Toxicity in Doberman Pinchers with Ventricular Arrhythmias Treated with Amiodarone (1996–2005)

Background: Asymptomatic Doberman Pinschers with dilated cardiomyopathy (DCM) often die suddenly owing to ventricular tachycardia that degenerates into ventricular fibrillation. A safe and effective antiarrhythmic drug treatment is needed. This will require a large, well-controlled, prospective study.
Hypothesis: Amiodarone toxicity is common in Dobermans with occult DCM and ventricular tachyarrhythmias refractory to antiarrhythmia therapy. Infrequent monitoring of hepatic function is inadequate. Frequent monitoring may be useful to determine dogs in which the dosage should be decreased or the drug withdrawn.
Methods: Medical records from the University of Georgia and Cornell University were searched for Doberman Pinschers diagnosed with preclinical DCM that received amiodarone for severe ventricular arrhythmias refractory to other antiarrhythmic agents. Echocardiographic data, Holter recording data, hepatic enzyme serum activity, and serum amiodarone concentrations were recorded. The presence of clinical signs of toxicity was recorded. Serum amiodarone concentrations were obtained in some dogs.
Results: Reversible toxicity was identified in 10 of 22 (45%) dogs.
Conclusion and Clinical Importance: Adverse effects from amiodarone were common and were, in part, dosage related. Patients should be monitored for signs of toxicity and liver enzyme activity should be measured at least monthly.     

Cardiac Troponin I in Doberman Pinschers with Cardiomyopathy

Background: Cardiac troponin I (cTnI) is useful for detection of cardiac myocyte damage, but its efficacy in detecting various stages of dilated cardiomyopathy (DCM) in Doberman Pinschers is unclear. Objectives: To evaluate the diagnostic value of cTnI in various stages of DCM in Dobermans. Animals: Six hundred and fifty‐three cTnI measurements of 336 Doberman Pinschers. Methods: Using a longitudinal study design, staging of the disease was based upon 24‐hour‐ambulatory‐ECG (Holter) and echocardiography. A total of 447 cTnI measurements were performed in 264 healthy Dobermans, and 206 cTnI measurements in 75 Dobermans with cardiomyopathy. Eighty‐eight cTnI samples were from dogs with >100 ventricular premature contractions (VPCs)/24 hour, but without echocardiographic changes (“VPC group”). Additional 19 samples originated from dogs with only echocardiographic changes (“ECHO group”), and 56 samples from dogs with both VPCs and echocardiographic changes (“VPC plus ECHO group”). Twenty samples were from dogs with clinical signs (“clinical group”). The group “incipient” included 23 dogs, that were considered to be normal according to Holter and echocardiography at the time of the exam, but that developed DCM within 1.5 years. Results: cTnI values of dogs in all disease groups, including the “incipient” (0.30 ± 0.20) and “VPC group” (0.36 ± 0.34), were significantly (P= .04, P < .001) higher than the control group (0.07 ± 0.16). A cut‐off value of >0.22 ng/mL had a sensitivity of 79.5% and a specificity of 84.4% to detect all forms of cardiomyopathy. Conclusions and Clinical Importance: cTnI measurement is a valuable diagnostic test that can detect cardiomyopathy in dogs that are otherwise clinically normal.     

