Increasing Referral for Renal Transplant Evaluation in Recipients of Nonrenal Solid-Organ Transplants: A Single-Center Experience

Kidney disease in non-kidney solid organ transplantation

Kidney disease after non-kidney solid organ transplantation (NKSOT) is a common post-transplant complication associated with deleterious outcomes. Kidney disease, both acute kidney injury and chronic kidney disease (CKD) alike, emanates from multifactorial, summative pre-, peri- and post-transplant events. Several factors leading to kidney disease are shared amongst solid organ transplantation in addition to distinct mechanisms unique to individual transplant types. The aim of this review is to summarize the current literature describing kidney disease in NKSOT. We conducted a narrative review of pertinent studies on the subject, limiting our search to full text studies in the English language. Kidney disease after NKSOT is prevalent, particularly in intestinal and lung transplantation. Management strategies in the peri-operative and post-transplant periods including proteinuria management, calcineurin-inhibitor minimization/ sparing approaches, and nephrology referral can counteract CKD progression and/or aid in subsequent kidney after solid organ transplantation. Kidney disease after NKSOT is an important consideration in organ allocation practices, ethics of transplantation. Kidney disease after SOT is an incipient condition demanding further inquiry. While some truths have been revealed about this chronic disease, as we have aimed to describe in this review, continued multidisciplinary efforts are needed more than ever to combat this threat to patient and allograft survival.

Kidney Disease After Nonkidney Solid Organ Transplant

Nonkidney solid organ transplants (NKSOTs) are increasing in the United States with improving long-term allograft and patient survival. CKD is prevalent in patients with NKSOT and is associated with increased morbidity and mortality especially in those who progress to end-stage kidney disease. Calcineurin inhibitor nephrotoxicity is a main contributor to CKD after NKSOT, but other factors in the pretransplant, peritransplant, and post-transplant period can predispose to progressive kidney dysfunction. The management of CKD after NKSOT generally follows society guidelines for native kidney disease. Kidney-protective and calcineurin inhibitor-sparing immunosuppression has been explored in this population and warrants a discussion with transplant teams. Kidney transplantation in NKSOT recipients remains the kidney replacement therapy of choice for suitable candidates, as it provides a survival benefit over remaining on dialysis.

Effects of mTOR inhibitor-related proteinuria on progression of cardiac allograft vasculopathy and outcomes among heart transplant recipients

We have previously described the use of sirolimus (SRL) as primary immunosuppression following heart transplantation (HT). The advantages of this approach include attenuation of cardiac allograft vasculopathy (CAV), improvement in glomerular filtration rate (GFR), and reduced malignancy. However, in some patients SRL may cause significant proteinuria. We sought to investigate the prognostic value of proteinuria after conversion to SRL. CAV progression and adverse clinical events were studied. CAV progression was assessed by measuring the Δ change in plaque volume (PV) and plaque index (PI) per year using coronary intravascular ultrasound. Proteinuria was defined as Δ urine protein ≥300 mg/24 h at 1 year after conversion to SRL. Overall, 137 patients were analyzed (26% with proteinuria). Patients with proteinuria had significantly lower GFR (P = .005) but similar GFR during follow-up. Delta PV (P < .001) and Δ PI (P = .001) were significantly higher among patients with proteinuria after adjustment for baseline characteristics. Multivariate Cox regression analysis showed higher all-cause mortality (hazard ratio 3.8; P = .01) with proteinuria but similar risk of CAV-related events (P = .61). Our results indicate that proteinuria is a marker of baseline renal dysfunction, and that HT recipients who develop proteinuria after conversion to SRL have less attenuation of CAV progression and higher mortality risk.

The Irish experience of kidney transplantation among recipients with prior non-renal solid organ transplants: A retrospective study on short- and long-term outcomes

BACKGROUND

This study aims to evaluate allograft and patient outcomes among recipients of kidney transplants after non-renal solid organ transplants. We also aim to compare our findings with recipients of a repeat kidney transplant.

