What are the recommendations for screening and managing a bicuspid aortic valve (BAV)?

Screening and Management of Bicuspid Aortic Valve (BAV)

Initial screening with transthoracic echocardiography (TTE) is recommended for all patients with known or suspected bicuspid aortic valve to evaluate valve morphology, measure severity of aortic stenosis/regurgitation, and assess the shape and diameter of the aortic sinuses and ascending aorta. 1

Diagnostic Imaging for BAV

• When a BAV is first diagnosed, initial TTE to assess diameters of the aorta at several levels (aortic annulus, sinuses, sinotubular junction, and mid-ascending aorta) is recommended 1
• Cardiac MRI or CT is indicated in patients with BAV when the morphology of the aortic root and ascending aorta cannot be accurately or fully assessed by TTE 1
• CCT or CMR of the entire thoracic aorta is recommended at first diagnosis and when important discrepancies in measurements are found between subsequent TTE controls during surveillance, or when the diameter of the aorta exceeds 45 mm 1
• MRI imaging is preferred over CT when possible due to absence of ionizing radiation exposure in patients who will likely require multiple imaging studies over their lifetime 1

Surveillance Recommendations

For Patients with BAV Without Significant Aortic Dilation:

• For aortic diameter <40 mm: Reimaging approximately every 2 years 1
• For aortic diameter >40 mm: Annual measurement of aortic diameter is indicated 1

For Patients with BAV with Aortic Dilation:

• For aortic diameter >45 mm or an increase of >3 mm per year measured by echocardiography: Annual measurement of aortic diameter is indicated 1
• For aortic diameter >50 mm or an increase of >3 mm per year measured by echocardiography: Confirmation of the measurement using another imaging modality (CT or MRI) is indicated 1
• After isolated aortic valve surgery: Surveillance serial imaging by TTE is recommended after 1 year, then if stability is observed, every 2-3 years 1

Family Screening

• Echocardiographic screening for the presence of BAV is recommended for first-degree relatives of patients with BAV 1
• Screening by TTE in first-degree relatives of BAV patients with root phenotype aortopathy and/or isolated aortic regurgitation is recommended 1, 2
• The prevalence of BAV in first-degree relatives is approximately 6.6%, supporting the need for family screening 2

Surgical Management Recommendations

Indications for Surgery of the Ascending Aorta in BAV:

• Surgery is recommended when the maximum aortic diameter is ≥55 mm 1, 3

• Surgery is recommended when aortic root or ascending aortic diameter >50 mm in the presence of risk factors (coarctation of the aorta, systemic hypertension, family history of dissection, or increase in aortic diameter of >3 mm per year) 1

• Surgery should be considered at a maximum diameter ≥50 mm if any of the following exist 1:

  • Age <50 years
  • Short stature
  • Ascending aortic length ≥11 cm
  • Aortic diameter growth rate >3 mm per year
  • Family history of acute aortic syndrome
  • Aortic coarctation
  • Resistant hypertension
  • Concomitant non-aortic-valve cardiac surgery
  • Desire for pregnancy

• For patients undergoing aortic valve surgery: Surgery for bicuspid aortopathy should be considered at a root or ascending diameter ≥45 mm 1

Special Considerations

Pregnancy Counseling

• Women with BAV and ascending aorta diameter greater than 4.5 cm should be counseled about the high risks of pregnancy 1
• Prophylactic aortic root surgery is recommended in women desiring pregnancy with aortic diameters >45 mm 1

Exercise Recommendations

• Patients with moderate to severe aortic stenosis should be counseled against participation in competitive athletics and strenuous isometric exercise 1
• Physical activity should be individualized based on aortic diameter, family history of aortic dissection, and pre-existing fitness 1

Clinical Pitfalls and Caveats

• BAV patients are heterogeneous with regard to patterns of root remodeling and valvular dysfunction, requiring careful assessment of both valve function and aortic dimensions 4, 5
• The actual incidence of aortic dissection in BAV patients is relatively low (approximately 4%), but the consequences are severe, justifying aggressive surveillance 3
• Different BAV phenotypes (fusion patterns of cusps) may have different risks of aortic dilation - fusion involving the noncoronary cusp is associated with higher risk of ascending aorta dilation 1
• Patients with BAV require lifelong cardiology follow-up, even after intervention, as they may develop progressive or recurrent aortic stenosis, regurgitation, or aortic enlargement 1
• More than 50% of patients with BAV will undergo aortic valve replacement during their lifetime, and more than 25% will undergo aortic surgery for dilation of the aortic root or ascending aorta 5