Percutaneous Pulmonary Valve Implantation
Overview of the Benefits of the PPVI Procedure
There are a variety of congenital heart diseases that may require replacement of the pulmonary valve. These congenital heart conditions involve the Right Ventricular Outflow Tract (RVOT) which is the pathway for the blood to move from the right ventricle into the lungs.
The right ventricle is the muscular pumping chamber of the right side of the heart and is responsible for pumping blood to the lungs where it can pick up oxygen, then be passed to the left ventricle to be distributed to the body.
Two problems may occur in the right ventricular outflow tract; there may be narrowing (stenosis) or it may leak. Either of these problems may cause a variety of symptoms such as shortness of breath, palpitations (feeling your heart beating rapidly), and fainting. The right ventricle may become enlarged and the function may decline.
To make matters a little more complex, in some congenital heart diseases that were operated on babies or children, the right ventricular outflow tract may not have been replaced directly and instead had to be bypassed with a conduit. A conduit may be made of animal tissue in its entirety or can be made from a fabric tube with a biologic valve sewn within it. The problem with these conduits is that, eventually, they fail and require replacement.
Traditionally surgery has been used to remove these old dysfunctional conduits and place new ones. Repeat surgery carries some risk, but equally as important requires a significant amount of time to recover and feel yourself again. Repeated surgeries require a significant amount of time for recovery in the important years when people are being educated or early in their work lives.
For the last 10 years or so, we have been using percutaneous valves for people with conduits and to replace biologic valves placed at previous operations. We call this procedure percutaneous pulmonary valve implantation (PPVI). This procedure allows us to replace a leaking or narrowed conduit without surgery. It involves an interventional catheterization procedure where a vein in the leg or neck is used to advance a new valve, mounted on a balloon, to the site of the old conduit. When in position the balloon is inflated and the new valve is deployed.
Melody Transcatheter Pulmonary Valve
In using PPVI we hope to reduce the number of surgeries that are required during a person’s lifetime.
While PPVI technology has mainly been used for conduits, some patients who have native (i.e. their own) outflow tracts can also be treated. The reason why we can’t treat all native right ventricular outflow tracts is usually because of size, SIZE MATTERS! The largest percutaneous pulmonary valve is 29 mm. So, if your native outflow tract is large, surgery will be required.
What does this mean for me?
Benefits of PPVI in Reducing Number of Surgeries
If you require the replacement of your right ventricle-pulmonary artery conduit, there is a good chance we can rehabilitate it with a percutaneous pulmonary valve. If your conduit was placed when you were very small, rehabilitation may not be adequate. It may need to be replaced with open heart surgery.
Patients who have conduits should have follow up every 12-18 months with their adult congenital heart disease doctor. At that visit, your symptoms will be reviewed, usually an echocardiogram will be done, and you may be asked to have an exercise test or MRI of the heart. In speaking to you and reviewing your symptoms and tests your doctor will have a pretty good idea of when it is time to start considering pulmonary valve replacement. If you notice a change in your symptoms between visits which may include worsening shortness of breath, palpitations, or fainting, it is prudent to contact your adult congenital heart disease specialist.
We use criteria such as symptoms, exercise performance, your electrocardiogram, and complex measurements on the echocardiogram and MRI to determine when it is time. The safest thing to do, if you have complex congenital heart disease, is to see your doctor as recommended. For many people, life gets in the way at times, however it is critically important not to let things go. We want to keep your right ventricle in good shape, it needs to last your whole life! Not worth it to miss an important timing point that would suggest it is time for your valve to be replaced.
Symptoms: When do I need to replace my RVOT Conduit?
RVOT conduit dysfunction can be tolerated, but can lead to adverse effects on the chambers of the heart if left untreated. Some of the symptoms you may feel as a result of dysfunctional conduit are the following:
Reduced exercise performance or breathlessness with exertion
Chest discomfort with exertion
Irregular or rapid heartbeats
What happens to my RVOT Conduit over Time?
RVOT conduits serve to effectively connect your heart and lungs to improve blood flow in an otherwise obstructed or narrow pathway. RVOT conduits do not last forever and all, unfortunately, will degenerate with time. With time, conduits may narrow (become stenotic) or leak (become regurgitant).
