Matthew W. Beal

Use of indwelling, double-pigtail stents for treatment of malignant ureteral obstruction in dogs: 12 cases (2006–2009)

OBJECTIVE To determine the outcome of minimally invasive ureteral stent placement for dogs with malignant ureteral obstructions. DESIGN-Retrospective case series. ANIMALS 12 dogs (15 ureters) with ureteral obstruction secondary to a trigonal urothelial carcinoma. PROCEDURES In all patients, indwelling, double-pigtail ureteral stents were placed by means of percutaneous antegrade needle and guide wire access under ultrasound and fluoroscopic guidance. RESULTS Stents were successfully placed in all patients. In 11 of 12 patients, percutaneous antegrade access was accomplished. One patient required access via laparotomy because percutaneous access could not be achieved. The median survival time from the date of diagnosis was 285 days (range, 10 to 1,571 days), with a median survival time of 57 days (range, 7 to 337 days) from the date of stent placement. Three complications occurred in 1 patient. Seven patients required concurrent urethral stent placement for relief of urethral obstruction. All animals were discharged from the hospital (median hospitalization time after stent placement, 18 hours [range, 4 hours to 7 days]) with an indwelling, double-pigtail ureteral stent (3 bilateral and 9 unilateral) in place. All stents evaluated 0.25 to 11 months after placement were considered patent. CONCLUSIONS AND CLINICAL RELEVANCE Findings suggested that ureteral stent placement was safe, effective, and well tolerated in patients with malignant ureteral obstructions. Stents could be reliably placed in a minimally invasive manner and remain patent long-term. Ureteral stent placement should be considered as early as possible in patients with neoplasia, prior to the development of permanent renal damage.

Comparative stability of canine and feline hemostatic proteins in freeze-thaw-cycled fresh frozen plasma.

Objective – To evaluate the stability of canine and feline hemostatic proteins in freeze-thaw-cycled (FTC) fresh frozen plasma (FFP). Design – Prospective study. Setting – Veterinary Teaching Hospital. Animals – Nine blood donor dogs and 10 blood donor cats. Interventions – Whole blood was collected and separated into packed RBC and plasma units according to standard methods. Each unit of plasma was divided into 2 equal aliquots and frozen (−41°C). One aliquot from each donor (FTC) was then thawed and then refrozen (−41°C) until time of analysis. The second aliquot (nonfreeze-thaw-cycled; NFTC) remained frozen until time of analysis. The hemostatic proteins assessed included coagulation factors, anticoagulant factors (antithrombin and Protein C), and adhesive proteins (fibrinogen and von Willebrand Factor). The coagulant activities of factors II, VII, VIII, IX, X, XI, and XII were measured in modified one-stage activated partial thromboplastin time or prothrombin time assays. Antithrombin and Protein C activities were measured in chromogenic substrate assays. Clottable fibrinogen was measured via the Clauss method, and von Willebrand Factor concentration (vWF:Ag) was measured in an ELISA. A paired t-test was utilized to identify differences in factor activity or concentration between FTC FFP and NFTC FFP. Measurements and Main results – No clinically or statistically significant differences (all P>0.05) were identified between FTC FFP and NFTC FFP. Conclusions – Refreezing FFP within 1 hour of initial thawing appeared to have no deleterious effects on the hemostatic protein activity or content of that unit. Transfusion of FTC FFP is expected to provide the recipient with comparable replacement of hemostatic proteins as FFP that has remained frozen.OBJECTIVE To evaluate the stability of canine and feline hemostatic proteins in freeze-thaw-cycled (FTC) fresh frozen plasma (FFP). DESIGN Prospective study. SETTING Veterinary Teaching Hospital. ANIMALS Nine blood donor dogs and 10 blood donor cats. INTERVENTIONS Whole blood was collected and separated into packed RBC and plasma units according to standard methods. Each unit of plasma was divided into 2 equal aliquots and frozen (-41 °C). One aliquot from each donor (FTC) was then thawed and then refrozen (-41 °C) until time of analysis. The second aliquot (nonfreeze-thaw-cycled; NFTC) remained frozen until time of analysis. The hemostatic proteins assessed included coagulation factors, anticoagulant factors (antithrombin and Protein C), and adhesive proteins (fibrinogen and von Willebrand Factor). The coagulant activities of factors II, VII, VIII, IX, X, XI, and XII were measured in modified one-stage activated partial thromboplastin time or prothrombin time assays. Antithrombin and Protein C activities were measured in chromogenic substrate assays. Clottable fibrinogen was measured via the Clauss method, and von Willebrand Factor concentration (vWF:Ag) was measured in an ELISA. A paired t-test was utilized to identify differences in factor activity or concentration between FTC FFP and NFTC FFP. MEASUREMENTS AND MAIN RESULTS No clinically or statistically significant differences (all P>0.05) were identified between FTC FFP and NFTC FFP. CONCLUSIONS Refreezing FFP within 1 hour of initial thawing appeared to have no deleterious effects on the hemostatic protein activity or content of that unit. Transfusion of FTC FFP is expected to provide the recipient with comparable replacement of hemostatic proteins as FFP that has remained frozen.

