Aortic Valve Disease
The human heart has four valves which regulate the flow of blood through the heart in a forward direction.
The Aortic valve is situated at the junction between the heart (the left ventricle (main pumping chamber of the heart)) and the aorta (the blood vessel carrying blood out of the heart to the body). It has three leaflets which open and close with each heartbeat allowing blood to leave the heart and not leak back into it.
The aortic valve can be affected by two disease processes:
- Aortic valve stenosis,
- Aortic valve regurgitation.
In certain individuals the valve can become tight (stenotic), not opening as much as it should to permit blood to flow normally to the rest of the body.
The leaflets of the valve are replaced by calcium deposits resulting in a stiff, small valve. This is a gradual process which occurs over years and results in the symptoms of aortic stenosis.
Symptoms range from chest pain and shortness of breath to dizziness.
This is due to excessive strain placed on the heart to pump blood out of the heart through the small opening. Over the course of time the heart muscle becomes thick and stiff in order to generate higher pressures to push blood through the stenotic valve and at a certain period of time the heart goes into failure.
Some people are born with a small valve from birth (congenital aortic stenosis) which needs to be tackled in infancy or childhood.
In adults most cases of aortic stenosis are due to calcification in bicuspid aortic valves (where the valve has two leaflets), in some it occurs years following recovery from Rheumatic heart disease or due to calcification of the aortic valve as part of the ageing process – senile calcific aortic stenosis.
When the leaflets of the aortic valve do not close efficiently blood leaks back into the heart.
This causes an extra volume load on the heart causing it to enlarge and eventually fail over the course of time.
Symptoms of aortic regurgitation are shortness of breath more so on exertion, easy fatiguability and in late cases swelling of the legs due to fluid retention.
The causes can be due to a valve defect at birth, a bicuspid aortic valve that manifests later in life or from acute injury where the valve is torn as in an aortic dissection.
In addition there might be aortic regurgitation when the entire valve structure and aorta are diseased in certain individuals leading to aneurysm formation.
How is aortic valve disease diagnosed?
The symptoms along with a physical examination are most often enough to arrive at a diagnosis of aortic valve disease. The same is confirmed by an echocardiogram (ECHO – an ultrasound of the heart).
What treatment options exists for aortic valve disease?
Aortic stenosis once it reaches a certain severity can only be managed surgically by replacing the valve. There is no medical management for the same.
Aortic regurgitation in most cases is managed by valve replacement – in a few cases the valve can be repaired.
Do I need to undergo surgery for my valve disease and what are my options?
- Aortic valve disease is commonly treated by aortic valve replacement.
- Surgery involves removing the old, diseased valve and replacing it with a new one.
- Surgery can be performed in many different ways.
- Most surgeons use the traditional method of cutting the breastbone (sternum) to approach the heart to perform surgery.
- Currently a few centers offer the option of minimally invasive aortic valve replacement.
- The two options in this approach are either to cut a small part of the breast bone (instead of its entire length) – upper hemi sternotomy approach or to not cut the bone at all but to perform the operation by a small cut in between the ribs – right anterior thoracotomy approach.
- The advantage of these approaches is that the surgical trauma is lesser and return to normal life and physical activity is quicker.
- Patients who are considering a minimally invasive approach need to undergo certain investigations to determine if they are suitable for the surgery.
- The aortic valve can either be replaced with a mechanical valve – which is long lasting and is considered in younger patients. The only drawback is that the patients need to be on lifelong anticoagulation.
- Older patients and certain other patients in whom a blood thinner is contraindicated – a bioprosthetic valve is used. These last for a duration of 10-15 years in most patients following which a repeat surgery is needed to re-replace the valve.
What is transcatheter aortic valve replacement?
- This was a procedure initially approved for older patients who were too sick to undergo open heart surgery.
- In this operation the valve is replaced using a wire inserted through the groin. A new valve is passed over the wire and valve replacement iscarried out. It can be considered the least invasive of all the aortic valve replacements and is specifically used in those patients who are either too old, frail or have other conditions which place them at a prohibitive risk of aortic valve replacement.
- This procedure has gained acceptance the world over and is currently being utilised more and more even in those patients who are considered moderate risk for surgery in the Western world.
- This procedure is best done in those centers who perform a high volume of cases and have expertise in such procedures.