Experience and Utility of the Protocol Kidney Biopsy in the First Year of Kidney Transplantation.

BACKGROUND: Protocol kidney biopsy (PKB) in kidney transplant is a useful tool for graft monitoring because the subclinical detection of histologic lesions helps to modulate immunosuppression. We analyze our experience. METHODS: We performed a descriptive study that analyzed the PKB results at the fourth to sixth month and the first year post transplant of patients with kidney transplant followed in our hospital between January 2015 and June 2021. RESULTS: A total of 100 patients and 134 biopsy results were included, of which 71 were obtained between the fourth and sixth month and 63 at the first year. The mean age was 57.8 years, and 66% were men. Unknown etiology was the most common underlying kidney disease (31%), followed by diabetes mellitus (15%) and polycystic kidney disease (14%). A total of 80% had panel-reactive antibody < 50%. Induction therapy consisted of thymoglobulin (51%) and basiliximab (49%), and maintenance therapy consisted of corticosteroids and tacrolimus (100%), mycophenolate mofetil (82%), and mammalian target of rapamycin inhibitor (18%). Of the total of the PKB results (n = 134), 19 episodes of subclinical rejection (14%) and 10 with borderline changes (7.4%) were observed. Regarding other findings, there were cases of nephrocalcinosis (4.4%), immunoglobulin A nephropathy (2.2%), and BK nephropathy (1.5%). The PKB brought about a change in the therapeutic attitude in 45 cases (33%) of the total number of biopsies, the most frequent change being the administration of boluses of methylprednisolone (12.6%) and the change to mammalian target of rapamycin inhibitor (8.9%). CONCLUSIONS: In our experience, PKB is a useful tool for monitoring and evaluating histologic changes without clinical expression in the kidney graft, allowing us to adapt the treatment during the first year of kidney transplant.

Diagnosis of iron deficiency in chronic renal failure.

The cause of anemia in chronic renal failure is multifactorial. Decreased erythropoietin (EPO) production is the main pathogenetic factor, but iron deficiency is the primary cause of unresponsiveness to EPO therapy. The diagnosis of iron deficiency in patients with chronic renal failure is difficult. We assessed the sensitivity and specificity of serum ferritin, total iron-binding capacity, transferrin saturation index, erythrocyte ferritin, and serum transferrin receptor in 63 patients with chronic renal failure undergoing dialysis (47 men, 16 women) with iron deficiency anemia. They were selected on the basis of clinical stability and absence of factors that may interfere with iron metabolism. None of the patients had received intravenous iron therapy or recombinant human erythropoietin (rHuEPO). Bone marrow biopsy with iron staining was the reference standard for iron stores. The receiver operating characteristic (ROC) curve and the area under the curve were calculated to assess the sensitivity and specificity of iron metabolism parameters. The parameter with the largest area under the ROC curve was serum ferritin (0.83). A cut point of 121 microgram/L showed a sensitivity and a specificity of 75%. The areas under the ROC curves of serum transferrin receptor and erythrocyte ferritin were 0.69 and 0.68, respectively. The remaining parameters showed areas under the ROC curve less than 0.65. Although serum transferrin receptor and erythrocyte ferritin may be acceptable markers for iron deficiency in stable chronic renal failure patients, serum ferritin level continues to be the most reliable diagnostic parameter. Transferrin saturation index is not a reliable parameter for the diagnosis of iron deficiency in stable patients not treated with rHuEPO.

Adequacy of dialysis in automated peritoneal dialysis: a clinical experience.

OBJECTIVES: To compare the peritoneal clearances of urea and creatinine in continuous ambulatory peritoneal dialysis (CAPD) with three types of automated peritoneal dialysis (APD): continuous cycling peritoneal dialysis (CCPD), 50% tidal peritoneal dialysis (TPD), and 25% TPD and to assess the usefulness of the peritoneal equilibration test (PET) in predicting peritoneal clearances in overnight APD. PATIENTS: Eleven uremic patients (mean age 44.5 +/- 15.45 years with a mean time on dialysis of 42.63 +/- 25.62 months) were included in the study. MEASUREMENTS: PET for urea and creatinine following Twardowski's method. Peritoneal clearances for urea and creatinine CAPD: samples of blood and dialysate within 24 hours. APD: blood mean levels of urea and creatinine before and after nighttime dialysis. Dialysate: urea and creatinine in nocturnal and daytime dialysate. RESULTS: Peritoneal clearance of creatinine was 38.14 +/- 9.99 L/week/1.73 m2 in CAPD, 44.28 +/- 12.4 L/week/1.73 m2 in CCPD, 50.07 +/- 17.86 L/week/1.73 m2 in 50% TPD (p < 0.05) and 40.18 +/- 6.65 L/week/1.73 m2 in 25% TPD. Peritoneal clearance of urea improved significantly in the three modalities of APD: 51.91 +/- 12.58 L/week/1.73 m2 in CAPD; 66.7 +/- 9.9 L/week/1.73 m2 in CCPD (p < 0.05); 76.3 +/- 14.5 L/week/1.73 m2 in 50% TPD (p < 0.001) and 64.4 +/- 11.4 L/week/1.73 m2 in 25% TPD (p < 0.05). The dialysate/ plasma (D/P) ratio of creatinine at 30, 60, 120, 180, and 240 minutes showed significant correlation with nighttime APD clearance. Nevertheless, only the D/P ratio of urea at 30, 60, and 120 minutes correlated with overnight APD clearance. CONCLUSIONS: A remarkable improvement was observed with APD regarding the clearance of urea mainly when 50% tidal peritoneal dialysis was used, whereas it was less noticeable in the clearance of creatinine. The PET is a helpful tool in predicting overnight peritoneal clearances of creatinine but it is less useful in predicting urea clearance.