William L. Whittier

Timing of complications in percutaneous renal biopsy.

Percutaneous renal biopsy (PRB) is a safe and effective tool in the diagnosis and management of renal disease; however, the optimal timing of observation after biopsy is not clearly established. With the use of real-time ultrasound guidance, PRB of native kidneys was performed in 750 adult patients at an academic institution by an attending nephrologist or fellow between June 1983 and June 2002. All patients were observed for 23 to 24 h after biopsy for the presence, severity, and timing of complications. Biopsy-related complications occurred in 98 (13%) patients; minor complications occurred in 50 (6.6%) patients, and major complications occurred in 48 (6.4%) patients. One (0.1%) patient died as a result of the biopsy. Multivariate analysis using logistic regression found only serum creatinine at baseline predictive of a complication. Patients with a serum creatinine > or = 5.0 mg/dl were 2.3 times as likely to have a complication (odds ratio, 2.3; 95% confidence interval, 1.3 to 4.1; P < 0.005). Complications were identified in 38 (42%) patients by < or = 4 h, in 61 (67%) patients by < or = 8 h, in 77 (85%) patients by < or = 12 h, and in 81 (89%) patients at < or = 24 h. The PRB remains a safe procedure, but the risk of complication is higher in patients with advanced renal insufficiency. After biopsy, an observation time of up to 24 h remains optimal as an observation period of < or = 8 h risks missing > or = 33% of complications.

Renal biopsy: update.

Purpose of reviewThe renal biopsy is an invaluable tool in the diagnosis, prognosis, and management of patients with kidney disease. As the success of the procedure is defined not only by the ability to obtain adequate tissue but also by the safety profile, significant advances which define risk factors and determine the optimal timing of observation after the percutaneous native renal biopsy merit discussion. Alternative methods of obtaining tissue, such as transvenous renal biopsies, have also been described, especially in patients with contraindications to the percutaneous method. Recent findingsThe percutaneous renal biopsy has been established as a safe and effective method of obtaining renal parenchyma. Complications, although rare, may occur and the majority of these are related to bleeding. The optimal timing of observation after the biopsy should be determined by when most complications occur, and, as over 33% of complications occur after 8 h, an observation period of at least 24 h is recommended. In patients with contraindications to the percutaneous approach, such as failure of adequate radiologic visualization or a bleeding diathesis, alternative methods of obtaining tissue have been attempted. These include open, laparascopic, transurethral, or transvenous renal biopsy. SummaryWithout contraindications, the percutaneous renal biopsy remains the standard method of acquiring renal tissue. At least 24 h of observation is recommended after the percutaneous native kidney biopsy for the development of potential complications. When a contraindication to the procedure exists, other methods of renal biopsy by experienced physicians may be attempted.

Percutaneous renal biopsy of native kidneys: a single-center experience of 1,055 biopsies.

Background: Percutaneous renal biopsy (PRB) of native kidneys is an essential tool in the diagnosis and management of renal disease. We report one of the largest single-center experiences on the success and safety of the procedure. Methods: From June 1983 to March 2012, 1,055 adults underwent PRB using real-time ultrasound guidance and 14-gauge biopsy needles. Data were collected prospectively for 826 biopsies (78%). Statistical analysis was performed using the Mann-Whitney test, Wilcoxon matched pairs test and Kruskal-Wallis test for continuous data or the Fishers exact test and χ2 test for categorical data. Multivariate analysis using logistic regression was performed to determine which feature at baseline was predictive of a complication following renal biopsy. Results: Patients were aged 46 ± 17 years; 38% were male, 40% were white and 43% were African-American. Serum creatinine (SCr) was 2.3 ± 2.3 mg/dl (>1.5 mg/dl in 47%). The pre-PRB hemoglobin was 12 ± 2 g/dl (<11.0 g/dl in 35%). Adequate tissue for diagnosis was obtained in 99% of biopsies. Minor complications occurred in 8.1% of biopsies (mainly gross hematuria, in 4.5%). Major complications occurred in 6.6% of biopsies, with transfusions required in 5.3%. Only 1 death (0.09%) resulted from post-PRB bleeding. By multivariate analysis, baseline features predictive of a complication were systolic blood pressure >170 mm Hg (OR 4.2, 95% CI 1.8-9.8), bleeding time >7.5 min (OR 1.7, CI 1.2-2.5) and SCr >3.5 mg/dl (OR 1.8, CI 1.2-2.9). Conclusions: PRB of native kidneys using real-time ultrasound with a 14-gauge automated needle remains a successful and safe procedure.

