In a patient with a congenital bicuspid (bileaflet) aortic valve, is chronic anticoagulation required?

Bicuspid Aortic Valve Does NOT Require Chronic Anticoagulation

A congenital bicuspid aortic valve (BAV) alone—without a mechanical prosthetic valve replacement—does not require chronic anticoagulation. This is a critical distinction that prevents unnecessary bleeding risk in a large population of patients.

Key Distinction: Native vs. Prosthetic Valve

• Native bicuspid aortic valves (the congenital anomaly itself) do not require anticoagulation, regardless of whether the valve is functioning normally, stenotic, or regurgitant 1, 2.
• Mechanical prosthetic valves (bileaflet or otherwise) implanted to replace a diseased bicuspid valve do require lifelong warfarin anticoagulation 3, 4, 5.
• The confusion arises because "bileaflet" can refer to either the congenital bicuspid anatomy or the mechanical prosthetic valve design, but the anticoagulation requirement applies only to the prosthetic valve 3, 4.

When BAV Patients DO Need Anticoagulation

Anticoagulation is indicated in BAV patients only when specific additional conditions develop:

Mechanical Valve Replacement

• If a BAV becomes severely stenotic or regurgitant and requires replacement with a mechanical prosthetic valve, lifelong warfarin is mandatory 3, 4, 5.
• Target INR 2.5 (range 2.0–3.0) for low-risk patients with bileaflet mechanical valves in the aortic position 3, 4.
• Target INR 3.0 (range 2.5–3.5) for high-risk patients (atrial fibrillation, prior thromboembolism, hypercoagulable state, severe LV dysfunction) 3, 5.
• Add aspirin 75–100 mg daily to warfarin for all mechanical valve patients 3.

Atrial Fibrillation

• If a BAV patient develops atrial fibrillation, anticoagulation is indicated based on CHA₂DS₂-VASc score, independent of the valve anatomy 5.

Infective Endocarditis Complications

• If endocarditis causes valve perforation with severe regurgitation and left atrial/ventricular thrombus formation, temporary anticoagulation may be needed 1.

Management of Native BAV Without Anticoagulation

Surveillance Strategy

• Lifelong echocardiographic follow-up is mandatory to monitor for valve dysfunction (stenosis or regurgitation) and ascending aortic dilation 1.
• Imaging intervals depend on severity: annually for moderate disease, every 2 years for mild disease 1.
• Cardiac MRI of the aorta is recommended in all BAV patients to assess for aortopathy, as up to 75% develop ascending aortic dilation 1, 6, 7.

Infective Endocarditis Prophylaxis

• Antibiotic prophylaxis is recommended before dental procedures involving gingival manipulation, as BAV is a predisposing factor for endocarditis 3, 8.
• This does not mean chronic anticoagulation; it refers to single-dose antibiotics before high-risk procedures 3.

Medical Therapy

• Beta-blockers may slow aortic root dilation in BAV patients with aortopathy, though evidence is limited 2.
• Statins have been studied but do not retard progression of aortic stenosis in BAV 1.
• Neither medication substitutes for anticoagulation, which is simply not indicated 1, 2.

Surgical Indications

• Valve replacement (mechanical or bioprosthetic) is indicated for severe symptomatic stenosis or regurgitation, following standard criteria for aortic valve disease 1.
• Ascending aortic surgery is indicated when diameter exceeds 5.5 cm (or 5.0 cm if additional risk factors present) 1.
• Only after mechanical valve replacement does lifelong anticoagulation become necessary 3, 4.

Common Pitfalls to Avoid

• Do not confuse "bileaflet mechanical valve" (prosthetic device requiring anticoagulation) with "bicuspid aortic valve" (congenital anomaly not requiring anticoagulation) 3, 4.
• Do not prescribe warfarin or DOACs for native BAV; this exposes patients to bleeding risk without benefit 3, 2.
• Do not assume all congenital heart defects require anticoagulation; BAV specifically does not unless complications develop 1, 2, 8.
• Do screen first-degree relatives of BAV patients, as 9% have familial inheritance and may have undiagnosed BAV or thoracic aortic aneurysms 1, 2.
• Do not delay surgical referral for severe valve dysfunction or aortic dilation; these are the actual indications for intervention, not anticoagulation 1.