Impact of BK Polyomavirus Plasma Viral Load in Kidney Transplant Outcomes.

BACKGROUND: BK polyomavirus infection (BKVi) is an important cause of kidney transplant (KT) loss, but there is scarce evidence on the impact of BK plasma viral load on graft function and long-term KT survival. METHODS: A retrospective cohort study including all KT recipients with BKVi (BK viremia identified in ≥3 consecutive samples by polymerase chain reaction) in our center from January 2010 to December 2020 was performed. A case-control study (1:2) was performed. We grouped the cases according to their highest peak viral load: low-level viremia (<10,000 copies/mL) and high-level viremia (≥10,000 copies/mL). To identify risk factors for BKVi, a logistic regression analysis was achieved, and a multivariable Cox regression was used to describe risk factors for graft loss. RESULTS: A total of 849 KTs were performed, and 67 presented BKVi (low-level viremia, n = 35 and high-level viremia, n = 26). In logistic regression analysis male sex (odds ratio [OR], 4.226; 95% CI, 1.660-10.758, P = .002), age (OR, 1.047; 95% CI, 1.008-1.088; P = .018), and retransplant (OR, 4.162; 95% CI, 1.018-17.015; P = .047) were predictors of BKVi. Acute rejection was more frequent in the BKVi group (18% vs 4.9%, P = .004), and graft survival was lower in patients with BKVi and high-level viremia (P = .027). In Cox regression analysis, BKVi (hazard ratio, 3.657; 95% CI, 1.146-11.670; P = .029) and specific BKV (BK polyomavirus) high-level viremia (hazard ratio, 1.988; 95% CI, 1.012-3.907; P = .046) were predictors of shorter graft survival. CONCLUSIONS: BKV high-level viremia was associated with BKV nephropathy and poorer graft survival. Additionally, acute rejection is more frequent after BKVi. It is necessary to develop strategies safe and effective for these patients.

Evaluation of Expanded Criteria Donors Using the Kidney Donor Profile Index and the Preimplantation Renal Biopsy.

The increasing comorbidity of kidney transplant (KT) donors make it necessary to develop scores to correctly assess the quality of kidney grafts. This study analyzes the usefulness of the preimplantation biopsy and the Kidney Donor Profile Index (KDPI) as indicators of KT survival from expanded criteria donors (ECD). Retrospective study of KT in our center between January 2010 to June 2019 who received a kidney from an ECD and underwent a preimplantation biopsy. 266 KT were included. Graft survival was categorized by KDPI quartiles: Q1 = 86%, Q2 = 95%, Q3 = 99% and Q4 = 100%. KT from KDPI Q1 presented better survival (p = 0.003) and Q4 donors had worse renal function (p = 0.018) and poorer glomerular filtration rate (3rd month; p = 0.017, 1st year; p = 0.010). KT survival was analyzed according to KDPI quartile and preimplantation biopsy score simultaneously: Q1 donors with biopsy score ≤3 had the best survival, especially comparing against Q3 with a biopsy score >3 and Q4 donors (p = 0.014). In multivariable analysis, hyaline arteriopathy, glomerulosclerosis, and KDPI Q4 were predictors for graft survival. High KDPI and a greater histological injury in the preimplantation biopsy, especially glomerular and vascular lesions, were related to a higher rate of KT loss from ECD.

Acute Kidney Injury and Urinary and Histopathological Disorders in Kidney Transplant Patients with SARS-CoV-2 Infection.

