Safety and tissue yield for percutaneous native kidney biopsy according to practitioner and ultrasound technique

Concordance between MITS and conventional autopsies for pathological and virological diagnoses

In pandemics or to further study highly contagious infectious diseases, new strategies are needed for the collection of post-mortem tissue samples to identify the pathogen as well as its morphological impact. In this study, an ultrasound-guided minimally invasive tissue sampling (MITS) protocol was developed and validated for post-mortem use. The histological and microbiological qualities of post-mortem specimens were evaluated and compared between MITS and conventional autopsy (CA) in a series of COVID-19 deaths. Thirty-six ultrasound-guided MITS were performed. In five cases more, specimens for histological and virological examination were also obtained and compared during the subsequently performed CA. Summary statistics and qualitative interpretations (positive, negative) were calculated for each organ tissue sample from MITS and CA, and target genes were determined for both human cell count (beta-globin) and virus (SARS-CoV-2 specific E gene). There are no significant differences between MITS and CA with respect to the detectability of viral load in individual organs, which is why MITS can be of utmost importance and an useful alternative, especially during outbreaks of infectious diseases.

Correlation of renal length with anthropometric and demographic data in healthy children: A prospective cross sectional study

Background

Renal size is an important parameter in the assessment of a child with renal disease. Renal size can be estimated by measuring renal length, renal volume, and cortical volume or thickness. Renal length depends on different factors, which include size, body mass index and gender. Ultrasonography is useful, non-invasive and easily available method for reliably performing the measurement of kidney length. This study was conducted to find out correlation between renal length and age and anthropometric variables in healthy children. This prospective cross sectional study was carried out with the following objectives: (a) To determine the anthropometric variable that correlated best with renal length in healthy children. (b) To develop a nomogram for renal length in healthy children.

Methods

Five hundred healthy children were included in this study. Sonographic assessment of renal length was performed using real time mechanical sector scanner with 5 MHz and 8 MHz frequency. The renal length was correlated with somatic parameters like age, weight, height, body surface area and body mass index. Regression equations were derived for each pair of dependent and independent variables.

Results

We performed the measurement of renal length in 500 healthy children. In our series, renal measuring parameters showed a good correlation with studied body parameters, height having the best correlation. Data from left and right kidneys are shown separately since there was small but statistically significant difference between them. Based on our study, using the height of the child, renal length may be calculated by using following equation: Left renal length (cm) = 0.052 × height (cm) + 1.042, Right renal length (cm) = 0.052 × height (cm) + 0.867.

Conclusions

This study provides values of renal length (mean ± 2SD) in normal Indian children and its correlation with body parameters. Renal length may be easily calculated by derived linear regression equation. Nomograms of renal length with respect to age and height have been formulated. Renal Length was found to correlate best with height of the child.

Comparative analysis of blind vs real-time ultrasound-guided pediatric renal biopsies: A cross-sectional study

Background

Renal biopsy has a definite role in the management of pediatric kidney diseases. Most centers have given up the earlier practice of performing blind biopsy using Tru-Cut needle and started doing real time ultrasound-guided renal biopsy with an automated spring-loaded gun, which has become standard of care in the last decade or so.

Methods

We performed a cross-sectional analysis of the pediatric biopsies conducted at our center over the years by both methods to evaluate whether ultrasound-guided renal biopsy with a disposable automated spring-loaded gun was superior to blind biopsy with a disposable needle of the same size in terms of reduction of complications and improving the yield. We also reviewed the indications and the histopathological diagnosis of pediatric renal biopsies at our center.

Results

A total of 45 native kidney biopsies were performed blind and 48 ultrasound-guided biopsies using the curvilinear probe (frequency 3-5 Hz) of GE Logiq P3 ultrasound machine with disposable spring-loaded automated guns. There was a significant increase in the yield of biopsy in terms of the number of glomeruli per pass. A significant increase in the mean number of glomeruli was noted when a biopsy was performed under ultrasound guidance (P < 0.0001). Gross hematuria was significantly reduced as compared to the earlier biopsies done blind i.e., without ultrasound (P ¼ 0.03). Nephrotic syndrome was the commonest indication for biopsy in our patients during both time periods studied. The most common histopathological diagnosis was MesPGN among the children who underwent kidney biopsy from 2005 to 2007, while Minimal Change Disease (MCD) and Focal Segmental Glomerulosclerosis (FSGS) were most frequently reported.

Conclusion

Ultrasound guided kidney biopsies in pediatric age group have significant reduction in incidence of post gross hematuria and significant increase in the mean number of glomeruli per pass.

Factors Associated with Glomerular Yield in Percutaneous Kidney Biopsy

Percutaneous kidney biopsy is essential for diagnosing various kidney diseases. However, insufficient glomerular yield leads to misdiagnosis, a critical problem. We retrospectively investigated the risk of insufficient glomerular yield in percutaneous kidney biopsies. We included 236 patients who underwent percutaneous kidney biopsies between April 2017 and September 2020. We retrospectively analyzed the relationship between glomerular yield and patient characteristics. After the biopsy, 31 patients produced insufficient glomerular yields (cases with yielded glomeruli <10). Glomerular yield correlated negatively with hypertension (β = -0.13, p = 0.04), and positively with glomerular density (β = 0.59, p < 0.0001) and the volume of the biopsy core (number of punctures, number of biopsy cores, total length of biopsy core, length of core collected by one puncture, and cortical length). Patients yielding <10 glomeruli had lower glomerular densities (14.4 ± 1.6 vs. 22.9 ± 0.6/cm; p < 0.0001). These results suggest that glomerular density is crucial to glomerular yield. Furthermore, glomerular density was negatively correlated with hypertension, diabetes, and age. Hypertension was independently associated with low glomerular density (β = -0.16, p = 0.02). Thus, the glomerular yield was associated with glomerular density and biopsy core length, and hypertension might be related to glomerular yield via low glomerular density.

