Overview
A bicuspid aortic valve is a common heart condition present from birth, in which the aortic valve has two leaflets (cusps) instead of the usual three. The aortic valve controls blood flow from the heart's main pumping chamber into the aorta, the body's largest artery.
It affects about 1 to 2 percent of people and is more common in men. Many people have no problems for decades, but a bicuspid valve tends to wear out earlier than a normal valve. It can become narrowed (aortic stenosis) or leaky (aortic regurgitation), usually in middle age, and it is often associated with enlargement of the aorta, which can lead to aneurysm or dissection. Regular check-ups allow problems to be found early, and valve replacement or aortic surgery is very effective when needed.
Many people only find out they have a bicuspid valve when a doctor hears a murmur during a routine check, or when a heart scan is done for another reason.
When to get urgent help
Seek emergency care for sudden severe chest, back or abdominal pain, fainting, or severe breathlessness.
Causes and risk factors
- Developmental: the valve leaflets fuse abnormally during development before birth
- Genetics: runs in families; first-degree relatives have a higher chance of having one; linked to genes such as NOTCH1
- Associated conditions: coarctation of the aorta, Turner syndrome
How it develops (pathophysiology)
Normal aortic valve
A normal aortic valve has three thin, flexible leaflets that open widely to let blood leave the heart and close tightly to stop it flowing back. The even distribution of stress across three leaflets helps the valve last a lifetime.
What goes wrong
In a bicuspid valve, two of the three leaflets are fused, usually the right and left coronary cusps, leaving two leaflets of unequal size, often with a ridge (raphe) where they joined.
Valve problems:
- Abnormal mechanics: two leaflets open less fully and fold unevenly, creating turbulent blood flow and concentrating stress on parts of the leaflets.
- Early calcification: stress and turbulence damage the leaflet surface, triggering inflammation, lipid deposition and calcium build-up, similar to age-related aortic stenosis but about 10 to 20 years earlier.
- Aortic stenosis: calcified, stiff leaflets narrow the opening, often in people aged 50 to 70.
- Aortic regurgitation: leaflets may not close properly, especially if one prolapses or the aortic root enlarges, causing leakage, more often in younger people.
- Endocarditis: abnormal flow and damaged surfaces make the valve more vulnerable to infection.
Aortic problems (aortopathy):
- The wall of the aorta in people with bicuspid valves often has structural weaknesses, with fragmentation of elastic fibres and loss of smooth muscle cells.
- Abnormal, eccentric jets of blood through the valve add stress to the aortic wall.
- The ascending aorta may gradually enlarge, forming an aneurysm, which increases the risk of aortic dissection, though this risk is low overall.
Why the symptoms happen
- Murmur or click is caused by turbulent flow and the abnormal valve opening.
- Breathlessness, chest pain, dizziness or fainting occur when stenosis restricts blood flow out of the heart.
- Palpitations and tiredness may occur with regurgitation and an enlarged heart.
- Sudden severe chest or back pain may indicate aortic dissection.
How treatment acts on the mechanism
Regular imaging monitors valve function and aortic size. Blood pressure control reduces stress on the aorta. Aortic valve replacement (surgical or, in selected people, TAVI) relieves stenosis or regurgitation. Aortic replacement surgery removes an enlarged section of aorta before it dissects.
Types
Classified by the pattern of leaflet fusion:
- Right-left coronary cusp fusion: the most common
- Right-non-coronary cusp fusion
- Left-non-coronary cusp fusion
- True bicuspid valve without a raphe
It can also be described by the type of aortic enlargement (root or ascending aorta).
Signs and symptoms
Many people have no symptoms for years. When symptoms develop:
- Breathlessness, especially on exertion
- Chest pain or tightness
- Dizziness or fainting
- Tiredness
- Palpitations
- Reduced exercise capacity
- Aortic dissection: sudden, severe chest or back pain
How it is diagnosed
- Heart murmur or ejection click found on examination
- Echocardiogram, the main test to see the valve and measure the aorta
- Cardiac MRI or CT to assess the aorta in detail
- ECG
- Exercise testing in some cases
- Screening of first-degree relatives with echocardiography
Possible complications
- Aortic stenosis
- Aortic regurgitation
- Infective endocarditis
- Aortic aneurysm
- Aortic dissection
- Heart failure
Goals of treatment
Management aims to monitor the valve and aorta, control blood pressure, and replace the valve or aorta at the right time.
Medicines
- Blood pressure medicines to reduce stress on the aorta
- Medicines for heart failure if needed
- Antibiotics for endocarditis
Other treatments
- Regular echocardiograms and imaging
- Aortic valve replacement: surgical or transcatheter
- Valve repair in selected people with regurgitation
- Aortic surgery for enlarged aorta
- Balloon valvotomy in children or young adults with stenosis
Living with it and prevention
- Attend regular check-ups
- Control blood pressure
- Do not smoke
- Maintain good dental hygiene
- Discuss heavy weightlifting and competitive sport with your cardiologist if the aorta is enlarged
- Family members should be screened
Monitoring and follow-up
Echocardiograms are typically every one to five years depending on valve function and aortic size. Imaging of the aorta may be repeated more often if it is enlarged.
Outlook
Most people with a bicuspid aortic valve have a normal life expectancy, though many will need valve surgery at some point. Regular monitoring allows timely treatment.
Regular heart scans throughout life let doctors track the valve and the aorta and plan treatment at the right time. Close relatives may be offered a scan too, because the condition can run in families, and good dental care lowers the risk of valve infection.
Special considerations
- Pregnancy: needs specialist assessment, particularly with valve narrowing or an enlarged aorta
- Athletes: activity advice depends on valve function and aortic size
- Children: may need treatment earlier if stenosis is severe