BACKGROUND: Acute kidney injury (AKI) is a manifestation of SARS-CoV-2 infection. The evidence in kidney transplant (KT) is limited, as there are scarce data about the histologic features in graft biopsies of these patients. MATERIAL AND METHODS: A retrospective cohort study of KTs with SARS-CoV-2 infection from August 28, 2020, to April 23, 2021. We collected the incidence of AKI and the presence of urinary and histopathological disorders. Both groups were compared (AKI vs no AKI). Immunohistochemical and reverse transcription-polymerase chain reaction studies were performed on the anatomopathological samples. RESULTS: In our study, 72 KTs had SARS-CoV-2 infection and, among them, 27 patients (35.1%) developed AKI related to increased severity and a worse evolution of the infection, defined by a greater presence of pneumonia (P < .001), hospitalization (P < .001), admission to the intensive care unit (P < .001), the need for ventilation support (P < .001), and continuous renal replacement therapy (P < .001). In the multivariable analysis, pneumonia behaved as an independent predictor for AKI development (P = .046). No differences were observed between proteinuria a month before and after infection (P = .224). In addition, 5 patients showed microhematuria and 2 patients presented transient glycosuria without hyperglycemia. Of the 5 kidney biopsies performed, 1 biopsy (20%) showed positive reverse transcription polymerase chain reaction for SARS-CoV-2. CONCLUSIONS: AKI is a frequent and potentially serious complication in KT patients. Occasionally it could be accompanied by abnormalities in the urinary sediment. Of 5 biopsied patients, 1 patient had positive reverse transcription polymerase chain reaction in renal tissue, which suggests the systemic spread of the virus and the tropism for the renal graft.

Surgical Wound Dehiscence in Kidney Transplantation: Risk Factors and Impact on Graft Survival.

BACKGROUND: Surgical wound dehiscence (SWD) is a frequent complication after kidney transplantation (KT) but there is not enough evidence of its impact on graft survival. METHODS: A retrospective cohort study including all KT patients with SWD in our center from January 2015 to July 2020 was performed. A case-control study was performed and for each case of SWD, 2 controls were selected (2:1). To identify risk factors for SWD, a logistic regression analysis was carried out and a multivariable Cox regression was used to describe risk factors for graft survival. RESULTS: In our center, 503 KT were performed, and 39 patients presented SWD. They were older (62.1 vs 57.1 years; P = .030), most had diabetes mellitus (59% vs 28.6%; P = .002) and their body mass index was higher (31 vs 26.9 kg/m2; P < .001). In multivariable logistic regression analysis, diabetes mellitus (P = .024) and a body mass index ≥30 kg/m2 at time of transplantation (P = .018) were predictors of SWD. A higher rate of delayed graft function was described in SWD (P = .013) and it was associated with a longer hospital stay (20.9 vs 15 days; P = .004). Graft survival was lower in patients with SWD (P = .036). In multivariable Cox regression analysis, time in renal replacement therapy (P = .020) and SWD (P = .028) were predictors of shorter graft survival. CONCLUSION: SWD is a risk factor for graft survival. The presence of diabetes mellitus and a higher body mass index are predictors for the appearance of this complication.

Changes in Antihypertensive Therapy After Renal Transplantation.

INTRODUCTION: Post-transplant hypertension is extremely frequent, occurring in 60% to 90% of cases. It is involved in the pathogenesis of chronic graft dysfunction and patient survival. OBJECTIVES: We sought to describe changes in antihypertensive therapy after renal transplantation (RT) depending on the type of pretransplant renal replacement therapy (RRT), hemodialysis (HD) or peritoneal dialysis (PD). METHODS: We performed a retrospective cohort study of RT patients who were divided into 2 groups according to the type of pretransplant RRT (HD group: 69 patients; PD group: 38 patients). Patients with a diagnosis of nonessential hypertension etiology, diagnosis of renal artery stenosis of the graft, active urologic complications, and history of acute graft rejection were excluded. Variables related to chronic kidney disease and RT as well as antihypertensive therapy were studied. RESULTS: PD patients had reduced number of antihypertensive drugs at 1 month after RT (1.39 ± 1.03) compared with pre-RT (2.16 ± 1.30; P = .001), a trend that was maintained at 6 months (1.70 ± 1.18; P = .06). In HD group, the number of antihypertensive drugs increased at 6 months after RT (1.59 ± 1.17) compared with pretransplant (1.15 ± 1.13; P = .027). The use of calcium channel blockers increased by 10.2% by 1 month (P = .071) and 9.2% (P = .036) by 6 months after RT. CONCLUSION: By 1 month after RT, antihypertensive therapy was reduced. Calcium channel blockers were the most common drug group, although it is usually necessary to use more than 1 drug.