What is the management plan for a patient with an aortic bicuspid valve?

Management of Bicuspid Aortic Valve

All patients with bicuspid aortic valve require initial transthoracic echocardiography to assess valve function and aortic dimensions, followed by CT or MRI imaging of the entire thoracic aorta to evaluate for associated aortopathy. 1, 2

Initial Diagnostic Workup

Echocardiographic Assessment

• Perform comprehensive transthoracic echocardiography measuring: 1
  • Valve morphology and cusp fusion pattern
  • Severity of aortic stenosis and/or regurgitation
  • Left ventricular dimensions and systolic function
  • Aortic dimensions at annulus, sinuses of Valsalva, sinotubular junction, and mid-ascending aorta

Advanced Aortic Imaging

• Obtain cardiac MRI or CT angiography of the entire thoracic aorta at initial diagnosis, as approximately 50% of bicuspid aortic valve patients have associated aortopathy that may not be fully visualized by echocardiography alone. 1, 2
• Cardiac MRI is preferred over CT when possible to avoid cumulative radiation exposure in patients requiring lifelong surveillance. 3

Family Screening

• Screen all first-degree relatives with transthoracic echocardiography, as 20-30% of family members also have bicuspid aortic valve disease and/or aortopathy. 1, 2

Surveillance Strategy

For Normal Aortic Dimensions (<4.0 cm)

• Perform transthoracic echocardiography every 3-5 years to monitor valve function, left ventricular dimensions, and aortic size. 2, 3

For Aortic Dilation (≥4.0 cm)

• Perform annual imaging (echocardiography, MRI, or CT) to assess progression of aortic dilation. 1, 2
• The mean rate of aortic diameter progression is 0.5-0.9 mm/year at various levels, though rates up to 2 mm/year have been reported. 1

For Severe Aortic Dilation (>4.5 cm)

• Perform annual imaging mandatory, with consideration for 6-month intervals if rapid growth (>0.5 cm/year) is documented or family history of aortic dissection exists. 1, 2

Medical Management

Blood Pressure Control

• Aggressively control hypertension using any effective antihypertensive agent, as hypertension is associated with rapid aortic root and ascending aorta dilation and valvular dysfunction progression. 1, 2, 4

Pharmacologic Considerations

• Beta-blockers or angiotensin receptor blockers may be considered for patients with aortic dilation, though no proven drug therapies have been shown to reduce the rate of aortic dilation progression in bicuspid aortic valve-associated aortopathy. 1, 2
• Avoid beta-blockers if moderate or severe aortic regurgitation develops, as they prolong diastole and may increase regurgitant volume. 2

Surgical Indications

Aortic Surgery Thresholds

• Surgery is indicated when ascending aorta diameter reaches ≥5.5 cm in most patients with bicuspid aortic valve. 1, 2
• Surgery is indicated at ≥5.0 cm for patients with root phenotype aortopathy (dilation primarily at sinuses of Valsalva). 2
• Consider surgery at 4.5-5.0 cm if:
  • Family history of aortic dissection exists 1, 2
  • Rapid progression (>0.5 cm/year) is documented 1, 2
  • Concomitant aortic valve surgery is required for severe stenosis or regurgitation 3, 5

The 2014 AHA/ACC guidelines moved away from body surface area-indexed measurements and recommend absolute diameter thresholds, acknowledging that aortic dissection risk in bicuspid aortic valve patients is relatively low (3.1 cases per 10,000 patient-years). 1

Valve Surgery Considerations

• Aortic valve-sparing operations are feasible in most patients with aortic dilation who do not have significant aortic regurgitation or valve calcification. 1, 6
• When aortic valve replacement is required for severe stenosis or regurgitation, concurrent aortic repair should be performed if diameter exceeds 4.5 cm, as there is no added surgical risk and late survival is improved. 5

Critical Pitfalls to Avoid

• Do not rely on color Doppler jet assessment alone for aortic regurgitation severity in bicuspid valves, as eccentric jets underestimate severity; use vena contracta width, holodiastolic flow reversal in descending aorta, and left ventricular dimensions instead. 2
• Do not assume echocardiography alone adequately images the ascending aorta; CT or MRI is required to assess beyond the proximal 2-3 cm. 1, 2
• Do not delay aortic imaging until symptoms develop, as aortic complications can occur independently of valve dysfunction severity. 2, 3
• Recognize that Sievers type 1 morphology (with raphe) is associated with more rapid aortic dilation and valvular dysfunction progression compared to type 0 (no raphe). 2, 4