METHODS

We performed an analysis on kidney transplant recipients who underwent kidney transplantation after a non-renal solid organ transplant. Survival data were stratified into 2 groups: Group A (n = 37) consisted of recipients of a kidney transplant after prior non-renal solid organ transplant, and Group B (n = 330) consisted of recipients of a repeat kidney transplant.

RESULTS

The 1-,5-, and 10-year graft survival (death-censored) for recipients of a kidney transplant post-non-renal solid organ transplant (Group A) were 97.3%, 91.5%, and 86.9%, compared with 97.9%, 90.2%, and 83.4% for recipients of a repeat kidney transplant (Group B) (p = .32). The 1-, 5-, and 10-year patient survival rates were 97.3%, 82.7%, and 79.1% in Group A compared to 97.9%, 90.2%, and 83.4% in Group B. Unadjusted overall patient survival was significantly lower for Group A (p = .017).

CONCLUSION

Kidney transplant recipients who have undergone a previous non-renal solid organ transplant have similar allograft survival outcomes, but higher long-term mortality rates compared to repeat kidney transplant recipients.

Outcomes in Older Kidney Transplant Recipients After Prior Nonkidney Transplants

BACKGROUND

Recipients of nonkidney solid organ transplants (nkSOT) are living longer, and 11%-18% will develop end stage renal disease (ESRD). While our general inclination is to treat nkSOT recipients who develop ESRD with a kidney transplant (KT), an increasing number are developing ESRD at an older age where KT may not be the most appropriate treatment. It is possible that the risk of older age and prior nkSOT might synergize to make KT too risky, but this has never been explored.

METHODS

To examine death-censored graft loss and mortality for KT recipients with and without prior nkSOT, we used Scientific Registry of Transplant Recipients data to identify 42 089 older (age ≥65) KT recipients between 1995 and 2016. Additionally, to better understand treatment options for these patients and survival benefit of KT, we identified 5023 older (age ≥65) with prior nkSOT recipients listed for subsequent KT, of whom 863 received transplants.

RESULTS

Compared with 41 159 older KT recipients without prior nkSOT, death-censored graft loss was similar (adjusted hazard ratio [aHR]: 1.13, 95% CI: 0.93-1.37, P = 0.2), but mortality (aHR: 1.40, 95% CI: 1.28-1.54, P < 0.001) was greater for older KT recipients with prior nkSOT. Nonetheless, in a survival benefit model (survival with versus without the transplant), among older prior nkSOT recipients, KT decreased the risk of mortality by more than half (aHR: 0.47, 95% CI: 0.42-0.54, P < 0.001).

CONCLUSIONS

Older prior nkSOT recipients who subsequently develop ESRD derive survival benefit from KT, but graft longevity is limited by overall survival in this population. These findings can help guide patient counseling for this challenging population.

Liver Transplant Recipients With End-Stage Renal Disease Largely Benefit From Kidney Transplantation

BACKGROUND

The incidence of end-stage renal disease (ESRD) after liver transplant (LT) has increased. The actual benefit of kidney transplantation (KT) is not completely understood in LT recipients with ESRD.

METHODS

We analyzed Scientific Registry of Transplant Recipients data for all KT candidates with prior LT from 1998 to 2014; the benefits of KT relative to remaining on dialysis were compared by means of multivariate Cox proportional hazards regression analysis.

RESULTS

The number of these KT candidates with prior LT has tripled from 98 in 1998 to 323 in 2015; LT recipients with ESRD remaining on dialysis have a 2.5-times increase in the risk of liver graft failure and a 3.6-times increase in the risk of patient death compared with these patients receiving KT. The adjusted liver graft and patient survival rates after donors from donation after cardiac death or expanded-criteria donor kidney transplantation were significantly higher than in patients remaining on dialysis in LT recipients with ESRD.

