Pilot evaluation of a vacuum-assisted biopsy instrument for percutaneous renal biopsy in dogs

Kidney biopsies in dogs are commonly obtained using automated spring-loaded biopsy instruments. Interpretation of biopsies from dogs with glomerular disease requires examination of at least 5-10 glomeruli, with at least two biopsies usually required for full evaluation. The purpose of this study was to compare quality and interpretability of renal biopsies obtained from healthy dogs with a large-gauge, vacuum-assisted biopsy instrument versus two biopsies obtained with a spring-loaded biopsy needle. Twenty dogs were randomized into two groups, and percutaneous, ultrasound-guided renal biopsies were evaluated using standard criteria. There were no significant differences in the number of biopsies that contained renal tissue, cortex, or medulla. Biopsies obtained with either instrument contained an adequate number of glomeruli and an equivalent number of arterioles and severity of tissue compression. Differences included easier penetration of the renal capsule and collection of sufficient tissue for interpretation with only one instrument pass when using the vacuum-assisted device (vs two passes required with the spring-loaded instrument). Before use in client-owned dogs, future studies should evaluate whether these differences are clinically relevant advantages in the diagnostic evaluation of dogs with kidney disease, and determine the prevalence and severity of complications when using this larger gauge device.     

ULTRASOUND-GUIDED TISSUE-CORE BIOPSY OF LIVER, SPLEEN AND KIDNEY IN NORMAL DOGS

Six normal dogs were subjected to ultrasound-guided biopsy of the liver, spleen and kidney to examine the accuracy of the technique (i.e. the presence of targeted tissue) and the histologic quality of the biopsies. Five consecutive tissue-core biopsies of each organ were taken on one or more occasions. The accuracy of the technique was 77% for hepatic, 90% for splenic, 53.5% for left kidney and 40% for right kidney biopsies. The histologic quality of the liver and kidney samples was sufficient, although for some samples the diagnostic value was limited by their size and in renal samples either cortical or medullary tissue was sometimes lacking. In contrast, the quality of the splenic sections was not good. The effect of reused and resterilized needles on the quality of the specimens was evaluated by histologic inspection of the samples and by the amount of biopsies lacking tissue. All tissue samples, including those taken with reused or resterilized needles had sharp-cut edges. Twenty-two of the total number of 120 biopsies (18%) contained no tissue. Absence of tissue in the samples was observed in biopsies taken with all needle types. The animals were observed for possible complications of the repeated needle biopsy. Apart from one case of hematuria, no complications were encountered.     

Effects of serial ultrasound-guided renal biopsies on kidneys of healthy adolescent dogs

Ten healthy mixed-breed dogs were used to evaluate the functional and structural effects of serial ultrasound-guided renal biopsies obtained with an automated biopsy needle. In each dog, one lateral renal cortex was biopsied at 2, 4, and 6 months of age; the other kidney was the control. Five dogs had two tissue cores and five dogs had four tissue cores taken on each biopsy occasion, and one core was examined microscopically. One week before each biopsy and a month after the final biopsy, the glomerular filtration rate (GFR) was determined by renal scintigraphy. Dogs were then euthanized for evaluation of gross and microscopic lesions attributable to the biopsies. There was no difference between GFR values for biopsied kidneys and those of control kidneys ( P >0.05). Microscopic lesions were not identified in biopsies taken at 2 and 4 months, but focal lesions were found in three of 10 specimens taken at 6 months of age. At necropsy, six of 10 biopsied kidneys had small visible capsular scars, and linear tracts <2 mm wide were observed on cut surfaces in six of 10 biopsied kidneys cut transversely into slices 5 mm thick. Discrete light microscopic lesions were observed in 25 of 452 (5.5%) of randomly selected 6-mm-diameter sections of renal cortex from biopsied kidneys. We conclude that serial renal cortical biopsies can be obtained by our method from healthy adolescent dogs with minimal risk of inducing changes that might be confused with those of a progressive renal disease.     

