Postimplantation X-ray parameters predict functional catheter problems in peritoneal dialysis.

Functional catheter problems are a major challenge for peritoneal dialysis (PD) programs. Here we performed a retrospective single-center study of 110 consecutive patients receiving a first PD catheter (swan neck double-cuff Missouri curled catheters, open surgical technique). Using postimplantation X-ray, the following categories were defined: swan neck angle (posterioanterio view (PA): under 45°, 45-90°, over 90°), inclination (angle between intramural part of catheter and horizontal line; lateral view: greater than/equal to 30°, under 30°), and the position of silicone bead relative to spine (PA view: L1-2, L3-4, lower) and catheter tip (PA view: hypogastric, umbilical, subcostal). Covariates included demographics, body size, previous abdominal surgery, and abdominal wall hernias. During a mean follow-up of 36 months, the time to first functional catheter problem was significantly associated with both the swan neck angle and inclination. The need for surgical intervention was significantly associated with inclination only. Technique failure was not associated with any parameter. In multivariate analysis, inclination was the sole variable significantly associated with functional catheter problems (hazard ratio 3.65 [1.98-6.72]) and the need for surgical intervention (hazard ratio 2.86 [1.19-6.88]). Thus, our study defines a set of X-ray variables that predict functional PD catheter problems and can be used for troubleshooting in individual cases as well as for education and internal audit purposes.

Intrarenal resistive index after renal transplantation.

BACKGROUND: The intrarenal resistive index is routinely measured in many renal-transplantation centers for assessment of renal-allograft status, although the value of the resistive index remains unclear. METHODS: In a single-center, prospective study involving 321 renal-allograft recipients, we measured the resistive index at baseline, at the time of protocol-specified renal-allograft biopsies (3, 12, and 24 months after transplantation), and at the time of biopsies performed because of graft dysfunction. A total of 1124 renal-allograft resistive-index measurements were included in the analysis. All patients were followed for at least 4.5 years after transplantation. RESULTS: Allograft recipients with a resistive index of at least 0.80 had higher mortality than those with a resistive index of less than 0.80 at 3, 12, and 24 months after transplantation (hazard ratio, 5.20 [95% confidence interval {CI}, 2.14 to 12.64; P<0.001]; 3.46 [95% CI, 1.39 to 8.56; P=0.007]; and 4.12 [95% CI, 1.26 to 13.45; P=0.02], respectively). The need for dialysis did not differ significantly between patients with a resistive index of at least 0.80 and those with a resistive index of less than 0.80 at 3, 12, and 24 months after transplantation (hazard ratio, 1.95 [95% CI, 0.39 to 9.82; P=0.42]; 0.44 [95% CI, 0.05 to 3.72; P=0.45]; and 1.34 [95% CI, 0.20 to 8.82; P=0.76], respectively). At protocol-specified biopsy time points, the resistive index was not associated with renal-allograft histologic features. Older recipient age was the strongest determinant of a higher resistive index (P<0.001). At the time of biopsies performed because of graft dysfunction, antibody-mediated rejection or acute tubular necrosis, as compared with normal biopsy results, was associated with a higher resistive index (0.87 ± 0.12 vs. 0.78 ± 0.14 [P=0.05], and 0.86 ± 0.09 vs. 0.78 ± 0.14 [P=0.007], respectively). CONCLUSIONS: The resistive index, routinely measured at predefined time points after transplantation, reflects characteristics of the recipient but not those of the graft. (ClinicalTrials.gov number, NCT01879124 .).

The predictive value of kidney allograft baseline biopsies for long-term graft survival.

