Exploring kidney biopsy findings in congenital heart diseases: Insights beyond cyanotic nephropathy.

BACKGROUND: The association between congenital heart disease and chronic kidney disease is well known. Various mechanisms of kidney damage associated with congenital heart disease have been established. The etiology of kidneydisease has commonly been considered to be secondary to focal segmental glomerulosclerosis (FSGS), however, this has only been demonstrated in case reports and not in observational or clinical trials. AIM: To identify baseline and clinical characteristics, as well as the findings in kidney biopsies of patients with congenital heart disease in our hospital. METHODS: This is a retrospective observational study conducted at the Nephrology Department of the National Institute of Cardiology "Ignacio Chávez". All patients over 16 years old who underwent percutaneous kidney biopsy from January 2000 to January 2023 with congenital heart disease were included in the study. RESULTS: Ten patients with congenital heart disease and kidney biopsy were found. The average age was 29.00 years ± 15.87 years with pre-biopsy proteinuria of 6193 mg/24 h ± 6165 mg/24 h. The most common congenital heart disease was Fallot's tetralogy with 2 cases (20%) and ventricular septal defect with 2 (20%) cases. Among the 10 cases, one case of IgA nephropathy and one case of membranoproliferative glomerulonephritis associated with immune complexes were found, receiving specific treatment after histopathological diagnosis, delaying the initiation of kidney replacement therapy. Among remaining 8 cases (80%), one case of FSGS with perihilar variety was found, while the other 7 cases were non-specific FSGS. CONCLUSION: Determining the cause of chronic kidney disease can help in delaying the need for kidney replacement therapy. In 2 out of 10 patients in our study, interventions were performed, and initiation of kidney replacement therapy was delayed. Prospective studies are needed to determine the usefulness of kidney biopsy in patients with congenital heart disease.

Urine Uromodulin, Kidney Tubulointerstitial Fibrosis, and Furosemide Response.

BACKGROUND: Interstitial fibrosis and tubular atrophy (IFTA) are common findings on biopsy in chronic kidney disease (CKD) and strongly predictive of kidney failure. IFTA is poorly correlated with estimated glomerular filtration rate (eGFR) and albuminuria, the most common metrics of kidney disease. Thus, IFTA is prognostically important, yet its presence and severity are invisible to the clinician except when kidney biopsies are obtained. OBJECTIVES: To investigate 1) the cross-sectional association between urine uromodulin (uUMOD) and IFTA, and 2) to determine whether uUMOD levels were associated with diuretic response after a furosemide stress test. METHODS: We performed logistic regression to evaluate the association between uUMOD and fibrosis. We used linear regression models to assess the association of uUMOD with urine output. RESULTS: Among 52 participants, the mean age was 42 ± 16 years, 48% were women, 23% had diabetes, and the median eGFR was 56 ml/min/1.73m2. The mean uUMOD concentration was 5.1 (8.4) mcg/mL. Each halving of uUMOD was associated with 1.74 higher odds (95% CI 1.10, 2.75) of grade 2 or 3 fibrosis. However, this association was no longer significant after adjusting for baseline eGFR and albuminuria. Each halving of urine uromodulin was associated with a decreased response to furosemide. This association was also no longer significant after adjusting for baseline eGFR and albuminuria. CONCLUSION: In a population of individuals with a wide range of kidney function undergoing clinically indicated kidney biopsies, we did not find an association between uUMOD and interstitial fibrosis or response to loop diuretics after adjusting for eGFR and albuminuria.

Venous excess ultrasound score and acute kidney injury in patients with acute coronary syndrome.