CONTRAST HARMONIC ULTRASOUND APPEARANCE OF CONSECUTIVE PERCUTANEOUS RENAL BIOPSIES IN DOGS

Ultrasound‐guided percutaneous renal biopsy may be associated with complications, especially when using larger needles. Contrast harmonic ultrasound increases blood pool echo intensity, enhancing parenchymal lesions. Therefore, contrast harmonic ultrasound is a potential alternative screening method for postbiopsy renal lesions. Renal biopsies were performed using 14 G needles in 11 healthy Beagles, at three occasions: 0 (“Baseline Biopsy”; BB), 4 (“Biopsy 2”; B2), and 6 months (“Biopsy 3”; B3). Ultrasound and contrast harmonic ultrasound of biopsied kidneys were performed approximately 30 min after biopsy (week 0) at BB and B2, and repeated once every week (weeks 1–3) until normal appearance. At B3, only contrast harmonic ultrasound was performed, both immediately and 30‐min postbiopsy. Contrast harmonic ultrasound images were reviewed using subjective and semiquantitative methods to describe lesions including number, shape, size, sharpness, echogenicity, and evolution. More renal lesions were detected with contrast harmonic ultrasound (22/22) compared with conventional ultrasound (14/22). The majority appeared at week 0 as hypoechoic tract(s) (27/33), the other (6/33) as ill‐defined areas or area/tract combination, all having variable size, shape, and echogenicity. Seven tracts had a small subcapsular hematoma. In most kidneys, similar or gradual decrease of size and sharpness, and increased echogenicity was observed until normal appearance occurred at week 1 (1/22), week 2 (18/22), or week 3 (22/22). Two Beagles developed complications. At B3, immediately postbiopsy, tracts were hyperechoic in 9/11 kidneys, becoming hypoechoic again 30 min later. Contrast harmonic ultrasound is a valuable method to evaluate postbiopsy renal lesions in dogs.     

Glomerular lesions in dogs infected with Leishmania organisms

OBJECTIVE: To histologically identify glomerular lesions in dogs infected with Leishmania organisms. ANIMALS: 41 dogs (17 sexually intact males and 14 sexually intact and 10 ovariohysterectomized females) that had positive results when tested for leishmaniosis as determined by use of serologic evaluation (indirect fluorescent antibody test, titers of 1:80 to 1:640) and direct microscopic identification of the protozoal organisms. PROCEDURE: Urine samples were collected by use of cystocentesis and examined by qualitative SDS-agarose gel electrophoresis (AGE). All dogs had non-selective (glomerular) or mixed (glomerular and tubular) proteinemia. Specimens were obtained from each dog during ultrasound-assisted renal biopsy and used for histologic examination. Each specimen was stained with H&E, periodic acid-Schiff, Goldner's trichrome, methenamine silver, and Congo Red stains. Specimens were adequate for evaluation when they contained at least 5 glomeruli/section, except for specimens stained with Congo Red in which 1 glomerulus/section was adequate. RESULTS: Examination of renal biopsy specimens revealed various glomerular lesions in all dogs and interstitial or tubular (or both) lesions in 23 of 41 (55%) dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Glomerular lesions that develop in dogs during infection with Leishmania organisms can be classified histologically as mesangial glomerulonephritis, membranous glomerulonephritis, membranoproliferative glomerulonephritis, and focal segmental glomerulonephritis. Tubulointerstitial histopathologic conditions were not observed as the primary lesion, despite being evident in 23 of 41 (55%) dogs. Use of SDS-AGE for qualitative evaluation of proteinuria and successive collection of specimens during renal biopsies following diagnosis of nonselective glomerular proteinuria provides the possibility for early identification of renal lesions.     

Efficacy and safety of ultrasound-guided percutaneous biopsy of the right kidney in cattle

The purpose of the present study was to develop a technique for biopsy of the kidneys of cattle and to evaluate its usefulness and safety based on 25 consecutive biopsies. Using a handheld 14G spinal biopsy needle, the right kidney was biopsied under ultrasound control by one operator. To assess the immediate effects of renal biopsy, twenty cattle were necropsied shortly after the procedure and examined. The remaining five animals were biopsied and examined daily for nine days and then necropsied. One pass was made for biopsy of the right kidney. No immediate or delayed macroscopic hematuria was observed post-biopsy. Six animals had a thin subcapsular hematoma (less than 2 cm in diameter). We conclude that percutaneous ultrasound-guided biopsy of the right kidney is safe, fast, cost-effective and practical as long as it is performed properly.     