Percutaneous kidney biopsy and the histopathologic patterns of kidney diseases in children: An observational descriptive study at a South-East Nigerian tertiary hospital

Background

Kidney biopsy remains the best standard for kidney tissue analysis. Although percutaneous kidney biopsy is an invasive procedure, it is an indispensable part of interventional nephrology for accurate diagnosis, selection of appropriate therapy protocol, and prognostication of kidney diseases in children. With improvement in expertise among pediatric nephrologists, data on procedure outcomes are now being documented. Aim: We aimed to describe the outcomes in a 5-year practice of kidney biopsy at the pediatric nephrology unit in a southeast Nigerian tertiary hospital.

Patients and Methods

An observational descriptive study conducted on the kidney biopsy performed in our facility from 2017 to 2022. The focus was on the patients' clinical profile, indications for biopsy, the adopted procedure, and the histopathologic findings.

Results

A total of 69 patients had kidney biopsy, 40 (58.0%) were males, while 29 (42.0%) were females. Sixty-four (92.7%) patients had the procedure at the age of >10 years, while five (7.2%) at the age of <7 years. The patients' prebiopsy mean systolic and diastolic blood pressures were 111.20 ± 16.93 and 74.64 ± 12.69 mmHg, respectively. Their estimated glomerular filtration rate (eGFR) was 119.27 ± 52.78 ml/min/1.73 m². The most frequent indication was steroid resistance (39/69, 56.5%). Focal segmental glomerulosclerosis was the commonest histopathologic finding (38/69, 55.0%).

Conclusion

Outcomes of percutaneous kidney biopsy at a Nigerian tertiary hospital are adjudged successful. The histopathologic patterns highlight FSGS as the major cause of steroid resistance in childhood nephrotic syndrome in this clime.

Cranial versus Caudal Direction Technique of Native Percutaneous Kidney Biopsy: A Randomized Controlled Trial

Background

Percutaneous kidney biopsy (PKB) is the gold standard for diagnosing various kidney diseases, but it can result in potential complications. This study aimed to compare kidney tissue adequacy and safety between the two biopsy techniques, including cranial direction (CN) and caudal direction (CD), of needle biopsy under real-time ultrasonogram guidance.

Methods

This single-center, prospective, single-blinded, randomized trial included patients undergoing native PKB from July 5, 2017, to June 30, 2019. Patients were randomized to the CN and CD groups. Adequacy and complications between the two groups were analyzed. All PKBs were performed under real-time ultrasonogram guidance with a 16-gauge kidney biopsy needle.

Results

A total of 107 participants were enrolled (53 in the CD group and 54 in the CN group). The CD group has more glomeruli than the CN group but with no statistical significance (16 versus 11, p = 0.0865). The CD group obtained more adequate kidney tissue samples than the CN group (69.8% versus 59.3%, p = 0.348). The number of inadequate glomeruli tissue sampling is similar in both groups (14 versus 15, respectively). Furthermore, the CN group had more adverse events, including Hb decline ≥10% after kidney biopsy, perinephric hematoma size ≥1 cm, hematuria, and the need for blood transfusion, than the CD group.

Conclusion

The CD technique of the percutaneous kidney biopsy in the native kidney has fewer complications and was possibly more effective than the CN technique.

The evolution of performing a kidney biopsy: a single center experience comparing native and transplant kidney biopsies performed by interventional radiologists and nephrologists

BACKGROUND

Kidney biopsy is the most vital tool guiding a nephrologist in diagnosis and treatment of kidney disease. Over the last few years, we have seen an increasing number of kidney biopsies being performed by interventional radiologists. The goal of our study was to compare the adequacy and complication rates between kidney biopsies performed by interventional radiology versus nephrology.  METHODS : We performed a single center retrospective analysis of a total of all kidney biopsies performed at our Institution between 2015 and 2021. All biopsies were performed using real-time ultrasound. Patients were monitored for four hours post biopsy and repeat ultrasound or hemoglobin checks were done if clinically indicated. The entire cohort was divided into two groups (Interventional radiology (IR) vs nephrology) based on who performed the biopsy. Baseline characteristics, comorbidities, blood counts, blood pressure, adequacy of the biopsy specimen and complication rates were recorded. Multivariable logistic regression was used to compare complication rates (microscopic hematuria, gross hematuria and need for blood transfusion combined) between these two groups, controlling for covariates of interest. ANCOVA (analysis of variance, controlling for covariates) was used to compare differences in biopsy adequacy (number of glomeruli per biopsy procedure) between the groups.

RESULTS

446 kidney biopsies were performed in the study period (229 native and 147 transplant kidney biopsies) of which 324 were performed by IR and 122 by nephrologist. There was a significantly greater number of core samples obtained by IR (mean = 3.59, std.dev. = 1.49) compared to nephrology (mean = 2.47, std.dev = 0.79), p < 0.0001. IR used 18-gauge biopsy needles while nephrologist exclusively used 16-gauge needles. IR used moderate sedation (95.99%) or general anesthesia (1.85%) for the procedures more often than nephrology, which used them only in 0.82% and 0.82% of cases respectively (p < 0.0001). Trainees (residents or fellows) participated in the biopsy procedures more often in nephrology compared to IR (97.4% versus 69.04%, p < 0.0001). The most frequent complication identified was microscopic hematuria which occurred in 6.8% of biopsies. For native biopsies only, there was no significant difference in likelihood of complication between groups, after adjustment for covariates of interest (OR = 1.01, C.I. = (0.42, 2.41), p = 0.99). For native biopsies only, there was no significant difference in mean number of glomeruli obtained per biopsy procedure between groups, after adjustment for covariates of interest (F(1,251) = 0.40, p = 0.53).

