The Kidney Not Taken: Single-Kidney Use in Deceased Donors.

BACKGROUND: The nonuse rate for kidneys recovered from deceased donors is increasing, rising to 27% in 2023. In 10% of these cases, 1 kidney is transplanted but the mate kidney is not. STUDY DESIGN: We conducted a retrospective, single-center cohort study from December 2001 to May 2023 comparing single kidneys transplanted at our center (where the contralateral kidney was not used) to kidneys where both were transplanted separately, at least 1 of which was at our center. RESULTS: We performed 395 single deceased-donor kidney transplants in which the mate kidney was not transplanted. Primary reasons for mate kidney nonuse were as follows: no recipient located or list exhausted (33.4%), kidney trauma or injury or anatomic abnormalities (18.7%), biopsy findings (16.7%), and poor renal function (13.7%). Mean donor and recipient ages were 51.5 ± 14.2 and 60 ± 12.6 years, respectively. Mean kidney donor profile index was 73% ± 22%, and 104 donors (26.3%) had kidney donor profile index >85%. Mean cold ischemia was 25.6 ± 7.4 hours, and 280 kidneys (70.7%) were imported. Compared with 2,303 concurrent control transplants performed at our center, primary nonfunction or thrombosis (5.1% single vs 2.8% control) and delayed graft function (35.4% single vs 30.1% control) were greater with single-kidney use (both p < 0.05). Median patient and death-censored graft survival were shorter in the single group (11.6 vs 13.5 years, p = 0.03 and 11.6 vs 19 years, p = 0.003), although the former was at least double median survival on the waiting list. In patients with functioning grafts in the single-kidney group, 1-year mean serum creatinine was 1.77 ± 0.8 mg/dL and estimated glomerular filtration rate was 44.8 ± 20 mL/min/1.73 m 2 . CONCLUSIONS: These findings suggest that many mate kidneys are being inappropriately rejected, given the acceptable outcomes that can be achieved by transplanting the single kidney in appropriately selected recipients.

Single center experience and literature review of kidney transplantation from non-ideal donors with acute kidney injury: Risk and reward.

INTRODUCTION: There is limited experience transplanting kidneys from either expanded criteria donors (ECD) or donation after circulatory death (DCD) deceased donors with terminal acute kidney injury (AKI). METHODS: AKI kidneys were defined by a donor terminal serum creatinine level >2.0 mg/dL whereas non-ideal deceased donor (NIDD) kidneys were defined as AKI/DCD or AKI/ECDs. RESULTS: From February 2007 to March 2023, we transplanted 266 single AKI donor kidneys including 29 from ECDs, 29 from DCDs (n = 58 NIDDs), and 208 from brain-dead standard criteria donors (SCDs). Mean donor age (43.7 NIDD vs. 33.5 years SCD), KDPI (66% NIDD vs. 45% SCD), and recipient age (57 NIDD vs. 51 years SCD) were higher in the NIDD group (all p < .01). Mean waiting times (17.8 NIDD vs. 24.2 months SCD) and dialysis duration (34 NIDD vs. 47 months SCD) were shorter in the NIDD group (p < .05). Delayed graft function (DGF, 48%) and 1-year graft survival (92.7% NIDD vs. 95.9% SCD) was similar in both groups. Five-year patient and kidney graft survival rates were 82.1% versus 89.9% and 82.1% versus 75.2% (both p = NS) in the NIDD versus SCD groups, respectively. CONCLUSIONS: The use of kidneys from AKI donors can be safely liberalized to include selected ECD and DCD donors.

Does dialysis modality or duration influence outcomes in simultaneous pancreas-kidney transplant recipients? Single center experience and review of the literature.