The effect of baseline histology and individual histologic lesions at the time of transplantation on long-term graft survival has been evaluated using different scoring systems, but the predictive capacity of these systems has not been adequately validated. All kidney recipients transplanted in a single institution between 1991 and 2009 who underwent a baseline kidney allograft biopsy at transplantation were included in this prospective study (N=548). All baseline biopsies were rescored according to the updated Banff classification, and the relationship between the individual histologic lesions and donor demographics was assessed using hierarchical clustering and principal component analysis. Survival analysis was performed using Cox proportional hazards analysis and log-rank testing. Mean follow-up time was 6.7 years after transplantation. Interstitial fibrosis, tubular atrophy, and glomerulosclerosis associated significantly with death-censored graft survival, whereas arteriolar hyalinosis and vascular intimal thickening did not. Notably, donor age correlated significantly with interstitial fibrosis, tubular atrophy, and glomerulosclerosis and associated independently with graft survival. On the basis of these findings, a novel scoring system for prediction of 5-year graft survival was constructed by logistic regression analysis. Although the predictive performance of previously published histologic scoring systems was insufficient to guide kidney allocation in our cohort (receiver operating characteristic area under the curve ≤0.62 for each system), the new system based on histologic data and donor age was satisfactory for prediction of allograft loss (receiver operating characteristic area under the curve = 0.81) and may be valuable in the assessment of kidney quality before transplantation.

Aortic calcifications and arterial stiffness as predictors of cardiovascular events in incident renal transplant recipients.

Renal transplant recipients have an increased risk of cardiovascular (CV) disease. Arterial stiffness (AS) and aortic calcifications (ACs) are well-known CV risk factors in patients with chronic kidney disease. We aimed to determine the prognostic value of AS and AC in incident renal transplant recipients (RTRs). We conducted a prospective study in 253 single RTR. AC were scored by means of lumbar X-ray. Carotid-femoral pulse wave velocity (PWV) was assessed in a subgroup of 115 patients. AC were present in 61% of patients. After a mean follow-up of 36 months, 32 CV events occurred in the overall group and 13 events in the PWV subgroup. When we accounted for age, gender, and CV history, AC score (HR, hazard ratio 1.09 per 1 unit increase; 95% CI 1.02-1.17) and PWV (HR 1.45 per 1 m/s; 95% CI 1.16-1.8) remained an independent predictor of CV events in Cox-regression analyses. Using receiver operating characteristics, the area under the curve for predicting CV events amounted to 0.80 and 0.72 for sum AC and PWV, respectively. Both AS and AC are strong predictors of future CV events in an incident RTR population. These vascular assessments are readily available and easy to perform, making them ideal tools for further risk stratification. (ClinicalTrials.gov number: NCT00547040).

Reasons for dose reduction of mycophenolate mofetil during the first year after renal transplantation and its impact on graft outcome.

UNLABELLED: Mycophenolate mofetil (MMF) decreases the risk of acute rejection and is associated with improved graft survival in renal transplant recipients. However, MMF-related side effects often necessitate dose reduction, which may expose patients to a higher risk of acute rejection and graft loss. This study's aim was to examine the reasons for MMF dose reduction during the first post-transplant year and its impact on acute rejection, overall and death-censored graft loss. METHODS: Single-center retrospective analysis of 749 renal transplant recipients treated with MMF in their initial maintenance immunosuppressive protocol. RESULTS: In 365 patients (48.7%) a total of 530 MMF dose reductions were done. Reasons for reduction were hematologic toxicity (46.5%), infection (16.1%), gastrointestinal side effects (12.3%), malignancy (2.1%), study protocol (14.6%), and unknown (13.5%). MMF dose reduction as such was not an independent predictor of acute rejection or graft survival, although reductions in ≥ 50% of initial dose were significantly associated with acute rejection. CONCLUSIONS: In this retrospective cohort, by far the most important reason for MMF dose reduction during the first post-transplantation year was hematologic. MMF dose reductions in ≥ 50% increased the risk of acute rejection but did not compromise graft survival.

Renal cell carcinoma in the allograft: what is the role of polyomavirus?

BK virus (BKV) is known to cause subclinical infection in childhood. The virus remains latent in the human body, mainly in the urinary tract epithelium. After initiation of an immunosuppressive treatment, reactivation can occur in renal transplant recipients. BKV can cause hemorrhagic cystitis, ureteral stenosis and BKV nephropathy in immunocompromised patients. Furthermore, a number of case reports suggest an association between BKV infection and the development of urinary tract cancer. So far, an oncogenic potential of BKV has been observed in vitro and in animal models; however, its oncogenic capacity in humans remains unclear. We report the case of a 59-year-old patient who developed a poorly differentiated renal cell carcinoma in her renal allograft, with pulmonary and abdominal metastasis. Surgical removal of the allograft and cessation of the immunosuppressive therapy resulted in complete resolution of the metastatic disease.

