The prevalence of pulmonary hypertension assessed using the pulmonary vein-to-right pulmonary artery ratio and its association with survival in West Highland white terriers with canine idiopathic pulmonary fibrosis

Abstract

Background: Pulmonary hypertension (PH) is a known co-morbidity in West Highland white terriers (WHWTs) affected with canine idiopathic pulmonary fibrosis (CIPF). The pulmonary vein-to-right pulmonary artery ratio (PV/PA) has recently been described for the detection of pre-capillary PH in dogs. The objective of the present study was to estimate the prevalence of PH at diagnostic, in WHWTs affected with CIPF, by using PV/PA, in comparison with a group of healthy breed-matched controls (CTRLs). Additional study objective was to explore whether the presence of PH at initial diagnosis of CIPF impacted survival time in dogs treated with sildenafil.

Results: Twenty-five client-owned WHWTs presented with CIPF and 19 CTRLs were included in the study. PV/PA in either two-dimensional mode (2D) or time-motion mode or both were measured from cineloops in each dog. Dogs were classified according to PV/PA value into non/mild PH (PV/PA measured in 2D ≥ 0.7) or moderate/severe PH (PV/PA < 0.7). Survival data of WHWTs affected with CIPF were extracted from medical record to assess association between presence of PH at diagnosis and outcome. 60 % overall prevalence for moderate/severe PH was estimated in this cohort of WHWTs presented with CIPF vs. 5 % in CTRLS (P = 0.0002). The presence of moderate/severe PH at initial presentation was not associated with survival.

Conclusions: Results of the present study confirm a high prevalence of PH at diagnosis in WHWTs affected with CIPF and highlight the utility of PV/PA as a non-invasive surrogate for assessment of PH in this population.

Keywords: Cardiac disease; Dog; Echocardiography; Pulmonary arterial pressure; Tricuspid regurgitation.

Fig. 1

Survival time in CIPF WHWTs with moderate to severe and none to mild PH. Kaplan-Meier curves to compare survival time in days from canine idiopathic pulmonary fibrosis (CIPF) diagnosis (x-axis) between West Highland white terriers (WHWTs) affected with CIPF with moderate to severe pulmonary hypertension (PH) (group 1) (pulmonary veinto-right pulmonary artery ratio (PV/PA) measured in two-dimensional mode (2D) < 0.7) and WHWTs affected with CIPF with none to mild PH (group 2) (PV/PA measured in 2D ≥ 0.7). CIPF-related mortality: moderate to severe PH median survival, 698 days; none to mild PH median survival, 733 days. Log-rank P-value of 0.528