CONCLUSIONS

The number of referrals to KT with prior LT is increasing at a rapid rate. Remaining on dialysis in LT recipients with ESRD has profound increased risks of liver graft failure and patient death in comparison to receiving a KT. LT recipients with ESRD can benefit from expanded-criteria donor and donation after cardiac death kidney transplantation.

Association of CYP3A5, CYP2C8, and ABCB1 Polymorphisms With Early Renal Injury in Chinese Liver Transplant Recipients Receiving Tacrolimus

BACKGROUND

The purpose of this study is to explore the association of CYP3A5, ABCB1, and CYP2C8 polymorphisms with the risk of developing early kidney impairment in Chinese liver transplant recipients receiving tacrolimus.

METHODS

CYP3A5, ABCB1, and CYP2C8 polymorphisms were genotyped in the Chinese liver transplant recipients in the study receiving tacrolimus for at least 2 years by polymerase chain reaction and high-resolution melting method. Serum cystatin C and urine microprotein (α1-microglobulin, microalbumin, transferrin, and immunoglobulin) of liver transplant recipients were used to determine both the status of early renal injury and the lesion part.

RESULTS

We documented 3 genotypes of CYP3A5 and ABCB1 and only 2 genotypes of CYP2C8 in our cohort. The levels of cystatin C and all 4 indicators of the urine microprotein in the recipient group were significantly higher than those in the control group (P < .05). The concentrations of transferrin differed significantly in each CYP3A5 genotype group (P < .05). Based on diverse CYP2C8 genotypes, we divided all the recipients into 2 groups: CYP2C8*1*1 group and CYP2C8*3*1 group. The concentrations of α1-microglobulin and cystatin C differed significantly between the 2 groups (P < .05). For CYP2C8*3, the positive predictive value is 68.5% and negative predictive value is 70.2%. For CYP3A5*3, the positive predictive value is 55.3% and negative predictive value is 60.4%.

CONCLUSIONS

CYP2C8*3 and CYP3A5*3 appear to be predictive of risk of tacrolimus-induced early renal impairment. CYP3A5*3 was associated with the risk of early renal glomerular lesion, while CYP2C8*3 was associated with the risk of the tubulointerstitial injury. ABCB1 polymorphisms (both C3435T and C1236T) were not associated with the early renal injury in liver transplant recipients.

Interaction of pre-transplant recipient characteristics and renal function in lung transplant survival

BACKGROUND

There has been little investigation into the potential interaction of recipient characteristics with the association of pre-transplant renal functions and survival after lung transplantation. In this study we tested the hypothesis that association of pre-transplant renal function and post-transplant mortality varies among recipient subgroups.

METHODS

We queried the United Network for Organ Sharing (UNOS) database for adult patients (≥18 years of age) undergoing lung transplantation between May 2005 and March 2015. The study population (n = 15,540) was split into 3 groups (90 to 150, 60 to 89.9 and 30 to 59.9 ml/min/1.73 m2) based on the estimated glomerular filtration rate (Chronic Kidney Disease Epidemiology Collaboration equation) at the time of listing. We utilized multivariable inverse probability weighted Cox proportional hazard models to compare the association of glomerular filtration rate (GFR) groups with mortality among recipient subgroups.

RESULTS

Overall, there was an independent and graded inverse association between the estimated GFR (eGFR) and mortality, with the hazard of mortality significantly rising with listing eGFR <60 ml/min/1.73 m2. The association between low eGFR and mortality was more consistent and stronger for older (>45 years), non-African-American and non-diabetic patients as well as those with low lung allocation score (LAS <40). Among the diagnosis groups, patients with vascular diseases had the strongest association between low eGFR and poor survival. Sensitivity analyses conducted using an alternate equation to estimate the GFR (Modification of Diet in Renal Disease) supported these associations.

CONCLUSIONS

Prognostic significance of pre-transplant renal functions varies significantly among recipient subgroups. It may be appropriate to develop a customized approach toward assessing and interpreting renal function to determine transplant candidacy.