A multicenter, randomized, double-blind study comparing different FK778 doses (manitimus) with tacrolimus and steroids vs. MMF with tacrolimus and steroids in renal transplantation.

BACKGROUND: This multicenter phase II study in renal transplantation compared 3 concentration-controlled ranges of FK778 (manitimus) with mycophenolate mofetil (MMF) both given in combination with tacrolimus and corticosteroids. METHODS: 364 patients were randomized to 12-month treatment: high-level FK778 group (H, N=87) received 4 x 600 mg/day (4 days) followed by 120 mg/day; mid-level FK778 group (M, N=92) received 3 x 600 mg/day (3 days) followed by 110 mg/day, low-level FK778 group (L, N=92) received 2 x 600 mg/day (2 days) followed by 100 mg/day, and control group received MMF 1 g/day (MMF, N=93). After week 6, FK778 doses were adjusted to trough ranges of 75-125 µg/mL (H), 50-100 µg/mL (M) and 25-75 µg/mL (L). Tacrolimus and steroids were administered at the same dose in each of the 4 groups. RESULTS: Biopsy proven acute rejection (BPAR) at 24 weeks, the primary study endpoint, was comparable in the L (22.8%) and MMF (17.2%) groups but higher in the H (34.5%) and M (29.3%) groups. BPAR at 12 months was comparable in the L (23.9%) and MMF (19.4%) groups but higher in the H (34.5%) and M (31.5%) groups. Graft and patient survival were lowest in the H group and renal function was poorest in the H and M groups. Premature study withdrawal was highest in the H group. CONCLUSIONS: Efficacy was similar between the low-level FK778 and MMF groups. Increased FK778 exposure was poorly tolerated and did not improve efficacy.

Prevalence and determinants of anemia in the immediate postkidney transplant period.

At the time of renal transplantation, erythropoiesis-stimulating agents and iron supplementation are routinely discontinued in the prospect of recovery of renal function. This recovery, however, is often delayed and suboptimal. In addition, blood loss because of frequent diagnostic phlebotomies may be substantial. Renal transplant recipients may thus be considered at high risk of anemia in the immediate post-transplant period. We performed a single-center observational study, including 391 recipients of a single kidney. Hemoglobin levels and parameters of iron metabolism were monitored during the immediate post-transplant period, i.e., the first 3 months after transplantation. Hemoglobin levels decreased by 3.8 ± 1.5 g/dl to reach a nadir of 9.1 ± 1.2 g/dl at day 7. Transient severe anemia was observed in 91.3% of the patients. Donor age, gender, renal diagnosis of polycystic disease, pretransplant hemoglobin and ferritin level, estimated glomerular filtration rate at month 3, and duration of initial hospitalization were observed to be independently associated with the hemoglobin level at month 3. Transient severe anemia is an almost universal observation in incident renal transplant recipients. Poor graft function, high donor age, and low iron stores are independently associated with low hemoglobin levels at month 3.

FTY720 combined with tacrolimus in de novo renal transplantation: 1-year, multicenter, open-label randomized study.

BACKGROUND: FTY720 (fingolimod), a novel immunomodulator, has demonstrated potential for prevention of acute rejection in combination with cyclosporine. METHODS: This study evaluated FTY720 2.5 mg versus mycophenolate mofetil (MMF) in a combination regimen with standard tacrolimus and corticosteroids in de novo renal transplant recipients for the composite efficacy within 6 months of transplantation. RESULTS: Incidence of treated biopsy-proven acute rejection was 22.9% with FTY720 and 18.5% with MMF. Increased incidence of macular oedema, transient decrease in heart rate and low rate of infections were seen in the FTY720 arm. CONCLUSION: FTY720 combined with tacrolimus and steroids did not show a significant therapeutic advantage over MMF for the prevention of acute rejection in de novo renal transplant recipients.

An integrated safety profile analysis of belatacept in kidney transplant recipients.

