The aortic valve lies between the left ventricle which is the main pumping chamber of the heart and the aorta which is the largest artery in the body that supplies all the organs with blood. If the aortic valve becomes narrowed or stenosed, the condition is called aortic stenosis. If the valve becomes leaky, the condition is known as aortic regurgitation.
When the aortic valve is stenosed, the blood flow through it is reduced and the heart has to work harder to pump blood to the body. It is more likely to occur in older people though can be present at birth.
Aortic stenosis is most commonly caused by age-related progressive calcification of a normal (trileaflet) valve, accounting for over 50% of cases. In younger patients, calcification of an abnormal (bicuspid) aortic valve since birth account for a quarter of cases. Rheumatic fever used to be a common cause of aortic stenosis but this is now much reduced in the Western world. The following diagram shows the position of the aortic valve in relation to the heart chambers and also what a diseased, stenosed aortic valve looks like.
Symptoms related to aortic stenosis depend on the degree of valve stenosis. In mild disease there may be no symptoms at all, or fatigue may be the only complaint. If the stenosis is moderate or severe, other symptoms may include chest pain, breathlessness especially on exertion, dizziness and losing consciousness. Palpitations and fainting episodes are also common complaints by patients. In advanced cases, heart failure can also develop resulting in shortness of breath and leg swelling.
While an ECG is helpful in determining if there is strain on the heart, echocardiography is the most suitable way of assessing the aortic valve anatomy and function. Technical measurements including the gradient across the valve and the opening area can also be determined by the echocardiogram. Any other coexistent valvular disease can be detected as can any deleterious effects on the heart muscle itself. Cardiac catherization performed in a very similar way to a coronary angiogram, can determine the pressures on either side of the aortic valve and also assess for co-existing coronary artery disease.
Usually while there are no symptoms and in mild to moderate cases of aortic stenosis, medical therapy to help reduce the work load of the heart will suffice. Routine assessment with echocardiography is recommended to monitor progression. In severe cases, aortic stenosis usually requires an operation called an aortic valve replacement. In certain circumstances it may be more appropriate to open the stenosed aortic valve with a balloon- this procedure is called balloon valvuloplasty. The need for this will be determined by your cardiologist.
Aortic regurgitation is when a leaking aortic valve causes blood to flow in the reverse direction when the heart is relaxed, from the aorta into the left ventricle which is the main pumping chamber of the heart.
The aortic valve can become leaky due to a problem with the valve itself or with the first part of the aorta called the aortic root. Approximately half of the causes of aortic regurgitation are due to this aortic root being dilated. The cause of the aortic root dilation is idiopathic in most cases but can otherwise result from high blood pressure, ageing or a weakness in the aortic wall. In bicuspid aortic valves (from birth) the aortic valve itself can become weaker. Connective tissue disorders such as Marfan's and ankylosing spondylitis are also associated with aortic regurgitation.
The symptoms are similar to those in heart failure- shortness of breath, fatigue and limb swelling. The breathlessness can be worse when lying down. Palpitations and chest pain may also be felt. Diagnosis is made in a similar way to aortic stenosis, with an echocardiogram, ECG and chest X-ray.
In the first instance, medical therapy will help reduce the strain on the heart pumping against the excess volume caused by the leaking aortic valve. In more severe cases, the treatment of choice in an aortic valve replacement. Again, your cardiologist will determine if and when this is required.