Predictors of renal function recovery among patients undergoing renal replacement therapy following orthotopic liver transplantation

Renal dysfunction frequently occurs during the periods preceding and following orthotopic liver transplantation (OLT), and in many cases, renal replacement therapy (RRT) is required. Information regarding the duration of RRT and the rate of kidney function recovery after OLT is crucial for transplant program management. We evaluated a sample of 155 stable patients undergoing post-intensive care hemodialysis (HD) from a patient population of 908 adults who underwent OLT. We investigated the average time to renal function recovery (duration of RRT required) and determined the risk factors for remaining on dialysis > 90 days after OLT. Log-rank tests were used for univariate analysis, and Cox proportional hazards models were used to identify factors associated with the risk of remaining on HD. The results of our analysis showed that of the 155 patients, 28% had pre-OLT diabetes mellitus, 21% had pre-OLT hypertension, and 40% had viral hepatitis. Among the patients, the median MELD (Model for End-Stage Liver Disease) score was 27 (interquartile range [IQR] 22-35). When they were listed for liver transplantation, 32% of the patients had serum creatinine (Scr) levels > 1.5 mg/dL or were on HD, and 50% had serum creatinine (Scr) levels > 1.5 mg/dL or were on HD at the time of OLT. Of the transplanted patients, 25% underwent pre-OLT intermittent HD, and 14% and 41% underwent continuous renal replacement therapy (CRRT) pre-OLT and post-OLT, respectively. At 90 days post-OLT, 118 (76%) patients had been taken off dialysis, and 16 (10%) patients had died while undergoing HD. The median recovery time of these post-OLT patients was 33 (IQR 27–39) days. In the multivariate analysis, fulminant hepatic failure as the cause of liver disease (p<0.001), the absence of pre-OLT hypertension (p = 0.016), a lower intraoperative fresh-frozen plasma (FFP) transfusion volume (p = 0.019) and not undergoing pre-OLT intermittent HD (p = 0.032) were associated with performing RRT for less than 90 days. Therefore, a high proportion of OLT patients showed improved renal function after OLT, and those who were diagnosed with fulminant hepatic failure, had no pre-OLT hypertension, received a lower transfused volume of intraoperative FFP and did not undergo pre-OLT intermittent HD had a higher probability of recovery.

Kidney transplant recipients after nonrenal solid organ transplantation show low alloreactivity but an increased risk of infection

The number of kidney transplant recipients (KTRs) after nonrenal solid organ transplantation (SOT) has increased to almost 5%. Knowledge on patient and allograft outcomes, infections, and alloreactivity, however, remains scarce. We studied 40 KTRs after nonrenal SOT. Seven hundred and twenty primary KTRs and 119 repeat KTRs were used for comparison. Samples were collected pretransplantation, at +1, +2, and +3 months post-transplantation. Alloreactive and CMV-specific T cells were measured by interferon-γ ELISPOT assay. Patient survival in KTRs after SOT, primary and repeat KTRs was comparable. While death-censored allograft survival was comparable between KTRs after SOT and primary KTRs, KTRs after SOT showed superior 5-year death-censored allograft survival of 92.5% compared to 81.2% in repeat KTRs. Interestingly, KTRs after SOT show less preformed panel-reactive antibodies, frequencies of alloreactive T cells, and acute rejections compared to repeat KTRs. KTRs after SOT, however, show higher incidences of EBV viremia and PTLD, sepsis, and death from sepsis. Impaired CMV-specific cellular immunity was associated with more CMV replication compared to repeat KTRs. Our results suggest comparable patient and allograft outcomes in KTRs after SOT and primary KTRs. The observed low alloreactivity may contribute to excellent allograft outcomes. Caution should be taken in KTRs after SOT regarding infectious complications due to overimmunosuppression.