Laparoscopic diagnosis of pancreatic disease in dogs and cats

BACKGROUND: Histopathology is the gold standard for the diagnosis of pancreatic disease. Laparoscopy offers a minimally invasive route by which to obtain pancreatic biopsies. HYPOTHESIS: Laparoscopy is a safe and effective technique for evaluating the pancreas in small animal patients. ANIMALS: Medical records of 18 dogs and 13 cats examined between 1999 and 2007 that underwent laparoscopy during which observation or biopsy of the pancreas was recorded. METHODS: The database for the Laparoscopy Laboratory at Colorado State University was searched for records that contained "pancreatitis,"pancreas," or "pancreatic." The presenting complaints, imaging studies, and histopathologic findings of animals were recorded. All hospital admissions were searched for animals with the same presenting complaints and of those it was determined which animals had exploratory surgery and their pancreas biopsied. RESULTS: Thirteen cats and 18 dogs underwent laparoscopy for presumptive pancreatic disease or had the appearance of the pancreas described, pancreatic biopsies obtained, or both. In 14 animals a laparoscopic biopsy of the pancreas resulted in a histopathologic diagnosis when the sonographic findings or the gross assessment failed to do so. In 35% of the animals a biopsy of the pancreas was not obtained despite findings consistent with pancreatic disease. Those animals examined for vomiting or anorexia were significantly more likely to have a biopsy of the pancreas obtained through laparoscopy versus surgery (P < .0001). CONCLUSIONS AND CLINICAL IMPORTANCE: Laparoscopy and pancreatic biopsy is useful for evaluation of pancreatic disease.     

Renal biopsy in the normal cat: examination of the effects of repeated needle biopsy

Three healthy cats were subjected to percutaneous renal biopsy of the left kidney on three occasions at monthly intervals. Three other cats were subjected to three consecutive biopsy attempts on one occasion using the left kidney. Thereafter the six cats were monitored clinically and by means of laboratory analyses of blood and urine until euthanasia four weeks after the last biopsy. Cautious insertion of the biopsy needle in an attempt to avoid over penetration of the kidney resulted in failure to obtain renal tissue on six occasions but in all 12 specimens which did contain renal tissue, glomeruli were present. Major blood vessels were present in two biopsy specimens. At necropsy, radiographic and histological studies demonstrated renal parenchymal and vascular changes in the biopsied kidneys which were similar to but less severe than those produced by a single biopsy attempt. This confirmed that avoidance of damage to major renal vessels is important and suggested that, with care, repeated biopsies need be no more harmful to the kidney than a single biopsy.     

Comparison of needle-core (Trucut) biopsy and surgical biopsy for the diagnosis of cutaneous and subcutaneous masses: a prospective study of 51 cases (November 1997-August 1998)

Cutaneous or subcutaneous masses in 51 dogs and cats were examined by needle-core (i.e., Trucut) biopsy, and results were compared to results of surgical biopsy to assess the accuracy of the former. Needle-core specimens obtained before surgical biopsy were submitted to a single pathologist who evaluated both samples and was blinded to the results of surgical biopsy when evaluating the Trucut specimen. The results indicate that needle-core biopsy can accurately predict surgical biopsy. Thus, needle-core biopsy performed before surgical excision of masses can facilitate planning and reduce the need for numerous surgical procedures. Needle-core biopsy can direct appropriate treatment of nonmalignant masses.     

