What are the complications and management options for a bicuspid aortic valve?

Medical Conditions Associated with Bicuspid Aortic Valve

Bicuspid aortic valve is most commonly associated with aortic stenosis, aortic regurgitation, ascending aortic dilation/aneurysm, aortic dissection, coarctation of the aorta, and endocarditis. 1

Valvular Complications

Aortic Stenosis

• Most patients with bicuspid aortic valve will develop aortic stenosis or aortic regurgitation over their lifetime, making these the primary valve-related complications. 1
• Congenital aortic stenosis is most often caused by a bicuspid aortic valve, though the rate of progression in young patients is lower than in older patients with degenerative disease. 1
• Aortic stenosis occurs in approximately 22% of bicuspid aortic valve patients and is more frequent in the right-non-coronary cusp fusion morphotype (BAV-RN). 2
• The presence of a raphe (fusion line) increases the risk of developing aortic stenosis (OR: 2.75), as do traditional cardiovascular risk factors including dyslipidemia (OR: 1.77) and smoking (OR: 1.63). 2

Aortic Regurgitation

• Degeneration of the bicuspid valve is the most common etiology of chronic aortic regurgitation, and this process is usually accelerated compared to tricuspid valves, with patients presenting with severe disease earlier. 1
• Aortic regurgitation occurs in approximately 23% of bicuspid aortic valve patients and is strongly associated with male sex (OR: 2.80) and valve prolapse (OR: 5.16). 2
• Severe aortic regurgitation is associated with significant cardiovascular morbidity and mortality, with 75% of patients dying or requiring aortic valve replacement within 10 years of diagnosis. 1

Aortopathy and Vascular Complications

Ascending Aortic Dilation

• Bicuspid aortic valves are frequently associated with aortic dilation either at the level of the sinuses of Valsalva or, more frequently, in the ascending aorta, with approximately 50% of bicuspid aortic valve patients having aortic root involvement. 1, 3
• The ascending aorta is dilated in 76% of bicuspid aortic valve patients, making it the most commonly dilated segment. 2
• The incidence of aortic dilation is higher in patients with fusion of the right and non-coronary cusps (68%) compared to the more common phenotype of fusion of the right and left coronary cusps (40%). 1
• Patients with fusion involving the non-coronary cusp are more likely to have dilation of the ascending aorta rather than the sinuses, which often extends to the transverse arch. 1

Aortic Root Dilation

• Aortic root dilation is present in approximately 34% of bicuspid aortic valve patients and is related to male sex and aortic regurgitation, but is less frequent in patients with aortic stenosis and BAV-RN morphotype. 2

Aortic Dissection

• Bicuspid aortic valve is associated with aortic dissection, and the risk is increased during pregnancy. 1
• Women with unrepaired coarctation of the aorta who have bicuspid aortic valve and aortic dilation are at increased risk of aortic rupture and rupture of cerebral aneurysm during pregnancy and delivery. 1
• All women with a bicuspid aortic valve should undergo imaging of the ascending aorta before pregnancy, and surgery should be considered when the aortic diameter is >50 mm. 1

Coarctation of the Aorta

• Aortic coarctation is associated with the presence of a bicuspid aortic valve and should be evaluated by Doppler interrogation of the proximal descending aorta. 1
• Bicuspid aortic valve and aortic dilation are risk factors for aortic rupture in patients with coarctation. 1

Familial Associations

Genetic Clustering

• In 20% to 30% of patients with bicuspid valves, other family members also have bicuspid valve disease and/or an associated aortopathy. 1
• A specific genetic cause has not been identified, and the patterns of inheritance are variable. 1
• Imaging of first-degree relatives is clearly appropriate if the patient has an associated aortopathy or a family history of valvular heart disease or aortopathy. 1

Other Complications

Endocarditis

• Endocarditis is a recognized complication in patients with bicuspid aortic valve, particularly in those with repaired tetralogy of Fallot who also have bicuspid valve disease. 1

Arrhythmias and Heart Failure

• Arrhythmias and worsening of NYHA class can occur during pregnancy in patients with bicuspid aortic valve and associated lesions. 1
• Heart failure risk exists primarily in women with severe regurgitation or impaired ventricular function. 1

Critical Management Implications

Initial Evaluation

• An initial transthoracic echocardiogram is indicated in all patients with a known bicuspid aortic valve to evaluate valve morphology, measure the severity of aortic stenosis and aortic regurgitation, and assess the shape and diameter of the aortic sinuses and ascending aorta. 1
• The echocardiographic report should include aortic measurements at the aortic annulus, sinuses, sinotubular junction, and mid-ascending aorta. 1

Advanced Imaging

• Aortic magnetic resonance angiography or CT angiography is indicated when morphology of the aortic sinuses, sinotubular junction, or ascending aorta cannot be assessed accurately or fully by echocardiography. 1
• All patients with a bicuspid valve should have evaluation of the aorta with MRI or CT angiography at some point, with cardiac MRI preferred in younger patients given cumulative radiation exposure concerns. 3

Common Pitfalls

• Do not assume that absence of valve dysfunction means absence of aortopathy—ascending aortic dilation can occur independent of valvular alterations. 4
• Normofunctional valves are more prevalent in bicuspid aortic valve without raphe, but these patients still require aortic surveillance. 2
• The BAV-RL morphotype increases the risk for dilation of the proximal aorta, whereas BAV-RN tends to spare this area but has higher risk of aortic stenosis. 2