Major Bleeding of Transjugular Native Kidney Biopsies. A French Nationwide Cohort Study

Safety and effectiveness of laparoscopic renal biopsy: a single-center review and meta-analysis

BACKGROUND

While renal biopsy remains the preferred diagnostic method for assessing proteinuria, hematuria, or renal failure, laparoscopic renal biopsy (LRB) can serve as an alternative for high-risk patients when percutaneous kidney biopsy (PKB) is not recommended. This study was aimed to evaluate the safety of LRB.

METHODS

In study 1, Fourteen patients from January 2021 to January 2023 had a LRB taken for various indications, such as morbid obesity, abnormal kidney construction, uncontrolled hypertension, and coagulopathy. We also conducted a Meta-analysis of the success rate and complication rate of previous LRB in study 2.

RESULTS

All the patients completed biopsies and adequate renal tissues were obtained. The success rate was 100%. The median number of glomeruli obtained was 22.5 (range:12.0, 45.0). The complication rate was 7.1% (urinary tract infection). There were no significant differences between levels of hemoglobin, serum creatinine, and urinary NAGL before and after surgery. In the meta-analysis, the success rate of operation, satisfactory rate of sample, and complication rate of surgery were 99.9%, 99.1%, and 2.6% respectively.

CONCLUSION

LRB can achieve a good success rate and specimen retrieval and does not increase the risk of complications for high-risk patients. It can present as one of the alternative methods for patients with glomerular diseases.

Assessment of epidemiology and outcomes of adult patients with kidney-limited thrombotic microangiopathies

Thrombotic microangiopathies (TMA) are usually associated with hematological features (RH-TMA). The epidemiology of TMA limited to kidneys (RL-TMA) is unclear Therefore, patients with TMA and native kidney biopsies were identified during 2009-2022 in 20 French hospitals and results evaluated. RL-TMA was present in 341/757 (45%) patients and associated with lower creatinine levels (median 184 vs 346 μmol/L) than RH-TMA. RL-TMA resulted from virtually all identified causes, more frequently from anti-VEGF treatment and hematological malignancies but less frequently from shigatoxin-associated hemolytic uremic syndrome (HUS), systemic sclerosis, gemcitabine and bacterial infection, and even less frequently when three or more causes/triggers were combined (RL-TMA: 5%; RH-TMA: 12%). RL-TMA was associated with significantly lower major cardiovascular events (10% vs 20%), kidney replacement therapy (23% vs 43%) and death (12% vs 20%) than RH-TMA during follow-up (median 28 months). Atypical HUS (aHUS) was found in 326 patients (RL-TMA: 43%, RH-TMA: 44%). Among the 69 patients with proven complement-mediated aHUS, eculizumab (anti-C5 therapy) was used in 43 (62%) (RL-TMA: 35%; RH-TMA: 71%). Among the 257 other patients with aHUS, including 51% with RL-TMA, eculizumab was used in 29 but with unclear effects of this treatment. Thus, RL-TMA represents a very high proportion of patients with TMA and results from virtually all known causes of TMA and includes 25% of patients with complement-mediated aHUS. Adverse outcomes of RL-TMA are lower compared to RH-TMA but remain significant. Anti-C5 therapy was rarely used in RL-TMA, even in proven complement-mediated aHUS, and its effects remain to be assessed.

Social deprivation and kidney failure due to an undiagnosed nephropathy

BACKGROUND

In France, kidney diseases of undetermined origin account for 5%-20% of all causes of end-stage kidney disease. We investigated the impact of social disadvantage on the lack of aetiological diagnosis of nephropathies.

METHODS

Data from patients who started dialysis in France between 1 January 2017 and 30 June 2018 were extracted from the French Renal Epidemiology and Information Network registry. The social deprivation of each individual was estimated by the European Deprivation Index (EDI) defined by the patient's address. Logistic regression was used to perform mediation analysis to study the potential association between social deprivation and unknown nephropathy.

RESULTS

Of the 7218 patients included, 1263 (17.5%) had unknown kidney disease. A total of 394 (31.4%) patients in the unknown kidney disease belonged to the most deprived quintile of the EDI [fifth quintile (Q5)], vs 1636 (27.5%) patients in the known kidney disease group. In the multivariate analysis, unknown kidney disease was associated with Q5 (odds ratio 1.40, 95% confidence interval 1.12-1.74, P = .003). Mediation analysis did not identify any variables (e.g. obesity, initiation of dialysis in emergency, number of visits to the general practitioner and nephrologist before initiation of dialysis, date of first nephrology consultation) that mediated the association between social deprivation and nephropathy of unknown origin.

CONCLUSIONS

Our results show that, compared with nondeprived subjects, individuals experiencing social deprivation have a higher risk of unknown nephropathy at dialysis initiation. However, mediation analysis did not identify any variables that explained the association between social deprivation and nephropathy of unknown origin.