Prevalence of Dilated Cardiomyopathy in Doberman Pinschers in Various Age Groups

Background: Dilated cardiomyopathy (DCM) in Doberman Pinschers is an autosomal dominant inherited disease. The prevalence of DCM in Doberman Pinschers of various age groups in Europe is currently unknown, but this information would be important to develop recommendations for screening programs. Objectives: To evaluate the prevalence of cardiomyopathy in various age groups of Dobermans. Animals: Seven hundred and seventy‐five examinations in 412 Doberman Pinschers. Methods: Dogs were included in a prospective longitudinal cohort study. Each examination included echocardiography and 24‐hour ECG (Holter) examination. A cut‐off value of >100 ventricular premature contractions (VPCs) per 24 hours on Holter examination or abnormal echocardiography was considered diagnostic for cardiomyopathy. The cumulative prevalence included all dogs with DCM and healthy dogs >7 years of age. Results: DCM prevalence in various age groups was as follows: age group 1 (1 to <2 years) 3.3%, age group 2 (2 to <4 years) 9.9%, age group 3 (4 to <6 years) 12.5%, age group 4 (6 to <8 years) 43.6%, and age group 5 (>8 years) 44.1%. The cumulative prevalence of Doberman Pinscher cardiomyopathy was 58.2%. There was an equal sex distribution, but male dogs showed earlier echocardiographic changes than did female dogs, which had significantly more VPCs. Conclusions and Clinical Importance: The prevalence of Doberman cardiomyopathy is very high in Europe. Disease manifestation and progression are different between male and female dogs. Yearly screening for DCM by Holter examination and echocardiography is recommended, starting at 2 years of age.     

Use of Simpson's Method of Disc to Detect Early Echocardiographic Changes in Doberman Pinschers with Dilated Cardiomyopathy

Background: M‐mode is the echocardiographic gold standard to diagnose dilated cardiomyopathy (DCM) in dogs, whereas Simpson's method of discs (SMOD) is the preferred method to detect echocardiographic evidence of disease in humans. Objectives: To establish reference values for SMOD and to compare those with M‐mode measurements. Animals: Nine hundred and sixty‐nine examinations of 471 Doberman Pinschers. Methods: Using a prospective longitudinal study design. Reference values for SMOD were established using 75 healthy Doberman Pinschers >8 years old with <50 ventricular premature contractions (VPCs) in 24 hours. The ability of the new SMOD cut‐off values, normalized to body surface area (BSA), for left ventricular end‐diastolic volume (LVEDV/BSA >95 mL/m²) and end‐systolic volume (LVESV/BSA > 55 mL/m²) to detect echocardiographic changes in Doberman Pinschers with DCM was compared with currently recommended M‐mode values. Dogs with elevated SMOD values but normal M‐mode measurements were followed‐up using a prospective longitudinal study design. Results: At the final examination 175 dogs were diagnosed with DCM according to both methods (M‐mode and SMOD). At previous examinations, M‐mode values were abnormal in 142 examinations only, whereas all 175 SMOD already had detected changes. Additionally, 19 of 154 dogs with >100 VPCs/24 hours and normal M‐mode values had abnormal SMOD measurement. Six dogs with increased SMOD measurements remained healthy at several follow‐up examinations (classified as false positive); in 24 dogs with increased SMOD measurements, no follow‐up examinations were available (classified as unclear). Conclusions and Clinical Importance: SMOD measurements are superior to M‐mode to detect early echocardiographic changes in Dobermans with occult DCM.     

European Society of Veterinary Cardiology screening guidelines for dilated cardiomyopathy in Doberman Pinschers

Background

Dilated cardiomyopathy (DCM) is the most common cardiac disease in large breed dogs and is inherited in Doberman Pinschers with a high prevalence (58%).

Follicular Dysplasia in Adult Black and Red Doberman Pinschers

Abstract— Four black and two red Doberman Pinschers with a slowly progressive, dorsal hypotrichosis were studied. All six dogs developed the hair loss as adults and hypotrichosis was permanent. Skin biopsies showed changes compatible with follicular dysplasia.
Résumé— L'etude porte sur 4 Dobermans noirs et 2 Dobermans marrons présentant une hypotrichose dorsale d'extension progressive. L'hypotrichose dorsale d'extension progressive. L'hypotrichose s'est développée chez les 6 chiens à l'âge adulte et est permanente. Les biopsies cutanées ont montré des images compatibles avec le diagnostic de dysplasie folliculaire.
Zusammenfassung— Bei vier schwarzen und zwei roten Dobermännern wurde eine langsam fortschreitende dorsale Hypotrichose festgestellt. Alle 6 Hunde verloren als adulte Tiere permanent Haare. Die histologischen Untersuchungen zeigten Veränderungen, die einer Follikeldysplasie entsprechen.
Resumen  Se describe la presencia de una hipotricosis dorsal de progresión lenta en cuatro perros de raza Doberman color negro y dos perros de raza Doberman y color rojo. En los seis animales la hipotricosis se inició cuando eran adultos y se mantuvo de forma permanente. Las biopsias cutáneas mostraron cambios histopatológicos compatibles con una displasia folicular.     