AIM: The influence of dialysis modality and duration on outcomes following simultaneous pancreas-kidney transplantation (SPKT) remains uncertain. METHODS: We performed a single-center retrospective review in 255 SPKT recipients according to dialysis modality (55 preemptive/no dialysis-ND, 70 peritoneal dialysis-PD, 130 hemodialysis-HD) and duration (55 none, 137 < 2 years, 41 2-4 years, 22 > 4 years). RESULTS: Mean follow-up was 9.4 years (median 9.2 years). Early (3-month) relaparotomy rate (20% ND vs. 36% PD/HD, p = .03) was lower in ND patients. There were no differences in early graft loss, patient survival, overall or death-censored kidney or pancreas graft survival rates (GSR) at 1 or 10 years follow-up. When analyzing dialysis duration, there were no differences in rates of pancreas thrombosis or early pancreas graft loss. Kidney delayed graft function (DGF) was lower in the ND/short dialysis groups combined (1.0%), compared to the intermediate/long dialysis groups combined (9.5%, p = .003). Early relaparotomy rates were higher with longer duration of dialysis (p = .045 between ND and >4 years of dialysis). Patient survival in the long dialysis group was 50% compared to 69.5% in the other three groups combined (p = .09). However, both overall and death-censored kidney and pancreas GSR were comparable. CONCLUSIONS: Preemptively transplanted patients had a lower incidence of kidney DGF and relaparotomy whereas patient survival was slightly lower with longer dialysis vintage prior to SPKT. Dialysis modality and duration did not influence either overall or death-censored pancreas or kidney GSR in patients with short waiting times, low KDPI donor organs, and dialysis duration up to 4 years.

Knowing When to Ignore the Numbers: Single-Center Experience Transplanting Deceased Donor Kidneys with Poor Perfusion Parameters.

BACKGROUND: Hypothermic machine perfusion is frequently used in evaluating marginal kidneys with poor perfusion parameters (PPP) contributing to delays in kidney placement or discard. We examined outcomes in deceased donor kidney transplants with PPP compared with those with optimal perfusion parameters (OPP). STUDY DESIGN: We conducted a retrospective single-center cohort study from 2001 to 2021 comparing PPP (n = 91) with OPP (n = 598) deceased donor kidney transplants. PPP was defined as terminal flow ≤80 mL/min and terminal resistance ≥0.40 mmHg/mL/min. OPP was defined as terminal flow ≥120 mL/min and terminal resistance ≤0.20 mmHg/mL/min. RESULTS: Mean terminal flow was PPP 66 ± 16 vs OPP 149 ± 21 mL/min and resistance was PPP 0.47 ± 0.10 vs OPP 0.15 ± 0.04 mmHg/mL/min (both p < 0.001). Donor age, donation after cardiac death, and terminal serum creatinine levels were similar between groups. Mean Kidney Donor Profile Index was higher among PPP donors (PPP 65 ± 23% vs OPP 52 ± 27%, p < 0.001). The PPP transplant group had more females and lower weight and BMI. Delayed graft function was comparable (PPP 32% vs OPP 27%, p = 0.33) even though cold ischemia times trended toward longer in PPP kidneys (PPP 28 ± 10 vs OPP 26 ± 9 hours, p = 0.09). One-year patient survival (PPP 98% vs OPP 97%, p = 0.84) and graft survival (PPP 91% vs OPP 92%, p = 0.23) were equivalent. PPP did predict inferior overall and death-censored graft survival long-term (overall hazard ratio 1.63, 95% CI 1.19 to 2.23 and death-censored hazard ratio 1.77, 95% CI 1.15 to 2.74). At 1 year, the estimated glomerular filtration rate was higher with OPP kidneys (PPP 40 ± 17 vs OPP 52 ± 19 mL/min/1.73 m 2 , p < 0.001). CONCLUSIONS: Short-term outcomes in PPP kidneys were comparable to OPP kidneys despite higher Kidney Donor Profile Index and longer cold ischemia times, suggesting a role for increased utilization of these organs with careful recipient selection.

Long-term outcomes of kidney transplantation from deceased donors with terminal acute kidney injury: Single center experience and literature review.

