Transplanting Kidneys from Deceased Donors With Severe Acute Kidney Injury

Our aim was to determine outcomes with transplanting kidneys from deceased donors with acute kidney injury, defined as a donor with terminal serum creatinine ≥2.0 mg/dL, or a donor requiring acute renal replacement therapy. We included all patients who received deceased donor kidney transplant from June 2004 to October 2013. There were 162 AKI donor transplant recipients (21% of deceased donor transplants): 139 in the standard criteria donor (SCD) and 23 in the expanded criteria donor (ECD) cohort. 71% of the AKI donors had stage 3 (severe AKI), based on acute kidney injury network (AKIN) staging. Protocol biopsies were done at 1, 4, and 12 months posttransplant. One and four month formalin-fixed paraffin embedded (FFPE) biopsies from 48 patients (24 AKI donors, 24 non-AKI) underwent global gene expression profiling using DNA microarrays (96 arrays). DGF was more common in the AKI group but eGFR, graft survival at 1 year and proportion with IF/TA>2 at 1 year were similar for the two groups. At 1 month, there were 898 differentially expressed genes in the AKI group (p-value <0.005; FDR <10%), but by 4 months there were no differences. Transplanting selected kidneys from deceased donors with AKI is safe and has excellent outcomes.

Single time point immune function assay (ImmuKnow) testing does not aid in the prediction of future opportunistic infections or acute rejection

BACKGROUND AND OBJECTIVES

Current assays and tests that are used to determine the degree of immunosuppression in renal transplant recipients are suboptimal. The ImmuKnow assay (Cylex), a measure of intracellular CD4+ T cell ATP release proposed as a means to quantify cell-mediated immunity in transplant recipients, could be considered as a potential tool to identify patients at risk for opportunistic infections (OI) or acute rejection (AR).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We retrospectively analyzed 1330 ImmuKnow assay values in 583 renal transplant recipients at a single center from 2004 to 2009 and correlated these values with episodes of OI and AR in the subsequent 90 days. Assay values were compared with a control population matched for age, gender, and time post-transplantation.

RESULTS

In patients with OI (n=94), there were no differences in prior mean assay values compared with matched controls (386 versus 417 ng/ml, P=0.24). In 47 patients with AR, again no differences were detected in prior assay results (390 versus 432 ng/ml, P=0.25) when compared with controls. "Low" values (≤225 ng/ml) lacked sensitivity and specificity as a predictive test for subsequent OI, as did "strong" (≥525 ng/ml) values as a predictive test for subsequent AR.

CONCLUSIONS

Our results fail to show an association between single time point ImmuKnow assay values and the subsequent development of an adverse event in the subsequent 90 days. The optimal use of the ImmuKnow assay in kidney transplantation has yet to be determined.

Trends in immune function assay (ImmuKnow; Cylex™) results in the first year post-transplant and relationship to BK virus infection

BACKGROUND

The ImmuKnow assay is a functional T-cell assay (TCA) that may quantify cellular immune responsiveness following renal transplantation. Using a standard protocol of TCA sampling in the first year post-transplant, we examined changes in TCA values over time and tested for an association between TCA and BK virus (BKV) infection as a marker of over-immunosuppression.

METHODS

We performed a single-center retrospective analysis of 897 TCA results in 414 renal transplant recipients obtained at 0 (N = 122), 1 (N = 316), 6 (N = 258) and 12 (N = 201) months post-transplant from May 2005 to July 2009 with concurrent urine and blood BKV polymerase chain reaction measurements.

RESULTS

Nearly 40% of patients experienced a decrease in TCA of >150 ng/mL from 1 to 6 months (mean 466-356 ng/mL, P < 0.0001) and remained stable from 6 to 12 months (mean 357 versus 370 ng/mL, P = 0.33). Neither a change in TCA of >150 ng/mL nor a TCA value of ≤ 225 ng/mL were associated with a diagnosis of BKV infection at 1 or 6 months, while TCA ≤ 225 ng/mL was associated with BKV infection at 12 months (P = 0.005).

CONCLUSIONS

A reduction in TCA from 1 to 6 months post-transplant is common and is not associated with conditions of over-immunosuppression, rendering the interpretation of changes in TCA during this time period difficult. BKV infection is associated with low TCA values at 12 months, suggesting that patients with low TCA values after 6 months may benefit from potential tailoring of immunosuppression or more aggressive monitoring to prevent subsequent BKV infection.

Minimal change disease: a CD80 podocytopathy?