Heart rate variability in Doberman Pinschers with and without echocardiographic evidence of dilated cardiomyopathy

OBJECTIVE: To characterize the salient variables of the time-domain analysis of heart rate variability (HRV) in clinically normal Doberman Pinschers and to compare those variables with those of Doberman Pinschers with cardiomyopathy and mild to moderate myocardial failure. ANIMALS: 46 Doberman Pinschers. PROCEDURE: HRV was analyzed in the time-domain from 24-hour Holter recordings obtained from 28 Doberman Pinschers with normal echocardiograms and 18 Doberman Pinschers with echocardiograms consistent with mild to moderate myocardial failure. RESULTS: Significant differences in HRV variables between the 2 groups of dogs were not detected. The HRV was greater during the nighttime (12 AM to 6 AM), compared with the 24-hour day and an 18-hour (6 AM to 12 AM) period. CONCLUSIONS AND CLINICAL RELEVANCE: HRV of dogs with mild to moderate myocardial failure was not different from that of clinically normal dogs, because there were no disturbances of autonomic balance, baroreceptor function, and other factors that influence HRV in the dogs with cardiomyopathy, or the sensitivity of time-domain analysis was overwhelmed by normal sinus arrhythmia. The techniques now used to study HRV have important limitations, especially in dogs, and better noninvasive tests of autonomic function are needed.     

Molecular evaluation of five cardiac genes in Doberman Pinschers with dilated cardiomyopathy

OBJECTIVE: To sequence the exonic and splice site regions of 5 cardiac genes associated with the human form of familial dilated cardiomyopathy (DCM) in Doberman Pinschers with DCM and to identify a causative mutation. ANIMALS: 5 unrelated Doberman Pinschers with DCM and 2 unaffected Labrador Retrievers (control dogs). PROCEDURES: Exonic and splice site regions of the 5 genes encoding the cardiac proteins troponin C, lamin A/C, cysteine- and glycine-rich protein 3, cardiac troponin T, and the beta-myosin heavy chain were sequenced. Sequences were compared for nucleotide changes between affected dogs and the published canine sequences and 2 control dogs. Base pair changes were considered to be causative for DCM if they were present in an affected dog but not in the control dogs or published sequences and if they involved a conserved amino acid and changed that amino acid to a different polarity, acid-base status, or structure. RESULTS: A causative mutation for DCM in Doberman Pinschers was not identified, although single nucleotide polymorphisms were detected in some dogs in the cysteine- and glycine-rich protein 3, beta-myosin heavy chain, and troponin T genes. CONCLUSIONS AND CLINICAL RELEVANCE: Mutations in 5 of the cardiac genes associated with the development of DCM in humans did not appear to be causative for DCM in Doberman Pinschers. Continued evaluation of additional candidate genes or a focused approach with an association analysis is warranted to elucidate the molecular cause of this important cardiac disease in Doberman Pinschers.     

Evaluation of the cardiac actin gene in Doberman Pinschers with dilated cardiomyopathy