INTRODUCTION: Long-term outcomes of kidney transplantation from deceased donors (DDKTs) with terminal acute kidney injury (AKI) are not well defined. METHODS: Single center retrospective review of DDKTs from 1/31/07-12/31/19. AKI kidneys were defined by a doubling of the donor's admission serum creatinine (SCr) level AND a terminal SCr ≥2.0 mg/dl. RESULTS: A total of 188 AKI DDKTs were performed, including 154 from brain-dead standard criteria donors (SCD). Mean donor age was 36 years and mean Kidney Donor Profile Index was 50%; mean admission and terminal SCr levels were 1.3 and 3.1 mg/dl, respectively. With a mean follow-up of 94 months (median 89 months), overall patient (both 71.3%) and graft survival (54% AKI vs. 57% non-AKI) rates were comparable to concurrent DDKTs from brain-dead non-AKI SCDs (n = 769). Delayed graft function (DGF) was higher in AKI kidney recipients (47% vs. 20% non-AKI DDKTs, p < .0001). DGF was associated with lower graft survival in recipients of both AKI and non-AKI SCD kidneys but the impact was earlier and more pronounced in non-AKI recipients. CONCLUSIONS: Despite having more than twice the incidence of DGF, kidneys from deceased donors with terminal AKI have long-term outcomes comparable to non-AKI SCD kidneys and represent a safe and effective method to expand the donor pool.

Influence of donor and recipient sex on outcomes following simultaneous pancreas-kidney transplantation in the new millennium: Single-center experience and review of the literature.

INTRODUCTION: The influence of sex on outcomes following simultaneous pancreas-kidney transplantation (SPKT) in the modern era is uncertain. METHODS: We retrospectively studied 255 patients undergoing SPKT from 11/2001 to 8/2020. Cases were stratified according to donor (D) sex, recipient (R) sex, 4 D/R sex categories, and D/R sex-matched versus mismatched. RESULTS: D-male was associated with slightly higher patient (p = .08) and kidney (p = .002) but not pancreas (p = .23) graft survival rates (GSR) compared to D-female. There were no differences in recipient outcomes other than slightly higher pancreas thrombosis (8% R-female vs. 4.2% R-male, p = .28) and early relaparotomy rates in female recipients (38% R-female vs. 29% R-male, p = .14). When analyzing the 4 D/R sex categories, the two D-male groups had higher kidney GSRs compared to the two D-female groups (p = .01) whereas early relaparotomy and pancreas thrombosis rates were numerically higher in the D-female/R-female group compared to the other three groups. Finally, there were no significant differences in outcomes between sex-matched and sex-mismatched groups although overall survival outcomes were lower with female donors irrespective of recipient sex. CONCLUSIONS: The influence of D/R sex following SPKT is subject to multiple confounding issues but survival rates appear to be higher in D-male/R-male and lower in D-female/R-male categories.

Improved surgical outcomes following simultaneous pancreas-kidney transplantation in the contemporary era.

BACKGROUND: Complications leading to early technical failure have been the Achilles' heel of simultaneous pancreas-kidney transplantation (SPKT). The study purpose was to analyze longitudinally our experience with early surgical complications following SPKT with an emphasis on changes in practice that improved outcomes in the most recent era. STUDY DESIGN: Single center retrospective review of all SPKTs from 11/1/01 to 8/12/20 with enteric drainage. Early relaparotomy was defined as occurring within 3 months of SPKT. Patients were stratified into two sequential eras: Era 1 (E1): 11/1/01-5/30/13; Era 2 (E2) 6/1/13-8/12/20 based on changes in practice that occurred pursuant to donor age and pancreas cold ischemia time (CIT). RESULTS: 255 consecutive SPKTs were analyzed (E1, n = 165; E2, n = 90). E1 patients received organs from older donors (mean E1 27.3 vs. E2 23.1 years) with longer pancreas cold CITs) (mean E1 16.1 vs. E2 13.3 h, both p < .05). E1 patients had a higher early relaparotomy rate (E1 43.0% vs. E2 14.4%) and were more likely to require allograft pancreatectomy (E1 9.1% vs. E2 2.2%, both p < .05). E2 patients underwent systemic venous drainage more frequently (E1 8% vs. E2 29%) but pancreas venous drainage did not influence either relaparotomy or allograft pancreatectomy rates. The most common indications for early relaparotomy in E1 were allograft thrombosis (11.5%) and peri-pancreatic phlegmon/abscess (8.5%) whereas in E2 were thrombosis, pancreatitis/infection, and bowel obstruction (each 3%). CONCLUSION: Maximizing donor quality (younger donors) and minimizing pancreas CIT are paramount for reducing early surgical complications following SPKT.