Next Steps: Investigation Plan
If you have symptoms of pulmonary valve stenosis and/or regurgitation is suspected, your doctor will likely order a number of investigations to measure the severity of the stenosis/regurgitation, function of your heart, and exercise performance.
Some of these tests include:
Cardiopulmonary exercise test
Magnetic Resonance Imaging (MRI) of the heart
Computed Tomography (CT) scan of the heart
The Process in Determining if a PPVI is Suitable for You
Long Term Health Implications
Studies have demonstrated that almost 46% of patients require conduit replacement every 10 years. Usually, patients will undergo invasive surgery to have their conduits replaced, and thus experience multiple surgeries throughout their life time.
Multiple open heart surgeries - while beneficial - are invasive and have associated risks to the patient.
To reduce the number of open heart procedures you will require throughout your lifetime, PPVI is used to rehabilitate conduits and increase the time between operations.
Treatment Options for RVOT Dysfunction
Percutaneous pulmonary valve implantation (PPVI) has been developed to provide a safe and effective alternative to surgical reconstruction of the right ventricular outflow tract (RVOT). This approach is considered as a primary strategy when patients have a degenerated conduit or biologic valve of an adequate size. In some patients whose last conduit was placed as a child, by the time the conduit is due for replacement, the patient may have grown so much, that even if this size conduit was brand new it would be too small. In that case, surgery is usually a preferred option.
PPVI is a minimally invasive approach to reduce the need for open-heart surgery. You will be asleep, under general anesthesia for the procedure. A catheter is inserted into a blood vessel of your leg or neck and guided to your heart using X-ray imaging. Angiograms (x ray pictures) of the the RVOT will be taken in different projections. Your doctor may start by using a soft balloon to measure the internal size of the conduit. The next step is to exclude an important potential issue. In about 6% of patients with conduits, the coronary arteries (the arteries that directly serve the heart muscle) are very close by. A balloon will be inflated in the conduit which is the final size of the valve that will be implanted. Simultaneously x ray dyes will be injected in the coronary arteries to make sure there is no risk of compressing them. Once this is done, the next step will be to place a stent within your conduit. This will help make sure that the conduit is well scaffolded and is free of any obstruction. The last step is to advance and position the percutaneous pulmonary valve, inflate the balloon it is mounted on, and deploy it. In some patients (about 5-10%) it may be difficult to get the valve to the spot through the leg and an attempt through the neck may be required.
Usually we will monitor people in the hospital overnight and they can be discharged the very next day or two. This is a significant improvement from the amount of recovery time needed after open-heart surgery. A follow-up visit with your cardiologist should be booked in 2-3 months time. We advise that patients take aspirin or an equivalent medication lifelong after the valve implantation.
Dr. Eric Horlick Explaining the PPVI Procedure
Frequently Asked Questions
Are there any lifestyle restrictions following PPVI?
In general there are no lifestyle restrictions, however activities such as contact sports should be avoided.
Will I need any further treatments following treatment?
Your cardiologist will provide full written guidelines in terms of activities and medications. It is important to follow these guidelines, and adhere to the prescriptions. A follow-up appointment will be scheduled 2-3 months post procedure to ensure a safe and smooth recovery. At that visit you will have an echocardiogram to monitor the device that has been placed and the progress your heart has made in returning to normal. You will likely have annual or biannual follow-ups of your health at the Toronto General Hospital.
Can I play sports?
Yes you can play sports, however it is advisable to utilize common sense - for example, contact-sports should be avoided.
Can a PPVI be redone?
Yes, as long as there is enough space left in the conduit. If you start out with a large conduit there is usually space for at least 2 valves inside
Will OHIP (public insurance) cover my procedure?
Yes. OHIP fully covers the cost of the procedure.
How urgent is the treatment?
Once a decision is made to proceed, we would like to try to arrange for the procedure over the coming 1-2 months.
Who is a candidate for PPVI in Ontario?
Once our team has reviewed all of your information we will make a recommendation as to what we feel is best and will discuss our rationale with you. We have decided that having our whole team review every case is the safest way to make decisions with the benefit of multiple disciplines present.
When is surgery preferable to intervention?
If a percutaneous intervention is possible we usually lean this way. The best we can achieve, is the original size of the conduit. If a patient has a conduit that is too small for their body size, we usually advise surgery unless the risk is very high. In some situations we believe that although the conduit needs to be fixed, there are also other surgical problems that need to be addressed and surgery is the best option.