CONCLUSION

Our results suggest that there is no significant difference in the adequacy or complication rates between kidney biopsies performed by IR or nephrology. This conclusion may indicate that kidney biopsies can be performed safely with adequate results either by IR or nephrologists depending on each institution's resources and expertise.

Kidney biopsy adequacy and complications in children - does technique matter?

Kidney biopsy is part of the diagnostic workup of many children with renal disease. Traditionally, a perpendicular approach to the biopsy has been used, but more recently, some proceduralists have favoured a tangential approach. It is not clear if one technique is superior with regards to tissue adequacy or complication rates. In our centre, interventional radiologists (IR) use general anaesthetic and a tangential approach, whereas paediatric nephrologists (PN) use sedation and a perpendicular approach. We examined consecutive native kidney biopsies performed between January 2008 and December 2017 for adequacy (sufficient tissue for light and electron microscopy and immunofluorescence) and examined the electronic medical records for data regarding technique and complications. IR performed 72 (29%) of the 245 native kidney biopsies, obtaining more total glomeruli (median 39 vs 16, p < 0.001) and more glomeruli per tissue core (median 13 vs 8, p < 0.001) than PN. No differences in specimen adequacy were observed between the two groups (79% IR vs 81% PN, p = 0.75) and a diagnosis could be made in 99% and 94% respectively (p = 0.1). A statistically lower rate of peri-nephric haematoma (28% vs 42%, p = 0.04) was detected in the IR group, but there were no significant differences in other complications. One patient required a blood transfusion (PN) and another required surgical intervention for a perinephric haematoma (IR).

CONCLUSION

IR obtained larger samples and number of glomeruli, but the overall adequacy for native kidney biopsies was good using both perpendicular and tangential techniques, with low rates of significant complications.

WHAT IS KNOWN

• Kidney biopsy is integral to the diagnostic work-up of many children with kidney disease. • Kidney biopsy is a safe procedure with well-established complications in a minority of children.

WHAT IS NEW

• Interventional radiologists had higher biopsy yield than paediatric nephrologists, possibly due to the tangential approach. • Biopsy adequacy rates are high using both techniques and provided a diagnosis in over 95% of cases.

A Systematic Review of Complications Associated With Percutaneous Native Kidney Biopsies in Adults in Low- and Middle-Income Countries

Introduction

Kidney biopsy is an important tool for making diagnoses and for assessing the drug treatment requirements and disease prognosis in the management of kidney diseases. There are variations in the rate of complications associated with kidney biopsies across countries, and this depends on various clinical and technical factors. The aim of this study is to report on complications associated with kidney biopsy performed in low- and middle-income countries.

Methods

Two reviewers searched studies in MEDLINE, Embase, Cochrane Reviews, and African Journals Online. A random effects meta-analysis method was used to pool estimates of complications.

Results

We identified 39 studies reporting on 19,500 kidney biopsies with overall complications (major + minor) rate of 14.9% (95% confidence interval = 11.4%–18.7%). Fewer complications were reported in biopsies performed with real-time ultrasound scans compared to those pre-marked using ultrasound or blind procedures (12.4% vs. 14.9% vs. 24.5%; P = 0.037), respectively. Complications, albeit lower for procedures performed with automated needles (13.3%), were not significantly different from those performed with nonautomated needles (17.3%; P = 0.588). Major complications included macroscopic hematuria (1.48%), nephrectomy (0.04%), blood loss requiring red cell transfusion (0.24%), angiographic intervention (0.22%), and death (0.01%).

Conclusion

Complications associated with kidney biopsy in low- and middle-income countries are low, are comparable to those in other settings, and occur more sparingly when real-time ultrasound techniques or automated kidney biopsy needles are used. This suggests the need to expand the use of this procedure to improve diagnosis of kidney pathologies and choice of therapy when indicated.

Acute Kidney Disease Increases the Risk of Post-Kidney Biopsy Bleeding Complications

INTRODUCTION

Kidney biopsy, providing the insightful information for most kidney diseases, is an invasive diagnostic tool with certain risks ranging from the least severe macroscopic hematuria to the most severe life-threatening bleeding necessitating renal artery embolization. We aimed to compare the postbiopsy bleeding complications between 2 common methods and to further explore the risk factors of bleeding complications in patients using the negative pressure suction puncture (NPS) method.

METHODS

We retrospectively collected the data from percutaneous native kidney biopsies in 2016. The clinical, laboratory tests, pathological findings, and the occurrence of bleeding complications following kidney biopsy were analyzed. The kidney biopsy was performed in our center by experienced nephrologists with 2 different methods, namely, NPS method and real-time ultrasound-guided needle (RTU) method. We compared rates of complications between 2 methods and evaluated univariate and multivariate association of risk factors with bleeding complications in the NPS group.

RESULTS

626 kidney biopsies were performed between January 2016 and December 2016. There were 83.2% (521/626) participants in the NPS group and 16.8% (105/626) in the RTU group. There were more participants in the RTU group needing >1 needle pass during biopsy than those in the NPS group (61.0 vs. 14.7%, p < 0.001). Acute kidney disease (AKD) occurred before the procedure of kidney biopsy accounted for 13.8% (72/521) in the NPS group and 1.9% (2/105) in the RTU group. The renal pathological findings revealed higher number of glomeruli in the NPS group than in the RTU group (26.8 ± 13.0 vs. 17.2 ± 8.6, p < 0.001). The incidence of bleeding complications in the NPS group was lower than that in the RTU group (9.2 vs. 21.9%, p < 0.01). Logistic multivariate regression showed that AKD was independently associated with bleeding complications after kidney biopsy in the NPS group.