Minimal change disease is the most common nephrotic syndrome in children. Although the etiology of minimal change disease remains to be elucidated, it has been postulated that it is the result of a circulating T-cell factor that causes podocyte cytoskeleton disorganization leading to increased glomerular capillary permeability and/or changes in glomerular basement membrane heparan sulfate glycosaminoglycans resulting in proteinuria. Minimal change disease has been associated with allergies and Hodgkin disease. Consistent with these associations, a role for interleukin-13 with minimal change disease has been proposed. Furthermore, studies evaluating podocytes also have evolved. Recently, increased expression of CD80 (also termed B7-1) on podocytes was identified as a mechanism for proteinuria. CD80 is inhibited by binding to CTLA-4, which is expressed on regulatory T cells. Recently, we showed that urinary CD80 is increased in minimal change disease patients and limited studies have suggested that it is not commonly present in the urine of patients with other glomerular diseases. Interleukin-13 or microbial products via Toll-like receptors could be factors that induce CD80 expression on podocytes. CTLA-4 appears to regulate CD80 expression in podocytes, and to be altered in minimal change disease patients. These findings lead us to suggest that proteinuria in minimal change disease is caused by persistent CD80 expression in podocytes, possibly initiated by stimulation of these cells by antigens or cytokines.

Transplanting kidneys from donation after cardiac death donors with acute kidney injury

Donation after cardiac death (DCD) and acute kidney injury (AKI) donors have historically been considered independent risk factors for delayed graft function (DGF), allograft failure, and inferior outcomes. With growing experience, updated analyses have shown good outcomes. There continues to be limited data, however, on outcomes specific to DCD donors who have AKI. Primary outcomes for this study were post-kidney transplant patient and allograft survival comparing two donor groups: DCD AKIN stage 2-3 and DBD AKIN stage 2-3. In comparing these groups, there were no short- or long-term differences in patient (hazard ratio [HR] 1.07, 95% confidence interval [CI] 0.54-1.93, P = .83) or allograft survival (HR 1.47, 95% CI 0.64-2.97, P = .32). In multivariate models, the DCD/DBD status had no significant impact on the estimated GFR (eGFR) at 1 (P = .38), 2 (P = .60), and 3 years (P = .52). DGF (57.9% vs 67.9%, P = .09), rejection (12.1% vs 13.9%, P = .12), and progression of interstitial fibrosis/tubular atrophy (IFTA) on protocol biopsy (P = .16) were similar between the two groups. With careful selection, good outcomes can be achieved utilizing severe AKI DCD kidneys. Historic concerns regarding primary nonfunction, DGF resulting in interstitial fibrosis and rejection, and inferior outcomes were not observed. Given the ongoing organ shortage, increased effort should be undertaken to further utilize these donors.

Chronic viral hepatitis in kidney transplantation

Chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection in potential kidney transplant candidates-once considered absolute contraindications to kidney transplantation-no longer creates overt barriers to transplantation. Advances in the medical management of HBV and HCV infection have created opportunities for a substantial number of patients to be effectively treated with antiviral therapy before transplantation. For HBV infection, a number of new drugs enable clearance of the virus with minimal adverse effects and drug resistance. Pretransplantation antiviral therapy is advisable for patients with HCV infection, but adverse effects are common and viral eradication remains challenging. Regardless of viral clearance, pretransplant patients without bridging fibrosis (as confirmed by liver biopsy) or clinical stigmata of cirrhosis should be considered for kidney transplantation as survival is superior when compared to treatment with dialysis, and progression of liver disease is unlikely. For patients with advanced liver disease, simultaneous liver-kidney transplantation is an important consideration. These treatment advances further increase the burden of organ donor shortage; however, organs from deceased donors with chronic HBV or HCV infection could be efficiently allocated to certain individuals with a viral infection of the same type to increase the pool of available transplant organs.

Rapid Resolution of Donor-Derived Glomerular Fibrin Thrombi After Deceased Donor Kidney Transplantation

The aim of this study was to determine the clinical and histologic outcomes related to transplanting kidneys from deceased donors with glomerular fibrin thrombi (GFT). We included all cases transplanted between October 2003 and October 2014 that had either a preimplantation biopsy or an immediate postreperfusion biopsy showing GFT. The study cohort included 61 recipients (9.9%) with GFT and 557 in the control group without GFT. Delayed graft function occurred in 49% of the GFT group and 39% in the control group (p = 0.14). Serum creatinine at 1, 4, and 12 months and estimated GFR at 12 months were similar in the two groups. Estimated 1-year graft survival was 93.2% in the GFT group and 95.1% in the control group (p = 0.22 by log-rank). Fifty-two of the 61 patients in the GFT group (85%) had a 1-month protocol biopsy, and only two biopsies (4%) showed residual focal glomerular thrombi. At the 1-year protocol biopsy, the prevalence of moderate to severe interstitial fibrosis and tubular atrophy was 24% in the GFT group and 30% in the control group (p = 0.42). We concluded that GFT resolves rapidly after transplantation and that transplanting selected kidneys from deceased donors with GFT is a safe practice.