BACKGROUND: Belatacept is associated with better renal function and an improved cardiovascular/metabolic risk profile versus cyclosporine in kidney transplant recipients. The current analysis examined pooled safety data for belatacept versus cyclosporine used in combination with basiliximab, mycophenolate mofetil, and steroids. METHODS: Patients enrolled in three core studies in de novo kidney transplantation were randomized to a more intensive (MI) or less intensive (LI) regimen of belatacept or cyclosporine. The pooled analysis included 1425 patients (MI: 477; LI: 472; cyclosporine: 476). Median follow-up was approximately 2.4 years. RESULTS: Belatacept was generally well tolerated. The frequency of deaths (MI: 7%; LI: 5%; cyclosporine: 7%) and serious infections (MI: 37%; LI: 32%; cyclosporine: 36%) were lower in the LI group versus cyclosporine. The frequency of malignancies was 10%, 6%, and 7% in the MI, LI, and cyclosporine groups, respectively. Sixteen cases of posttransplant lymphoproliferative disorder (PTLD) occurred (n=8 MI; n=6 LI; n=2 cyclosporine), including nine cases involving the central nervous system (CNS) (n=6 MI; n=3 LI). The risk of CNS PTLD was highest in Epstein-Barr virus(-) recipients; more CNS PTLD cases occurred in the MI group. One case of progressive multifocal leukoencephalopathy was reported in the MI group. CONCLUSIONS: Treatment with belatacept-based regimens was generally safe for a period of at least 2 years. There was a greater risk of PTLD--specifically CNS PTLD--in the belatacept groups versus cyclosporine, especially in Epstein-Barr virus(-) patients and with the MI dose. The number of deaths and serious infections was lower in the LI regimen versus MI and cyclosporine. The overall safety profile favored the LI over the MI regimen.

Belatacept-based regimens versus a cyclosporine A-based regimen in kidney transplant recipients: 2-year results from the BENEFIT and BENEFIT-EXT studies.

BACKGROUND: At 1 year, belatacept was associated with similar patient/graft survival, better renal function, and an improved cardiovascular/metabolic risk profile versus cyclosporine A (CsA) in the Belatacept Evaluation of Nephroprotection and Efficacy as Firstline Immunosuppression Trial (BENEFIT) and Belatacept Evaluation of Nephroprotection and Efficacy as Firstline Immunosuppression Trial-EXTended criteria donors (BENEFIT-EXT) studies. Acute rejection was more frequent with belatacept in BENEFIT. Posttransplant lymphoproliferative disorder (PTLD)--specifically central nervous system PTLD--was observed more frequently in belatacept-treated patients. This analysis assesses outcomes from BENEFIT and BENEFIT-EXT after 2 years of treatment. METHODS: Patients received a more intensive (MI) or a less intensive (LI) regimen of belatacept or a CsA-based regimen. RESULTS: Four hundred ninety-three of 666 patients (74%) in BENEFIT and 347 of 543 (64%) in BENEFIT-EXT completed 2 years of treatment. The proportion of patients who survived with a functioning graft was similar across groups (BENEFIT: 94% MI, 95% LI, and 91% CsA; BENEFIT-EXT: 83% MI, 84% LI, and 83% CsA). Belatacept's renal benefits were sustained, as evidenced by a 16 to 17 mL/min (BENEFIT) and an 8 to 10 mL/min (BENEFIT-EXT) higher calculated glomerular filtration rate in the belatacept groups versus CsA. There were few new acute rejection episodes in either study between years 1 and 2. Because PTLD risk was highest in Epstein-Barr virus (EBV) (-) patients, an efficacy analysis of EBV (+) patients was performed and was consistent with the overall population results. There were two previously reported cases of PTLD in each study between years 1 and 2 in the belatacept groups. The overall balance of safety and efficacy favored the LI over the MI regimen. CONCLUSIONS: At 2 years, belatacept-based regimens sustained better renal function, similar patient/graft survival, and an improved cardiovascular/metabolic risk profile versus CsA; outcomes that were maintained in EBV (+) patients. No new safety signals emerged.

Five-year safety and efficacy of belatacept in renal transplantation.