CONCLUSION

Regarding the bleeding risk, there was noninferiority of NPS over RTU. AKD contributes to higher risks of bleeding complications after kidney biopsy.

Kidney Biopsy Adequacy: A Metric-based Study

There are differences in renal biopsy yield related to on-site evaluation, tissue division, and operator, among others. To understand these variations, we collected adequacy-associated data (%cortex, glomeruli, arteries, length) from consecutive native and allograft kidney biopsies over a 22-month period. In total, 1332 biopsies (native: 873, allograft: 459) were included, 617 obtained by nephrologists, 663 by radiologists, and 559 with access to on-site division. Proceduralists with access to on-site evaluation had significantly lower inadequacy rates and better division of tissue for light microscopy (LM), immunofluorescence, and electron microscopy than those without access to on-site evaluation. Radiologists in our region were significantly less likely to have access to on-site evaluation than nephrologists. On multivariate analysis for native kidney biopsies, the effect of having a radiologist perform the biopsy and having access to on-site division were both significant predictors of obtaining greater calculated amount of cortex for LM. Despite the trend for radiologists to obtain more tissue in general, biopsies from nephrologists contained a greater percentage of cortex and were more likely to be considered adequate for LM (native kidney inadequacy rate for LM: 1.11% vs. 5.41%, P=0.0086). Biopsies in which inadequate or marginal cortical tissue was submitted for LM had only minor decreases in the amount of cortex submitted for immunofluorescence and electron microscopy, revealing an opportunity for improved specimen triaging when limited tissue is obtained. In conclusion, both on-site evaluation/division and proceduralist significantly affect quantitative kidney biopsy metrics, which in turn affects the pathologist's ability to render an accurate diagnosis with appropriate prognostic information for the patient and treating nephrologist.

Needle Biopsy Adequacy in the Era of Precision Medicine and Value-Based Health Care

CONTEXT.—

Needle biopsy of diseased tissue is an essential diagnostic tool that is becoming even more important as precision medicine develops. However, the capability of this modality to efficiently provide samples adequate for diagnostic and prognostic analysis remains quite limited relative to current diagnostic needs. For physicians and patients, inadequate biopsy frequently leads to diagnostic delay, procedure duplication, or insufficient information about tumor biology leading to delay in treatment; for health systems, this results in substantial incremental costs and inefficient use of scarce specialized diagnostic resources.

OBJECTIVE.—

To review current needle biopsy technology, devices, and practice with a perspective to identify current limitations and opportunities for improvement in the context of advancing precision medicine.

DATA SOURCES.—

PubMed searches of fine-needle aspiration and core needle biopsy devices and similar technologies were made generally, by tissue site, and by adequacy as well as by health economics of these technologies.

CONCLUSIONS.—

Needle biopsy adequacy can be improved by recognizing the importance of this diagnostic tool by promoting common criteria for needle biopsy adequacy; by optimizing needle biopsy procedural technique, technologies, clinical practice, professional education, and quality assurance; and by bundling biopsy procedure costs with downstream diagnostic modalities to provide better accountability and incentives to improve the diagnostic process.

The efficacy of blind versus real-time ultrasound-guided percutaneous renal biopsy in developing country

Introduction:

Renal biopsy is a useful diagnostic procedure. In developing countries, two techniques of renal biopsy, blind percutaneous renal biopsy and real-time ultrasound-guided percutaneous renal biopsy, have been performed. The majority of studies compared these using different types and sizes of biopsy needle. The aim of this study was to compare both techniques in resource constraint country.

Method:

We reviewed renal biopsy database, between 1 January 2014 to 30 June 2017. The primary outcome was the total number of glomeruli. The other outcomes were tissue adequacy and bleeding complications. We also analyzed multivariable logistic regression to find factors associated with tissue adequacy and bleeding complications.

Result:

Of the 204 renal biopsies, 100 were blind percutaneous renal biopsy and 104 real-time ultrasound-guided percutaneous renal biopsy. The number of native renal biopsies was 169 (82.8%). Baseline characteristics of two groups were comparable. The mean number of total glomeruli from real-time ultrasound-guided percutaneous renal biopsy was significantly more than blind percutaneous renal biopsy (20.8 ± 12.1 vs 16.0 ± 13.0, p = 0.001). The real-time ultrasound-guided percutaneous renal biopsy obtained more adequate tissues than blind percutaneous renal biopsy (45.2% vs 16%, p < 0.001) and was the only factor associated with adequate tissue. Moreover, 16 renal biopsies from blind percutaneous renal biopsy obtained inadequate tissue. The overall bleeding complications were not statistically different. We found being female, lower eGFR and lower hematocrit were associated with bleeding complications.

Conclusion:

In comparison with blind percutaneous renal biopsy, real-time ultrasound-guided percutaneous renal biopsy obtained more adequate tissue and number of glomeruli. While the complications of both were comparable. We encourage to practice and perform real-time ultrasound-guided percutaneous renal biopsy in resource constraint countries.

Superselective renal artery embolization for bleeding complications after percutaneous renal biopsy: a single-center experience

OBJECTIVE

This study aimed to determine if superselective renal artery embolization is a safe and effective method of treating bleeding complications after percutaneous renal biopsy.

METHODS

From January 2006 to December 2017, 43 patients (22 men and 21 women, mean age: 44.5 ± 14.0 years) underwent angiography for post-biopsy bleeding complications following percutaneous biopsy. Patients underwent angiography and superselective artery embolization. We recorded serum creatinine and hemoglobin values to assess the effect of embolization.