Computed tomographic and magnetic resonance imaging features of canine segmental caudal vena cava aplasia

OBJECTIVE To describe the computed tomographic and magnetic resonance imaging features of segmental caudal vena cava aplasia and associated vascular anomalies in dogs. METHODS A retrospective study was performed reviewing computed tomographic and magnetic resonance imaging archives of eight institutions for dogs with segmental caudal vena cava aplasia. Inclusion criteria included a computed tomographic or magnetic resonance imaging study and supportive diagnostic and follow-up information. Abdominal vessels were reviewed for size, shape, location and course (including tributaries and branches) and classified as normal, abnormal or shunt vessels. RESULTS Ten dogs with segmental caudal vena cava aplasia were identified. In all dogs, postrenal caval blood was shunted to either a right or a left azygos vein, with seven different angiographic patterns. Affected dogs were predominantly female (70 per cent) and young (mean 2.6 years). Additional portocaval and porto-azygos shunt vessels were identified in two cases each. Computed tomographic angiography and magnetic resonance angiography depicted details of abdominal vessels including thrombus formation in one dog. CLINICAL SIGNIFICANCE Segmental caudal vena cava aplasia is a vascular congenital anomaly in the dog that can be associated with thrombosis and portosystemic shunts. Computed tomographic angiography and magnetic resonance angiography are excellent tools to demonstrate the complex vascular anatomy and to guide treatment planning for portosystemic shunts and thrombolytic therapy.

Survival after surgery for tracheal collapse and the effect of intrathoracic collapse on survival.

Objectives To determine (1) long-term survival of dogs with tracheal collapse (TC) receiving cervical extraluminal prosthetic rings (ELR) and (2) whether intrathoracic collapse effects long-term survival of dogs receiving ELR. Study Design Retrospective case series. Animals Dogs (n = 33) with TC that had ELR. Methods Medical records (July 2002–July 2008) were searched for TC dogs treated with ELR. Age, breed, gender, location of TC, and age at follow-up (death or censor) were recorded. Kaplan–Meier survival curves were generated. Results Of 114 TC dogs, 33 had ELR. Breeds and gender were consistent with previous reports; mean (±SD) age at presentation was 6.3±2.6 years. TC was categorized as cervical or cervical and intrathoracic. All dogs had cervical TC and 15 had concurrent intrathoracic collapse; 8 of these had collapse of mainstem bronchi. Median survival time was >2500 days (median not reached) for cervical TC alone and 1500 days for cervical and intrathoracic TC with no difference in median survival time between groups (P = .26). Conclusion Dogs with TC have a median survival time of 1680 days (4.6 years) after ELR and no differences were seen when dogs had intrathoracic collapse. Intrathoracic collapse does not exclude a dog from receiving ELR.OBJECTIVES To determine (1) long-term survival of dogs with tracheal collapse (TC) receiving cervical extraluminal prosthetic rings (ELR) and (2) whether intrathoracic collapse effects long-term survival of dogs receiving ELR. STUDY DESIGN Retrospective case series. ANIMALS Dogs (n = 33) with TC that had ELR. METHODS Medical records (July 2002-July 2008) were searched for TC dogs treated with ELR. Age, breed, gender, location of TC, and age at follow-up (death or censor) were recorded. Kaplan-Meier survival curves were generated. RESULTS Of 114 TC dogs, 33 had ELR. Breeds and gender were consistent with previous reports; mean (±SD) age at presentation was 6.3±2.6 years. TC was categorized as cervical or cervical and intrathoracic. All dogs had cervical TC and 15 had concurrent intrathoracic collapse; 8 of these had collapse of mainstem bronchi. Median survival time was >2500 days (median not reached) for cervical TC alone and 1500 days for cervical and intrathoracic TC with no difference in median survival time between groups (P = .26). CONCLUSION Dogs with TC have a median survival time of 1680 days (4.6 years) after ELR and no differences were seen when dogs had intrathoracic collapse. Intrathoracic collapse does not exclude a dog from receiving ELR.