OBJECTIVE: To evaluate the coding region of the cardiac actin gene in Doberman Pinschers with dilated cardiomyopathy (DCM) for mutations that could be responsible for the development of the condition ANIMALS: 28 dogs (16 Doberman Pinschers with DCM and 12 mixed-breed control dogs). PROCEDURE: Ten milliliters of blood was collected from each dog for DNA extraction. Polymerase chain reaction (PCR) primers were designed to amplify canine exonic regions, using the sequences of exons 2 to 6 of the cardiac actin gene. Single-stranded conformational polymorphism analysis was performed for each exon with all samples. Autoradiographs were analyzed for banding patterns specific to affected dogs. The DNA sequencing was performed on a selected group of affected and control dogs. RESULTS: Molecular analysis of exons 2 to 6 of the cardiac actin gene did not reveal any differences in base pairs between affected dogs and control dogs selected for DNA evaluation. CONCLUSIONS: Mutations in exons 5 and 6 of the cardiac actin gene that have been reported in humans with familial DCM do not appear to be the cause of familial DCM in Doberman Pinschers. Additionally, evaluation of exons 2 to 6 for causative mutations did not reveal a cause for inherited DCM in these Doberman Pinschers. Although there is evidence that DCM in Doberman Pinschers is an inherited problem, a molecular basis for this condition remains unresolved. Evaluation of other genes coding for cytoskeletal proteins is warranted.     

Plasma fatty acid concentrations in Boxers and Doberman Pinschers

OBJECTIVE: To compare plasma fatty acid concentrations and the relationships of fatty acids to arrhythmias in Boxers versus Doberman Pinschers. ANIMALS: 38 Boxers and 13 Doberman Pinschers. PROCEDURES: Boxers and Doberman Pinschers evaluated via Holter recording and for which a blood sample was available were included. Echocardiograms were performed in 49 of 51 dogs. The number of ventricular premature complexes (VPCs)/24 h was counted and fatty acids analyzed. Plasma fatty acid concentrations and VPCs/24 h, as well as correlations between the 2 variables, were compared between the 2 breeds. RESULTS: Compared with the Doberman Pinschers, Boxers had significantly higher plasma concentrations of gamma-linolenic acid but lower concentrations of arachidonic acid. Total n-6 fatty acids and total polyunsaturated fatty acid concentrations were higher in Doberman Pinschers. There were significant, but weak, positive correlations between VPCs and oleic acid, total n-3 fatty acids, and total n-9 fatty acids in Boxers but not in Doberman Pinschers. CONCLUSIONS AND CLINICAL RELEVANCE: Data suggested that plasma fatty acid concentrations may differ between Boxers and Doberman Pinschers and that the relationship between fatty acid concentrations and VPCs may be different between these 2 breeds.     

Factor VIII activity in canine von Willebrand disease

This study was conducted to determine the relationship between factor VIII (FVIII) activity and von Willebrand factor antigen (vWf:Ag) concentration in canine von Willebrand Disease (vWD). In addition, the clinical utility of measuring FVIII activity in vWD was assessed. This was performed by the concurrent analysis of both FVIII activity and vWf:Ag concentration in three breeds of dogs, namely Dobermans (n=183), Scottish Terriers (n=169), and Labrador Retrievers (n=146). In the three breeds tested, linear regression analysis illustrated a positive relationship between FVIII activity and vWf:Ag concentration. This was reaffirmed in the Doberman and Scottish Terrier breeds, in which dogs with vWf:Ag concentrations < 50 CU/dL ("carriers") had lower median FVIII activities than dogs with vWf:Ag concentrations > 70 CU/dL ("normals"). The determination of various FVIII "cut-off" values was a poor test to separate Dobermans with and without clinical signs of hemorrhage attributable to vWD. In addition, the occurrence of hemorrhage in Dobermans with vWf:Ag concentrations < 50 CU/dL was not influenced by the FVIII activity. Various tests were performed to determine if the measurement of FVIII activity aided in the identification of "carriers" of the vWD gene in the Doberman and Scottish Terrier breeds. These included the use of optimal FVIII "cut-off" values for each breed and a FVIII "cut-off" value of 55 CU/dL; FVIII/vWf:Ag ratios and FVIII/vWf:Ag ratio "cut-off" values; and linear regression analysis of vWf:Ag concentration against FVIII activity. Of all these tests, only the determination of FVIII/vWf:Ag ratios appeared to have promise for "carrier" detection. The data in the present study indicated that routine FVIII assessment in vWD is not warranted; however, measurement of FVIII activity may be of use in confirming the "carrier" status of vWD.     