RESULTS

Successful embolization was achieved in all patients. There was a pseudoaneurysm in 10 cases, arteriovenous fistula in eight, contrast media extravasation in 16, arteriovenous fistula combined with contrast media extravasation in five, and pseudoaneurysm combined with arteriovenous fistula in four. The embolic substance was a microcoil only or combined with a gelatin sponge. The mean creatinine value was not different at 1 day and 1 week after embolization compared with before embolization. Mean hemoglobin values were significantly higher at 1 day and 1 week after embolization than before embolization.

CONCLUSIONS

Superselective renal artery embolization is a safe and effective treatment for post-biopsy bleeding complications after percutaneous renal biopsy. Lumbar or iliolumbar artery angiography is necessary if renal arteriography shows no signs of hemorrhage.

Ultrasound-guided Bedside Core Needle Biopsy: A Hospitalist Procedure Team's Experience

Tissue pathology is integral for the diagnosis of various conditions, especially malignancy. Traditionally, biopsy procedures, including core needle biopsy (CNB), are performed by surgeons or radiologists. With the increasing utilization of point of care ultrasound (POCUS) skills and competence in bedside procedures by general internists, CNB can be safely moved to the patient's bedside with maintained accuracy and increased cost savings compared to traditional procedural methods. We aim to review the experience of our hospitalist-run medical procedure service in performing these ultrasound-guided procedures at the bedside.

A retrospective analysis of complication and adequacy rates of ultrasound-guided native and transplant non-focal renal biopsies

PURPOSE

To assess non-focal ultrasound (US)-guided renal biopsy complication and adequacy rates at our institution.

METHODS

A retrospective analysis of 1067 non-focal renal biopsy cases between 2012 and 2015. Information collected including type of US-guided procedure (US-localized by nephrology vs. real-time US-guided by radiology), sample adequacy, complications, blood work, and histologic data.

RESULTS

602 biopsies were performed by radiology (56.4%) and 465 (43.6%) by nephrology. The overall adequacy rate was 96.1%, with an US-localized rate of 95.7% and real-time US-guided rate of 96.3% (p = 0.58). A lower adequacy rate was noted for 1 biopsy core but there were no differences between 2 and 6 cores (p = 0.001). A lower adequacy rate was found for transplant biopsies vs. native biopsies (p = 0.03). Complication rates were as follows-minor 5.9%, major 4.3%, and life-threatening 0.8%. There were no differences in complication rates between the US-localized and real-time US-guided techniques (p = 0.63). Complications were more likely in patients with a lower hemoglobin, higher serum creatinine, and lower albumin (p < 0.05). No differences were found between the number of cores performed and the complication rates. The complication rate was similar between transplant biopsies vs. native biopsies (p = 0.2). The adequacy rate was lower in trainees (p = 0.01) than experienced radiologists.

CONCLUSIONS

No significant differences were found between US-localized vs. real-time US-guided techniques. A lower adequacy rate was found for trainee radiologists and for transplant biopsies. A lower adequacy rate was also observed when only 1 biopsy pass was performed.

An integrated pathology and ultrasonography-based simulation for training in performing kidney biopsy

Background: Medical practice trends and limitations in trainees’ duty hours have diminished the interest and exposure of nephrology fellows to percutaneous kidney biopsy (PKB). We hypothesized that an integrated nephrology-pathology-led simulation may be an effective educational tool. Materials and methods: A 4-hour PKB simulation workshop (KBSW), led by two ultrasonography (US)-trained nephrologists and two nephropathologists, consisted of 6 stations: 1) diagnostic kidney US with live patients, 2) kidney pathology with plasticine models of embedded torso cross-sections, 3) US-based PKB with mannequin (Blue Phantom™), 4) kidney pathology with dissected cadavers, 5) US-based PKB in lightly-embalmed cadavers, and 6) tissue retrieval adequacy examination by microscope. A 10-question survey assessing knowledge acquisition and procedural confidence gain was administered pre- and post-KBSW. Results: 21 participants attended the KBSW and completed the surveys. The overall percentage of correct answers to knowledge questions increased from 55 to 83% (p = 0.016). The number of “extremely confident” answers increased from 0 – 5% to 19 – 28% in all 4 questions (p = 0.02 – 0.04), and the number of “not at all confident” answers significantly decreased from 14 – 62% to 0 – 5% in 3 out of 4 questions (p = 0.0001 – 0.03). Impact of the imparted training on subsequent practice pattern was not assessed. Conclusion: A novel KBSW is an effective educational tool to acquire proficiency in PKB performance and could help regain interest among trainees in performing PKBs.

Survey of Kidney Biopsy Clinical Practice and Training in the United States

BACKGROUND AND OBJECTIVES

Practicing clinical nephrologists are performing fewer diagnostic kidney biopsies. Requiring biopsy procedural competence for graduating nephrology fellows is controversial.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

An anonymous, on-line survey of all Walter Reed training program graduates (n=82; 1985-2017) and all United States nephrology program directors (n=149; August to October of 2017), regarding kidney biopsy practice and training, was undertaken.

RESULTS

Walter Reed graduates' response and completion rates were 71% and 98%, respectively. The majority felt adequately trained in native kidney biopsy (83%), transplant biopsy (82%), and tissue interpretation (78%), with no difference for ≤10 versus >10 practice years. Thirty-five percent continued to perform biopsies (13% did ≥10 native biopsies/year); 93% referred at least some biopsies. The most common barriers to performing biopsy were logistics (81%) and time (74%). Program director response and completion rates were 60% and 77%. Seventy-two percent cited ≥1 barrier to fellow competence. The most common barriers were logistics (45%), time (45%), and likelihood that biopsy would not be performed postgraduation (41%). Fifty-one percent indicated that fellows should not be required to demonstrate minimal procedural competence in biopsy, although 97% agreed that fellows should demonstrate competence in knowing/managing indications, contraindications, and complications. Program directors citing ≥1 barrier or whose fellows did <50 native biopsies/year in total were more likely to think that procedural competence should not be required versus those citing no barriers (P=0.02), or whose fellows performed ≥50 biopsies (P<0.01).

