The long-term outcome and changes in tricuspid regurgitation pressure gradient in dogs diagnosed with pulmonary hypertension and Angiostrongylus vasorum infestation.

Objectives: Angiostrongylus vasorum (AV) is a metastrongylid parasite that has been associated with pulmonary hypertension (PH) in dogs. The objectives of the study were to describe the clinical presentation of dogs with AV and PH, document changes in tricuspid regurgitation maximum pressure gradient (TR Max PG) in subsequent months and years, record the survival to discharge and report the long-term survival of these dogs and factors associated with mortality.

Materials and methods: Data from client-owned dogs presenting to a teaching hospital between January 2007 and October 2023 with AV and PH were reviewed retrospectively. Signalment, presenting signs and echocardiographic reports were collected, and their survival to discharge noted. Date of death and loss of follow-up were recorded. Univariable analysis was used to assess the association of different factors on long-term survival.

Results: Twenty-eight cases were identified with concurrent PH and AV, commonly presented in respiratory distress. Tricuspid regurgitation, as measured by TR Max PG on echocardiography, resolved in 9 of 28 (32.1%) cases. Survival to discharge was favourable at 92.9% (26/28). The median duration of follow-up was 196 days. Survival time was documented, with 6 of 11 (54.5%) known dogs still alive at 2 years post discharge. Treatment with sildenafil (Viagra; Pfizer) was associated with longer survival time and increased age was associated with a shorter survival time. The presence of right-sided congestive heart failure was not associated with a shorter survival time.

Clinical significance: Dogs with AV infestation and PH can live for prolonged periods (>2 years).