Virginia-Maryland College of Veterinary Medicine (VMCVM)

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https://hdl.handle.net/10919/5559
The Virginia-Maryland College of Veterinary Medicine is a two-state, three-campus professional school operated by the land-grant universities of Virginia Tech in Blacksburg and the University of Maryland at College Park. In addition to the main campus installation at Virginia Tech, the College also operates the Avrum Gudelsky Veterinary Center at College Park, and the Marion duPont Scott Equine Medical Center in Leesburg.

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Browsing Virginia-Maryland College of Veterinary Medicine (VMCVM) by Author "Abbott, Jonathan A."

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    Comparison of the mitral valve morphologies of Cavalier King Charles Spaniels and dogs of other breeds using 3D transthoracic echocardiography
    Menciotti, Giulio; Borgarelli, Michele; Aherne, Michael; Camacho, Paula; Haggstrom, Jens; Ljungvall, Ingrid; Lahmers, Sunshine M.; Abbott, Jonathan A. (Wiley, 2018-09-01)
    Background: Myxomatous mitral valve disease (MMVD) is more prevalent in Cavalier King Charles Spaniels (CKCSs) compared to dogs of other breeds at a given age. Abnormal valvular stress is thought to contribute to the development and progression of MMVD, and a relationship exists between mitral valve (MV) morphology and stress acting on the valve. Objectives: To determine whether the MV morphology of healthy adult CKCSs differs from the morphology of healthy adult dogs of other breeds determined by RT-3DTTE. Animals: Thirty-five healthy CKCSs and 41 healthy dogs of other breeds. Methods: Prospective cross-sectional study. Dogs underwent physical examination, conventional echocardiography, and RT-3DTTE. RT–3DTTE datasets were analyzed using dedicated software for MV morphologic analysis. Morphologic variables were compared between CKCSs and dogs of other breeds. Results: The MV of healthy CKCSs had a smaller annulus height (0.46 ± 0.11 vs. 0.56 ± 0.17; P =.0021), tenting height (0.26 ± 0.12 vs. 0.42 ± 0.18; P <.001), tenting area (0.42 ± 0.15 vs. 0.79 ± 0.34; P <.001), normalized tenting volume (0.09 [0.05–0.13] vs. 0.14 [0.10–0.20]; P <.001), and normalized area of the posterior leaflet (0.57 ± 0.15 vs. 0.66 ± 0.18; P =.016) compared to healthy dogs of other breeds; this results in CKCSs having a flatter MV with reduced tenting, compared to the MV of other breeds. Conclusions and Clinical Importance: These morphologic features could confer a mechanical disadvantage and play a role in the predisposition of CKCSs to the early development of MMVD.
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    Echocardiographic and electrocardiographic evaluation of North American Irish Wolfhounds
    Tyrrell, William D., Jr.; Abbott, Jonathan A.; Rosenthal, Steven L.; Dentino, Mariellen; Abrams, Frances (2020-03)
    Background Cardiac disease is an important cause of morbidity and mortality in Irish Wolfhounds (IWs), but its prevalence and clinical characteristics in North American IWs are incompletely described. Hypothesis/Objectives That atrial fibrillation (AF) is a diagnostic marker of echocardiographic abnormalities, and that clinical characteristics predict development of IW cardiomyopathy (IWCM). To define the prevalence of arrhythmias and echocardiographic abnormalities in North American IWs. Animals Six hundred and forty-five adult IWs presented for screening examinations intended to identify familial cardiac disease. Methods In this retrospective cohort study, reference intervals defined based on echocardiographic data from IW classified as normal, were used to define the prevalence of structural and functional abnormalities. A logistic model was developed to identify clinical findings that predict future development of IWCM. Results The prevalence of AF was 8.9% (95% confidence interval [CI], 6.6-11.2) of which 55.5% had echocardiographic abnormalities. IWCM defined by left atrial enlargement, left ventricular dilatation, and systolic dysfunction had a prevalence of 1.8% (0.72-2.8). Positive and negative likelihood ratios for AF in the identification of IWCM were, respectively, 10.8 (7.29-16) and 0.2 (0.06-0.69). Multivariable logistic regression identified AF (odds ratio [OR]; 10.6, 95% CI, 2.67-42.3) and male sex (OR; 3.8, 95% CI, 1.02-14) as predictors of future development of IWCM. Conclusions and Clinical Importance Atrial fibrillation is common in North American IW. It occurs in association with structural cardiac disease but also in its absence. Irish Wolfhounds cardiomyopathy is characterized by chamber enlargement but minimally decreased ejection phase indices of myocardial function. Atrial fibrillation is a risk factor for future development of IWCM.
