What is Pulmonic Stenosis?
Pulmonic stenosis is the failure of the pulmonic valve to open fully. As a result the blood flows through a narrowed canal and this obstruction leads to heart failure or weakness/collapse on exertion.
What does the operation involve?
Balloon dilatation (valvuloplasty) involves passing a specially designed catheter via the vein in the neck or back leg (‘keyhole’ surgery) into the heart and through the narrowed valve. This sausage-shaped balloon is then inflated to stretch the defective valve, allowing it to open more normally. It is then deflated and removed. A number of contrast studies (angiograms) and pressure measurements are performed before and after balloon dilatation to assess the effectiveness. If there is an inadequate response, then a larger balloon catheter is used (but remaining within pre-calculated size safety limits).
Other considerations prior to and following surgery
Prior to referral for balloon dilatation of pulmonic stenosis – we prefer your pet to be on beta blockers for a week or two prior to the procedure and continue on that for 6 months after.
Before recommending balloon dilatation, a thorough ultrasound scan by our cardiologist is necessary to check the severity of the stenosis, to what extent heart function is reduced and to obtain measurements to assist in the decision of what size balloon catheter is required, and also to double check for any other concurrent defects such as an abnormal coronary artery that would preclude such surgery. A follow-up scan by our cardiologist will be performed after surgery to measure the degree of success of the procedure.
What is the prognosis (outlook)?
North Downs Specialist Referrals is one of the few specialist centres in the UK to perform balloon catheter dilatation interventions. Due to our experience we have a good success rate and the long-term outcome is typically good. Anaesthesia is one area in which complications can arise, however we have a experience in anaesthesia of these complicated cases.
The success rate is good with approximately 90% of cases showing a significant clinical improvement following surgery. The procedure is not without risk and a small number of patients (approximately 5%) may not survive the procedure. Our cardiologists currently recommend pre-treating patients with beta blockers for some time before surgery, because in our experience this appears to minimise anaesthetic complications and can help alleviate heart muscle thickening.
A follow-up scan is important 6 to 12 months after surgery, and beta blockers should be continued until that time (unless advised otherwise). Thereafter, depending upon the severity, the defect needs to be regularly monitored by ultrasound scan every couple of years.
If you have any queries or concerns, please do not hesitate to contact us.