Right and left heart morphology and function in dogs with compensated chronic right ventricular pressure overload secondary to pulmonic stenosis or precapillary pulmonary hypertension.

Abstract

OBJECTIVE: The study objective was to compare right and left heart morphology and function in dogs with compensated chronic right ventricular (RV) pressure overload secondary to pulmonic stenosis (PS) and chronic precapillary pulmonary hypertension (cPCPH). ANIMALS AND PROCEDURE: This cross-sectional observational retrospective study included 64 client-owned dogs, including healthy controls (= 15) and groups with PS (= 31) and cPCPH (= 18). The RV pressure gradient (RVPG) was determined by peak pulmonic or peak tricuspid regurgitation velocity and needed to be > 55 mmHg. Echocardiographic parameters assessing RV size [indexed diameter (RVIDd/Ao), area (N-RVAd) in diastole], hypertrophy [(RVFWd/LVFWd), (RVFWd/RVIDd)], and systolic function [fractional area change (RVFAC), indexed area in systole (N-RVAs)] were documented. Interventricular septal flattening was assessed using left ventricular (LV) eccentricity index (EI). RESULTS: The RVPG was lower in cPCPH compared to PS [91 mmHg (55 to 158 mmHg) vs 108 mmHg (56 to 219 mmHg);= 0.022]. The cPCPH group displayed more dilated [RVID/Ao: 0.13 (0.09 to 0.25) vs 0.10 (0.07 to 0.19),= 0.004; N-RVAd: 1.17 (0.65 to 1.66) vs 0.83 (0.45 to 1.45),= 0.010] and less hypertrophied RV [RVFWd/LVFWd: 0.9 (0.44 to 1.4) vs 1.0 (0.75 to 2.0),< 0.020; RVFWd/RVIDd: 0.30 (0.19 to 0.55) vs 0.44 (0.24 to 0.67),< 0.001], RV with poorer systolic function [N-RVAs: 0.69 (0.27 to 1.23) vs 0.35 (0.16 to 0.92),= 0.001; RVFAC: 0.37 (0.14 to 0.66) vs 0.57 (0.29 to 0.71),= 0.004], and more interventricular septal flattening [EIs:1.5 (1.09 to 5.71) vs 1.22 (0.88 to 2.1),= 0.013] compared to PS. The RVID/Ao, N-RVAd, N-RVAs, RVFAC, RVFWd/RVIDd, and EIs were influenced by RVPG and the cause of RV pressure overload (independent of RVPG). Tricuspid regurgitation was more commonly observed in dogs with cPCPH. CONCLUSION AND CLINICAL RELEVANCE: After adjusting for RVPG, dogs with PS had less RV dilation, better RV function, and less left heart compromise compared to dogs with cPCPH.