Kidney Transplant Outcomes After Primary, Repeat and Kidney After Nonrenal Solid Organ Transplantation: A Single-Center Experience

Background

Improvements in renal allograft outcomes have permitted kidney transplantation after prior kidney allograft failure as well as after nonrenal solid organ transplantation. This study compares renal allograft outcomes in the 3 groups, that is, primary, repeat, and kidney after nonrenal solid organ transplantation, where transplant group was coded as a time-dependent variable.

Methods

We retrospectively reviewed registry data for kidney transplant recipients at University of Pittsburgh Medical Center from January 2000 to December 2011. We compared overall graft survival between the 3 groups using Cox regression modeling. We calculated 1-, 3-, and 5-year graft survival and half-lives for each group where feasible.

Results

The study cohort (N = 2014) consisted of group A (primary kidney transplant, n = 1578, with 7923.2 years of follow-up time), group B (repeat kidney transplant, n = 314, with 1566.7 years of follow-up time) and group C (kidney post-nonrenal solid organ transplant, n = 176, with 844.8 years of follow-up time). Of the 1578 patients in the primary kidney transplant group, 74 later received a repeat transplant and thus also have follow-up counted in the repeat kidney transplant group. The median follow-up was 56, 53, and 55 months, respectively. The 5-year actuarial and death-censored graft survival was 68.69%, 68.79%, and 66.48% and 65.53%, 67.68%, and 62.92%, respectively (P = 0.70). There was no difference in overall graft survival in the Cox-adjusted analysis (group B: odds ratio, 1.02; 95% confidence interval, 0.84-1.26; P = 0.79; group C: odds ratio, 0.96; 95% confidence interval, 0.75-1.23; P = 0.76).

Conclusions

The adjusted kidney graft survivals in the 3 groups were similar.

Prevalence of renal dysfunction in tacrolimus-treated pediatric transplant recipients: a systematic review

Renal dysfunction after non-renal transplantation in adult tacrolimus-treated transplant patients is well documented. Little is known about its prevalence in children. Age-related changes in both disposition and effect of tacrolimus as well as renal function may preclude extrapolation of adult data to children. To systematically review the literature on renal dysfunction in non-renal pediatric transplant recipients treated with tacrolimus. PubMed/Medline, Embase, and Google were searched from their inception until April 19, 2012, with the search terms "tacrolimus," "renal function," "transplantation," and "children." Eighteen of 385 retrieved papers were considered relevant. Twelve dealt with liver, four with heart transplant, one with heart and lung transplant, and one with intestinal recipients. Reported prevalences of mild and severe chronic kidney disease ranged from 0% to 39% and 0% to 71.4%, respectively, for liver, and from 22.7% to 40% and 6.8% to 46%, respectively, for heart and/or lung transplant recipients. Ranges remained wide after adjusting for follow-up time and disease severity. Possible explanations are inclusion bias and definitions used for renal dysfunction. A considerable proportion of pediatric non-renal transplant patients who receive tacrolimus-based immunosuppression, appear to suffer from chronic kidney disease. This conclusion warrants further research into the real risk, its risk factors, and individualization of immunosuppressant therapy.

Risk of post-lung transplant renal dysfunction in adults with cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is one of the leading indications for lung transplantation. The incidence and pre-lung transplant risk factors for posttransplant renal dysfunction in the CF population remain undefined.

METHODS

We conducted a cohort study using adults (≥ 18 years old) in the CF Foundation Patient Registry from 2000 to 2008 to determine the incidence of post-lung transplant renal dysfunction, defined by an estimated glomerular filtration rate of < 60 mL/min/1.73 m(2). Multivariable Cox proportional hazards modeling was used to identify independent pretransplant risk factors for post-lung transplant renal dysfunction.