Surveillance of Hemodialysis Vascular Access

A mature, functional arteriovenous (AV) access is the lifeline for a hemodialysis (HD) patient as it provides sufficient enough blood flow for adequate dialysis. As the chronic kidney disease (CKD) and end-stage renal disease (ESRD) population is expanding, and because of the well-recognized hazardous complications of dialysis catheters, the projected placement and use of AV accesses for HD is on the rise. Although a superior access than catheters, AV accesses are not without complications. The primary complication that causes AV accesses to fail is stenosis with subsequent thrombosis. Surveying for stenosis can be performed in a variety of ways. Clinical monitoring, measuring flow, determining pressure, and measuring recirculation are all methods that show promise. In addition, stenosis can be directly visualized, through noninvasive techniques such as color duplex imaging, or through minimally invasive venography. Each method of screening has its advantages and disadvantages, and several studies exist which attempt to answer the question of which test is the most useful. Ultimately, to maintain the functionality of the access for the HD patient, a team approach becomes imperative. The collaboration and cooperation of the patient, nephrologist, dialysis nurse and technician, vascular access coordinator, interventionalist, and vascular surgeon is necessary to preserve this lifeline.

Complications of the Percutaneous Kidney Biopsy

Percutaneous kidney biopsy is an integral part of a nephrologists practice. It has helped to define nephrology as a subspecialty. When indicated, it is a necessary procedure to help patients, as it allows for diagnostic, prognostic, and therapeutic information. Although very safe, this procedure can give rise to complications, mainly related to bleeding. Since its development in the 1950s, modifications have been made to the approach and the technique, which have improved the diagnostic yield while keeping it a safe procedure. Alterations to the standard approach may be necessary if risk factors for bleeding are present. In addition, obesity, pregnancy, and solitary kidney biopsy are all special circumstances that change the procedure itself or the risk of the procedure. Today, kidney biopsy is a vital procedure for the nephrologist: clinically relevant, safe, and effective.

Pathogenetic features of severe segmental lupus nephritis

BACKGROUND Accumulating evidence supports the notion that the pathogenesis of severe lupus glomerulonephritis is multifactorial and not solely an immune complex-mediated glomerular disease. Alternate mechanisms for glomerular destruction may exist. METHODS We conducted a retrospective clinicopathologic analysis of 213 patients with lupus nephritis. Twenty-six patients had severe segmental glomerulonephritis (SSGN) and 15 patients had diffuse proliferative glomerulonephritis (DPGN). Patients with pure mesangial lupus nephritis [mesangial glomerulonephritis (MesGN)] (N = 13) were used as histologic controls. The degree of immunologic activity detailed by histologic data including light, fluorescent (IF) and electron microscopy (EM) on kidney biopsies and clinical data from patients with severe lupus nephritis were analysed. RESULTS Biopsies from patients with SSGN had fewer glomeruli with wire loops (3 +/- 6% versus 35 +/- 34% P = 0.005) and hyaline thrombi (0.8 +/- 3% versus 16 +/- 22%, P = 0.02) compared to DPGN. The amount of IgG by IF was less in SSGN lesions compared to DPGN lesions, and IgG was absent in 30% of the SSGN group compared to none of the DPGN group (P = 0.04). There was no difference in mesangial deposits among the three groups (SSGN, DPGN and MesGN). The EM data supported the IF data. Anti-neutrophil cytoplasmic antibodies (ANCA) were essentially negative in all three groups and the C3 values tended to be lower in DPGN compared to SSGN (48 +/- 15 mg/dl versus 60 +/- 26 mg/dl, P = 0.09). CONCLUSIONS The findings in DPGN involve a classic immune complex-mediated glomerulonephritis as demonstrated by the abundant immune aggregates witnessed in the peripheral capillary wall. In contrast, a paucity of peripheral immune aggregates is seen in SSGN implying a different pathogenesis. Our data support a mechanism of glomerular injury in SSGN that is separate from the generally accepted unitary concept of immune complex deposition in lupus nephritis.