Use of fresh platelet concentrate or lyophilized platelets in thrombocytopenic dogs with clinical signs of hemorrhage: A preliminary trial in 37 dogs

OBJECTIVE To examine the safety and feasibility of using lyophilized platelets (LYO) and fresh platelet concentrate (FRESH) in bleeding thrombocytopenic dogs. DESIGN Preliminary prospective randomized clinical trial. SETTING Two private referral centers and 3 university teaching hospitals. ANIMALS Thirty-seven dogs with a complaint of hemorrhage associated with thrombocytopenia (platelet count <70 × 10(9) /L [70,000/μL], a hematocrit >15%, and that had received neither vincristine nor platelet-containing transfusions within 72 h of enrollment were studied. INTERVENTIONS Animals were randomized to receive LYO or FRESH, dosed according to weight. Physical examination, complete blood counts, and coagulation testing (prothrombin time and activated partial thromboplastin time) were performed at enrollment. Physical examinations were also performed immediately post transfusion, and at 1 and 24 h after transfusion. Complete blood counts were repeated immediately post transfusion and at 24 h. Collected data included bleeding score (BLS), response to transfusion, adverse reactions, hospitalization time, need for additional transfusions, survival to discharge, and 28-d survival. MEASUREMENTS AND MAIN RESULTS Twenty-two dogs received LYO and 15 received FRESH. There was no difference between groups in age, weight, BLS, platelet count, white blood cell count, hematocrit, or presence of melena. There was no difference between groups in transfusion reaction rates, the need for additional transfusions, 24-h BLS, hospitalization time, survival to discharge, or 28-d survival. CONCLUSIONS Transfusion of LYO was feasible and associated with a low transfusion reaction rate in this limited study of thrombocytopenic canine patients presenting with mild-to-severe hemorrhage. LYO were easy to use and provided storage advantages over FRESH. Further study of this product, including examination of efficacy and platelet life span, is warranted.

Use of a balloon-expandable metallic stent to relieve malignant urethral obstruction in a cat

CASE DESCRIPTION A 19-year-old neutered male domestic shorthair cat was evaluated because of signs of urinary tract obstruction. CLINICAL FINDINGS Physical examination findings were consistent with urethral obstruction, and a mass could be palpated in the region of the bladder neck. Abdominal ultrasonography and thoracic radiography revealed a mass in the trigone of the urinary bladder and a solitary mass in the left caudal lung lobe. Cytologic examination of the urine sediment, samples obtained by means of traumatic urethral catheterization, and fine-needle aspirates of the bladder mass did not result in a diagnosis. TREATMENT AND OUTCOME A balloon-expandable metallic stent was placed in the proximal portion of the urethra to relieve the malignant obstruction. After stent placement, the cat had signs of urinary incontinence and detrusor atony, both of which resolved with medical treatment. The cat was euthanized 1 month after stent placement because of progressive azotemia. Histologic examination of necropsy samples revealed grade III urothelial carcinoma and papillary pulmonary adenocarcinoma. CLINICAL RELEVANCE Findings suggested that stent placement may be a viable palliative treatment in cats with malignant urinary obstruction.

