Bicuspid Aortic Valve

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• History of murmur since infancy, aortic coarctation repair, or endocarditis

• Early systolic ejection sound, harsh crescendo-decrescendo systolic murmur, or early decrescendo diastolic murmur

• Left ventricular hypertrophy

• Abnormal bicuspid or dysplastic aortic valve with stenosis or regurgitation on Doppler echocardiography

GENERAL CONSIDERATIONS

• Most common congenital heart disease with a prevalence of about 2% of the population

• Represents about 50% of all congenital outflow tract obstructive lesions

• Occurs more commonly in men than women by 3:1

• Bicuspid aortic valve is a misnomer since a raphe caused by the fusion of 2 aortic valve leaflets usually exists

• Associated lesions include:

  • – Patent ductus arteriosus

  • – Coarctation of the aorta

  • – Ventricular septal defects

• Hemodynamic distortions:

  • – Lead to progressive valvular degeneration

  • – Result in moderate to severe aortic stenosis in about 25% of patients

  • – Result in moderate to severe aortic regurgitation in about 25% of patients

• Aortic root or ascending aorta dilatation occurs in about 33% of patients

• Infective endocarditis occurs in about 5% of patients

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Dyspnea

• Angina

• Effort syncope

• Sudden cardiac death

PHYSICAL EXAM FINDINGS

• Pulsus parvus et tardus

• Increased size, amplitude, and duration of the apical impulse

• Systolic ejection sound, diminished A₂, and presence of an S₄

• Harsh systolic ejection murmur radiating to the neck

• Often a high-pitched decrescendo murmur of aortic regurgitation

• Systolic murmur augmented in intensity in the beat after a premature beat

• Physical findings of associated lesions may be present

DIFFERENTIAL DIAGNOSIS

• Discrete subaortic stenosis

• Hypertrophic obstructive cardiomyopathy

• Marfan’s syndrome with aortic regurgitation

• Pulmonic stenosis

• Ventricular septal defect

• Mitral valve prolapse with mitral regurgitation

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• No specific tests

ELECTROCARDIOGRAPHY

• Left ventricular hypertrophy if significant aortic stenosis is present

• Left atrial abnormality

IMAGING STUDIES

• Chest x-ray often shows left ventricular enlargement; dilated ascending aorta in some

• Echocardiography demonstrates the bicuspid aortic valve

  • – In most, the leaflet orientation is anterior and posterior

  • – In some, it is right to left

  • – Occasionally, a raphe on a leaflet may mimic a tricuspid leaflet arrangement and transesophageal echo is needed to diagnose a bicuspid valve

• Doppler echocardiography can be used:

  • – To measure the pressure gradient across the valve

  • – To estimate orifice area size

• Color flow Doppler is useful for assessing associated lesions such as aortic regurgitation

• Cardiac MRI is excellent for defining the anatomy in difficult echocardiographic imaging cases

DIAGNOSTIC PROCEDURES

• Cardiac catheterization is usually reserved for assessing the coronary arteries in older patients with ...