RESULTS

The study cohort included 993 adult lung transplant recipients with CF, with a median follow-up of 2 years. During the study period, 311 individuals developed renal dysfunction, with a 2-year risk of 35% (95% CI, 32%-39%). Risk of posttransplant renal dysfunction increased substantially with increasing age (25 to < 35 years vs 18 to < 25 years: hazard ratio [HR], 1.60; 95% CI, 1.15-2.23; vs ≥ 35 years: HR, 2.45; 95% CI, 1.73-3.47) and female sex (HR, 1.56; 95% CI, 1.22-1.99). CF-related diabetes requiring insulin therapy (HR, 1.30; 95% CI, 1.02-1.67) and pretransplant renal function impairment (estimated glomerular filtration rate, 60-90 mL/min/m(2) vs > 90 mL/min/m(2): HR, 1.58; 95% CI, 1.19-2.12) also increased the risk of posttransplant renal dysfunction.

CONCLUSIONS

Renal dysfunction is common following lung transplant in the adult CF population. Increased age, female sex, CF-related diabetes requiring insulin, and pretransplant renal impairment are significant risk factors.

The influence of induction therapy for kidney transplantation after a non-renal transplant

BACKGROUND AND OBJECTIVES

Non-renal transplant recipients who subsequently develop ESRD and undergo kidney transplantation are medically and immunologically complex due to comorbidities, high cumulative exposure to immunosuppressants, and sensitization to alloantigen from the prior transplant. Although prior non-renal transplant recipients are one of the fastest growing segments of the kidney wait list, minimal data exist to guide the use of antibody induction therapy (IT+) at the time of kidney after lung (KALu), heart (KAH), and liver (KALi) transplant.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This retrospective cohort study used national registry data to examine IT use and survival after kidney transplantation. Separate multivariate Cox regression models were constructed to assess patient survival for IT+ and IT- KALu (n=232), KAH (n=588), and KALi (n=736) recipients.

RESULTS

Use of IT increased during the study period. The percentage of patients considered highly sensitized (panel reactive antibody ≥20%) was not statistically significant between IT+ and IT- groups. IT+ was not associated with improvement in 1- and 10-year patient survival for KALu (P=0.20 and P=0.22, respectively) or for KAH (P=0.90 and P=0.14, respectively). However, IT+ among KALi was associated with inferior patient survival at 1 and 10 years (P=0.04 and P=0.02, respectively).

CONCLUSIONS

Use of IT for kidney transplantation among prior non-renal transplant recipients may not offer a survival advantage in KALu or KAH. However, due to limited power, these findings should be interpreted cautiously. IT+ was associated with inferior outcomes for KALi. Use of IT should be judicially reconsidered in this complex group of recipients.

Wait list death and survival benefit of kidney transplantation among nonrenal transplant recipients

The disparity between the number of patients waiting for kidney transplantation and the limited supply of kidney allografts has renewed interest in the benefit from kidney transplantation experienced by different groups. This study evaluated kidney transplant survival benefit in prior nonrenal transplant recipients (kidney after liver, KALi; lung, KALu; heart, KAH) compared to primary isolated (KA1) or repeat isolated kidney (KA2) transplant. Multivariable Cox regression models were fit using UNOS data for patients wait listed and transplanted from 1995 to 2008. Compared to KA1, the risk of death on the wait list was lower for KA2 (p < 0.001;HR = 0.84;CI = 0.81-0.88), but substantially higher for KALu (p < 0.001; HR = 3.80;CI = 3.08-4.69), KAH (p < 0.001; HR = 1.92; CI = 1.66-2.22), and KALi (p < 0.001; HR = 2.69; CI = 2.46-2.95). Following kidney transplant, patient survival was greatest for KA1, similar among KA2, KALi, KAH, and inferior for KALu. Compared to the entire wait list, renal transplantation was associated with a survival benefit among all groups except KALu (p = 0.017; HR = 1.61; CI = 1.09-2.38), where posttransplant survival was inferior to the wait list population. Recipients of KA1 kidney transplantation have the greatest posttransplant survival and compared to the overall kidney wait list, the greatest survival benefit.