Renal Biopsy for Diagnosis in Kidney Disease: Indication, Technique, and Safety

Renal biopsies are the gold standard for diagnosis, staging, and prognosis of underlying parenchymal kidney disease. This article provides an overview of the current indications and highlights ways to reduce bleeding complications in order to achieve optimal diagnostic yield with minimal risk to the patient. Novel indications have emerged from the increasing use of new molecularly targeted oncologic therapies in recent years, which often induce immune-mediated renal disease. On the other hand, the detection of specific antibodies against target antigens on podocytes in the sera of patients with new-onset nephrotic syndrome has now relativized the indication for biopsy in membranous nephropathy. The use of semi-automatic spring-loaded biopsy devices and real-time ultrasound considerably declined the complication rate and is the current standard. Percutaneous renal biopsies are overall a safe procedure if contraindications are considered. A coagulation disorder needs to be excluded beforehand, and an elevated blood pressure must be reduced to the normotensive range with medications. A laparoscopic approach or a radiology interventional procedure through the internal jugular vein may be considered for obtaining a kidney tissue sample if there is an urgent indication and a bleeding tendency cannot be adequately corrected. Major bleeding after a percutaneous renal biopsy can usually be managed with selective arterial embolization of the injured renal vessel. The use of a 16-gauge needle is the most reasonable compromise between diagnostic benefit and risk of complication. In the routine diagnostic, the biopsy specimen is examined with light microscopy, immunohistochemistry, and electron microscopy. Combination with modern molecular pathology techniques will contribute to more precise insights into the development and progression of kidney disease, which will likely refine future treatments in nephrology.

Diagnosis of Kidney Diseases of Unknown Etiology Through Biopsy-Genetic Analysis

Introduction

Previous studies have suggested that genetic kidney diseases in adults are often overlooked, representing up to 10% of all cases of chronic kidney disease (CKD). We present data obtained from exome sequencing (ES) analysis of patients with biopsy-proven undetermined kidney disease (UKD).

Methods

ES was proposed during routine clinical care in patients with UKD from January 2020 to December 2021. We used in silico custom kidney genes panel analysis to detect pathological variations using American College of Medical Genetics guidelines in 52 patients with biopsy-proven UKD with histological finding reassessment.

Results

We detected 12 monogenic renal disorders in 21 (40.4%) patients. The most common diagnoses were collagenopathies (8/21,38.1%), COL4A3 and COL4A4 accounting for 80% of these diagnoses, and ciliopathies (5/21, 23.8%). The diagnostic yield of ES was higher in female patients and patients with a family history of kidney disease (57.1% and 71%, respectively). Clinical nephropathy categories matched with the final genetic diagnoses in 72.7% of cases, whereas histological renal lesions matched with the final diagnoses in 92.3% of cases. The genetics diagnoses and histopathological findings were in complete agreement for both glomerular and tubulointerstitial cases. Interstitial inflammation without tubulitis was only observed in tubulopathies or ciliopathies. Isolated CKD, CKD with proteinuria or hematuria, and isolated proteinuria or hematuria yielded the highest diagnostic yields (54.6%, 52.6%, and 42.9%, respectively).

Conclusion

ES done in patients with biopsy-proven UKD should be considered as a first-line tool for CKD patients with a family history of kidney disease. Combination of ES and kidney biopsy may have major impacts on kidney disease ontology.

A Universal Bleeding Risk Score in Native and Allograft Kidney Biopsies: A French Nationwide Cohort Study

BACKGROUND

The risk of bleeding after percutaneous biopsy in kidney transplant recipients is usually low but may vary. A pre-procedure bleeding risk score in this population is lacking.

METHODS

We assessed the major bleeding rate (transfusion, angiographic intervention, nephrectomy, hemorrhage/hematoma) at 8 days in 28,034 kidney transplant recipients with a kidney biopsy during the 2010-2019 period in France and compared them to 55,026 patients with a native kidney biopsy as controls.

RESULTS

The rate of major bleeding was low (angiographic intervention: 0.2%, hemorrhage/hematoma: 0.4%, nephrectomy: 0.02%, blood transfusion: 4.0%). A new bleeding risk score was developed (anemia = 1, female gender = 1, heart failure = 1, acute kidney failure = 2 points). The rate of bleeding varied: 1.6%, 2.9%, 3.7%, 6.0%, 8.0%, and 9.2% for scores 0 to 5, respectively, in kidney transplant recipients. The ROC AUC was 0.649 (0.634-0.664) in kidney transplant recipients and 0.755 (0.746-0.763) in patients who had a native kidney biopsy (rate of bleeding: from 1.2% for score = 0 to 19.2% for score = 5).

CONCLUSIONS

The risk of major bleeding is low in most patients but indeed variable. A new universal risk score can be helpful to guide the decision concerning kidney biopsy and the choice of inpatient vs. outpatient procedure both in native and allograft kidney recipients.