Results of ambulatory electrocardiography in overtly healthy Doberman Pinschers with echocardiographic abnormalities

OBJECTIVE: To identify, by means of 24-hour ambulatory electrocardiography, electrocardiographic abnormalities in overtly healthy Doberman Pinschers in which results of echocardiography were abnormal. DESIGN: Clinical case series. ANIMALS: 56 (35 male, 21 female) overtly healthy Doberman Pinschers with echocardiographic evidence of cardiomyopathy on initial examination that subsequently died of cardiomyopathy. PROCEDURE: Twenty-four-hour ambulatory electrocardiographic (Holter) recordings obtained at the time of initial examination were reviewed. For all dogs, scan quality was > 90%. RESULTS: Initial Holter recordings of all 56 dogs contained ventricular premature contractions (VPC). Thirty-six (65%) dogs had > 1,000 VPC/24 h, 17 (31%) had > 5,000 VPC/24 h, and 11 (19%) had > 10,000 VPC/24 h. Fifty-four (96%) dogs had couplets of VPC, 37 (66%) had triplets of VPC, and 36 (64%) had episodes of nonsustained (< 30 seconds) ventricular tachycardia. Number of VPC/24 h during the initial Holter recordings was positively correlated with numbers of couplets and triplets of VPC and number of ventricular escape beats and negatively correlated with left ventricular fractional shortening. Twenty-eight dogs died suddenly prior to the putative onset of congestive heart failure. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that along with echocardiography, 24-hour ambulatory electrocardiography can be used to help identify overtly healthy Doberman Pinschers with cardiomyopathy.     

Results of ambulatory electrocardiography in overtly healthy Doberman Pinschers with equivocal echocardiographic evidence of dilated cardiomyopathy

OBJECTIVE: To determine results of ambulatory electrocardiography in and outcome of overtly healthy Doberman Pinschers with equivocal echocardiographic evidence of dilated cardiomyopathy. DESIGN: Case series. ANIMALS: 44 overtly healthy (25 male, 19 female) Doberman Pinschers. PROCEDURE: 24-hour ambulatory electrocardiographic (Holter) recordings with > 90% scan quality obtained the same day that echocardiography was performed were reviewed. RESULTS: Holter recordings from 42 of 44 (95%) dogs contained ventricular premature complexes (VPC). Fifteen of 44 (34%) dogs had > 100 VPC, 9 (20%) had > 500 VPC, and 5 (11%) had > 1,000 VPC. Nonsustained (< 30 seconds) ventricular tachycardia was detected in 4 dogs. Eighteen of 27 (67%) dogs with > 100 VPC, any couplets or triplets of VPC, or ventricular tachycardia developed dilated cardiomyopathy within 1 year, compared with 8 of 17 (47%) dogs with < 100 VPC, no couplets or triplets of VPC, and no ventricular tachycardia. Of the 18 dogs that did not develop dilated cardiomyopathy within 1 year, 11 (61%) did so within 3 years. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a high percentage of Doberman Pinschers with equivocal echocardiographic evidence of dilated cardiomyopathy will be found to have VPC during 24-hour ambulatory electrocardiography and that most will develop echocardiographic abnormalities indicative of cardiomyopathy.     

A retrospective study of heart disease in doberman pinscher dogs

The prevalence of gross and/or histological cardiac lesions was found to be much greater in Doberman pinscher dogs (16/26 or 62%) than in non-Doberman dogs (124/417 or 30%). At least some of the affected Dobermans were unrelated. Middle aged (mean age 4.7 yr) Dobermans of both sexes (11 M:5F) were affected. Four of the Dobermans with heart lesions had congestive cardiomyopathy; three of these four had congestive heart failure and the other one died suddenly. Prominent gross lesions were ventricular dilation and atrioventricular valvular endocardiosis. Histological lesions noted were prominent myocardial fibrosis, myofiber degeneration with fatty replacement, myofiber vacuolation and arterial intimal cushion formation. A spectrum of myocardial disease exists in Dobermans and clinically overt congestive cardiomyopathy represents one end of this spectrum.     