CONCLUSIONS

Almost two-thirds of graduate respondents from a single military training program no longer perform biopsy, and 51% of responding nephrology program directors indicated that biopsy procedural competence should not be required. These findings should inform discussion of kidney biopsy curriculum requirements.

Point-of-care ultrasound in the practice of nephrology

Sonography is increasingly being performed by clinicians and has applications throughout the spectrum of nephrology, including acute and chronic renal failure, urinary obstruction, cystic disease, pain, hematuria, transplantation, kidney biopsy, temporary and permanent vascular access, and assessment of fluid status. The skill is relatively easily acquired, expedites patient care, and enhances the practice of nephrology. However, the lack of exposure in most training programs remains a major obstacle.

Safety and adequacy of percutaneous kidney biopsy performed by nephrology trainees

BACKGROUND

Recently there has been a progressive loss of specialty related skills for nephrologists. Among the skills we find the kidney biopsy that has a central role in diagnosis of renal parenchymal disease. One of the causes might be the belief that the kidney biopsy should be performed only in larger Centers which can rely on the presence of a renal pathologist and on nephrologists with a large experience. This trend may increase in the short term procedural safety but may limit the chance of in training nephrologists to become confident with the technique.

METHODS

We evaluated renal biopsies performed from May 2002 to October 2016 in our Hospital, a mid-sized facility to determine whether the occurrence of complications would be comparable to those reported in literature and whether the increase in the number of biopsy performing physicians including nephrology fellows which took place since January 2012, after our Nephrology Unit became academic, would be associated to an increase of complications or a reduction of diagnostic power of renal biopsies. Three hundred thirty seven biopsies were evaluated. Patients underwent ultrasound guided percutaneous renal biopsy using a 14 G core needle loaded on a biopsy gun. Observation lasted for 24 h, we evaluated hemoglobin levels 6 and 24 h and kidney ultrasound 24 h after the biopsy.

RESULTS

Complications occurred in 18.7% of patients, of these only 1,2% were major complications. Complications were more common in female (28%) compared to male patients (14,8%) (p = 0.004). We found no correlation between diagnosis, kidney function and complication rates; hypertension was not associated to a higher risk in complications. The increase of biopsy performing personnel was not associated to an increase in complication rates (18,7% both pre and post 2012) or with an increase of major complications (1.2% vs 1,2%).

CONCLUSIONS

Kidney biopsy can be safely performed in mid-sized hospitals. Safety and adequacy are guaranteed even if the procedure is performed by a larger number of less experienced nephrologists as long as under tutor supervision, thus kidney biopsy should become an integral part of a nephrology fellow training allowing more widespread diffusion of this technique.

Pediatric renal transplant biopsy with ultrasound guidance: the 'core' essentials

This review provides a comprehensive and practical approach to pediatric percutaneous renal transplant biopsies, highlighting techniques and strategies to optimize adequate sample yield and ensure patient safety. In children with end-stage renal disease, transplantation is the preferred choice of therapy, providing for overall lower long-term morbidity and mortality compared with dialysis. In the ongoing management of renal transplant patients, core tissue sampling via a percutaneous renal biopsy remains the gold standard when transplant dysfunction is suspected. Indications for renal transplant biopsy and techniques/tools for adequate sample yield are discussed. Strategies for common challenges such as poor visualization and renal transplant mobility are addressed. We discuss the clinical signs, techniques and imaging findings for common complications including hematomas, arteriovenous fistulas and pseudoaneurysms. Although the percutaneous renal transplant biopsy procedure is generally safe with rare complications, care must be taken to ensure major complications are promptly recognized and treated. Adequate tissue samples obtained via renal biopsy are imperative to promptly identify transplant rejection to provide valuable information for patient diagnosis, treatment and outcomes. Radiologist and nephrologist attention to proper ultrasound techniques and optimal biopsy tools are critical to ensure tissue adequacy and minimize complications.

Kidney Biopsy Yield: An Examination of Influencing Factors

Kidney biopsies are conducted under varying scenarios, presenting variables that could potentially influence yield and adequacy of tissue collected. We retrospectively reviewed 636 native and allograft kidney biopsies, and compared tissue collected between differing practitioners performing the biopsy (nephrologists or radiologists), imaging modalities for guidance (ultrasound or computed tomography), gauge needle used (18 or 16 G), and between on-site evaluators of biopsy adequacy conducted at the time of biopsy (general pathologists, renal pathologists, nephrologists). For radiologists using ultrasound guidance and 18 G needles, those using on-site evaluation of adequacy collected more glomeruli and glomeruli per length of tissue core than those not using on-site evaluation. Radiologists not using on-site evaluation but who used a larger bore needle (16 vs. 18 G) could generally collect comparable tissue as other biopsy performers who used on-site evaluation. Radiologists performing ultrasound-guided biopsies with 18 G needles without on-site evaluation consistently provided poorer tissue yield and had a higher rate of providing insufficient tissue so that a diagnosis could not be rendered. Nephrologists collected less total length of tissue cores, glomeruli, and arteries per case (whether performing the biopsy and/or performing on-site adequacy) compared with other groups using on-site evaluation, however, providing comparable density of glomeruli and arteries. Complication rates did not differ between compared groups using 18 G needles. It is our observation that the various conditions by which a kidney biopsy is obtained influences the yield of tissue collected and the subsequent ability for a pathologist to effectively provide a diagnosis.