Copeptin in heart transplant recipients depends on kidney function and intraventricular septal thickness

Copeptin is cosynthesized with vasopressin, also known as antidiuretic hormone, with plasma levels similar to vasopressin. In the past 2 years, copeptin has been studied as a diagnostic and prognostic marker in infections and other diseases. In patients with destabilized heart failure, copeptin is an accurate prognostic marker for mortality. The aim of this study was to assess copeptin in orthotopic heart recipients in relation to New York Heart Association class and kidney function. The studies were performed on 139 prevalent patients after orthotopic heart transplantation-(OHT) including 105 males and 34 females. Glomerular filtration rate (GFR) was estimated using simplified Modification of Diet in Renal Disease (MDRD), Cockcroft-Gault, and new the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. In addition 24-hour creatinine clearances were performed on each patient. Complete blood count, urea, serum lipids, fasting glucose, creatinine, BNP were studied by standard laboratory method in the hospital central laboratory. Plasma copeptin was measured using a commercially available kit. Copeptin correlated with parameters of kidney function: creatinine (r = .39, P < .001), estimated GFR by MDRD (r = -.24, P < .01), estimated GFR by CKD-EPI (r = -.25, P < .01), creatinine clearance by Cockcroft-Gault (r = -.27, P < .01), 24-hour creatinine clearance (r = -.21, P < .05), cystatin C (r = .45, P < .001), and high-density lipoprotein (r = .18, P < .05), BNP (r = .25, P < .01), intraventricular septal diameter/thickness (IVS); r = -.30, P < .01), ejection fraction (r = -.17, P < .05), ferritin (r = .21, P < .05). Upon multiple regression analysis, predictors of copeptin were cystatin C and IVS, which explained 51% of copeptin variations (F = 3.21, P < .03 and Standard error of estimate was 0.57). Beta value for cystatin C was 0.51 (P = .024) and for IVS was -0.59 (P = .018). Copeptin in a heart transplant population was independently associated with kidney function and IVS.

Serum neutrophil gelatinase-associated lipocalin correlates with kidney function in heart allograft recipients

The value of neutrophil gelatinase-associated lipocalin (NGAL) as a novel marker for early detection of acute renal failure has been highlighted recently. The aim of this study was to assess whether serum NGAL correlated with kidney function in heart allograft recipients. We evaluated serum NGAL, creatinine, and estimated glomerular filtration rate (GFR) in 164 heart allograft recipients on triple therapy. Heart transplant recipients showed significantly higher NGAL values than the control group. Kidney function was estimated using CKD-EPI, Modification of Diet in Renal Disease (MDRD), Cockcroft-Gault formula, 24-hour creatinine clearance, and serum creatinine. Kidney function was significantly impaired among heart transplant recipients compared with healthy volunteers. On univariate analysis serum NGAL strongly correlated with serum creatinine (r = .70, P < .001), estimated GFR (CKD-EPI, r = -.57, P < .001, MDRD r = .56, P < .001, Cockcroft-Gault, r = -.56, P < .001), 24-hour creatinine clearance (r = .43, P < .001), and cystatin C (r = .74, P < .001). In contrast, it was moderately correlated with red blood cell count (r = -.39, P < .01), hemoglobin level (r = -.42, P < .01), NT-proBNP (r = .25, P < .01), and only weakly with New York Heart Association class (r = .21, P < .05), time after transplantation (r = .21, P < .05), or age (r = .19, P < .05) upon multiple regression analysis, the best predictor of serum NGAL was estimated GFR (beta -0.87, P < .0001), explaining 89% of the NGAL concentrations. Even a successful heart transplantation is associated with kidney injury as reflected by elevated serum NGAL and reduced estimated GFR. Therefore, NGAL needs to be investigated as a potential early marker for impaired kidney function/injury, especially among patients with risk factors for renal damage, i.e., hypertension or diabetes, other than heart pathology.

