Transcatheter Aortic Valve Implantation (TAVI and also called TAVR) is a new option for the treatment of aortic stenosis that is suitable for patients who are too high-risk to undergo traditional surgery. TAVI is an innovative minimally invasive option for high-risk patients that has been carried out in increasing numbers around the world. St Andrew’s War Memorial Hospital became the first private hospital in Queensland to perform TAVI procedures in July 2015 and the program continues to attract a large number of referrals from across the state.
When you are referred for treatment of aortic stenosis, it's important to have a full team composed of several specialist teams engaged in your care. At St Andrew’s we combine the expertise of a collaborative Heart Team that includes some of the most experienced Interventional Cardiologists, Cardiothoracic Surgeons, general cardiologists, intensivists, Anaesthetists and Geriatricians. This team will conduct a thorough evaluation to determine whether you are an appropriate TAVI candidate.
The TAVI Procedure
Valvular Heart Disease
The heart is a muscle which pumps blood to your lungs and around the body. There are four valves within the heart. These valves normally open to let blood flow through the heart and then shut to prevent blood flowing backwards.
If a valve becomes diseased or damaged this can affect the flow of blood in two ways:
- If the valve does not open fully it will obstruct the flow. This is called valve stenosis.
- If the valve does not close properly it will allow blood to flow backwards in the wrong direction. This is called valve regurgitation.
Aortic Valve Stenosis
Aortic stenosis typically occurs in individuals greater than 65 years of age and involves progressive thickening and hardening of the leaflets (heart valve flaps) which restrict their opening when the heart contracts. This in turn can cause a thickening of the heart muscle and decrease the flow of blood to the body and coronary arteries (arteries which supply blood to the heart muscle).
The most common intervention for heart valve replacement is open-heart surgery. However, a less invasive way of performing the surgery has been developed where the valve replacement is done without open heart surgery known as Transcatheter Aortic Valve Implantation (TAVI). The majority of TAVI valves can be inserted via the femoral artery (the main artery at the top of your leg).
What does the TAVI procedure involve?
The procedure is usually done under a general anaesthetic. An anaesthetist will see you before the procedure and you will be anaesthetised before it starts. You will have a plastic tube called a sheath inserted into a large arterial blood vessel in your groin. This will allow catheters (thin tubes) to pass through your femoral (groin) artery to your heart.
A temporary pacing wire is inserted into a vein in your neck or leg and advanced to the right ventricle (pumping chamber of the right side of your heart), it is then connected to a temporary pacemaker (a small battery operated box, which can control heart rate). This is done to allow the Doctor to control your heart rate during deployment of the valve. The temporary pacing wire is typically removed during the procedure but in rare case may be left in for a few days.
A Transoesophageal Echocardiogram (TOE) probe may be passed through your mouth and positioned in your oesophagus. This imaging assists with guiding the procedure and assessing for complications. This is done whilst you are under general anaesthetic and you are not aware of any discomfort associated with the probe.
A thin tube with a balloon attached (balloon catheter) will then be placed within the narrowed aortic valve. The balloon will then be inflated to open the narrowed leaflets (heart valve flaps) of the valve, and the balloon removed. X-rays will be used to enable the doctors to see the exact position of the catheters and the valve.
The valve consists of a bovine (from a cow) heart valve that is fixed on a metal frame. This valve is mounted onto another balloon catheter and passed through the sheath in your groin and placed in your now freely moving but still diseased aortic valve.
As the balloon is inflated the new valve will be expanded to fit the opening of the diseased valve. The balloon catheter will then be deflated and removed, leaving the new valve in place. Your own diseased valve will not be cut or removed, it is simply pushed aside by the new prosthetic valve. The new valve will immediately start to function.
This new procedure differs from the standard treatment offered for patients requiring valve replacement because it involves the insertion of a valve through a catheter via a small puncture in your groin rather than standard treatment which is via open heart surgery and using a cardiopulmonary bypass machine to maintain the body’s blood circulation (being maintained by a machine outside the body). This avoids the need for open chest surgery and recovery is generally a lot easier on patients.
Additional detailed information on the procedure including videos can be found here.