Sildenafil citrate therapy in 22 dogs with pulmonary hypertension.
BACKGROUND
Pulmonary hypertension (PH) is a disease condition characterized by abnormally increased pulmonary artery pressures and often is associated with a poor prognosis. Sildenafil is a phosphodiesterase inhibitor that causes pulmonary arterial vasodilation and reduction in pulmonary artery pressures.


OBJECTIVE
Treatment with sildenafil will improve echocardiographic determinants of PH in dogs, while also improving quality of life and survival.


METHODS
Twenty-two dogs with clinical and echocardiographic evidence of pulmonary hypertension.


METHODS
A retrospective study evaluating the effects of sildenafil on physical examination, ECG and radiographic findings, blood pressure and echocardiographic findings of PH, clinical score, and outcome was completed. PH was defined as a peak tricuspid regurgitation flow velocity > or = 2.8 m/s or a peak pulmonic insufficiency flow velocity > or = 2.2 m/s.


RESULTS
Sixteen of 22 dogs with PH were elderly females of small body size. Their clinical score was significantly improved (P = .0003) with sildenafil treatment, but physical examination findings remained unchanged. Heart rate, respiratory rate, vertebral heart size, ECG heart rate, and systolic blood pressure did not change significantly with sildenafil treatment (P > .05). Peak tricuspid regurgitation flow velocities did not change significantly with the treatment of sildenafil, but selected systolic time intervals were significantly improved. Survival times for all dogs ranged from 8 to > 734 days.


CONCLUSIONS
Sildenafil did not significantly lower the degree of measurable PH in dogs. Clinical improvement and increased quality of life was seen with sildenafil treatment, despite lack of significant change in other variables.
Kellum
Heidi B
HB
Section of Cardiology, Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA. kellumh@svm.vetmed.wisc.edu
Stepien
Rebecca L
RL
D000818:Animals; D004285:Dogs; D005260:Female; D006976:Hypertension, Pulmonary / Q000188:drug therapy / Q000662:veterinary*; D008297:Male; D010879:Piperazines / Q000627:therapeutic use*; D011687:Purines / Q000627:therapeutic use; D012189:Retrospective Studies; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000627:therapeutic use*; D014665:Vasodilator Agents / Q000627:therapeutic use*
D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014665:Vasodilator Agents; D000068677:Sildenafil Citrate