Familial nephropathy in cocker spaniels

In 21 normal dogs of different breeds and ages the number of nephrons was calculated from paraffin sections in comparison with a maceration method. With these methods the number of glomeruli x 1000 per kidney appeared to be 502 +/- 213 and 515 +/- 230 respectively. The histological method appeared to be acceptable for the determination of the number of glomeruli in incomplete kidneys. The examined Cocker Spaniels consisted of 5 animals without renal problems for control and 21 animals with nephropathy: 12 of 1-2 years, 6 of 4-6 years and 3 of 9-10 years old dogs. As indication for the present number of nephrons the glomeruli were counted in bands of whole cortex with a width of 1 mm. The number of glomeruli per band of cortex in the nephropathic Cocker Spaniels (15.0 +/- 3.0) was not drastic lower than those of the normal Cockers (20.8 +/- 2.5) and of 7 normal adult dogs of different breeds (17.2 +/- 2.2). On pathological examination the nephropathic kidneys showed a membranoproliferative-sclerosing glomerulonephritis with extra-capillary reaction leading to glomerular obsolescence. The animals showed evident proteinuria and final renal insufficiency. It was concluded that the pathogenesis of the familial nephropathy in this breed will not be caused by cortical hypoplasia, but by a primary glomerulopathy.     

ULTRASOUND-GUIDED BIOPSY OF THE CANINE LIVER, KIDNEY, AND PROSTATE

Sixty-nine hepatic, 25 renal, and 16 prostatic biopsies were performed under ultrasound guidance using a biopsy guide. The majority (98 of 110) were tissue-core biopsies. Multiple attempts at obtaining a sample were required; however, in the kidney, the number of attempts was restricted to two. Adequate samples were obtained in 94% (65/69) hepatic, 88% (22/25) renal, and 94% (5/6) prostatic biopsies. Postbiopsy scanning did not demonstrate parenchymal hemorrhage. In three renal and one prostatic biopsy, gross hematuria, noted immediately following biopsy, resolved in 2–3 days. Animals with prostatic disease frequently had hematuria, making evaluation for this complication difficult. One animal died acutely 2 days following prostatic biopsy due to an unrelated problem, a ruptured aortic àneurysm. Complications were not encountered with the liver biopsy procedure. Animals biopsied under sedation tolerated the procedure well. The authors preferred to anesthetize uncooperative animals and those needing kidney biopsy to minimize the likelihood of complications. Problems encountered during the procedure, overlying bowel gas obscuring the target organ or poor visualization of the biopsy needle, were corrected by changing patient or transducer position or the procedure was postponed. The usefulness of the biopsy procedure is illustrated in four case reports.     

Renal allograft histopathology in dog leukocyte antigen mismatched dogs after renal transplantation

OBJECTIVE: To evaluate allograft histopathology in dog leukocyte antigen (DLA)-mismatched dogs undergoing renal transplantation, with transient immunosuppression. STUDY DESIGN: Prospective study. ANIMALS: Ten healthy adult mongrel dogs. METHODS: Reciprocal renal transplantation and bilateral nephrectomy were performed. Immune conditioning consisted of nonmyeloablative (200 cGy), total body irradiation (TBI), bone marrow transplantation (BMT; 7 dogs), cyclosporine (CSA; 15 mg/kg every 12 hours), mycophenolate mofetil (MMF; 10 mg/kg every 12 hours) and intermittent prednisone (1 mg/kg every 12-24 hours). Biopsies were collected at transplantation, during full immunosuppression (44-90 days), and once medications were reduced or discontinued (228-580 days). Biopsies were evaluated for interstitial, tubular, vascular, and glomerular lesions. Blood urea nitrogen, creatinine, serum CSA concentrations, and clinical score were determined at each biopsy. RESULTS: Seven dogs survived >200 days (mean, 380 days). Transient CSA toxicity was suspected in 6 dogs. Lymphocytic, plasmacytic interstitial inflammation, and tubulitis progressed when immunosuppressive medications were decreased. All 7 dogs had histologic lesions consistent with some degree of allograft rejection at study end. CONCLUSION: Nonmyeloablative TBI, BMT, and short-term immunosuppression with CSA, MMF, and prednisone allowed renal allograft function and dog survival for >200 days. It appears unlikely that total drug withdrawal will be possible in unrelated DLA-mismatched dogs using this protocol. CLINICAL RELEVANCE: Transient immunosuppression with MMF, CSA, and prednisone along with BMT and nonmyeloablative TBI may make kidney transplantation a clinical reality for treatment of kidney failure in dogs. Initiating both MMF and CSA at lower dosages may potentially eliminate early renal allograft injury.     

