Utility of tricuspid annular plane systolic excursion normalized by right ventricular size indices in dogs with postcapillary pulmonary hypertension

BACKGROUND: Tricuspid annular plane systolic excursion (TAPSE) is a common right ventricular (RV) function indicator. However, TAPSE was not decreased in dogs with myxomatous mitral valve disease (MMVD) and postcapillary pulmonary hypertension (PH) because of its load, angle, and body weight dependency, and TAPSE was considered a preload‐dependent index. OBJECTIVES: To evaluate the utility of TAPSE normalized by RV size in dogs with postcapillary PH. ANIMALS: Twenty healthy dogs and 71 MMVD dogs with or without PH. METHODS: In this prospective observational study, end‐diastolic RV internal dimension (RVIDd), end‐diastolic and end‐systolic RV area, and end‐diastolic RV wall thickness were measured as RV size indices. The TAPSE was measured using B‐mode and M‐mode methods. Normalized TAPSE was calculated by dividing TAPSE by each RV size index. The RV strain was obtained as the detailed RV function using 2‐dimensional speckle tracking echocardiography. All indices were compared among the PH severity groups and in the presence of right‐sided congestive heart failure (R‐CHF). RESULTS: Although nonnormalized TAPSE was higher with PH severity progression, each normalized TAPSE showed a significant decrease in the severe PH group (P < .05). The TAPSE(B‐mode)/RVIDd ratio had high area under the curve to predict R‐CHF and had moderate correlation with RV strain (P < .05). The TAPSE(B‐mode)/RVIDd and left atrial‐to‐aortic diameter ratios were independent predictors for R‐CHF. CONCLUSIONS AND CLINICAL IMPORTANCE: Normalized TAPSE could reflect RV systolic dysfunction in dogs with severe PH, which could not be detected by nonnormalized TAPSE. The TAPSE(B‐mode)/RVIDd ratio might predict R‐CHF with high sensitivity and reproducibility.