Improving Outcomes after Allograft Nephrectomy through Use of Preoperative Angiographic Kidney Embolization.

BACKGROUND: Allograft nephrectomy (AN) has been associated with considerable perioperative morbidity. We aimed to determine if preoperative angiographic kidney embolization (PAKE) to induce graft thrombosis before AN improves outcomes. STUDY DESIGN: We reviewed adult kidney transplant alone patients who underwent AN at a single center from 2002 to 2020 and compared perioperative outcomes for patients with and without PAKE. RESULTS: Eighty patients underwent AN, including 54 (67.5%) with PAKE before AN and 26 (32.5%) with AN alone. PAKE was associated with significantly reduced blood loss (PAKE: mean 266 ± 292 mL vs AN alone: 495 ± 689 mL; p = 0.04) and reduced transfusion requirements (PAKE: mean 0.5 ± 0.8 packed red blood cell units vs AN alone: 1.6 ± 2.6 units; p = 0.004) despite similar preoperative hemoglobin levels. Mean operating time (PAKE: 142 ± 43 minutes vs AN alone: 202 ± 111 minutes; p = 0.001) and length of hospital stay (PAKE: 4.3 ± 2.0 days vs AN alone: 9.3 ± 9.4 days; p = 0.0003) also favored PAKE, as did the surgical complication rate (PAKE: 6/54 [11%] vs AN alone: 9/26 [35%], p = 0.02). Long-term patient survival after AN was comparable in both groups. CONCLUSIONS: PAKE was associated with lower intraoperative blood loss, fewer transfusions, reduced operating time, shorter length of stay, and fewer surgical complications compared with AN alone at our center.

Simultaneous pancreas-kidney transplantation in Caucasian versus African American patients: Does recipient race influence outcomes?

The influence of African American (AA) recipient race on outcomes following simultaneous pancreas-kidney transplantation (SPKT) is uncertain. METHODS: From 11/01 to 2/19, we retrospectively studied 158 Caucasian (C) and 57 AA patients (pts) undergoing SPKT. RESULTS: The AA group had fewer patients on peritoneal dialysis (30% C vs. 14% AA), more patients with longer dialysis duration (28% C vs. 51% AA), more sensitized (PRA ≥20%) patients (6% C vs. 21% AA), and more patients with pretransplant C-peptide levels ≥2.0 ng/ml (11% C vs. 35% AA, all P < .05). With a mean 9.2 year follow-up, patient survival (65% C vs. 77% AA, P = .098) slightly favored the AA group, whereas kidney (55% C vs. 60% AA) and pancreas (48% C vs. 54% AA) graft survival rates (GSRs) were comparable. Death-censored kidney (71% C vs. 68% AA) and pancreas (both 62%) GSRs demonstrated that death with a functioning graft (DWFG) was more common in C vs. AA patients (23% C vs. 12% AA, P = .10). The incidence of death-censored dual graft loss (usually rejection) was 7% C versus 21% AA (P = .005). CONCLUSIONS: Following SPKT, AA patients are at a greater risk for dual immunological graft loss whereas C patients are at greater risk for DWFG.

Early Graft Loss after Deceased-Donor Kidney Transplantation: What Are the Consequences?