AIMS: Systemic venous congestion is associated with an increased risk of acute kidney injury (AKI) in critically ill patients. Venous Excess Ultrasound Score (VExUS) has been proposed as a non-invasive score to assess systemic venous congestion. We aimed to evaluate the association between VExUS and AKI in patients with acute coronary syndrome (ACS). METHODS AND RESULTS: This is a prospective study including patients with the diagnosis of ACS (both ST elevation and non-ST elevation ACS). VExUS was performed during the first 24 h of hospital stay. Patients were classified according to the presence of systemic congestion (VExUS 0/≥1). The primary objective of the study was to determine the occurrence of AKI, defined by KDIGO criteria. A total of 77 patients were included. After ultrasound assessment, 31 (40.2%) patients were categorized as VExUS ≥1. VExUS ≥1 was more frequently found in inferior vs. anterior myocardial infarction/non-ST-segment elevation acute myocardial infarction (48.3 vs. 25.8 and 22.5%, P = 0.031). At each increasing degree of VExUS, a higher proportion of patients developed AKI: VExUS = 0 (10.8%), VExUS = 1 (23.8%), VExUS = 2 (75.0%), and VExUS = 3 (100%; P < 0.001). A significant association between VExUS ≥1 and AKI was found [odds ratio (OR): 6.75, 95% confidence interval (CI): 2.21-23.7, P = 0.001]. After multivariable analysis, only VExUS ≥1 (OR: 6.15; 95% CI: 1.26-29.94, P = 0.02) remained significantly associated with AKI. CONCLUSION: In patients hospitalized with ACS, VExUS is associated with the occurrence of AKI. Further studies are needed to clarify the role of VExUS assessment in patients with ACS.

Changes in the Inferior Vena Cava Are More Sensitive Than Venous Pressure During Fluid Removal: A Proof-of-Concept Study.

BACKGROUND: Congestion is central to the pathophysiology of heart failure (HF); thus, tracking congestion is crucial for the management of patients with HF. In this study we aimed to compare changes in inferior vena cava diameter (IVCD) with venous pressure following manipulation of volume status during ultrafiltration in patients with cardiac dysfunction. METHODS AND RESULTS: Patients with stable hemodialysis and with systolic or diastolic dysfunction were studied. Central venous pressure (CVP) and peripheral venous pressure (PVP) were measured before and after hemodialysis. IVCD and PVP were measured simultaneously just before dialysis, 3 times during dialysis and immediately after dialysis. Changes in IVCD and PVP were compared at each timepoint with ultrafiltration volumes. We analyzed 30 hemodialysis sessions from 20 patients. PVP was validated as a surrogate for CVP. Mean ultrafiltration volume was 2102 ± 667 mL. IVCD discriminated better ultrafiltration volumes ≤ 500 mL or ≤ 750 mL than PVP (AUC 0.80 vs 0.62, and 0.80 vs 0.56, respectively; both P< 0.01). IVCD appeared to track better ultrafiltration volume (P< 0.01) and hemoconcentration (P< 0.05) than PVP. Changes in IVCD were of greater magnitude than those of PVP (average change from predialysis: -58 ± 30% vs -28 ± 21%; P< 0.001). CONCLUSIONS: In patients undergoing ultrafiltration, changes in IVCD tracked changes in volume status better than venous pressure.

Intraocular Pressure Changes during Hemodiafiltration with Two different Concentrations of Sodium in the Dialysate.

Ocular complications are common among end-stage renal disease patients and some complications had been linked to increments of intraocular pressure (IOP) during hemodialysis. The changes of IOP during hemodiafiltration (HDF) have been scarcely investigated and the potential influence of the sodium dialysate concentration is unknown. The aim of this study was to compare the IOP changes during HDF with sodium dialysate concentration, either fixed or individualized. Thirteen end-stage renal disease patients participated in the study; they were treated with HDF using a dialysate sodium profile fixed at 138 mmol and another session with an individualized sodium profile. The intraocular pressure was measured before and after each session and every 30 min during HDF. Both groups had a similar HDF prescription, blood pressure, and biochemical parameters. At the end of hemodiafiltration, sodium concentration decreased only in the fixed sodium profile group. The number of patients with at least an episode of intraocular hypertension during HDF ranged from 5 (19%) to 8 (31%) without significant differences between right and left eye nor between dialysate sodium concentration. During HDF, there is a large variability of IOP; transient events of intraocular hypertension are highly prevalent in this sample, and they are not related to the sodium dialysate concentration.