Is a bicuspid aortic valve a significant medical issue?

Bicuspid Aortic Valve: A Significant Medical Issue Requiring Lifelong Surveillance

Yes, a bicuspid aortic valve (BAV) is a significant medical issue that requires systematic evaluation and lifelong monitoring, as most patients will develop valve dysfunction or aortic complications during their lifetime. 1

Why BAV Matters

BAV is the most common congenital cardiac malformation, affecting 1-2% of the population, and carries substantial long-term risks 2, 3, 4:

• Most patients develop valve dysfunction over their lifetime, with nearly half developing varying degrees of stenosis or regurgitation requiring intervention 1, 3
• Aortic dilation occurs frequently, with 40-68% of BAV patients developing ascending aortic dilatation depending on the fusion pattern 1
• Risk of aortic dissection is elevated compared to the general population (HR: 8.4), though the absolute incidence remains relatively low at 3.1 cases per 10,000 patient-years 1

Immediate Diagnostic Requirements

When BAV is first diagnosed, you must obtain comprehensive imaging 5, 6:

• Transthoracic echocardiography (TTE) is mandatory to assess valve morphology, measure stenosis/regurgitation severity, and evaluate aortic dimensions at the annulus, sinuses of Valsalva, sinotubular junction, and mid-ascending aorta 1
• Advanced imaging with cardiac MRI or CT angiography is required when TTE cannot adequately visualize the ascending aorta beyond 4.0 cm from the valve plane 1
• Cardiac MRI demonstrates superior accuracy (96% vs 73% for TTE) for valve morphology assessment 5

Surveillance Strategy Based on Aortic Size

The surveillance interval depends critically on aortic diameter 1:

• Aortic diameter >4.5 cm: Annual imaging is required with echocardiography, CMR, or CT angiography 1
• Aortic diameter 4.0-4.5 cm: Interval imaging with frequency determined by rate of progression and family history 1
• Expected progression rate: Mean 0.5-0.9 mm per year at different aortic levels, though some patients progress up to 2 mm per year 1

Surgical Intervention Thresholds

Operative intervention for aortic replacement is indicated when the ascending aorta or sinuses reach >5.5 cm 1. However, earlier intervention at 5.0-5.5 cm is reasonable if high-risk features are present 1:

• Family history of aortic dissection
• Rapid progression (>0.5 cm per year)
• Concomitant valve surgery being performed

This represents a more conservative approach than older guidelines, which recommended surgery at >5.0 cm, reflecting limited evidence for dissection risk at smaller diameters 1.

Family Screening Requirements

First-degree relatives should undergo echocardiographic screening because 20-30% of family members also have BAV or associated aortopathy 1, 7, 6. The American Heart Association recommends this screening particularly when 1:

• The patient has associated aortopathy
• Family history of valvular heart disease exists
• Family history of aortopathy is present

Medical Management Considerations

No proven drug therapies prevent progression of aortic dilation in BAV patients 1. However:

• Hypertension must be treated with any effective antihypertensive medication, starting at low doses and titrating gradually 6
• Beta-blockers and ARBs have theoretical advantages but lack clinical trial evidence demonstrating benefit in slowing aortic progression 1

Critical Pitfalls to Avoid

Do not assume BAV is benign simply because the valve functions normally at diagnosis 1, 4. The natural history involves progressive dysfunction in most patients, and aortic complications can occur even with normal valve function 4, 8.

Do not use BAV as an indication for transcatheter aortic valve replacement (TAVR) in standard practice, as BAV is considered a relative contraindication due to asymmetric anatomy predisposing to paravalvular regurgitation and device malposition 1.

Do not apply body surface area adjustments to aortic diameter thresholds for surgical intervention, as current guidelines do not recommend this approach 1.

Do not forget that the sinuses of Valsalva are normally 0.5 cm larger than the tubular ascending aorta, and measurements must be site-specific 1.