Clinical outcomes of hepatitis C treatment before and after kidney transplantation and its impact on time to transplant: A multicenter study

Waitlist time for kidney transplantation is long but may be shortened with the utilization of hepatitis C positive allografts. We retrospectively reviewed the course of 36 hepatitis C positive patients awaiting kidney transplantation at 2 large centers within the same health system, with near-identical care delivery models with the exception of timing of hepatitis C treatment, to determine the impact of timing of hepatitis C treatment on access to transplant, waitlist time, and treatment efficacy and tolerability. The majority of patients had hepatitis C genotype 1a or 1b, and all received direct acting antiviral therapy with 100% treatment response. One patient underwent transplantation in the pretransplant treatment group. The 1-year transplantation rate was 12.5% vs 67.9% (P = .0013) in those treated posttransplantation. The median waitlist time in the posttransplant group was 122 (interquartile range [IQR] 21.5, 531.0) days, which was significantly shorter than the center's regional and national wait time. Pathologic review revealed no difference in allograft quality. Overall treatment related adverse events were not different between the 2 groups. A strategy of posttransplant hepatitis C treatment increased access to transplant and reduced waitlist time. Delaying treatment until after transplant did not appear to adversely affect recipients' kidney allograft or overall survival.

Cardiorespiratory Fitness (Peak Oxygen Uptake): Safe and Effective Measure for Cardiovascular Screening Before Kidney Transplant

BACKGROUND

Significant heterogeneity exists in practice patterns and algorithms used for cardiac screening before kidney transplant. Cardiorespiratory fitness, as measured by peak oxygen uptake (VO_2peak), is an established validated predictor of future cardiovascular morbidity and mortality in both healthy and diseased populations. The literature supports its use among asymptomatic patients in abrogating the need for further cardiac testing.

METHODS AND RESULTS

We outlined a pre-renal transplant screening algorithm to incorporate VO_2peak testing among a population of asymptomatic high-risk patients (with diabetes mellitus and/or >50 years of age). Only those with VO_2peak <17 mL/kg per minute (equivalent to <5 metabolic equivalents) underwent further noninvasive cardiac screening tests. We conducted a retrospective study of the a priori dichotomization of the VO_2peak <17 versus ≥17 mL/kg per minute to determine negative and positive predictive value of future cardiac events and all-cause mortality. We report a high (>90%) negative predictive value, indicating that VO_2peak ≥17 mL/kg per minute is effective to rule out future cardiac events and all-cause mortality. However, lower VO_2peak had low positive predictive value and should not be used as a reliable metric to predict future cardiac events and/or mortality. In addition, a simple mathematical calculation documented a cost savings of ≈$272 600 in the cardiac screening among our study cohort of 637 patients undergoing evaluation for kidney and/or pancreas transplant.

CONCLUSIONS

We conclude that incorporating an objective measure of cardiorespiratory fitness with VO_2peak is safe and allows for a cost savings in the cardiovascular screening protocol among higher-risk phenotype (with diabetes mellitus and >50 years of age) being evaluated for kidney transplant.

De novo coccidioidomycosis among solid organ transplant recipients 1 or more years after transplant

Solid organ transplant recipients who contract coccidioidomycosis are at risk for complicated, protracted, disseminated, and severe disease. To date, no studies have described outcomes for patients who develop coccidioidomycosis only after the first posttransplant year. This study was a joint project of Mayo Clinic Hospital, Phoenix, Arizona, and the University of Arizona/Banner University Medical Center, Tucson, Arizona. We retrospectively reviewed electronic health records for patients with a history of solid organ transplant between January 1, 1998, and October 11, 2014, who developed coccidioidomycosis after the first transplant year. We identified 91 patients. Of those, 37/91 (40.7%) had pulmonary coccidioidomycosis (29/37 [78.4%] were symptomatic); and 5/91 (5.5%) had extrapulmonary disease (all were symptomatic). One patient (1.1%) died. Coccidioidomycosis was evident in 2/91 (2.2%) patients within 3 months of antirejection treatment. Many of the patients (51/91 [56.0%]) had asymptomatic coccidioidomycosis, 27 (27.9%) of whom were followed up closely but did not receive antifungal medication and had no sequelae. Although solid organ recipients taking low-level immunosuppression after the first posttransplant year appeared to have less symptomatic, disseminated, or fatal coccidioidal infection than historical cohorts, this remains an important infection with morbidity and mortality even after the first posttransplant year.