Bleeding complications post ultrasound guided renal biopsy - A single centre experience from Pakistan

INTRODUCTION

Renal biopsy is the diagnostic modality of choice for the diagnosis of renal parenchymal diseases. The advent of improved imaging techniques and biopsy needles over the years has increased the safety of the procedure and the ability to obtain adequate renal tissue for diagnosis. However, there is paucity of data in this regard from Pakistan. This study shall help in establishing the local perspective of the frequency of bleeding complications in percutaneous ultrasound guided renal biopsy.

MATERIALS AND METHODS

This is a prospective case series of hospitalized patients from January till December 2015 at Nephrology Department, Aga Khan University Hospital, Karachi, Pakistan. After enrolment, each participant was followed for 24 h after renal biopsy.

RESULTS

A total of 220 patients were included. Mean age was 41.65 ± 8.627 years, 82 (37.2%) were male and 138 (62.8%) were female. Pre and post biopsy haemoglobin, pre and post biopsy haematocrit were 10.92 ± 1.25 and 10.60 ± 1.22, and 30.82 ± 4.73 and 30.49 ± 4.68 respectively. Out of 220 patients, 16 (7.27%) developed major complications and 26 (11.8%) developed minor complications in 24 h after renal biopsy.

CONCLUSIONS

Percutaneous kidney biopsy is a relatively safe procedure. Complication rates following the procedure are minimal. It is important that all nephrology programs train the trainees in performing biopsies, so that there is a wider clinical use of this important investigation even in underprivileged & developing countries.

Innovative Perspective: Gadolinium-Free Magnetic Resonance Imaging in Long-Term Follow-Up after Kidney Transplantation

Since the mid-1980s magnetic resonance imaging (MRI) has been investigated as a non- or minimally invasive tool to probe kidney allograft function. Despite this long-standing interest, MRI still plays a subordinate role in daily practice of transplantation nephrology. With the introduction of new functional MRI techniques, administration of exogenous gadolinium-based contrast agents has often become unnecessary and true non-invasive assessment of allograft function has become possible. This raises the question why application of MRI in the follow-up of kidney transplantation remains restricted, despite promising results. Current literature on kidney allograft MRI is mainly focused on assessment of (sub) acute kidney injury after transplantation. The aim of this review is to survey whether MRI can provide valuable diagnostic information beyond 1 year after kidney transplantation from a mechanistic point of view. The driving force behind chronic allograft nephropathy is believed to be chronic hypoxia. Based on this, techniques that visualize kidney perfusion and oxygenation, scarring, and parenchymal inflammation deserve special interest. We propose that functional MRI mechanistically provides tools for diagnostic work-up in long-term follow-up of kidney allografts.

Serum 1,25-dihydroxyvitamin D Better Reflects Renal Parameters Than 25-hydoxyvitamin D in Patients with Glomerular Diseases

Background: Impaired vitamin D metabolism may contribute to the development and progression of chronic kidney disease. The purpose of this study was to determine associations of circulating vitamin D with the degree of proteinuria and estimated glomerular filtration rate (eGFR) in patients with biopsy-proven glomerular diseases. Methods: Clinical and biochemical data including blood samples for 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)₂D) levels were collected from patients at the time of kidney biopsy. Results: Serum 25(OH)D levels were not different according to eGFR. However, renal function was significantly decreased with lower serum 1,25(OH)₂D levels (P < 0.001). The proportions of nephrotic-range proteinuria and renal dysfunction (eGFR ≤ 60 mL/min/1.73 m²) progressively increased with declining 1,25(OH)₂D but not 25(OH)D. Multivariable linear regression analysis showed that 25(OH)D was significantly correlated with serum albumin and total cholesterol (β = 0.224, P = 0.006; β = -0.263, P = 0.001) and 1,25(OH)₂D was significantly correlated with eGFR, serum albumin and phosphorus (β = 0.202, P = 0.005; β = 0.304, P < 0.001; β = -0.161, P = 0.024). In adjusted multivariable linear regression, eGFR and 24hr proteinuria were independently correlated only with 1,25(OH)₂D (β = 0.154, P = 0.018; β = -0.171, P = 0.012), but not 25(OH)D. The lower level of 1,25(OH)₂D was associated with the frequent use of immunosuppressive agents (P < 0.001). Conclusion: It is noteworthy in these results that circulating 1,25(OH)₂D may be superior to 25(OH)D as a marker of severity of glomerular diseases.

Achieving Procedural Competence during Nephrology Fellowship Training: Current Requirements and Educational Research

Concerns have previously been raised as to whether training programs are ensuring that nephrology fellows achieve competence in the procedural skills required for independent practice. We sought to review the current requirements for procedural training as well as educational research pertaining to achieving competence in the core nephrology procedures of nontunneled (temporary) hemodialysis catheter insertion and percutaneous kidney biopsy. At this time, there is no universal approach to procedural training and assessment during nephrology fellowship. Nonetheless, simulation-based mastery learning programs have been shown to be effective in improving fellows' skills in nontunneled (temporary) hemodialysis catheter insertion and should be provided by all nephrology training programs. For percutaneous kidney biopsy, the development and evaluation of inexpensive simulators are a promising starting point for future study. Current practice with respect to procedural training during nephrology fellowship remains imperfect; however, the ongoing shift toward competency-based evaluation provides opportunities to refocus on improvement.

Identification of a novel GLA mutation (Y88C) in a Korean family with Fabry nephropathy: a case report

BACKGROUND

Fabry disease is a rare X-linked lysosomal storage disorder caused by α-galactosidase A deficiency. With the advancement of molecular diagnostic tools, more disease-causing mutations in α-galactosidase A (GLA) have been identified in Fabry disease. We found a novel mutation in a Korean family with predominant renal manifestations of the disease.

