Tomoya Morita1, Kensuke Nakamura2, Tatsuyuki Osuga1, Nozomu Yokoyama1, Keitaro Morishita2, Noboru Sasaki1, Hiroshi Ohta1, Mitsuyoshi Takiguchi1. 1. Department of Veterinary Clinical Sciences, Laboratory of Veterinary Internal Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan. 2. Department of Veterinary Clinical Sciences, Veterinary Teaching Hospital, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan.
Abstract
BACKGROUND: The assessment of hemodynamic change by echocardiography is clinically useful in patients with pulmonary hypertension. Recently, mild elevation of the mean pulmonary arterial pressure (PAP) has been shown to be associated with increased mortality. However, changes in the echocardiographic indices of right ventricular (RV) function are still unknown. The objective of this study was to validate the relationship between echocardiographic indices of RV function and right heart catheterization variables under a mild RV pressure overload condition. METHODS AND RESULTS: Echocardiography and right heart catheterization were performed in dog models of mild RV pressure overload induced by thromboxane A2 analog (U46619) (n=7). The mean PAP was mildly increased (19.3±1.1 mm Hg), and the cardiac index was decreased. Most echocardiographic indices of RV function were significantly impaired even under a mild RV pressure overload condition. Multivariate analysis revealed that the RV free wall longitudinal strain (RVLS), standard deviation of the time-to-peak longitudinal strain of RV six segments (RV-SD) by speckle-tracking echocardiography, and Tei index were independent echocardiographic predictors of the mean PAP (free wall RVLS, β=-0.60, P<.001; RV-SD, β=0.40, P=.011), pulmonary vascular resistance (free wall RVLS, β=-0.39, P=.020; RV-SD, β=0.47, P=.0086; Tei index, β=0.34, P=.047), and cardiac index (Tei index, β=-0.65, P<.001). CONCLUSIONS: Free wall RVLS, RV-SD, and Tei index are useful for assessing the hemodynamic change under a mild RV pressure overload condition.
BACKGROUND: The assessment of hemodynamic change by echocardiography is clinically useful in patients with pulmonary hypertension. Recently, mild elevation of the mean pulmonary arterial pressure (PAP) has been shown to be associated with increased mortality. However, changes in the echocardiographic indices of right ventricular (RV) function are still unknown. The objective of this study was to validate the relationship between echocardiographic indices of RV function and right heart catheterization variables under a mild RV pressure overload condition. METHODS AND RESULTS: Echocardiography and right heart catheterization were performed in dog models of mild RV pressure overload induced by thromboxane A2 analog (U46619) (n=7). The mean PAP was mildly increased (19.3±1.1 mm Hg), and the cardiac index was decreased. Most echocardiographic indices of RV function were significantly impaired even under a mild RV pressure overload condition. Multivariate analysis revealed that the RV free wall longitudinal strain (RVLS), standard deviation of the time-to-peak longitudinal strain of RV six segments (RV-SD) by speckle-tracking echocardiography, and Tei index were independent echocardiographic predictors of the mean PAP (free wall RVLS, β=-0.60, P<.001; RV-SD, β=0.40, P=.011), pulmonary vascular resistance (free wall RVLS, β=-0.39, P=.020; RV-SD, β=0.47, P=.0086; Tei index, β=0.34, P=.047), and cardiac index (Tei index, β=-0.65, P<.001). CONCLUSIONS: Free wall RVLS, RV-SD, and Tei index are useful for assessing the hemodynamic change under a mild RV pressure overload condition.