BACKGROUND: Decreasing kidney discards continues to be of paramount importance for improving organ transplant access, but transplantation of nonideal deceased donor kidneys may have higher inherent risks of early graft loss (EGL). Patients with EGL (defined as graft failure within 90 days after transplant) are allowed reinstatement of waiting time according to United Network for Organ Sharing (UNOS) policy. The purpose of this study was to examine outcomes for patients experiencing EGL. STUDY DESIGN: We performed a single center retrospective review of adult deceased donor kidney transplant (DDKT)-alone recipients from 2001 to 2018, comparing those with EGL (including primary nonfunction [PNF]) to those without. RESULTS: EGL occurred in 103 (5.5%) of 1,868 patients, including 57 (55%) PNF, 25 (24%) deaths, 16 (16%) thrombosis, 3 (3%) rejection, and 2 (2%) disease recurrence. Kidney Donor Profile Index (KDPI) > 85% and donation after circulatory death (DCD) DDKTs did not increase risk of either EGL or PNF unless combined with prolonged cold ischemic time (CIT). For KDPI >85% with CIT >24 hours, the risk of EGL or PNF was tripled (EGL odds ratio [OR] 2.9, 95% CI 1.6-5.2; PNF OR3.6, 95% CI1.7-7.7). For DCD with CIT > 24 hours, increased risks were likewise seen for EGL (OR 2.4, 95% CI 1.3-4.3), and PNF (OR 3.2, 95% CI 1.5-7). One-year and 5-year patient survival rates were 60% and 50% after EGL, 80% and 73% after PNF, and 99% and 87% for controls, respectively. Only 24% of either EGL or PNF patients underwent retransplantation. CONCLUSIONS: EGL and PNF were associated with low retransplantation rates and inferior patient survival. Prolonged CIT compounds risks associated with KDPI > 85% and DCD donor kidneys. Therefore, policies promoting rapid allocation and increased local use of these kidneys should be considered.

Difference in Survival in Early Kidney after Liver Transplantation Compared with Simultaneous Liver-Kidney Transplantation: Evaluating the Potential of the "Safety Net".

BACKGROUND: Decisions on who requires simultaneous liver-kidney (SLK) transplantation are controversial. United Network for Organ Sharing implemented a "safety net" in 2017 providing prioritization on the kidney waitlist for patients with renal failure after liver transplantation. We aimed to compare survival after early kidney after liver transplantation (KALT) and SLK. STUDY DESIGN: We compared SLK, KALT, and liver transplantation alone (LTA) in adult patients who underwent deceased donor (DD) liver transplantation in the US, from 2002 to 2018. Early KALT was defined as 60 to 365 days between liver and subsequent kidney transplantation (reflecting safety net listing criteria). Patients who died within 60 days were excluded to mitigate immortal time bias favoring KALT. RESULTS: There were 6,774 SLK, 120 KALT at 60 to 365 days, and 11,501 LTA. Early KALT had equivalent survival compared with SLK, both for all KALT (hazard ratio [HR] 0.58, 95% CI 0.34-1.00, p = 0.05) and for DD KALT only (HR 0.72, 95% CI 0.37-1.38, p = 0.32). Simultaneous liver-kidney transplantation was associated with improved survival compared with LTA (HR 0.82. 95% CI 0.76-0.87, p < 0.01). Early KALT was associated with a greater reduction in mortality compared with LTA, but this was not significant (HR 0.58, 95% CI 0.39-1.00, p = 0.05). There was a lower proportion of early KALT in African Americans relative to SLK transplantations (7% vs 16%, p = 0.04). CONCLUSIONS: Early KALT has equivalent survival compared with SLK transplantation, both for all KALT and for DD KALT only, supporting the promise of the "safety net." There was a lower proportion of African-American patients undergoing early KALT, indicating the importance of monitoring access to early KALT under the "safety net" policy.

Practical Considerations for APOL1 Genotyping in the Living Kidney Donor Evaluation.

BACKGROUND: Association between the apolipoprotein L1 gene (APOL1) and nephropathy has altered the epidemiology of chronic kidney disease. In addition, donor APOL1 genotypes play important roles in the time to allograft failure in kidneys transplanted from deceased donors and the safety of living kidney donation. METHODS: This article reviews genetic testing for inherited kidney disease in living kidney donors to improve donor safety. APOL1 genotyping in donors with recent African ancestry is considered. RESULTS: Based on current data, transplant physicians should discuss APOL1 genotyping with potential living kidney donors self-reporting recent African ancestry. Until results from APOL1 Long-term Kidney Transplant Outcomes Network ancillary studies are available, we present practical approaches from our experience for considering APOL1 genotyping in the living donor evaluation. CONCLUSIONS: Transplant physicians should inform potential living kidney donors at risk for APOL1-associated nephropathy about the gene and possibility of genetic testing early in the donor evaluation, well before scheduling the donor nephrectomy. Transplant programs must weigh risks of performing a donor nephrectomy in those with 2 APOL1 renal risk variants (high-risk genotypes), particularly younger individuals. Our program counsels kidney donors with APOL1 high-risk genotypes in the same fashion as with risk genotypes in other nephropathy genes. Because most African American kidney donor candidates lacking hypertension, proteinuria and reduced kidney function after workup will not possess APOL1 high-risk genotypes, genetic testing is unlikely to markedly increase donor declines and may reassure donors with regard to their long-term kidney outcomes, potentially increasing the number of African American donors.

