Search Results

You are looking at 11 - 20 of 36 items for

  • Author or Editor: Bruce W. Keene x
  • Refine by Access: All Content x
Clear All Modify Search

SUMMARY

A technique for transvenous endomyocardial biopsy of the right ventricle was developed and evaluated for safety and efficacy in healthy dogs and dogs with dilated cardiomyopathy positioned in lateral recumbency. This technique allowed acquisition of multiple biopsy specimens from the right ventricle of each of 22 hemodynamically normal dogs and 40 of 42 dogs with congestive heart failure. In 2 dogs with dilated cardiomyopathy, transvenous access to the right ventricle could not be achieved, but left ventricular biopsy was performed without complication. Complications were infrequent, and dogs recovered to at least their baseline status within 48 hours. Evaluation of the efficacy and complication rate of the procedure with each of the 2 biopsy instruments currently available identified no differences between them.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine the correlation between activity as measured by an accelerometer and videographic measurements of movement and mobility in healthy dogs.

Animals—4 healthy dogs.

Procedures—After determination that accelerometers had good agreement, 5 identical accelerometers were used simultaneously to test their output at 8 locations (rotated among collar, vest, and forelimb stocking locations) on each dog. Movement and mobility for each dog were recorded continuously with a computerized videography system for 7-hour ses-sions on 4 consecutive days. Accelerometer values were combined into 439 fifteen-minute intervals and compared with 3 videographic measurements of movement and mobility (distance traveled, time spent walking > 20 cm/s, and time spent changing position by > 12% of 2-dimensional surface area during 1.5 seconds).

Results—96% of values compared between the most discordant pair of accelerometers were within 2 SDs of the mean value from all 5 accelerometers. All mounting locations provided acceptable correlation with videographic measurements of movement and mobility, and the ventral portion of the collar was determined to be the most convenient location.

Conclusions and Clinical Relevance—Use of an accelerometer was adequate for at-home activity monitoring, an important end point in clinical trials of treatment for chronic disease, and provided information about daily activity that is unattainable by other methods.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare the pharmacokinetic properties and bioavailability following oral and IV administration of bisoprolol, a second-generation β1-adrenoceptor–selective blocking agent, with those of carvedilol, a third-generation β12 and α1-adrenoceptor blocking agent, in dogs.

Animals—12 healthy adult Beagles.

Procedures—A prospective, parallel group study was performed. The dogs were allocated to 1 of 2 groups (6 dogs/group) and were administered orally a 1 mg/kg dose of either bisoprolol or carvedilol. Following a 1-week washout period, each cohort received a 1 mg/kg dose of the same drug IV. Blood samples were collected before and after drug administration, and serum concentrations, pharmacokinetic variables, and bioavailability for each agent were assessed.

Results—After oral administration of bisoprolol, the geometric mean value of the area under the concentration-time curve extrapolated to infinity (AUCinf) was 2,195 μg/L (coefficient of variation [CV], 15%). After IV administration of bisoprolol, the dose-normalized geometric mean AUCinf was 2,402 μg/L (CV, 19%). Oral bioavailability of bisoprolol was 91.4%. After oral administration of carvedilol, the geometric mean AUCinf was 70 μg/L (CV, 81%). After IV administration of carvedilol, the geometric mean AUCinf was 491 μg/L (CV, 23%). Oral bioavailability of carvedilol was 14.3%. Total body clearance was low (0.42 L/h/kg) for bisoprolol and high (2.0 L/h/kg) for carvedilol.

Conclusions and Clinical Relevance—After oral administration, carvedilol underwent extensive first-pass metabolism and had limited bioavailability; bisoprolol had less first-pass effect and higher bioavailability. Collectively, these differences suggested that, in dogs, bisoprolol has less interindividual pharmacokinetic variability, compared with carvedilol.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the effect of administration of the labeled dosage of pimobendan to dogs with furosemide-induced activation of the renin-angiotensin-aldosterone system (RAAS).

Animals—12 healthy hound-type dogs.

Procedures—Dogs were allocated into 2 groups (6 dogs/group). One group received furosemide (2 mg/kg, PO, q 12 h) for 10 days (days 1 to 10). The second group received a combination of furosemide (2 mg/kg, PO, q 12 h) and pimobendan (0.25 mg/kg, PO, q 12 h) for 10 days (days 1 to 10). To determine the effect of the medications on the RAAS, 2 urine samples/d were obtained for determination of the urinary aldosterone-to-creatinine ratio (A:C) on days 0 (baseline), 5, and 10.

Results—Mean ± SD urinary A:C increased significantly after administration of furosemide (baseline, 0.37 ± 0.14 μg/g; day 5, 0.89 ± 0.23 μg/g) or the combination of furosemide and pimobendan (baseline, 0.36 ± 0.22 μg/g; day 5, 0.88 ± 0.55 μg/g). Mean urinary A:C on day 10 was 0.95 ± 0.63 μg/g for furosemide alone and 0.85 ± 0.21 μg/g for the combination of furosemide and pimobendan.

Conclusions and Clinical Relevance—Furosemide-induced RAAS activation appeared to plateau by day 5. Administration of pimobendan at a standard dosage did not enhance or suppress furosemide-induced RAAS activation. These results in clinically normal dogs suggested that furosemide, administered with or without pimobendan, should be accompanied by RAAS-suppressive treatment.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To characterize risk factors, clinical findings, usefulness of diagnostic tests, and prognosis in cats with naturally occurring heartworm infection (HWI).

Design—Retrospective study.

Animals—50 cats with Dirofilaria immitis infection.

Procedure—Medical records, thoracic radiographs, and echocardiograms were reviewed and findings compared with appropriate reference populations.

