What is the management and treatment for a bicuspid aortic valve?

Management of Bicuspid Aortic Valve

All patients with bicuspid aortic valve require initial transthoracic echocardiography to assess valve function and measure aortic dimensions, followed by lifelong surveillance with imaging intervals determined by aortic diameter and valve dysfunction severity. 1, 2

Initial Diagnostic Evaluation

Perform transthoracic echocardiography (TTE) at diagnosis to evaluate:

• Valve morphology and phenotype 1, 2
• Severity of aortic stenosis or regurgitation 2, 3
• Left ventricular size and systolic function 3
• Aortic root and ascending aorta diameters at multiple levels (sinuses of Valsalva, sinotubular junction, ascending aorta) 1, 2

Obtain cardiac MRI or CT angiography when:

• TTE cannot accurately assess aortic root or ascending aorta morphology 1
• At initial diagnosis to evaluate the entire thoracic aorta, as approximately 50% of BAV patients have associated aortopathy 3, 4
• Aortic diameter exceeds 45 mm 2
• MRI is preferred over CT to avoid cumulative radiation exposure in patients requiring lifelong surveillance 1, 4

Screen first-degree relatives with TTE for bicuspid aortic valve, particularly when the patient has root phenotype aortopathy or isolated aortic regurgitation 2, 3

Surveillance Strategy

The surveillance interval depends on aortic diameter and rate of progression:

For aortic diameter <40 mm:

• Repeat imaging every 2 years 2

For aortic diameter 40-45 mm:

• Annual TTE measurement 1, 2
• If mild valve dysfunction without progression, imaging every 3-5 years is acceptable 3

For aortic diameter >45 mm:

• Annual imaging with TTE, MRI, or CT 1, 2
• Consider more frequent surveillance (every 6 months) if rapid growth >3 mm/year is documented 2, 3

Monitor for valve dysfunction progression:

• Yearly clinical evaluation for symptom changes 4
• Serial assessment of left ventricular function and dimensions, particularly with aortic regurgitation 4
• Jet velocity, gradient, and valve area assessment with aortic stenosis 4

Medical Management

No proven drug therapies reduce aortic dilation progression in BAV-associated aortopathy. 1

For hypertensive patients:

• Control blood pressure aggressively with any effective antihypertensive agent 1, 3
• Beta-blockers and ARBs have theoretical advantages but lack proven benefit in clinical studies 1, 3

Avoid beta-blockers if aortic regurgitation becomes moderate or severe, as they prolong diastole and may increase regurgitant volume 3

Surgical Indications for Aortic Dilation

The 2014 AHA/ACC guidelines represent the most recent high-quality evidence and recommend a more individualized, conservative approach compared to earlier guidelines:

Surgery is indicated when aortic diameter reaches ≥55 mm at any level (sinuses of Valsalva or ascending aorta) 1, 2

Surgery is indicated at ≥50 mm when risk factors are present:

• Family history of aortic dissection 1, 2
• Rapid aortic growth (>3 mm/year) 1, 2
• Age <50 years 2
• Aortic coarctation 2
• Desire for pregnancy in women 2
• Concomitant cardiac surgery for valve dysfunction 2

Important caveat: The 2008 guidelines recommended surgery at 50 mm for all BAV patients 1, but the 2014 guidelines raised this threshold to 55 mm for most patients, citing limited evidence for the lower threshold 1. The writing committee does not recommend adjusting aortic diameter for body size using formulas 1.

When concurrent aortic valve replacement is performed for severe stenosis or regurgitation, repair or replace the aorta if diameter exceeds 45 mm 1, 4

Valve-sparing operations are feasible in patients without significant aortic regurgitation or valve calcification 1

Surgical Indications for Valve Dysfunction

Follow standard criteria for aortic stenosis or regurgitation severity, independent of aortic diameter considerations 4, 5

Special Populations

Women of childbearing age:

• Counsel about high pregnancy risks when ascending aorta diameter >45 mm 2
• Consider prophylactic aortic root surgery before pregnancy if diameter >45 mm 2

Elderly patients (>75 years):

• More likely to develop symptoms or left ventricular dysfunction at earlier stages of dilation 1
• Symptoms should guide surgical decision-making to improve quality of life 1
• Consider surgery for asymptomatic patients with left ventricular dysfunction if surgical risks are acceptable 1

Athletes:

• Counsel patients with moderate to severe aortic stenosis against competitive athletics and strenuous isometric exercise 2
• Individualize physical activity recommendations based on aortic diameter and family history 2

Critical Pitfalls to Avoid

Inadequate aortic imaging: TTE alone often cannot visualize the mid-ascending aorta adequately; obtain MRI or CT for complete assessment 1, 3

Underestimating aortic regurgitation severity: Eccentric jets in BAV may appear mild on color Doppler; use vena contracta width, holodiastolic flow reversal in descending aorta, and left ventricular dimensions instead 3

Delayed aortic imaging: Aortic complications can occur independently of valve dysfunction severity; do not wait for symptoms to develop before assessing the aorta 3

Different BAV phenotypes carry different risks: Fusion involving the noncoronary cusp is associated with higher risk of ascending aorta dilation 2

Lifelong follow-up is mandatory even after intervention, as patients may develop progressive or recurrent valve dysfunction or aortic enlargement 2