Belatacept is a first-in-class co-stimulation blocker in development for primary maintenance immunosuppression. A Phase II study comparing belatacept with cyclosporine (CsA) for prevention of acute rejection and protection of renal function in kidney transplant recipients demonstrated similar efficacy and significantly higher measured GFR at 1 year for belatacept, but the incidence of posttransplantation lymphoproliferative disorder was higher. Here, we present the results for the extension of this trial, which aimed to assess long-term safety and efficacy of belatacept. Seventy-eight of 102 patients who were receiving belatacept and the 16 of 26 who were receiving CsA completed the long-term extension period. GFR remained stable in patients who were receiving belatacept for 5 years, and the incidences of death/graft loss or acute rejection were low. The frequencies of serious infections were 16% for belatacept and 27% for CsA, and neoplasms occurred in 12% of each group. No patients who were treated with belatacept and one patient who was treated with CsA developed posttransplantation lymphoproliferative disorder during the follow-up period. Serious gastrointestinal disorders occurred more frequently with belatacept (12% belatacept versus 8% CsA), and serious cardiac disorders occurred more frequently with CsA (2% belatacept versus 12% CsA). Pharmacokinetic analyses showed consistent exposure to belatacept over time. CD86 receptor saturation was higher in patients who were receiving belatacept every 4 weeks (74%) compared with every 8 weeks (56%). In conclusion, this study demonstrated high patient persistence with intravenous belatacept, stable renal function, predictable pharmacokinetics, and good safety with belatacept over 5 years.

Tacrolimus dose requirements and CYP3A5 genotype and the development of calcineurin inhibitor-associated nephrotoxicity in renal allograft recipients.

OBJECTIVES: Prolonged calcineurin inhibitor maintenance therapy in kidney allograft recipients is complicated by the development of chronic irreversible drug-induced nephrotoxicity (CNIT). METHODS: In 304 de novo renal graft recipients, the association among tacrolimus exposure indices (dose, C(0), AUC(0-12h)), CYP3A5, CYP3A4 and ABCB1 polymorphisms, clinical covariables and de novo arteriolar hyalinization as a histologic sign of CNIT was examined. RESULTS: Tacrolimus C(0) and AUC(0-12h) at 3 and 12 months posttransplantation did not differ between patients with and without CNIT. Patients who developed CNIT more often carried the CYP3A5*1 allele (32.4% versus 15.2%, P = 0.01). Twenty-five percent of recipients with tacrolimus dose requirements exceeding 0.2 mg/kg per day at 3 months posttransplantation developed CNIT, whereas 16.2% of patients with dose requirements between 0.10 and 0.20 mg/kg per day and 4.5% of patients who needed less than 0.10 mg/kg per day developed CNIT (P < 0.0001). These early differences in tacrolimus dose requirements between recipients with and without CNIT persisted during subsequent follow-up. In a Cox proportional hazards analysis, the CYP3A5*1 allele (hazard ratio: 2.38; 95% confidence interval: 1.15-4.92) or tacrolimus dose range (hazard ratio: 2.06; 95% confidence interval: 1.30-3.27) and continued corticosteroid therapy (hazard ratio: 4.75; 95% confidence interval: 1.13-19.98) were independently associated with CNIT. A Kaplan-Meier survival curve demonstrated a significant difference in CNIT-free survival (93.5% versus 81.8% versus 66.9%; log-rank test: P = 0.0006) between patients with, respectively, tacrolimus dose requirements less than 0.1, 0.1 or greater, less than 0.2, and 0.2 mg/kg per day or greater. More patients with CNIT sustained graft loss during follow-up (32.3% versus13.7%, P = 0.004). CONCLUSIONS: High early tacrolimus dose requirements, predominantly but not exclusively encountered in CYP3A5*1 expressers, are associated with the development of calcineurin inhibitor-related nephrotoxicity, especially in recipients who continue corticosteroid therapy.

Thymoglobulin induction and sirolimus versus tacrolimus in kidney transplant recipients receiving mycophenolate mofetil and steroids.