Adequacy and Complication Rates with 14- vs. 16-gauge Automated Needles in Percutaneous Renal Biopsy of Native Kidneys

In performing percutaneous renal biopsy (PRB) of native kidneys, an increasing use of 16‐gauge automated biopsy needles has been observed. We compare the adequacy and safety of PRBs in adults performed with a 14‐gauge (n = 82) vs. 16‐gauge (n = 55) automated needle using real‐time ultrasound (US) from 1/2010 to 12/2013. Baseline clinical and laboratory data along with outcome data (renal US 1‐hour postbiopsy, biopsy adequacy, and safety) were collected prospectively. There was no difference in age, gender, blood pressure, serum creatinine, or pre‐PRB hemoglobin at baseline for PRBs performed with a 14‐ vs. 16‐gauge needle. The number of glomeruli obtained per biopsy was similar (29 ± 11 vs. 31 ± 14, p = 0.6) and adequate tissue for diagnosis was obtained in 99% and 100% of biopsies. The clinical complication (8.5% vs. 9.1%, p = 1.0), transfusion (7.3% vs. 7.2%, p = 1.0), and embolization (3.7% vs. 1.8%, p = 0.6) rates were not significantly different for 14‐ vs. 16‐gauge needles, but by routine renal US 1‐hour post‐PRB, a perinephric hematoma was demonstrated more often in biopsies done with the 14‐gauge needle (39% vs. 22%, P 0.04). Thus, while the success of PRB of native kidneys is similar for both needle gauges, the potential for complication may be less using a 16‐gauge automated needle.

Comparison of hemodialysis access flow measurements using flow dilution and in-line dialysance.

Measurement of hemodialysis (HD) access flow (QA) is a noninvasive approach for arteriovenous graft or fistula surveillance. Flow dilution (FD) and in-line dialysance (DD) are two common methods for measuring QA. In a randomized fashion, we prospectively evaluated QA using FD and DD in 48 HD patients during three separate HD sessions over a span of 3 months. The measurement of QA was similar (1,016 ± 412 ml/min for FD and 1,009 ± 425 ml/min for DD, p = 0.44 and 0.79 for the mean and standard deviation, respectively). While FD successfully measured QA ≥2,000 ml/min, DD “saturated” (indicating a QA ≥2,000 ml/min without providing a numerical QA value) (n = 17). The correlation coefficient for QA ≤2,000 ml/min between DD and FD measurements from the same dialysis sessions was high (r = 0.9, p < 0.001) with a straight line slope of 0.997. Access flow values for FD and DD methods were comparable at QA ≤2,000 ml/min and no single method tended to over- or underestimate QA compared with the other. For QA >2,000 ml/min, FD provided a quantitative QA measure, and is therefore a potentially useful tool for QA above this threshold, while DD is not.

Proteinuria in membranous lupus nephritis: the pathology is in the podocyte

Background Patients with membranous lupus glomerulonephritis (MLN) can present with a broad range of urine protein excretion. The glomerular lesion underlying this functional abnormality has been presumed to be immune complexes which aggregate in the subepithelial area. However, the amount of proteinuria often fails to correlate with the quantity of immune deposits demonstrable on fluorescent and electron microscopy. The purpose of this study is to determine the correlation of alterations of the morphologic components of the glomerular capillary wall with the amount of proteinuria in MLN. Design We conducted a retrospective clinicopathologic study of patients with lupus nephritis (n = 236). In those with pure MLN and proteinuria (n = 20), the degree of immune aggregates in the capillary walls and mesangium was detailed using fluorescent and electron microscopy. The degree of foot process effacement (FPE) was detailed using electron microscopy. Result Eleven patients had nephrotic range proteinuria (≥3 g proteinuria/g creatinine (g/g)) and nine demonstrated subnephrotic range proteinuria (<3 g/g) (nephrotic, 8.3 ± 5.1 g/g vs. subnephrotic, 1.63 ± 0.83 g/g, p = 0.001). All patients demonstrated peripheral capillary wall granular deposits by immunofluorescence microscopy, and the degree of moderate (2 +) to severe (3 +) deposition was not different (nephrotic, 8/11, 73% vs. subnephrotic, 5/9, 55%, p = 0.64). By electron microscopy, FPE (88.6 ± 11% vs. 48.3 ± 36.1%, p = 0.002) and foot process width (1798 ± 736 nm vs. 1000 ± 333 nm, p = 0.008) was greater in the nephrotic group compared with subnephrotic. There were no other histopathologic differences between the groups. Conclusions In patients with MLN, a distinguishing morphologic feature of those with nephrotic range proteinuria is diffuse visceral epithelial cell FPE. We conclude that nephrotic range proteinuria in patients with MLN may be a manifestation of concomitant glomerular visceral epithelial cell dysfunction.

