTRs at Houston Methodist Hospital. RESULTS: Mycophenolate mofetil use, a shorter time since transplant, and older age were the strongest predictors of a negative antibody response, collectively contributing to 76% of the model's prediction performance. Other clinical factors, including transplanted organ, vaccine type (mRNA-1273 versus BNT162b2), sex, race, and other immunosuppressants, showed comparatively weaker associations with an antibody response. This model showed moderate prediction performance, with an area under the receiver operating characteristic curve of 0.79 in our cohort and 0.67 in the external validation cohort. An online calculator based on our prediction model is available at http://transplantmodels.com/covidvaccine/ . CONCLUSIONS: Our machine learning model helps understand which transplant patients need closer follow-up and additional doses of vaccine to achieve protective immunity. The online calculator based on this model can be incorporated into transplant providers' practice to facilitate patient-centric, precision risk stratification and inform vaccination strategies among SOTRs.

Evaluation of Carotid Ultrasonography Screening Among Kidney Transplant Candidates: A Single-Center, Retrospective Study.

BACKGROUND: Kidney transplant candidates undergo rigorous testing prior to clearance for transplantation. Because kidney transplant candidates may be at increased risk for carotid artery stenosis because of arteriosclerosis and atherosclerosis secondary to hypertension, vascular calcification, and diabetes, carotid ultrasound is often performed with the intent of preventing a cerebrovascular accident in the perioperative or posttransplant period. To our knowledge, there has not been a study investigating the utility of screening carotid ultrasonography in pretransplant candidates. The purpose of the present study was to investigate the yield of carotid ultrasonography in end-stage renal disease patients, at high risk for having clinically significant vascular disease evaluated at our center for kidney transplantation during the years 2009 to 2014. METHODS: Data for carotid ultrasound findings and risk factors for carotid artery disease were extracted from the medical records. RESULTS: A total of 882 patients were included in our study of which only 13 patients (1.47% of the cohort) had significant carotid artery stenosis (>70%) on ultrasound testing. Using multiple logistic regression on the outcome of carotid stenosis, congestive heart failure (adjusted odds ratio, 5.2), and peripheral vascular disease (adjusted odds ratio, 4.4) were positively associated with carotid stenosis. CONCLUSIONS: The prevalence of significant carotid artery stenosis was only 1.47% in our cohort of kidney transplant candidates, and the routine use of carotid ultrasound testing in this population may not be an efficient use of clinical resources. Use of risk factors, such as congestive heart failure or peripheral vascular disease, may identify patients who are more likely to benefit from carotid ultrasonography screening.

Intermediate-term graft loss after renal transplantation is associated with both donor-specific antibody and acute rejection.

BACKGROUND: Renal transplant recipients with de novo DSA (dDSA) experience higher rates of rejection and worse graft survival than dDSA-free recipients. This study presents a single-center review of dDSA monitoring in a large, multi-ethnic cohort of renal transplant recipients. METHODS: The authors performed a nested case-control study of adult kidney and kidney-pancreas recipients from July 2007 through July 2011. Cases were defined as dDSA-positive whereas controls were all DSA-negative transplant recipients. DSA were determined at 1, 3, 6, 9, and 12 months posttransplant, and every 6 months thereafter. RESULTS: Of 503 recipients in the analysis, 24% developed a dDSA, of whom 73% had dDSA against DQ antigen. Median time to dDSA was 6.1 months (range 0.2-44.6 months). After multivariate analysis, African American race, kidney-pancreas recipient, and increasing numbers of human leukocyte antigen mismatches were independent risk factors for dDSA. Recipients with dDSA were more likely to suffer an acute rejection (AR) (35% vs. 10%, P<0.001), an antibody-mediated AR (16% vs. 0.3%, P<0.001), an AR ascribed to noncompliance (8% vs. 2%, P=0.001), and a recurrent AR (6% vs. 1%, P=0.002) than dDSA-negative recipients. At a median follow-up of 31 months, the death-censored actuarial graft survival of dDSA recipients was worse than the DSA-free cohort (P=0.002). Yet, for AR-free recipients, there was no difference in graft survival between cohorts (P=0.66). CONCLUSIONS: Development of dDSA was associated with an increased incidence of graft loss, yet the detrimental effect of dDSA was limited in the intermediate term to recipients with AR.