Renal biopsy in liver transplant recipients

BACKGROUND

Renal impairment post-liver transplant (LT) is often attributed to calcineurin inhibitors (CNIs). A renal biopsy can be a useful tool but may be complicated in LT recipients. We aimed to determine the clinical scenarios that prompted a decision to perform a renal biopsy in this patient population, to assess histological findings and evaluate patient management and survival and renal outcome.

METHODS

Information on clinical variables and renal histology was extracted from single-centre prospectively compiled databases from 1996 onwards.

RESULTS

Over 2100 adults received an LT in the time period studied, and 54 of these (35 males and 19 females) were referred for renal review. Of these, 43% underwent a renal biopsy. They had a higher creatinine (P = 0.02), a greater deterioration in creatinine over the year prior to review and were more likely to be nephrotic (both P < 0.01). Histological findings included hypertensive changes (44%), CNI nephrotoxicity (48%), IgA nephropathy (9%), membranoproliferative glomerulonephritis (17%), acute tubular necrosis (4%), crescentic glomerulonephritis (4%) and diabetic nephropathy (9%). Major bleeding complications occurred in 17%. Treatment changed in the majority but, it was not significantly different in the two groups. Although initial renal function was worse in the biopsied group, final patient and renal survival did not differ between the two groups.

CONCLUSION

A renal biopsy is a valuable tool in those with renal insufficiency and/or proteinuria and haematuria but the benefits must be weighed against the relatively high complication rate in LT recipients.

Kidney transplantation in previous heart or lung recipients

Outcomes after heart and lung transplants have improved, and many recipients survive long enough to develop secondary renal failure, yet remain healthy enough to undergo kidney transplantation. We used national data reported to United Network for Organ Sharing (UNOS) to evaluate outcomes of 568 kidney after heart (KAH) and 210 kidney after lung (KAL) transplants performed between 1995 and 2008. Median time to kidney transplant was 100.3 months after heart, and 90.2 months after lung transplant. Renal failure was attributed to calcineurin inhibitor toxicity in most patients. Outcomes were compared with primary kidney recipients using matched controls (MC) to account for donor, recipient and graft characteristics. Although 5-year renal graft survival was lower than primary kidney recipients (61% KAH vs. 73.8% MC, p < 0.001; 62.6% KAL vs. 82.9% MC, p < 0.001), death-censored graft survival was comparable (84.9% KAH vs. 88.2% MC, p = 0.1; 87.6% KAL vs. 91.8% MC, p = 0.6). Furthermore, renal transplantation reduced the risk of death compared with dialysis by 43% for KAH and 54% for KAL recipients. Our findings that renal grafts function well and provide survival benefit in KAH and KAL recipients, but are limited in longevity by the general life expectancy of these recipients, might help inform clinical decision-making and allocation in this population.

Should heart, lung, and liver transplant recipients receive immunosuppression induction for kidney transplantation?

As the outcomes of heart, liver, and lung transplantation continue to improve, more patients will present for subsequent renal transplantation. It remains unclear whether these patients benefit from induction immunosuppression. We retrospectively reviewed induction on solid organ graft recipients who underwent renal transplant at our center from January 1, 1995 to March 30, 2007. Induction and the non-induction groups were compared by univariate and Kaplan-Meier analyses. There were 21 patients in each group, with mean follow-up of 4.5-6.0 years. Forty-seven percent of patients receiving induction had a severe post-operative infection, compared with 28.6% in the non-induction group (p = NS). The one yr rejection rate in the induction group was 9.5% compared with 14.3% for non-induction (p = NS). One-yr graft survival was 81.0% and 95.2% in the induction and non-induction group (p = NS). In summary, there is a trend toward lower patient and graft survival among patients undergoing induction. These trends could relate to selection bias in the decision to prescribe induction immunosuppression, but further study is needed to better define the risks and benefits of antibody-induction regimens in this population.