About Aortic Stenosis

Aortic Stenosis

‘Aortic stenosis’ means narrowing of the aortic valve, the valve through which blood leaves the heart and passes into the aorta. This is a common valve problem and although it has a number of causes, the commonest cause by far is ‘degenerative’ aortic stenosis ie. ‘wear and tear’. This therefore tends to occur in older people and it affects about 4% of those over 80 years old. The valve leaflets become thickened and stiff with fibrosis and calcium, thus creating an obstruction to heart (left ventricular) output. This puts a strain on the heart which is constantly having to work harder to pump blood out into the body.

Once aortic stenosis becomes severe, it causes symptoms of breathlessness, chest tightness and sometimes dizziness and these symptoms are usually much worse on physical exertion. By this stage the heart is working hard against the obstruction of the narrowed aortic valve and this is a serious situation with a poor prognosis unless treated.

INVESTIGATION OF AORTIC STENOSIS

There are a number of tests that you may undergo if a diagnosis of aortic stenosis is suspected:

 

1. Echocardiography – this is a detailed ultrasound of the heart which obtains pictures and measurements of the narrowed aortic valve. It involves an ultrasound probe being placed on your chest in a number of positions to get the best pictures and is completely non-invasive;
2. Trans-oesophageal echocardiography – this is sometimes necessary for a closer evaluation of the heart valves and involves an echo probe being passed into the oesophagus – similar to an endoscopy. This is done under sedation and is more involved than a standard echocardiogram;
3. Stress echo – Sometimes it helps the Cardiology team if we find out how your heart behaves on exercise. This test involves looking at your heart with an echo whilst you exercise – either on a treadmill or a static bicycle;
4. CT of the heart and aorta – this is a very important test to assess the size of the blood vessels in your body to see whether a TAVI valve can be used and assess which size/type of valve may be needed. This will involve X-rays from the CT scanner and an injection into a vein to administer a small amount of ‘contrast’ (dye) to show up the blood vessels.

 

 

TREATMENT OF AORTIC STENOSIS

There are two effective treatments for aortic stenosis:

 

1. Trans-catheter Aortic Valve Implantation (TAVI) 
2. Surgical Aortic Valve Replacement

 

Both of these procedures are now well established treatments done at high volume in the UK. They are procedures that are done in Cardiac Specialist Units and require a team of Specialists to perform. Your Cardiologist will be part of a specialist multidisciplinary ‘Heart Team’ which is comprised of Consultants from a number of disciplines (Cardiology, Cardiothoracic surgery, Anaesthetics, Care of the Elderly etc). This team will assess you and your investigations and advise you of the pro’s and con’s of each procedure and which is best in your particular case.

 

 

WHAT HAPPENS DURING A TAVI PROCEDURE

A TAVI is much less invasive than a surgical aortic valve replacement. The TAVI is done in the catheter laboratory or a variation of this, the so-called ‘hybrid lab’ which can double up as an operating theatre. There is a large mobile X-ray camera which moves around you and allows us to see where our catheters (tubes) are going and the table you lie on can also move. There are also several other machines in the room including an echo machine to allow us to use echo at various points in the procedure.

 

We try to avoid a full general anaesthetic if we can and use sedation – medications given to you by a Specialist Anaesthetist to keep you comfortable. The TAVI involves placing fine tubes (‘sheaths’) into the blood vessels in the groins and wrist (we usually need 2 or 3) after numbing the skin with local anaesthetic. When everything is ready, the TAVI valve is then passed through one of these sheaths and steered up the arteries to your narrowed aortic valve. We spend some minutes positioning the valve precisely within your narrowed aortic valve before we deploy the new valve, which stretches the old narrowed valve out of the way and forms a brand new valve within it.

 

TAVI valves are made of metallic frames, inside of which are valve leaflets made up of biological material (bovine or porcine) which have a long record of this type of use and work well for many years.

 

When the new TAVI valve is in place, the sheaths are removed and special suture devices are used to stop any bleeding. The whole procedure usually takes less than 1 hour and when we are happy that you are stable and comfortable, you are transferred back to the ward.

 

Read more

The following websites give additional information about the procedure:

 

1. https://www.bhf.org.uk/informationsupport/treatments/tavi
2. https://heartvalvevoice.com/heart-valve-disease/treatment
3. https://www.valveforlife.co.uk/transcatheter-heart-therapies

 

Learn more about deciding between Aortic Valve Surgery and TAVI:

1. American College of Cardiology CardioSmart Decision Aid
2. Choosing beween surgery, TAVI and symptom management