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    Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study-A Randomized Clinical Trial
    Boswood, Adrian; Haggstrom, Jens; Gordon, Sonya G.; Wess, G.; Stepien, R. L.; Oyama, Mark A.; Keene, Bruce W.; Bonagura, John; MacDonald, Kristin A.; Patteson, M.; Smith, S.; Fox, P. R.; Sanderson, Karen; Woolley, Richard; Szatmari, Viktor; Menaut, Pierre; Church, Whitney M.; O'Sullivan, M. Lynne; Jaudon, J-P; Kresken, Jan-Gerd; Rush, J.; Barrett, K. A.; Rosenthal, S. L.; Saunders, Ashley B.; Ljungvall, Ingrid; Deinert, Michael; Bomassi, Eric; Estrada, Amara H.; Fernandez Del Palacio, Maria J.; Moise, N. Sydney; Abbott, Jonathan A.; Fujii, Yoko; Spier, Alan; Luethy, Michael W.; Santilli, Roberto A.; Uechi, Masami; Tidholm, Anna; Watson, P. (American College of Veterinary Internal Medicine, 2016-11)
    Background: Pimobendan is effective in treatment of dogs with congestive heart failure (CHF) secondary to myxomatous mitral valve disease (MMVD). Its effect on dogs before the onset of CHF is unknown. Hypothesis/Objectives: Administration of pimobendan (0.4-0.6 mg/kg/d in divided doses) to dogs with increased heart size secondary to preclinical MMVD, not receiving other cardiovascular medications, will delay the onset of signs of CHF, cardiac-related death, or euthanasia. Animals: 360 client-owned dogs with MMVD with left atrial-to-aortic ratio >= 1.6, normalized left ventricular internal diameter in diastole >= 1.7, and vertebral heart sum >10.5. Methods: Prospective, randomized, placebo-controlled, blinded, multicenter clinical trial. Primary outcome variable was time to a composite of the onset of CHF, cardiac-related death, or euthanasia. Results: Median time to primary endpoint was 1228 days (95% CI: 856-NA) in the pimobendan group and 766 days (95% CI: 667-875) in the placebo group (P = .0038). Hazard ratio for the pimobendan group was 0.64 (95% CI: 0.47-0.87) compared with the placebo group. The benefit persisted after adjustment for other variables. Adverse events were not different between treatment groups. Dogs in the pimobendan group lived longer (median survival time was 1059 days (95% CI: 952-NA) in the pimobendan group and 902 days (95% CI: 747-1061) in the placebo group) (P = .012). Conclusions and Clinical Importance: Administration of pimobendan to dogs with MMVD and echocardiographic and radiographic evidence of cardiomegaly results in prolongation of preclinical period and is safe and well tolerated. Prolongation of preclinical period by approximately 15 months represents substantial clinical benefit.