Dual Kidney Transplantation from Donors at the Extremes of Age.

BACKGROUND: The study purpose was to analyze outcomes in recipients of pediatric dual en bloc (PEB) kidneys from small pediatric donors (SPDs, age ≤ 3 years) and dual kidney transplants (KTs) from adult marginal deceased donors (DDs) in the context of the Kidney Donor Profile Index (KDPI). STUDY DESIGN: This was a single center retrospective review. Recipient selection included primary transplant, low BMI, low immunologic risk, and informed consent. All patients received antibody induction with FK/MPA/± prednisone. RESULTS: From 2002 to 2015, we performed 34 PEB and 73 adult dual KTs. Mean donor ages were 17 months for the PEB and 59 years for the dual KTs; mean KDPIs were 73% for PEB and 83% for dual KT, and mean cold ischemia times were 21.0 hours for PEB and 26.5 hours for dual KT. Adult dual KT recipients were older (mean age 38 years for PEB and 60 years for dual KT) and had shorter waiting times (mean 25 months for PEB and 12 months for dual KT). With a mean follow-up of 7.6 years, actual patient survival (88% for PEB and 62% for dual KT) and graft survival (71% for PEB and 44% for dual KT) rates were higher in PEB compared with dual KT. Death-censored kidney graft survival rates were 77% for PEB and 58% for dual KT. Delayed graft function (DGF) rates were 15% for PEB and 23% for dual KT; incidences of DGF in single kidney transplantations from SPDs and adult nonmarginal DDs were 20% and 32%, respectively. Based on actual 5-year graft survival rates, the adjusted KDPIs for dual PEB and dual KTs were 3% and 60%, respectively. CONCLUSIONS: Acceptable mid-term outcomes are associated with PEB and adult dual KTs, which may expand the donor pool and prevent kidney discard. The KDPI is inaccurate for predicting outcomes from either PEB from SPDs or dual KT from adult marginal DDs, which may prevent acceptance of these organs.

Identifying Barriers to Preemptive Kidney Transplantation in a Living Donor Transplant Cohort.

BACKGROUND: Despite substantial evidence demonstrating clear benefit, rates of preemptive kidney transplantation (PreKTx) remain low in the United States. Our goal was to identify barriers to PreKTx. METHODS: Using a telephone-administered questionnaire including questions about barriers, timing of referral, timing of education, we retrospectively studied first living donor kidney transplant recipients (2006-2010) at Mayo Clinic, Rochester, MN. Of 235 patients, 145 (62%) responded to the questionnaire (74 PreKTx and 71 non-PreKTx). We compared categorical data with Fisher exact test and median times with Wilcoxon rank sum test. RESULTS: Polycystic kidney disease (PCKD), longer median time between diagnosis and transplant, and time between education about transplant and transplant correlated with PreKTx (P < 0.01). The presence of at least 1 patient-identified barrier (lack of referral, financial barriers, medical barriers, no identified living donor and donor evaluation delays) was associated with non-PreKTx (0.034) though no single barrier predominated. Age, education level, insurance status and source of referral (primary care, nephrology, and nonphysician referral) were not associated with the rate of PreKTx. Univariate logistic regression identified white race, PCKD, and increased time from diagnosis as factors favoring PreKTx; PCKD and increased time remained significant factors after multivariate analysis. CONCLUSIONS: Even among a patient population that is primarily white, educated, and has a spouse or first-degree relative donor, PreKTx rates remain concerningly low. Increased time between diagnosis or education and transplant are predictors of PreKTx. Greater emphasis on transplant education earlier in the stages of chronic kidney disease and community outreach from transplant centers may help to increase the rate of PreKTx.