What are the associated anomalies with a bicuspid aortic valve?

Associated Anomalies with Bicuspid Aortic Valve

Bicuspid aortic valve (BAV) is commonly associated with aortic dilation, coarctation of the aorta, and other left-sided heart obstructive lesions that require regular monitoring and may impact timing of intervention. 1

Common Associated Anomalies

BAV is the most common congenital cardiac malformation, occurring in 1-2% of the general population. Key associated anomalies include:

Aortic Abnormalities

• Aortic dilation/aneurysm: Present in up to 40% of BAV patients 1
  • Most commonly affects the ascending aorta (70-75% of cases)
  • Root phenotype occurs in 15-20% of cases
  • Extended phenotype (equal dilation of sinusal and tubular segments or ascending dilation extending into arch) in 5-10% 1
• Aortic dissection: 8-10 times more frequent than in general population 1
• Aortic coarctation: Present in 4-12% of BAV patients 2

Other Cardiovascular Anomalies

• Subvalvular aortic stenosis (SubAS) 1
• Ventricular septal defect (VSD): Found in approximately 6% of BAV patients 2
• Patent ductus arteriosus (PDA): Present in about 3% of cases 2
• Coronary artery anomalies: Present in approximately 4% of BAV patients 2
  • Left-dominant coronary artery system is more frequent with BAV 1
• Parachute mitral valve 1
• Mitral valve prolapse: Occurs in approximately 1.5-2% of BAV patients 2

Syndromic Associations

• Turner syndrome: Associated with both BAV and aortic coarctation 1
• Shone's syndrome: Multiple levels of left-sided heart obstructions (SubAS, BAV, coarctation, parachute mitral valve, or supramitral ring) 1

Clinical Implications

Aortic Complications

• BAV patients have intrinsic abnormalities of aortic wall elastin that can lead to ascending aortic dilation even with a normally functioning valve 1
• Aortic dilation can progress to aneurysm, rupture, or dissection 1
• Aortic dissection can occur at smaller aortic diameters (12.5% of BAV patients with aortic diameter <5 cm) 1

Monitoring Recommendations

1. Initial evaluation: TTE to evaluate valve morphology, measure AS/AR severity, and assess aortic sinuses and ascending aorta dimensions 1
2. Regular imaging:
   • Annual TTE monitoring of aortic root/ascending aorta 1
   • CMR/CCT imaging every 3-5 years for complete aortic assessment 1
   • If TTE cannot adequately visualize the ascending aorta (≥4.0 cm from valve plane), MR or CT angiography is indicated 1

Family Screening

• 20-30% of patients with BAV have family members with BAV disease and/or associated aortopathy 1
• First-degree relatives of patients with BAV should be evaluated for BAV and asymptomatic thoracic aortic disease 1

Surgical Considerations

• Prophylactic aortic root surgery should be considered when aortic diameter reaches ≥45 mm, or at lower diameters with additional risk factors 1
• Risk factors for aortic dissection include:
  • Family history of dissection with minimal or no dilatation
  • Young age
  • Rapid growth (≥3 mm per year) 1

Important Caveats

1. BAV patients require lifelong surveillance even with normal valve function due to progressive risk of aortopathy
2. Different BAV morphologies (fusion patterns) correlate with different patterns of aortopathy:
   • Fusion of right/non-coronary cusps has higher prevalence of aortic dilation than right/left coronary cusp fusion (68% vs. 40%) 1
3. Patients presenting in childhood with LVOT obstruction generally have more complex disease than those found to have BAV in adulthood 1
4. Despite potential complications, life expectancy in adults with BAV is not necessarily shortened compared to the general population with appropriate management 3