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    Longitudinal Analysis of Quality of Life, Clinical, Radiographic, Echocardiographic, and Laboratory Variables in Dogs with Preclinical Myxomatous Mitral Valve Disease Receiving Pimobendan or Placebo: The EPIC Study
    Boswood, Adrian; Gordon, Sonya G.; Haggstrom, Jens; Wess, G.; Stepien, R. L.; Oyama, Mark A.; Keene, Bruce W.; Bonagura, John; MacDonald, Kristin A.; Patteson, M.; Smith, S.; Fox, P. R.; Sanderson, Karen; Woolley, Richard; Szatmari, Viktor; Menaut, Pierre; Church, Whitney M.; O'Sullivan, M. Lynne; Jaudon, J-P; Kresken, Jan-Gerd; Rush, J.; Barrett, K. A.; Rosenthal, S. L.; Saunders, Ashley B.; Ljungvall, Ingrid; Deinert, Michael; Bomassi, Eric; Estrada, Amara H.; Fernandez Del Palacio, Maria J.; Moise, N. Sydney; Abbott, Jonathan A.; Fujii, Yoko; Spier, Alan; Luethy, Michael W.; Santilli, Roberto A.; Uechi, Masami; Tidholm, Anna; Schummer, Christoph; Watson, P. (American College of Veterinary Internal Medicine, 2018-01)
    Background: Changes in clinical variables associated with the administration of pimobendan to dogs with preclinical myxomatous mitral valve disease (MMVD) and cardiomegaly have not been described. Objectives: To investigate the effect of pimobendan on clinical variables and the relationship between a change in heart size and the time to congestive heart failure (CHF) or cardiac-related death (CRD) in dogs with MMVD and cardiomegaly. To determine whether pimobendan-treated dogs differ from dogs receiving placebo at onset of CHF. Animals: Three hundred and fifty-four dogs with MMVD and cardiomegaly. Materials and Methods: Prospective, blinded study with dogs randomized (ratio 1:1) to pimobendan (0.4-0.6 mg/kg/d) or placebo. Clinical, laboratory, and heart-size variables in both groups were measured and compared at different time points (day 35 and onset of CHF) and over the study duration. Relationships between short-term changes in echocardiographic variables and time to CHF or CRD were explored. Results: At day 35, heart size had reduced in the pimobendan group: median change in (D) LVIDDN -0.06 (IQR: -0.15 to +0.02), P < 0.0001, and LA: Ao -0.08 (IQR: -0.23 to +0.03), P < 0.0001. Reduction in heart size was associated with increased time to CHF or CRD. Hazard ratio for a 0.1 increase in DLVIDDN was 1.26, P - 0.0003. Hazard ratio for a 0.1 increase in DLA: Ao was 1.14, P = 0.0002. At onset of CHF, groups were similar. Conclusions and Clinical Importance: Pimobendan treatment reduces heart size. Reduced heart size is associated with improved outcome. At the onset of CHF, dogs treated with pimobendan were indistinguishable from those receiving placebo.
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    Measurement Variation and Repeatability of Echocardiographic Variables Used to Estimate Pulmonary Artery Pressure in Dogs
    Abbott, Jonathan A.; Gentile-Solomon, J. M. (American College of Veterinary Internal Medicine, 2017-11)
    Background: Pulmonary hypertension (PH) is an important clinical entity in dogs. Pulmonary hypertension is generally identified based on echocardiographic findings, but measurement variation of the variables most often used in this context has not been reported. Objective: To define measurement variation of echocardiographic variables that are used to estimate pulmonary artery pressure. Animals: Four dogs with subclinical tricuspid valve regurgitation were selected from a hospital population. Methods: Prospective descriptive study - dogs were subject to repeated echocardiographic examination by 2 operators. Each dog was echocardiographically examined 12 times, once by each operator during mornings and afternoons of 3 nonconsecutive days. Measurement variation was defined by coefficients of variation and by mean square errors (MSE) from ANOVA models. Repeatability coefficients (RC) were calculated from MSE. Results: Of 50 within-day, between-day, and interoperator coefficients of variation (CVs), 37 were less than 10% and 46 were less than 15%. The range of peak velocity of tricuspid valve regurgitation (VTR) V-TR was 1.87-3.34 m/s. Analysis of variance revealed a significant effect (P < 0.05) of operator for 7 of 10 measurements. Within-operator/between-day/withinsubject and between-operator/between-day/within-subject RCs of V-TR were, respectively, 0.3 and 0.6 m/s. Conclusions and Clinical Importance: With regard to repeatability, VTR is superior to other methods used for echocardiographic estimation of systolic pulmonary artery pressure. When TR is absent, the acceleration time of pulmonary ejection and the acceleration-to-ejection time ratio are alternative measures. A change in V-TR exceeding 0.3 m/s might be outside the range of expected within-operator variation.