Early technical pancreas failure in Simultaneous Pancreas-Kidney Recipients does not impact renal allograft outcomes

Early pancreas loss in simultaneous pancreas-kidney (SPK) transplants has been associated with longer perioperative recovery and reduced kidney allograft function. We assessed the impact of early pancreas allograft failure on transplant outcomes in a contemporary cohort of SPK patients (n = 218). Early pancreas allograft loss occurred in 12.8% (n = 28) of recipients. Delayed graft function (DGF) was more common (21.4% vs. 7.4%, p = 0.03) in the early pancreas loss group, but there were no differences in hospital length of stay (median 6.5 vs. 7.0, p = 0.22), surgical wound complications (p = 0.12), or rejection episodes occurring in the first year (p = 0.87). Despite differences in DGF, both groups had excellent renal function at 1 year post-transplant (eGFR 64.1 ± 20.8 vs. 65.8 ± 22.9, p = 0.75). There were no differences in patient (HR 0.58, 95% CI 0.18-1.87, p = 0.26) or kidney allograft survival (HR 0.84, 95% CI 0.23-3.06, p = 0.77). One- and 2-year protocol kidney biopsies were comparable between the groups and showed minimal chronic changes; the early pancreas loss group showed more cv changes at 2 years (p = 0.04). Current data demonstrate good outcomes and excellent kidney allograft function following early pancreas loss.

BK polyomavirus DNAemia in pancreas transplant recipients compared to pancreas-kidney recipients

BACKGROUND

BK polyomavirus (BKV) infection is a common complication of kidney transplantation. While BKV has been described in non-kidney transplant recipients, data are limited regarding its epidemiology and outcomes in pancreas transplant recipients.

METHODS

We conducted a retrospective cohort study of adults who underwent pancreas transplantation from 2010-2020. The primary outcome was BKV DNAemia. Secondary outcomes were estimated glomerular filtration rate (eGFR) reduction by 30%, eGFR < 30 mL/min/1.73 m2 , endstage kidney disease, and pancreas allograft failure. Cox regression with time-dependent variables was utilized.

RESULTS

Four hundred and sixty-six patients were analyzed, including 74, 46, and 346 with pancreas transplant alone (PTA), pancreas-after-kidney, or simultaneous pancreas-kidney transplants, respectively. PTA recipients experienced a lower incidence of BKV DNAemia (8.8% vs. 32.9%; p < .001) and shorter duration of DNAemia (median 28.0 vs. 84.5 days). No PTA recipients with BKV DNAemia underwent kidney biopsy or developed endstage kidney disease. Lymphopenia, non-PTA transplantation, and older age were associated with BKV DNAemia, which itself was associated with pancreas allograft failure (adjusted hazard ratio 2.14, 95% confidence interval 1.27-3.60; p = .004). Among PTA recipients, BKV DNAemia was not associated with eGFR reduction or eGFR < 30 mL/min/1.73 m2 .

CONCLUSIONS

BKV DNAemia was common among PTA recipients, though lower than a comparable group of pancreas-kidney recipients. However, BKV DNAemia was not associated with adverse native kidney outcomes and no PTA recipients developed endstage kidney disease. Conversely, BKV DNAemia was associated with pancreas allograft failure. Further studies are needed to estimate the rate of BKV nephropathy in this population, and further evaluate long-term kidney outcomes.

Renal transplantation in the setting of aortic atresia: Utilizing hepatic artery inflow with donor vessel jump graft

Both congenital and acquired recipient anatomy can present a significant challenge to renal transplantation. A patient with congenital aortic atresia and limited dialysis access options presented to our institution for consideration of transplant. Through multidisciplinary planning, a strategy to accommodate the patient's variant anatomy was devised and successfully performed. A deceased donor vessel graft was used as conduit in combination with the recipient hepatic artery for renal graft inflow.