CASE PRESENTATION

A 24-year-old man who wanted to donate a kidney to his 28-year-old brother with end-stage renal disease of unknown cause was evaluated. The 24-year-old man underwent percutaneous renal biopsy because of an accidentally found proteinuria. Electron microscopy of his renal biopsy showed numerous electron-dense multi-lamellar inclusions in the epithelial cytoplasm, typical for Fabry disease. Clinical and laboratory evaluation including the assessment of GLA enzyme activity and direct DNA sequencing in four members of the family were performed. Renal biopsy findings in the two affected male patients were described. Re-evaluation of a renal biopsy specimen of his 28-year-old brother obtained when he was diagnosed with renal failure revealed a very focal area of suspicious multilamellated structures in the Bowman's space. DNA sequencing on the young man, his brother, and his mother revealed a novel GLA gene mutation, c.263A > G (p.Tyr88Cys). The three all showed decreased α-galactosidase A activity.

CONCLUSION

A novel GLA mutation, c.263A > G (p.Tyr88Cys), was found in a Korean family with predominant renal manifestations of Fabry disease.

Hemodynamic characteristics and the occurrence of renal biopsy-related arteriovenous fistulas in native kidneys

Purpose

Renal biopsy-related arteriovenous fistula (RB-AVF), although usually asymptomatic, may sometimes result in serious clinical implications. The aim of the study was to prospectively evaluate the incidence of RB-AVF in native kidneys, together with the assessment of hemodynamic characteristics and the impact of the histopathological results of biopsy.

Methods

The study included 138 patients (age 46.2 ± 15.2; 70 F, 68 M), who underwent percutaneous renal biopsy (PRB) of the native kidney. In all patients, 2D and color Doppler ultrasound was performed 24 h after PRB in order to exclude RB-AVF.

Results

Bleeding complications in the form of hematomas were found in 136 patients (98.55 %), and 23 cases of RB-AVF were observed (16.67 %). RB-AVF group had an increased maximal hematoma diameter and reduced number of glomeruli in PRB. The segmental arteries supplying the fistulas are characterized by higher maximum flow velocity (FV) and a lower resistance index (RI) compared to the normal segmental arteries (difference 45.9 ± 20.0 cm/s and 0.252 ± 0.104, respectively). In the ROC analysis, RI ≤ 0.524 allowed to detect RB-AVF with a sensitivity of 91 % and specificity of 100 % (AUC 0.998, p < 0.001). In approximately 39 % of RB-AVF cases, 2D ultrasound detected a hyperechogenic ischemic area between the fistula and the renal capsule.

Conclusions

Arteriovenous fistula is a quite frequent complication of native renal biopsy and can cause ischemia in the renal parenchyma detected by ultrasound. The arteries supplying the fistula are characterized by an increased flow velocity and reduced resistance index.

Factors Contributing to the Success of Ultrasound-Guided Native Renal Biopsy

OBJECTIVES

The purpose of this study was to evaluate factors contributing to the success of ultrasound-guided native renal biopsy.

METHODS

We retrospectively identified patients who had ultrasound-guided native renal biopsy at our institution over a 10-year period. We reviewed the imaging and electronic medical records to collect demographic information and clinical data, including pathologic results. Biopsy samples were categorized and compared on the basis of the number of glomeruli (optimal [≥20] versus suboptimal [<20]) and the pathologist's reported diagnostic confidence (high confidence versus limited confidence). Procedure details, including the operator and the use of the cortical tangential approach, were also obtained.

RESULTS

For 282 patients with biopsies using 18-gauge needles, the number of passes made was significantly higher for optimal (P < .001) and high-confidence (P < .001) specimens than for suboptimal and limited-confidence specimens. The cortical tangential approach was used more frequently for optimal (P< .001) and high-confidence (P = .01) specimens than for suboptimal and limited-confidence specimens. Radiologists routinely doing ultrasound-guided procedures of all types had significantly more optimal (P= .01) and high-confidence (P= .001) specimens than radiologists with limited ultrasound experience. The distance to the kidney, cortical thickness, glomerular filtration rate, and body mass index were not significant factors.

CONCLUSIONS

The ultrasound-guided procedural experience of the operator, taking more than 1 specimen, and the use of the cortical tangential approach significantly improved the pathologic material obtained during native renal biopsies.

The Native Kidney Biopsy: Update and Evidence for Best Practice

The kidney biopsy is the gold standard in the diagnosis and management of many diseases. Since its introduction in the 1950s, advancements have been made in biopsy technique to improve diagnostic yield while minimizing complications. Here, we review kidney biopsy indications, techniques, and complications in the modern era. We also discuss patient populations in whom special consideration must be given when considering a kidney biopsy and the important role that the kidney biopsy plays in nephrology training. These data are presented to develop best practice strategies for this essential procedure.

Resolution of proteinuria after transarterial embolization of aberrant renal artery in a patient with focal segmental glomerulosclerosis

A 24-year-old man was admitted to our hospital for persistent proteinuria. He was born with a low birth weight but had grown up uneventful until the age of 20 when he was found to have proteinuria. Because his body mass index was 30.9 kg/m² at that time, he was diagnosed as obesity-related nephropathy. However, weight reduction and administration of ACE inhibitor were minimally effective for the amelioration of proteinuria. Ultrasound-guided percutaneous renal biopsy at the lower pole of right kidney was performed. As serious bleeding occurred from the right aberrant renal artery soon after biopsy, he was treated with transarterial embolization (TAE). The day after TAE, proteinuria completely disappeared. Renal biopsy showed benign nephrosclerosis with secondary focal segmental glomerulosclerosis (FSGS). Proteinuria could be induced by increased blood flow and pressure due to abnormal blood supply from aberrant renal artery. This is the first report of resolution of proteinuria after TAE of aberrant renal artery in a patient with FSGS.