Written with Lars Svensson, MD, PhD
What is bicuspid aortic valve disease?
The aortic valve is a one-way valve between the heart and the aorta, the main artery from the heart that distributes oxygen-rich blood to the body. Normally, the aortic valve has three small flaps or leaflets that open widely and close securely to regulate blood flow, allowing blood to flow from the heart to the aorta and preventing blood from flowing backwards into the heart.
In bicuspid aortic valve disease (BAVD), the valve has only two leaflets. With this deformity, the valve doesn’t function perfectly, but it may function adequately for years without causing symptoms or obvious signs of a problem.
The latest studies suggest that bicuspid aortic valve disease is caused by a connective tissue disorder that also causes other circulatory system problems. People with bicuspid aortic valve disease also may have abnormal coronary arteries, aortic aneurysm or an abnormal thoracic aorta (the portion of the aorta that passes through the upper chest) and unstable (labile) high blood pressure.
What causes bicuspid aortic valve disease?
The actual cause of bicuspid aortic valve disease is not completely clear. We do know that the two-leaflet valve develops in the early stages of pregnancy, and the defect is present at birth. About 2% of the population has BAVD, and it is twice as common in males as in females.
What are the symptoms and signs of BAVD?
Although bicuspid aortic valve disease is present at birth, it usually is not diagnosed until adulthood because the defective valve can function for years without causing symptoms. Rarely, the disease is so severe at birth that the baby develops congestive heart failure early in life. More commonly, patients will have a history of having a childhood murmur and symptoms develop in mid-life as the valve ages.
Calcium deposits on and around the leaflets eventually cause the valve to stiffen and narrow, a condition known as stenosis. As stenosis develops, the heart must pump increasingly harder to force the blood through the valve. Symptoms of a stenotic valve include chest pain, shortness of breath and dizziness or fainting caused by inadequate blood flow to the brain.
If the bicuspid valve does not close completely, blood can flow backwards into the heart. This is regurgitation, also called aortic valve insufficiency. The heart then must pump that same blood out again, causing strain on the heart’s lower left chamber, the left ventricle. Over time, the ventricle will dilate, or over-expand. The main symptom of aortic valve regurgitation is shortness of breath during exertion, like walking up stairs.
As the disease progresses, these symptoms start occurring more frequently, even without exercise. When a physician listens to the person's heart, characteristic murmurs can be heard.
How is bicuspid aortic valve disease diagnosed?
Individuals experiencing symptoms such as shortness of breath typically begin with their family doctor, who will perform a physical examination that includes listening to the person's heart. When the patient’s symptoms and the sounds heard on the cardiac exam raise the suspicion of bicuspid aortic valve disease, the patient needs to be referred to a specialist in valvular heart disease.
At Cleveland Clinic Heart and Vascular Institute, specialists use echocardiography (heart ultrasound), transesophageal echocardiography (an up-close heart ultrasound performed through the esophagus), CT scans, and magnetic resonance imaging (MRI) of the heart to evaluate the heart, valves and aorta.
Other tests such as an electrocardiogram (to test the heart’s electrical activity) or coronary angiography (an X-ray of the heart's blood vessels using a special dye) can help diagnose other problems with the heart and arteries that may be associated with bicuspid aortic valve disease. Cleveland Clinic specialists also evaluate patients with BAVD for aneurysms, coronary artery disease and heart rhythm disorders.
Can BAVD cause complications?
Yes, about 30% of people with bicuspid aortic valve disease develop complications. They can be very serious, even life-threatening. This is why people diagnosed with BAVD should be under the ongoing care of a specialist in heart valve disease who can monitor changes in the heart, valves and aorta over time.
The major complications are:
Over time, a stenotic valve will cause the left ventricle to thicken due to the extra pumping required to force blood through the valve. This enlarged ventricle and in inefficient pumping can lead to heart failure. Smoking or high cholesterol can accelerate the process.
Aortic Aneurysm and Dissection
The underlying connective tissue disorder that causes BAVD also affects the tissue layers that form the walls of the aorta. As the tissue layers degenerate, the aorta walls lose their strength and stretch out of shape. Eventually, this can cause the formation of an aneurysm, a bulging out area of the aorta where the walls are thin and over-stretched.
