Objective—To determine the within-day and between-day variability of regurgitant fraction (RF) assessed by use of the proximal isovelocity surface area (PISA) method in awake dogs with degenerative mitral valve disease (MVD), measure RF in dogs with MVD, and assess the correlation between RF and several clinical and Doppler echocardiographic variables.
Animals—6 MVD-affected dogs with no clinical signs and 67 dogs with MVD of differing severity (International Small Animal Cardiac Health Council [ISACHC] classification).
Procedures—The 6 dogs were used to determine the repeatability and reproducibility of the PISA method, and RF was then assessed in 67 dogs of various ISACHC classes. Mitral valve regurgitation was also assessed from the maximum area of regurgitant jet signal-to-left atrium area (ARJ/LAA) ratio determined via color Doppler echocardiographic mapping.
Results—Within- and between-day coefficients of variation of RF were 8% and 11%, respectively. Regurgitation fraction was significantly correlated with ISACHC classification and heart murmur grade and was higher in ISACHC class III dogs (mean ± SD, 72.8 ± 9.5%) than class II (57.9 ± 20.1%) or I (40.7 ± 19.2%) dogs. Regurgitation fraction and left atriumto-aorta ratio, fractional shortening, systolic pulmonary arterial pressure, and ARJ/LAA ratio were significantly correlated.
Conclusions and Clinical Relevance—Results suggested that RF is a repeatable and reproducible variable for noninvasive quantitative evaluation of mitral valve regurgitation in awake dogs. Regurgitation fraction also correlated well with disease severity. It appears that this Doppler echocardiographic index may be useful in longitudinal studies of MVD in dogs.
Objective—To determine the intra- and interobserver variability of systolic arterial pressure (SAP) and diastolic arterial pressure (DAP) measurements obtained with 2 indirect methods in awake dogs and percentage of successful measurements.
Animals—6 healthy conscious adult dogs.
Procedures—4 observers with different levels of training measured SAP and DAP on 4 days by use of Doppler ultrasonography (DU) and high-definition oscillometry (HDO). The examinations were randomized. Measurements for each technique were recorded 5 consecutive times, and mean values (total, 720 measurements) were used for statistical analysis.
Results—All within- and between-day coefficients of variation (CVs) for SAP were < 15% irrespective of the observer or method (HDO, 3.6% to 14.1%; DU, 4.1% to 12.4%). Conversely, half the CVs for DAP were > 15% with the highest within- and between-day CVs obtained by the least experienced observer by use of DU (19.5% and 25.9%, respectively). All attempts with HDO were successful, whereas DAP could not be measured by use of DU by the least experienced observer in 17% of attempts.
Conclusions and Clinical Relevance—SAP may be assessed in healthy dogs by use of DU and HDO with good repeatability and reproducibility after a short period of training. Conversely, the variability of DAP is higher and longer training is required to assess DAP via DU than via HDO.
Objective—To determine the prevalence of Doppler echocardiography–derived evidence of pulmonary arterial hypertension (DEE-PAH) in dogs with mitral valve disease (MVD) classified according to the International Small Animal Cardiac Health Council (ISACHC) heart failure classification scheme and various echocardiographic and Doppler indices of MVD severity.
Design—Retrospective case series.
Animals—617 dogs examined from 2001 to 2005 with MVD in ISACHC classes I to III.
Procedures—Dogs were examined echocardiographically. Criteria used for systolic and diastolic DEE-PAH were detection of high tricuspid (≥ 2.5 m/s) and telediastolic pulmonic (≥ 2.0 m/s) valvular peak regurgitant jet velocities, respectively, by use of continuous-wave Doppler echocardiography.
Results—86 (13.9%) dogs with MVD had a diagnosis of DEE-PAH. Severity and prevalence of DEE-PAH increased with ISACHC class (3.0%, 16.9%, 26.7%, and 72.2% prevalences for ISACHC classes Ia, Ib, II, and III, respectively). A significant correlation between systolic or diastolic pulmonary arterial pressure and left atrial-to-aortic diameter ratio (LA/Ao) was detected. Doppler echocardiography–derived evidence of pulmonary arterial hypertension was detected in 18 dogs with values of LA/Ao within reference range, all of which had moderate (n = 2 dogs) or severe (16) mitral valve regurgitation on color Doppler imaging.
Conclusions and Clinical Relevance—The prevalence and degree of DEE-PAH were related to the severity of MVD. Changes associated with DEEPAH may be detected in early stages of the disease, but only in dogs with severe mitral valve regurgitation.