Results—Findings suggested that male cats were not predisposed to HWI, domestic shorthair cats were at increased risk, and indoor housing was only partially protective. Fewer cases of HWI were identified in the final quarter of the year, compared with other periods, and prevalence is not apparently increasing. Signs of respiratory tract disease were most common, followed by vomiting. Infection was diagnosed incidentally in > 25% of cats; conversely, 10% of infected cats died suddenly without other clinical signs. Serologic tests were most useful for diagnosis, followed by radiography and echocardiography. Eosinophilia supported the diagnosis. Overall median survival time was 1.5 years but exceeded 4 years in cats surviving beyond the day of diagnosis.

Conclusions and Clinical Relevance—Sex does not appear to be a risk factor for HWI in cats, and indoor housing provides only incomplete protection. Signs of respiratory tract disease (dyspnea and cough) are the strongest indicators of HWI in cats, and some radiographic evidence of infection is detected in most cases. Antibody screening for HWI in cats is efficacious, and antigen testing and echocardiography are most useful for making a definitive antemortem diagnosis. (J Am Vet Med Assoc 2000;217: 355–358)

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To determine the accuracy of a point-of-care lung ultrasonography (LUS) protocol designed to diagnose cardiogenic pulmonary edema (CPE) in dyspneic dogs and cats.

DESIGN Diagnostic test evaluation.

ANIMALS 76 dogs and 24 cats evaluated for dyspnea.

PROCEDURES Dogs and cats were evaluated by LUS; B lines were counted at 4 anatomic sites on each hemithorax. A site was scored as positive when > 3 B lines were identified. Animals with ≥ 2 positive sites identified on each hemithorax were considered positive for CPE. Medical records were evaluated to obtain a final diagnosis (reference standard) for calculation of the sensitivity and specificity of LUS and thoracic radiography for the diagnosis of CPE.

RESULTS Dogs and cats with a final diagnosis of CPE had a higher number of positive LUS sites than did those with noncardiac causes of dyspnea. Overall sensitivity and specificity of LUS for the diagnosis of CPE were 84% and 74%, respectively, and these values were similar to those of thoracic radiography (85% and 87%, respectively). Use of LUS generally led to the misdiagnosis of CPE (ie, a false-positive result) in animals with diffuse interstitial or alveolar disease. Interobserver agreement on LUS results was high (κ > 0.85).

CONCLUSIONS AND CLINICAL RELEVANCE LUS was useful for predicting CPE as the cause of dyspnea in dogs and cats, although this technique could not be used to differentiate CPE from other causes of diffuse interstitial or alveolar disease. Point-of-care LUS has promise as a diagnostic tool for dyspneic dogs and cats.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To evaluate the frequency of variants in the pyruvate kinase dehydrogenase 4 (PDK4) and titin (TTN) genes in a group of Doberman Pinschers with dilated cardiomyopathy (DCM) and to determine whether there were unique clinical attributes to each variant.

ANIMALS

48 Doberman Pinschers with DCM.

PROCEDURES

Doberman Pinschers with recently diagnosed DCM were identified, and genomic DNA from each was genotyped with a PCR assay for detection of PDK4 and TTN genetic variants. Dogs were grouped on the basis of whether they had the TTN variant alone, PDK4 variant alone, both variants, or neither variant. Descriptive statistics were compiled for dog age, body weight, and left ventricular dimensions and fractional shortening and for the presence of ventricular and supraventricular arrhythmias and heart failure. Results were compared across groups.

RESULTS

Of the 48 dogs, 28 had the TTN variant alone, 10 had both variants, 6 had neither variant, and 4 had the PDK4 variant alone. The mean age was younger for dogs with the PDK4 variant alone, compared with other dogs. However, the number of dogs with the PDK4 variant alone was very small, and there was an overlap in age across groups. No other meaningful differences were detected across groups, and independent genotype-phenotype relationships were not identified.

CONCLUSIONS AND CLINICAL RELEVANCE

Although findings indicated that the TTN variant was most common, 6 dogs had neither variant, and this fact supported the concept of ≥ 1 other genetic contributor to DCM in Doberman Pinschers. Future studies are warranted to evaluate genotype-phenotype relationships in Doberman Pinschers with DCM.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Case Description—A 6-year-old Siberian Husky–mix dog was examined for episodes of collapse.

Clinical Findings—Physical examination, echocardiography, abdominal ultrasonography, ECG, and thoracic computed tomography with contrast were performed and revealed a 2.5 × 2.3 × 2.0-cm mass over the pulmonic valve leaflets, resulting in moderate pulmonic stenosis. Other abnormal findings included systemic hypertension, right bundle branch block, proteinuria, and a urinary bladder mass.

Treatment and Outcome—Pulmonary arteriotomy was performed under inflow occlusion, and the mass was resected with transesophageal echocardiographic guidance and direct visualization. Results of histologic examination of the mass revealed a vascular hamartoma. Sequential follow-up examinations and telephone contacts (at 0.5, 5, and 15 months after surgery) revealed that the patient had been free from episodes of collapse since surgery. No regrowth of the mass was noted on follow-up echocardiograms, and the pulmonic stenosis had resolved, although mild to moderate pulmonary insufficiency later developed. The bladder mass was excised 15 months after the first surgery when hematuria developed, and results of histologic examination of this mass revealed a vascular hamartoma. The dog was eventually euthanized 31 months after the initial surgery for reasons that could not be directly linked to any recurrence of the pulmonary artery mass.

Clinical Relevance—Hamartomas are benign tumors that can be located in various tissues, including large arteries. Computed tomography was helpful in predicting the resectability of the intracardiac mass in this dog. Treatment with arteriotomy under inflow occlusion and mild hypothermia resulted in a favorable outcome.

Full access
in Journal of the American Veterinary Medical Association