Who Should Perform the Percutaneous Renal Biopsy: A Nephrologist or Radiologist?

Piercing the kidney with a sharp object has been observed in nature by the Kea (Nestor notabilis) (1). This alpine parrot, originally domestic to Australia, was described as a “honey-eater,” as it survived on a diet of fruit and grains. When the bird’s habitat changed to the South Island of New Zealand, it was forced to become an omnivore. Witnesses have recorded the parrot landing on the dorsal surface of sheep, lacerating the kidney with its long sharp beak, and killing the animal by inducing hemorrhage. Contrary to what has been observed with the Kea, since the initial description in 1951 (2), the percutaneous biopsy of the native kidney in humans has remained a relatively safe and successful procedure. The percutaneous renal biopsy (PRB) was the original diagnostic tool that opened the door for Nephrology to become a subspecialty, by unlocking many of the mysteries of the pathogenesis of systemic and primary glomerular diseases (3,4). Over the last 60 years, the information obtained from the PRB has provided valuable insight into basic science, translational, and clinical research, and more importantly, it has improved the care of our patients, by defining the diagnosis, prognosis, and ultimately by directing therapy. As a result of the modifications to the procedure by Kark and Muehrcke in 1954 (5) and with improved technology, including the use of real-time ultrasound imaging and automated biopsy needles, the diagnostic yield with the PRB has improved to over 95% and the complication rate has remained low (4,6). Life-threatening complications are observed in less than 0.1% of biopsies and those requiring an intervention such as a blood transfusion or a surgical or interventional procedure occur in only 1–7% of biopsies (6). While the procedure had originally been performed exclusively by Nephrologists, over the last 20 years, this percentage has dwindled (7–11). Due to time constraints, increased workload, liability, reimbursement issues, clinical demands, and a lack of comfort with the procedure, Radiologists are now performing the PRB more often. In 1990, 95% of Nephrologists performed renal biopsies (7). By 2011, only 55% of practising Nephrologists performed PRBs (11). Recently, one study determined that PRBs are performed 38% of the time by Nephrologists and 62% by Radiologists (10). Given the history and importance of this procedure to Nephrologists, one would think that this trend should be of concern to the renal community (9). Despite this, there is an apparent lack of interest in performing the PRB not only by Nephrologists but also by Interventional Nephrologists. In the program for the 2014 American Society of Diagnostic and Interventional Nephrology Meeting, only one lecture over a period of 3 days has been devoted to the procedure. Thus, it appears that Nephrologists are willingly handing the PRB over to Radiologists. This raises the important question as to whether or not Radiologists perform the procedure equally, with a similar safety and adequacy profile. The ideal biopsy technique is one that is completely safe without complications and also obtains adequate tissue to determine a diagnosis, prognosis, and guide treatment. Therefore, the balance between these two factors (complication rate and diagnostic yield) is what should determine a successful PRB. In comparing the technical aspects between the two specialties, Radiologists and Nephrologists perform the PRB using the same technique, with one exception: needle gauge. Both specialties use the prone positioning as previously described (5) and both typically use ultrasound or occasionally computed tomography. More often, however, Radiologists will use the smaller 18-gauge automated needle while Nephrologists utilize a 14or 16-gauge (8,10,12). The rationale for this discrepancy seems to be based on an assumption by Radiologists that the use of smaller gauge needles is associated with fewer complications while providing an equally adequate tissue sample as compared with larger gauge needles (13). As a result, the use of an 18-gauge needle is recommended in the 2013 practice guideline for the performance of image-guided percutaneous needle biopsy published by the American College of Radiology (13). Address correspondence to: William L. Whittier, MD, FASN, Division of Nephrology, Department of Internal Medicine, Rush University Medical Center, 1426 W. Washington Blvd, Chicago, IL 60514, Tel.: 312-850-8434, Fax: 312-850-8431, or e-mail: william_whittier@rush.edu. Seminars in Dialysis—Vol 27, No 3 (May–June) 2014 pp. 243–245 DOI: 10.1111/sdi.12215