Pulmonic Stenosis (PS)

Pulmonic stenosis is a congenital heart disease where the pulmonic valve (the valve protecting the artery which takes blood to the lungs) doesn't open properly. As a result, there is a narrowing which makes it more difficult for blood to flow to the lungs. This narrowing means the heart has to push blood with more pressure which leads to enlargement and thickening of the heart chamber (right ventricle). This can lead to weakness, collapse and fluid build-up (heart failure). 


Owner information sheet on PS

Balloon dilation (also called valvuloplasty) involves passing a specially designed catheter via a vein into the heart and across the narrowed pulmonic valve. We then inflate the balloon to stretch the defective valve and open up the artery, allowing blood to flow into the artery more easily. We then deflate and remove the balloon so nothing is left inside the heart.  We use dye (contrast) and pressure catheters to measure the size of the artery, degree of stenosis (narrowing) and to measure the change in pressure after stretching the valve. Sometimes we need to stretch the valve with several sizes of balloon to improve the blood flow. This is something we are very careful about, to minimise any damage to the heart. 

These X-rays show the balloon in place across the narrowed valve (red arrow). Once we have fully inflated the balloon, the valve is stretched open and blood can flow much more easily to the lungs, taking the pressure off the heart. 

The dent in the balloon on the left image shows the tight constriction created by the narrowed valve. 

To see a movie of an angiogram and a balloon dilatation visit us at: 


HeartVets is one of the few specialist centres in the UK to regularly perform balloon catheter operations. Thanks to the considerable experience of our team, our success rates are excellent and we expect good long-term results. 

The success rate of this operation is good, with approximately 90% of cases showing a significant clinical improvement following surgery.  Of course there are risks with this operation and sadly a small number of patients (<5 %) may not survive the procedure. 

Prior to referral for balloon dilatation of pulmonic stenosis

We prefer your pet to be on beta blockers for at least two weeks prior to the procedure and continue on them until the recheck with the cardiologist, typically 3-6 months after the operation.

Before recommending balloon valvuloplasty, our cardiologists need to do a thorough ultrasound scan (echo), to check confirm the diagnosis, look for other heart defects, and make the measurements needed to help plan the balloon procedure. Sometimes there are other heart problems which stop us advising surgery so it is vital we do this examination, even if the patient has been scanned previously. 


Long term management

It is important that a follow-up scan is done 3 to 6 months later, to see how the heart has changed after the operation. Typically we will then recommend further monitoring with an ultrasound scan every couple of years. 

If your pet has been diagnosed with pulmonic stenosis, ask your vet to contact us to discuss options for treatment. 

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