The aneurysm can rupture or the inner and outer tissue layers of the aorta can shred apart (aortic dissection). Rupture and dissection are life-threatening emergencies. Cleveland Clinic heart and valve specialists are experienced at monitoring the aorta in patients with BAVD to plan surgical intervention before rupture or dissection occurs.
In the Cleveland Clinic experience, with over 5,000 patients with BAVD, 20 % had associated aneurysms. At Cleveland Clinic, we have developed a special mathematical formula we use to determine when surgery is necessary, based on the patient’s height and weight and the size of the aorta. The formula described by Dr. Svensson is the ratio between the cross sectional area of the aorta in centimeters and the height in meters. If the measurement exceeds 10, surgery is usually considered.
What is the treatment for BAVD?
In the most severe cases, when symptoms are present at birth or in early infancy, surgical repair of the valve must be performed immediately. In other cases, people can go their whole lives without knowing they have BAVD.
About 80 percent of people with BAVD will require surgical treatment to repair or replace the valve and part of the aorta, usually when they are in their 30s or 40s. Cleveland Clinic specialists can determine the best time to do the surgical repair and whether multiple repairs to the valve and aorta can be done at the same time if needed. As of December 2010, they have operated on 4,700 patients with BAVD, the largest experience in the world in treating this disease.
For the patient who has stenosis and symptoms, the preferred treatment is to replace the valve with a mechanical or biological valve. The mortality rate for this procedure at Cleveland Clinic is less than 1%.
When regurgitation is present, the aortic valve can be repaired successfully. Cleveland Clinic is one of only a handful of centers in the world to repair bicuspid aortic valves, and 91% of patients who undergo the procedure here do not need another valve operation for at least 10 years. After repair, if failure does occur, it will take place in the first year to 18 months after surgery - but thereafter the risks of re-operation are low. However, because the valve is abnormal, it is likely that it will need to be replaced after a few decades.
An aorta that is enlarged and forming an aneurysm can be repaired, but at Cleveland Clinic we more often replace the damaged section with a section of plastic tubing that is sewn into position. This is usually done with a minimally invasive “J” incision. The timing for repair of an aortic aneurysm is critical. When the valve is faulty and the aorta has enlarged to greater than 4.5 cm, we repair the aorta at the same time we repair or replace the valve. If the aorta has enlarged but the valve is still good, the optimal time to repair the aorta varies. At Cleveland Clinic, we have developed a special mathematical formula we use to determine this, based on the patient’s height and weight and the size of the aorta - surgery is usually recommended when the aortic cross sectional area in square centimeters, divided by the patient's height in meters is more than 10.
How do I learn more about BAVD or find a doctor who specializes in treating it?
More information can be found at:
If you need more information about BAVD, it's treatment, or how to make an appointment with a specialist, contact us, chat online with a nurse or call the Miller Family Heart and Vascular Institute Resource & Information Nurse at 216.445.9288 or toll-free at 866.289.6911. We would be happy to help you.
- Svensson LG. Aortic valve stenosis and regurgitation: an overview of management. J Cardiovasc Surg (Torino). 2008 Apr; 49(2):297-303. Review.
- Svensson LG. Minimally invasive surgery with a partial sternotomy "J" approach. Semin Thorac Cardiovasc Surg. 2007 Winter; 19(4):299-303. Review.
- Svensson LG, Deglurkar I, Ung J, Pettersson G, Gillinov AM, D'Agostino RS, Lytle BW. Aortic valve repair and root preservation by remodeling, reimplantation, and tailoring: technical aspects and early outcome. J Card Surg. 2007 Nov-Dec; 22(6):473-9.
- Svensson LG, Blackstone EH, Feng J, de Oliveira D, Gillinov AM, Thamilarasan M, Grimm RA, Griffin B, Hammer D, Williams T, Gladish DH, Lytle BW. Are Marfan syndrome and marfanoid patients distinguishable on long-term follow-up? Ann Thorac Surg. 2007 Mar; 83(3):1067-74
- Svensson LG, Blackstone EH, Cosgrove DM 3rd. Surgical options in young adults with aortic valve disease. Curr Probl Cardiol. 2003 Jul; 28(7):417-80. Review.