2016 ACVIM Forum Research Abstract Program

Signalment data including age, sex, and weight were not significantly different in dogs diagnosed with AT compared to dogs not diagnosed with AT. Dogs with AT were commonly diagnosed concurrently with PLN. Contrary to previous reports, cardiac disease was not a common concurrent diagnosis in the dogs with AT included in this study. The function of right ventricle (RV) has gained increased recognition over the past years. In pulmonary hypertension (PH) patients, this led to the reconceptualization of the RV as part of right ventricular pulmonic circulation unit and the acknowledgement that RV function is a major determinant of prognosis in pulmonary arterial hypertension. With this in mind, we sought to investigate the RV systolic function in dogs with post-capillary PH ascribed to mitral valve disease (MVD). Twenty nine dogs with PH (2.5-17.2 kg; 7-15 years) and 51 dogs without PH (1.5-32.0 kg; 2-16 years) were recruited into this prospective cross-sectional observational study. The PH group was subdivided into mild PH (n = 19), moderate PA (n = 6), and severe PH (n = 4). Several breeds were represented. All animals underwent a complete echocardiogram, which included the measurement of RV fractional area change (RV FAC); tricuspid annular plane systolic excursion (TAPSE); RV free-wall longitudinal systolic velocity (tricuspid annular S´wave), and RV fractional shortening (RV FS % ). For improved statistical analysis and normalization of data according to animal size, a body weight-indexed TAPSE (TAPSE BW-indexed ) was created. Some standard echocardiographic indices of congestion and LV function, including early-to-late LV filling velocities ratio (E/A), isovolumic relaxation time (IVRT), E-to-IVRT ratio (E/IVRT), left atrium-to-aorta ratio (LA/Ao), and LV fractional shortening (LV FS % ) were recorded as well. The data was not normally distributed. The Mann-Whitney test showed no differences (P > 0.05) to exist for RV FAC, RV FS % , TAPSE, TAPSE BWindex , and tricuspid annular S´wave between dogs with PH and those without PH. Also, the analysis of the subdivided PH group showed no statistical difference between the three degrees of PH. Spearman correlation coefficients between RV systolic data and LV indices of congestion and function showed a significant positive correlation between TAPSE and E/IVRT (R = 0.3917, P = 0.0003), TAPSE and LA/Ao (R = 0.3298, P = 0.0029), and TAPSE BW-indexed and LV FS% (R = 0.2757, P = 0.0166). Finally, a significant positive correlation was documented between RV FAC and RV FS % (R = 0.3507, P = 0.0100), as well as between TAPSE and tricuspid annular S´wave (R = 0.4575, P < 0.0001). Because only a few animals with severe PH were recruited into this study, the absence of association between the severity of PH and the identification of RV systolic impairment needs further investigation. Nevertheless, we observed a downward trend for RV FS %, TAPSE, TAPSE BW-indexed , and tricuspid annular S´wave along with the aggravation of PH. Our study found correlations between a few congestion and LV function parameters, which may prove useful in monitoring RV function in dogs with severe MVD and overt signs of post-capillary PH. Since the majority of PH cases were mild, it is likely that only a few had reactive PH, which may explain why RV function of either group behaved very similarly. Also, it is not clear whether RV remodeling and impairment would be stronger if pre-capillary PH dogs had been included in this inves