SAFETY OF PERCUTANEOUS ULTRASOUND–GUIDED BIOPSY OF RENAL ALLOGRAFTS IN THE CYNOMOLGUS MONKEY: RESULTS OF 348 CONSECUTIVE BIOPSIES

The safety of a technique for ultrasound-guided biopsy of renal allografts was evaluated based on 348 consecutive procedures in cynomolgus monkeys. A spring-loaded biopsy device with an 18G tru-cut biopsy needle was used to biopsy renal allografts in 139 cynomolgus monkeys performed either on clinical indication (n = 95 animals) or as serial protocol biopsies (n = 44 animals) for a total of 348 biopsies. Monkeys having serial biopsies received between 3-9 biopsies per animal. All others received non-protocol biopsies that were performed on clinical indication, and the range was 1-15 biopsies per animal. No life-threatening complications or deaths occurred and there were no clinically detectable minor complications such as macrohematuria. Self-limiting complications such as small arteriovenous fistulas (n = 4, 3-5 mm large) were detected with Doppler ultrasound and resolved hemodynamically after 2-4 weeks. Three animals developed hematomas ranging 4 mm-2 cm in diameter and were no longer sonographically evident 2-4 weeks later. Ultrasound-guided biopsy of renal allografts can be performed with a high degree of safety in small (3-5 kg) laboratory animals such as the cynomolgus monkey and provides a valuable tool for renal transplantation research. Even when cores were taken at two week intervals no major complications occurred and only rarely were clinically irrelevant complications detected. Experience with diagnostic ultrasound, both gray scale and Doppler, is important for both safety and the recognition of complications that may arise.     

Evaluation of renal biopsies in cats and dogs — histopathology in comparison with clinical data

Histopathological findings of renal biopsies in cats and dogs with diffuse nephropathies generally lead to an exact diagnosis and facilitate prognostic judgements. Complications following renal biopsy are usually slight, provided the biopsy is performed properly. Routine renal laboratory data have been compared with histopathological findings. High urine protein values are often the result of glomerular lesions, whereas high creatinine values are frequently related to tubulointerstitial lesions. In general, there is no relationship between different types of nephropathy and age; nevertheless animals with chronic tubulointerstitial nephritis were, on average, older than animals with glomerulopathies.     

Immunohistochemical localization of fibroblast growth factor 18 in hair follicles of healthy beagle dogs

Increasing emphasis is being placed on the role of fibroblast growth factors (FGFs) in hair follicle cycling. In mice, expression of FGF18 mRNA peaks during the late telogen phase, leading to the hypothesis that FGF plays a role in anagen induction. There are no data on the presence of FGF18 in dogs. The main objective of this study was to identify and locate FGF18 in the canine hair follicle. The second objective was to assess potential differences in FGF18 concentration between biopsies taken in winter and summer, shoulder and flank regions, and between different sexes. Skin tissue from 10 healthy beagle dogs (three intact females, three spayed females and four intact males) was collected from the shoulder and flank. The biopsies were collected in February and August on day 0, after which the dogs were clipped and biopsies collected again from the shoulder and flank on days 1, 3, 7 and 17. Paraffin sections (4 μm thick) of the biopsies were stained with an anti-FGF18 antibody. The FGF18-positive cells were counted in the hair follicle epithelium from seven follicular units of each biopsy. Fibroblast growth factor 18 was detected as granular cytoplasmatic staining in follicles at the level of the inner root sheath, and rarely in the outer root sheath and dermal papilla. It was also detected in the apocrine glands, in arrector pili muscles and in vascular endothelial cells. There was no statistical difference in the number of FGF18-positive cells or follicles between sexes, different anatomical locations, seasons or the consecutive days of sampling.     