Bicortical implant insertion in caudal cervical spondylomyelopathy: a computed tomography simulation in affected Doberman Pinschers

Objective— To evaluate the safety of the angle of insertion of bicortical implants in Doberman Pinschers affected by caudal cervical spondylomyelopathy (CCSM) using simulation on computed tomography (CT) images.
Animals— Doberman Pinschers (n=9) with dynamic spinal compression attributed to CCSM.
Methods— Dogs had CT evaluation of the cervical vertebral column. Digital images were used to evaluate the safety of bicortical implant insertion from the midline at 30, 35, and 40° inclination by drawing a line simulating implant position. Correct surgical positioning of dogs was evaluated by measuring the degree of rotation of the spine along the longitudinal axis.
Results— Insertion of an implant at 30, 35, and 40° inclination was considered safe in 42%, 59%, and 67% of selected sites. Rotation of the spine from 9° counter clockwise to 10° clockwise along the longitudinal axis occurred in 53% of the areas considered.
Conclusions— These results suggest that bicortical implants in the caudal cervical area in Doberman Pinschers affected by CCSM carry a high risk of vertebral canal and intervertebral foramina violation.
Clinical Relevance— Bicortical implants inserted at 30 and 35° in the caudal cervical area in Doberman Pinschers affected by CCSM carry a high risk of vertebral canal and intervertebral foramina violation. CT planning for individual dogs can facilitate selection of the appropriate insertion plane and vertebral column rotation needs to be considered in surgical planning.     

Assessment of mechanical ventricular synchrony in Doberman Pinschers with dilated cardiomyopathy

Objectives

Loss of temporal synchrony of myocardial contraction has been shown to reduce systolic function and be responsible for disease progression in people. The objective of this study is the assessment of inter- and intra ventricular synchrony in healthy Doberman Pinschers and those with dilated cardiomyopathy (DCM) by use of conventional Doppler and tissue velocity imaging.

Animals

A total of 60 scans from 35 client-owned Doberman Pinschers presented for cardiac evaluation were analysed.

Methods

Retrospective analysis of data. Using the European Society of Veterinary Cardiology DCM taskforce scoring system, Doberman Pinschers were classified into 4 groups: Control (Group 1; n = 12), depressed systolic function other than DCM (Group 2; n = 9), preclinical DCM (Group 3; n = 8) and symptomatic DCM (Group 4; n = 6). The time intervals between the beginning of the QRS complex and the peak velocity of pulmonic flow (Q-P) and the peak aortic flow (Q-Ao) were used to assess global synchrony between both ventricles. The time intervals between the beginning of the QRS complex and the peak myocardial systolic velocity (Q-peak S) and the onset of myocardial systolic velocity (Q-start S) were measured at the base of the right and left ventricular free wall (RVFW and LVFW) and interventricular septum (IVS), and used to determine segmental longitudinal inter- and intra ventricular synchrony.

Results

No significant loss of global or segmental longitudinal inter- or intra ventricular synchrony was identified between the groups.

Conclusion

Impairment of longitudinal fibre synchrony does not appear to be significantly associated with clinical status of DCM in Doberman Pinschers, although it was identified in certain individuals.     

Heart rate turbulence after ventricular premature beats in healthy Doberman pinschers and those with dilated cardiomyopathy

Objectives

To describe the measurement of heart rate turbulence (HRT) after ventricular premature beats and compare HRT in healthy Doberman pinschers and those with dilated cardiomyopathy (DCM), with and without congestive heart failure (CHF).

