Keynote Message

Canine valvular pulmonic stenosis has been categorised based on the degree of leaflet thickening, leaflet fusion, and pulmonary artery hypoplasia. Dogs with mild and moderate disease have normal life expectancies but those with severe disease die prematurely. Balloon dilation is often successful in severe cases with thin fused leaflets, resulting in decreased clinical signs and increased life expectancy. Dogs with thickened, dysplastic valves and pulmonary artery hypoplasia show limited response to balloon dilation. Larger dogs may respond better to a double balloon technique and higher burst pressure/cutting balloons have been used. However, there is a subset of dogs that do not show a significant decrease in gradients. For these, implantation of a bare metal stent in the right ventricular outflow tract can relieve the obstruction. Case examples will be used to illustrate the procedure and discuss the medium-term outcome. However, the catheters required for stent implantation are large and a novel hybrid technique to implant the stent allowing the procedure to be performed in small dogs will be shown.

Key References

1.  Swift S, Sosa I Estrada, et al. Stent angioplasty for treatment of balloon resistant canine valvular pulmonic stenosis. Journal of Veterinary Internal Medicine. 2015;29:1263. DOI: 10.1111/jvim.13002.

2.  Locatelli C, Spalla I, Domenech O, et al. Pulmonic stenosis in dogs: survival and risk factors in a retrospective cohort of patients. Journal of Small Animal Practice. 2013;54:445–452. DOI: 10.1111/jsap.12113.

3.  Scansen BA, Kent AM, Cheatham SL, et al. Stenting of the right ventricular outflow tract in 2 dogs for palliation of dysplastic pulmonary valve stenosis and right-to-left intracardiac shunting defects. Journal of Veterinary Cardiology. 2014;16:205–214.

4.  Stafford Johnson M, Martin M, Edwards D, et al. Pulmonic stenosis in dogs: balloon dilation improves clinical outcome. Journal of Veterinary Internal Medicine. 2004;18:656–662. DOI: 10.1111/j.1939-1676.2004.tb02602.x.

5.  Bussadori C, De Madron E, Santilli R, et al. Balloon valvuloplasty in 30 dogs with pulmonic stenosis: effects of valve morphology and annular size on initial and one-year outcomes. Journal of Veterinary Internal Medicine. 2001;15:553–558. DOI: 10.1111/j.1939-1676.2001.tb01590.x.