Acquisition and persistence of antimicrobial-resistant bacteria isolated from dogs and cats admitted to a veterinary teaching hospital

OBJECTIVE To assess antimicrobial resistance among bacteria isolated from dogs and cats admitted to a veterinary teaching hospital (VTH), determine the incidence of acquisition of and frequency of persistent colonization by antimicrobial-resistant organisms among these animals, and identify risk factors associated with these variables. DESIGN Prospective longitudinal study. ANIMALS 622 dogs and 92 cats admitted to a VTH and expected to stay ≥ 48 hours. PROCEDURES Samples were collected with rectal and nasal or oropharyngeal swabs at admission and discharge. Isolates of enterococci, staphylococci, and Escherichia coli were tested for antimicrobial resistance via microbroth dilution methods. A subset of isolates was analyzed with pulsed-field gel electrophoresis and multilocus sequence typing. Significant trends in proportions of organisms with antimicrobial resistance over the 3-year study period were assessed. RESULTS The proportion of staphylococci with antimicrobial resistance increased, whereas the proportion of E coli with resistance decreased, over time; resistance among enterococci was more variable. For 506 dogs with paired admission and discharge samples, multidrug-resistant (MDR) E coli was acquired by 40 (8%) and methicillin-resistant Staphylococcus aureus (MRSA) was acquired by 7 (1.4%); hospitalization for > 3 days was significantly associated with both variables. Most (5/7 isolates) acquired MRSA was of sequence type (ST) 5. CONCLUSIONS AND CLINICAL RELEVANCE Extended hospitalization was associated with increased risk of acquiring MDR E coli or MRSA, although few animals acquired MRSA. It is unclear whether associations were confounded by illness severity or use of infection control measures. Additionally, MRSA of ST5, which has been associated with small animal medicine, was the most commonly acquired MRSA in this study.

Evaluation of freshwater submersion in small animals: 28 cases (1996–2006)

OBJECTIVE To determine clinical characteristics, treatments, and outcome in dogs and cats evaluated after submersion in freshwater. DESIGN Retrospective case series. ANIMALS 25 dogs and 3 cats. PROCEDURES Medical records were reviewed for signalment; causes, location, and month of submersion; physical examination findings at admission; results of blood gas analysis; treatments administered; duration of hospitalization; and outcome, including evidence of organ failure or compromise. RESULTS All submersions involved bodies of freshwater. Fourteen animals were submerged in man-made water sources, 13 were submerged in natural water sources, and the body of water was not recorded in 1 case. Twenty (71%) submersions occurred from May through September. Cause was identified in 16 animals and included extraordinary circumstances (n = 6), falling into water (5), breaking through ice (3), and intentional submersion (2). Twelve animals were found submerged in water with unclear surrounding circumstances. Treatment included administration of supplemental oxygen, antimicrobials, furosemide, corticosteroids, and aminophylline and assisted ventilation. Respiratory dysfunction was detected in 21 animals. Neurologic dysfunction was detected in 12 animals, hepatocellular compromise was detected in 6 animals, and cardiovascular dysfunction was detected in 4 animals. Three dogs had hematologic dysfunction, and 2 dogs had acute renal dysfunction. Eighteen (64%) animals survived to hospital discharge, but all of the cats died. In 9 of 10 nonsurvivors, respiratory tract failure was the cause of death or reason for euthanasia. CONCLUSIONS AND CLINICAL RELEVANCE Results suggest that submersion is an uncommon reason for veterinary evaluation but is associated with a good prognosis in dogs in the absence of respiratory tract failure.

Prevalence and antimicrobial resistance of Enterococcus spp and Staphylococcus spp isolated from surfaces in a veterinary teaching hospital

