Doppler Echocardiographic Prediction of Pulmonary Hypertension in West Highland White Terriers with Chronic Pulmonary Disease

Background: Pulmonary hypertension (PH) is commonly diagnosed by Doppler echocardiography (DE) of tricuspid regurgitation (TR). However, TR may be absent or difficult to measure. Hypothesis: Doppler-derived systolic time intervals of pulmonary artery (PA) flow may be used to predict PH in dogs. Animals: Seventy-three healthy dogs and 45 West Highland white terriers (WHWT) with interstitial pulmonary disease (IPD). Methods: Echocardiographic studies, including determination of right ventricular acceleration time (AT), ejection time (ET), and AT:ET ratio; right ventricular shortening fraction (RV-SF); and TR velocity, were performed. Pulmonary hypertension was defined by TR > 3.1 m/s. Results: In healthy WHWT, AT (median, range) was 73 ms (53 to 104) and AT:ET was 0.40 (0.28 to 0.55). AT:ET was minimally affected by age (R2= 0.04, 95% confidence interval [CI] 0.01–0.07, P < .001) but not by heart rate, body weight, or RV-SF. In all WHWT with TR, AT and AT: ET were inversely related to calculated systolic PA pressure (R2= 0.52, 95% CI 0.42–0.62, P < .001 and R2= 0.36, 95% CI 0.29–0.42, P = .001). Clinical cutoffs to predict systolic PH were defined for AT (58 ms; sensitivity [Se] 88% and specificity [Sp] 80%) and AT:ET (0.31; Se 73% and Sp 87%). Conclusion and Clinical Importance: PH is common in WHWT with IPD. Analysis of right ventricular AT and AT: ET may be predictive of PH and should be particularly useful if TR is absent.