Kidney Transplant Program at the Mayo Clinic in Arizona

Since 1999, we have performed 2,302 kidney transplants at the Mayo Clinic in Arizona. Transplant volume has increased by 45% since 2010. Our center performed 269 kidney transplants in 2013. Our growth is related to multiple factors, including an experienced, committed team and strong support from our institution and referring nephrologists. Areas of program innovation at our center include: transplanting deceased donors with acute kidney injury, outcomes in older kidney transplant recipients, alemtuzumab induction with steroid avoidance, living donor paired kidney exchange-3 site experience, and other non-traditional deceased donor kidney transplants. Of the 162 acute kidney injury (AKI) donor transplants done at our program, 71% had severe AKI. The AKI donor kidneys had more delayed graft function; but graft survival, estimated glomerular filtration rate, and biopsy findings at 1 year were not different form the control group. We have transplanted 188 patients ≥ 70 years old at the time of transplantation. Graft survival at 1, 3, and 5 years was similar to that of patients < 70. Since 2008, 778 (37%) patients received alemtuzumab induction, therapy with excellent patient and graft survival. We have used steroid avoidance immunosuppression with excellent outcomes since 2003. Since starting kidney paired donation in 2009, it has resulted in 54 kidney transplants, including 4 compatible pairs. More than half of the deceased donor transplants done at our center are from non-traditional donors such as Public Health Service increased risk, donation after cardiac death, extended criteria donors/high kidney donor profile index, and pediatric en-bloc donors. One- and 3-year graft survival of the non-traditional deceased donor kidney transplants are not different than the traditional deceased donor kidney transplants.

Risk of cytomegalovirus infection and subsequent allograft failure after pancreas transplantation

Cytomegalovirus (CMV) is a common cause of infection after transplantation, but few studies have evaluated its epidemiology, risk factors, and outcomes among pancreas transplant recipients. We performed a retrospective cohort study of adults who underwent pancreas transplantation from January 1, 2010, through December 31, 2020, at 3 sites in Arizona, Florida, and Minnesota. The primary outcome was clinically significant CMV infection (csCMVi), defined as CMV disease or infection requiring antiviral therapy. The secondary outcome was pancreas allograft failure. Among 471 pancreas transplant recipients, 117 (24.8%) developed csCMVi after a median of 226 (interquartile range 154-289) days. CMV donor (D)+/R- patients had a significantly higher incidence of csCMVi (hazard ratio [HR] 4.01, 95% confidence interval [CI] 2.10-7.64; P < .001). In adjusted analysis, a lower absolute lymphocyte count (ALC) was associated with a greater risk of csCMVi among seropositive recipients (HR 1.39 per 50% decrease, 95% CI 1.13-1.73; P = .002) but not among D+/R- patients (HR 1.04 per 50% decrease, 95% CI 0.89-1.23; P = .595). csCMVi, lower ALC, and acute rejection (P < .001) were independently associated with pancreas allograft failure. In conclusion, CMV D+/R- was associated with csCMVi in pancreas recipients, although ALC was associated with csCMVi only among seropositive patients. The development of csCMVi in pancreas recipients was associated with poor pancreas allograft outcomes.

Impact of Perioperative Prophylaxis With Enterococcus Activity on Risk of Surgical-Site Infection After Pancreas Transplantation

Surgical-site infection (SSI) is the most common early infectious complication after pancreas transplantation (PT). Although SSI has been shown to worsen outcomes, little data exist to guide optimal choices in perioperative prophylaxis.

Methods

We performed a retrospective cohort study of PT recipients from 2010-2020 to examine the effect of perioperative antibiotic prophylaxis with Enterococcus coverage. Enterococcus coverage included antibiotics that would be active for penicillin-susceptible Enterococcus isolates. The primary outcome was SSI within 30 d of transplantation, and secondary outcomes were Clostridioides difficile infection (CDI) and a composite of pancreas allograft failure or death. Outcomes were analyzed by multivariable Cox regression.

Results

Of 477 PT recipients, 217 (45.5%) received perioperative prophylaxis with Enterococcus coverage. Eighty-seven recipients (18.2%) developed an SSI after a median of 15 d from transplantation. In multivariable Cox regression analysis, perioperative Enterococcus prophylaxis was associated with reduced risk of SSI (hazard ratio [HR] 0.58; 95% confidence interval [CI], 0.35-0.96; P = 0.034). Anastomotic leak was also significantly associated with elevated risk of SSI (HR 13.95; 95% CI, 8.72-22.32; P < 0.001). Overall, 90-d CDI was 7.4%, with no difference between prophylaxis groups (P = 0.680). SSI was associated with pancreas allograft failure or death, even after adjusting for clinical factors (HR 1.94; 95% CI, 1.16-3.23; P = 0.011).

Conclusions

Perioperative prophylaxis with Enterococcus coverage was associated with reduced risk of 30-d SSI but did not seem to influence risk of 90-d CDI after PT. This difference may be because of the use of beta-lactam/beta-lactamase inhibitor combinations, which provide better activity against enteric organisms such as Enterococcus and anaerobes compared with cephalosporin. Risk of SSI was also related to anastomotic leak from surgery, and SSI itself was associated with subsequent risk of a poor outcome. Measures to mitigate or prevent early complications are warranted.