Outcomes after combined percutaneous balloon valvuloplasty and external beam radiation therapy for the treatment of congenital pulmonic stenosis in four dogs

Repeat balloon valvuloplasty for dogs with recurrent or persistent pulmonary stenosis

INTRODUCTION/OBJECTIVES

Pulmonary stenosis (PS) is a common congenital defect in the dog. Severe valvar PS can be treated with balloon valvuloplasty (BV) to reduce obstruction severity and improve clinical signs. Repeat BV is often unnecessary, as restenosis is uncommon. Repeated pulmonary BV in people is generally successful and safe, but outcomes in dogs with recurrent or persistent stenosis have not been reported. The objectives of this study were to retrospectively evaluate outcomes of repeat BV in dogs.

ANIMALS, MATERIALS, AND METHODS

Medical records and stored echocardiographic images were reviewed from dogs that received repeat BV for pulmonary valvar restenosis or persistent stenosis. Echocardiographic variables included maximum systolic ejection velocity (PVmax), velocity-derived maximal pressure gradient (PGmax) and velocity time integral (VTI) across the pulmonary valve, and ratios of pulmonic to aortic maximum velocity (PVmax/AVmax) and VTI (VTI_PV/VTI_AV).

RESULTS

Twenty-three dogs were included; one underwent three BV procedures. The median time between BV procedures was 18.3 months (interquartile range, 6.3-43.6). One dog died during repeat BV, but no others experienced adverse effects. Reductions in PVmax, PGmax, and VTI_PV after initial and repeat BV were 1.85 m/s, 76.2 mmHg, and 44.7 cm and 1.33 m/s, 55.6 mmHg, and 30.2 cm, respectively (all p < 0.01). Differences between pre-BV and post-BV PVmax, PGmax, VTI_PV, PVmax/AVmax, and VTI_PV/VTI_AV were not different comparing initial to repeat BV (all p > 0.10).

CONCLUSIONS

Repeat BV for recurrent or persistent PS is well tolerated and effective in a majority of dogs.