Alterations in the organisation, ultrastructure and biochemistry of the myocardial collagen matrix in doberman pinschers with dilated cardiomyopathy

Remodelling of the collagen matrix of the myocardium has been implicated in the pathogenesis of dilated cardiomyopathy, a major cause of heart failure in Doberman pinschers. The aim of this study was to characterise the myocardial collagen matrix of Dobermans. In clinically normal Dobermans there was evidence of focal fibrosis. Collagen cross-links were altered in both diseased and clinically normal Doberman myocardium as compared with myocardium from control dogs. Extensive remodelling, in the form of a loss of collagen tethers, increased collagen synthesis and alterations in the collagen cross-links, occurs in diseased Doberman myocardium. Changes in the collagenous matrix are also present in apparently normal Dobermans. These changes are likely to be involved in the progression of the disease and may explain the predisposition of this breed to dilated cardiomyopathy.     

Effect of desmopressin on von Willebrand factor multimers in Doberman Pinschers with type 1 von Willebrand disease

OBJECTIVE: To assess the effect of desmopressin (DDAVP) administration in Doberman Pinschers with type 1 von Willebrand disease (vWD) on plasma von Willebrand factor (vWF) multimers through determination of vWF collagen binding activity (vWF:CBA; a functional vWF assay dependent on the presence of high-molecular-weight [HMWI multimers), comparison of vWF antigen concentration (vWF:Ag) to vWF:CBA, and vWF multimer size distribution. ANIMALS: 16 Doberman Pinschers with type 1 vWD and 5 clinically normal control dogs. PROCEDURE: Plasma vWF:Ag and vWF:CBA assays and vWF multimer analysis were performed before and 1 hour after administration of DDAVP (1 microg/kg, SC). RESULTS: Following DDAVP administration, dogs with type 1 vWD had an increase in mean baseline values of plasma vWF:Ag and vWF:CBA from 10% to 17% for both variables. The mean vWF Ag:CBA ratio at baseline (0.95) was similar after DDAVP administration (0.97), indicating concordant increases in plasma vWF concentration and activity. In control dogs, mean plasma vWF:Ag and vWF:CBA increased from baseline values of 64% to 113% and 58% to 114%, respectively, and the vWF Ag:CBA ratios were unchanged (1.1 vs 1.0) after DDAVP administration. Plasma vWF multimer analysis revealed proportional increases in band intensity for all multimer sizes following DDAVP administration, in comparison to baseline for the control dogs and Doberman Pinschers with vWD, consistent with vWF Ag:CBA ratios of approximately 1. CONCLUSIONS AND CLINICAL RELEVANCE: Beneficial effects of DDAVP on primary hemostasis in Doberman Pinschers with type 1 vWD cannot be explained by preferential increases in HMW vWF multimers.     

Morphometric dimensions of the caudal cervical vertebral column in clinically normal Doberman Pinschers, English Foxhounds and Doberman Pinschers with clinical signs of disk-associated cervical spondylomyelopathy

Client-owned, clinically normal Doberman Pinschers (n=20), English Foxhounds (n=17), and Doberman Pinschers with clinical signs of disk-associated cervical spondylomyelopathy (DA-CSM) (n=17) were prospectively studied. All dogs underwent magnetic resonance imaging (MRI) of the cervical vertebral column. To evaluate vertebral canal stenosis, the canal occupying ratios of the spinal cord and cerebrospinal fluid (CSF)-column were calculated from C5 to C7. To evaluate the degree of spinal cord compression and the amount of canal compromise, the compression ratio, remaining spinal cord and CSF-column area, and vertebral canal and dorsoventral vertebral canal compromise ratios were calculated at the site of most severe compression. For each canal occupying ratio, there was a significant higher value (implicating less space available for the spinal cord in the vertebral canal) at the level of C7 for clinically affected Doberman Pinschers compared with clinically normal English Foxhounds. The remaining spinal cord area was significantly smaller in dogs with clinically relevant spinal cord compression compared to dogs with clinically irrelevant spinal cord compression. Relative stenosis of the caudal cervical vertebral canal occurred more often in Doberman Pinschers with DA-CSM compared to English Foxhounds and a critical degree of spinal cord compression should be reached to result in clinical signs.