ULTRASOUND-GUIDED PERCUTANEOUS LIVER BIOPSY IN SNAKES

Percutaneous ultrasound-guided liver biopsies were conducted in 15 snakes using 18-gauge automatic biopsy devices. The liver samples collected ranged in size from 1.16 ± 0.40 mm to 8.3 ± 0.55 mm. Upon histologic examination, all biopsy samples were of diagnostic quality. Anesthesia with complete immobilization of the snake was necessary to allow proper selection of the target site and limit complications associated with biopsy collection. Percutaneous ultrasound-guided liver biopsy is a rapid, minimally invasive method for collecting liver tissue in snakes.     

THE USE OF RADIONUCLIDE ANGIOGRAPHY TO STUDY BLOOD FLOW THROUGH ENDOTHELIAL CELL SEEDED EXTRATHORACIC BYPASS GRAFTS IN THE DOG

Endothelial seeding of vascular grafts has been shown to decrease graft thrombogenicity and prolong longevity when implanted in vivo. Previous studies have utilized anatomic grafts to study endothelialization and healing. Anatomic thoracoabdominal grafts do not allow for sequential biopsy for evaluation of individual grafts nor do they approximate the environment for long bypass grafts used in limb salvage. This study evaluated the use of an extra-anatomic aortic bypass graft to assess the healing of endothelial cell seeded expanded polytetrafluoroethylene (ePTFE). Radionuclide angiography was used to evaluate graft patency and quantify blood flow through the graft. Dogs underwent placement of an extra-anatomic 60 cm long, 8 mm internal diameter, graft seeded with autologous endothelium. Grafts were biopsied from 2 weeks up to 1 year. Radionuclide studies were performed postimplantation and following each graft biopsy. Graft placement and biopsies were well tolerated in all dogs. Biopsied segments of graft allowed for sequential studies of the healing of implanted grafts by scanning electron and light microscopy. Flow through the implanted graft was close to 50% of the total caudal abdominal aortic flow. No significant difference in graft flow was noted either between animals or overtime.     

A COMPARISON OF MANUAL AND AUTOMATIC ULTRASOUND-GUIDED BIOPSY TECHNIQUES

A manual, ultrasound-guided biopsy technique was compared to a new automatic method using a new biopsy device. The liver and the left kidney of 10 dogs were biopsied using the two methods. The specimens from the biopsies were compared for size and quality. Results demonstrate that larger and higher quality samples were obtained with the new automatic method.     

A comparative study of chronic kidney disease in dogs and cats: induction of cyclooxygenases

The present study investigated whether renal cyclooxygenase (COX) induction is associated with the severity of chronic kidney disease (CKD) in dogs and cats. The collected kidneys were examined histopathologically and immunohistochemically. The immunoreactivities of COX-1 and COX-2 were evaluated quantitatively, and the correlations to the plasma creatinine concentrations, glomerular size, glomerulosclerosis, interstitial fibrosis, and interstitial cell infiltration were evaluated statistically. Immunoreactivities for COX-1 were heterogeneously observed in the medullary distal tubules and collecting ducts; no correlations with the severity of renal damage were detected. Immunoreactivities for COX-2 were heterogeneously observed in the macula densa (MD) regions. In dogs, the percentage of COX-2-positive MD was significantly correlated with the glomerular size. In cats, glomeruli with COX-2-positive MD had significantly higher sclerosis scores than those with COX-2-negative MD. In conclusion, renal COX-2 is induced in canine and feline CKD, especially in relation to the glomerular changes.     

Evaluation of laparoscopy for obtaining renal biopsy specimens from dogs and cats

Laparoscopic direction of renal biopsy was evaluated in 37 dogs and 1 cat suspected of having renal disease. Specimens adequate for morphologic diagnosis were obtained in 37 cases (97%). Eleven of the 38 animals were necropsied and the biopsy diagnosis was confirmed in 10 of the cases (91%). Excessive pericapsular hemorrhage and severe hematuria developed in 1 dog. Three dogs (8%) had macroscopic hematuria for 24 hours after biopsy.