OBJECTIVE To determine the prevalence and antimicrobial resistance of enterococci and staphylococci collected from environmental surfaces at a veterinary teaching hospital (VTH). DESIGN Longitudinal study. SAMPLE Samples collected from surfaces in 5 areas (emergency and critical care, soft tissue and internal medicine, and orthopedic wards; surgery preparation and recovery rooms; and surgery office and operating rooms) of a VTH. PROCEDURES Selected surfaces were swabbed every 3 months during the 3-year study period (2007 to 2009). Isolates of enterococci and staphylococci were identified via biochemical tests, and antimicrobial susceptibility was evaluated with a microbroth dilution technique. A subset of isolates was analyzed to assess clonality by use of pulsed-field gel electrophoresis. RESULTS 430 samples were collected, and isolates of enterococci (n = 75) and staphylococci (110) were identified. Surfaces significantly associated with isolation of Enterococcus spp and Staphylococcus spp included cages and a weight scale. Fourteen Enterococcus spp isolates and 17 Staphylococcus spp isolates were resistant to ≥ 5 antimicrobials. Samples collected from the scale throughout the study suggested an overall increase in antimicrobial resistance of Enterococcus faecium over time. Clonality was detected for E faecium isolates collected from 2 different surfaces on the same day. CONCLUSIONS AND CLINICAL RELEVANCE Although not surprising, the apparent increase in antimicrobial resistance of E faecium was of concern because of the organisms ability to transmit antimicrobial resistance genes to other pathogens. Results reported here may aid in identification of critical control points to help prevent the spread of pathogens in VTHs.

Clinical experience utilizing a novel fluoroscopic technique for wire-guided nasojejunal tube placement in the dog: 26 cases (2006-2010).

Objective – To describe the clinical use of a novel, minimally invasive fluoroscopic technique for the wire-guided placement of nasojejunal tubes (NJT) in dogs. Design – Retrospective study (September 22, 2006–October 2, 2010). Setting – University veterinary teaching hospital. Animals – Twenty-six consecutive dogs with intolerance of, or contraindications to gastric feeding that underwent attempted fluoroscopic NJT placement. No dogs were excluded from analysis. Interventions – All dogs underwent attempted fluoroscopic NJT placement using a novel fluoroscopic wire-guided technique. Measurements and Main Results – Patient data were collected in concert with information about the NJT placement procedure as well as the maintenance and utilization of the tube. The primary diagnosis in dogs undergoing NJT placement was pancreatitis in 60%. The ability to achieve transpyloric passage of the tube was 92.3% (24/26) and the ability to achieve jejunal access was 78.2%. In the second half of the study period, the ability to achieve jejunal access was significantly higher than in the first half of the study period suggesting that technical proficiency improves over time. Mean duration of the procedure was 35.3±20 minutes. Significant oral migration was a complication of NJT placement in some dogs. The median duration of feeding was 3.3 days (range 0.3–10.5). Conclusions – Fluoroscopic wire-guided NJT placement is a viable method for sustained postpyloric feeding in dogs. Success in acquiring jejunal access improves with experience. The NJT may be utilized as a strategy to provide enteral nutritional support to the population of dogs with contraindications to, or intolerance of gastric feeding.OBJECTIVE To describe the clinical use of a novel, minimally invasive fluoroscopic technique for the wire-guided placement of nasojejunal tubes (NJT) in dogs. DESIGN Retrospective study (September 22, 2006-October 2, 2010). SETTING University veterinary teaching hospital. ANIMALS Twenty-six consecutive dogs with intolerance of, or contraindications to gastric feeding that underwent attempted fluoroscopic NJT placement. No dogs were excluded from analysis. INTERVENTIONS All dogs underwent attempted fluoroscopic NJT placement using a novel fluoroscopic wire-guided technique. MEASUREMENTS AND MAIN RESULTS Patient data were collected in concert with information about the NJT placement procedure as well as the maintenance and utilization of the tube. The primary diagnosis in dogs undergoing NJT placement was pancreatitis in 60%. The ability to achieve transpyloric passage of the tube was 92.3% (24/26) and the ability to achieve jejunal access was 78.2%. In the second half of the study period, the ability to achieve jejunal access was significantly higher than in the first half of the study period suggesting that technical proficiency improves over time. Mean duration of the procedure was 35.3±20 minutes. Significant oral migration was a complication of NJT placement in some dogs. The median duration of feeding was 3.3 days (range 0.3-10.5). CONCLUSIONS Fluoroscopic wire-guided NJT placement is a viable method for sustained postpyloric feeding in dogs. Success in acquiring jejunal access improves with experience. The NJT may be utilized as a strategy to provide enteral nutritional support to the population of dogs with contraindications to, or intolerance of gastric feeding.