BACKGROUND: To define the role of mammalian target of rapamycin inhibitors in kidney transplantation, we compared efficacy and safety of two immunosuppressive regimens-a calcineurin inhibitor-free regimen with depletive induction versus a calcineurin inhibitor-based regimen. METHODS: De novo renal allograft recipients were randomized before transplantation to receive sirolimus (SRL; n=71, group A) or tacrolimus (n=70, group B). All patients received mycophenolate mofetil and corticosteroids. In group A, patients received rabbit antithymocyte globulin induction. In group B, antithymocyte globulin therapy could be given in case of delayed graft function. The estimated glomerular filtration rate (GFR) (Nankivell's formula) at month 12 was the primary endpoint. RESULTS: GFR showed no significant difference at month 12, with 56.1 in group A versus 58.4 mL/min/1.73 m in group B. In functioning grafts, renal function was significantly better in the SRL group, with higher GFR values at months 1, 2, 3, 6, and 9 (P<0.05). At month 12, patient survival and incidence of biopsy-proven rejection were not different between groups (95.8% vs. 97.1%, and 16.9% vs. 12.9%, respectively). However, proportion of graft loss was higher with SRL at months 6 and 12 (11.3% vs. 0.0%, P=0.004; 14.1% vs. 4.3%, P=0.044, respectively). Adverse events and premature withdrawals were more frequent with SRL (P<0.001 and P<0.05, respectively), whereas cytomegalovirus infections were more frequent with tacrolimus (P<0.001). CONCLUSION: Patients treated with induction plus SRL, mycophenolate mofetil, and corticosteroids may obtain good renal function but have a higher risk of adverse events, drug withdrawal, and graft loss.

Calcium metabolism in the early posttransplantation period.

BACKGROUND AND OBJECTIVES: Information on the time course of serum calcium levels after renal transplantation is scanty, especially in the early posttransplantation period. Both the abrupt cessation of calcium-containing phosphorus binders and vitamin D (analogs) at the time of surgery and the recovery of renal function may be hypothesized to affect serum calcium levels in this period. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In this prospective observational study, biointact parathyroid hormone, calcidiol, calcitriol, calcium, and phosphorus levels were monitored in 201 renal transplant recipients at the time of transplantation and 3 mo thereafter. In addition, the serum calcium nadir and peak in each individual patient within this time frame were identified and the urinary fractional calcium excretion was determined at month 3. RESULTS: Serum calcium levels followed a biphasic pattern with a significant decline during the first postoperative week, followed by a significant increase. High pretransplantation parathyroid hormone levels protect against hypocalcemia within the first postoperative week but put patients at risk for hypercalcemia later. These complications, occurring in 41 and 14% of the patients, respectively, most probably reflect inappropriate calcium release from the skeleton, rather than inappropriate renal calcium handling. CONCLUSIONS: Our data indicate that both hypo- and hypercalcemia are prevalent in the early posttransplantation period. Pretransplantation parathyroid function is an important predictor of posttransplantation calcium levels.

Calcium requirements after parathyroidectomy in patients with refractory secondary hyperparathyroidism.

BACKGROUND/AIMS: Calcium supplements are often required following successful parathyroidectomy (PTX) in order to prevent overt hypocalcemia. The current study aims to quantify these calcium needs and to identify predictors of a high calcium need present at the time of surgery. METHODS: Charts of 42 patients with chronic kidney disease stage 5D, who underwent a successful subtotal PTX, were reviewed in detail. Biochemical indices of mineral metabolism available within a time frame of 4 weeks before and 6 weeks after the surgery were registered. Details concerning active vitamin D (1-alpha-calcidiol and calcitriol) and calcium supplementation were recorded as well. RESULTS: Serum calcium, phosphorus and PTH levels declined whereas total alkaline phosphatase levels increased significantly in the early post-PTX period. Transient hypocalcemia was observed in 83% of the patients. The median daily postoperative elemental calcium requirements amounted to 3.2 g during week 1, and declined to 2.4 g during week 6. A high preoperative PTH level and a low serum calcium level were identified as independent predictors of a high postoperative calcium need. CONCLUSION: Substantial amounts of elemental calcium are required following successful subtotal PTX in order to avoid frank hypocalcemia, especially in patients with a high PTH level and a low calcium level before surgery.

AA amyloidosis due to chronic oxalate arthritis and vasculitis in a patient with secondary oxalosis after jejunoileal bypass surgery.

We report a case of a woman with secondary oxalosis after jejunoileal bypass surgery for obesity, who presented with oxalate stone disease and renal insufficiency requiring dialysis. Thirty years after surgery, longstanding osteoarticular symptoms were recognized as oxalate arthritis. Eventually, she also developed oxalate vasculitis, which improved with corticoid treatment and intensification of dialysis. Work-up for kidney transplantation revealed AA amyloidosis on gastric and colonic biopsies. Since no other cause of chronic inflammation could be identified, it was concluded that the amyloidosis was secondary to oxalate arthritis and vasculitis. To our knowledge, this is the first report on this association.