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    Prevalence and Prognostic Importance of Pulmonary Hypertension in Dogs with Myxomatous Mitral Valve Disease
    Borgarelli, Michele; Abbott, Jonathan A.; Braz-Ruivo, L.; Chiavegato, D.; Crosara, S.; Lamb, K.; Ljungvall, Ingrid; Poggi, M.; Santilli, Roberto A.; Haggstrom, Jens (American College of Veterinary Internal Medicine, 2015-03)
    BackgroundPulmonary hypertension (PH) is common in dogs with myxomatous mitral valve disease (MMVD) but its effect on clinical outcome has not been investigated. Hypothesis/objectivesThe presence of PH worsens the outcome in dogs with MMVD. To compare survival times of dogs with MMVD and PH to those without PH. AnimalsTwo hundred and twelve client-owned dogs. MethodsCase review study. Medical records of dogs diagnosed with ACVIM stage B2 and C MMVD between January 2010 and December 2011 were retrospectively reviewed. Long-term outcome was determined by telephone interview or from the medical record. End of the observation period was March 2013. PH was identified if tricuspid regurgitation peak velocity was >3m/s. ResultsTwo hundred and twelve were identified. Eighty-three dogs (39%) had PH. PH was more commonly identified in stage C compared to B2 (P<.0001). One hundred and five (49.5%) dogs died during the observation period. Median survival time for the entire study population was 567days (95% CI 512-743). Stage C (P=.003), the presence of PH (P=.009), left atrial to aortic root ratio (LA/Ao) >1.7 (P=.0002), normalized left-ventricular end-diastolic diameter (LVEDn) >1.73 (P=.048), and tricuspid regurgitation pressure gradient (TRPG) >55mmHg (P=.009) were associated with worse outcomes in the univariate analyses. The presence of TRPG >55mmHg (HR 1.8 95% CI 1-2.9; P=.05) and LA/Ao>1.7 (HR 2 95% CI 1.2-3.4; P=.01) remained significant predictors of worse outcome in the multivariate analysis. Conclusions and Clinical ImportanceIn dogs with MMVD, moderate to severe PH worsens outcome.
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    Temporal changes in clinical and radiographic variables in dogs with preclinical myxomatous mitral valve disease: The EPIC study
    Boswood, Adrian; Gordon, Sonya G.; Haggstrom, Jens; Vanselow, Martin; Wess, Gerhard; Stepien, Rebecca L.; Oyama, Mark A.; Keene, Bruce W.; Bonagura, John; MacDonald, Kristin A.; Patteson, Mark; Smith, Sarah; Fox, Philip R.; Sanderson, Karen; Woolley, Richard; Szatmari, Viktor; Menaut, Pierre; Church, Whitney M.; O'Sullivan, M. Lynne; Jaudon, Jean-Philippe; Kresken, Jan-Gerd; Rush, John; Barrett, Kirstie A.; Rosenthal, Steven L.; Saunders, Ashley B.; Ljungvall, Ingrid; Deinert, Michael; Bomassi, Eric; Estrada, Amara H.; Fernandez Del Palacio, Maria J.; Moise, N. Sydney; Abbott, Jonathan A.; Fujii, Yoko; Spier, Alan; Luethy, Michael W.; Santilli, Roberto A.; Uechi, Masami; Tidholm, Anna; Schummer, Christoph; Watson, Philip (2020-02)
    Background The Evaluation of pimobendan in dogs with cardiomegaly caused by preclinical myxomatous mitral valve disease (EPIC) study monitored dogs with myxomatous mitral valve disease (MMVD) as they developed congestive heart failure (CHF). Objectives To describe the changes in clinical and radiographic variables occurring as dogs with MMVD and cardiomegaly develop CHF, compared to similar dogs that do not develop CHF. Animals One hundred and thirty-five, and 73 dogs that did or did not develop CHF, respectively. Materials and methods The following variables were evaluated in 2 groups of dogs (dogs that did or did not develop CHF): Heart rate (HR), clinic respiratory rate (RR), home-measured resting respiratory rate (RRR), rectal temperature (RT), body weight (BW), and vertebral heart sum (VHS). Absolute value and rate of change of each variable were calculated for each day a dog was in study. Daily means were calculated and plotted against time. The onset of CHF or last visit before leaving the study were set as reference time points. Results The most extreme values and rate of change occurred in variables immediately before onset of CHF. Vertebral heart sum increased earliest. Heart rate, RR, and RRR also increased. Rectal temperature and BW decreased. Increases in RR and RRR were most extreme and occurred immediately before CHF. Conclusions and Clinical Importance Dogs with MMVD and cardiomegaly experience increases in HR, RR, RRR, and VHS, and decreases in BW and RT as they develop CHF. The variables with highest absolute change and rate of change were RR and RRR. These findings reinforce the value of RR and RRR as indicators of impending or incipient CHF.