Echocardiographic Diagnosis of Bicuspid Aortic Valve

Key Diagnostic Features

The European Society of Cardiology recommends that the diagnosis of a bicuspid aortic valve (BAV) is most reliable when two cusps are seen in systole with only two commissures framing an elliptical systolic orifice in the short-axis view, which is the primary diagnostic view 1, 2
In the short-axis view, BAV is characterized by two cusps in systole instead of three, only two commissures visible, and an elliptical systolic orifice, according to the European Heart Journal 1
The presence of a raphe, which represents the fusion line between two cusps, can be mistaken for a commissure in the diastolic appearance of BAV, as noted by the European Heart Journal 1, 2

The European Heart Journal states that Type 1 BAV, which accounts for approximately 80% of BAV cases, results in larger anterior and smaller posterior cusp, with both coronary arteries typically arising from the anterior cusp 1
Type 2 BAV, which accounts for approximately 20% of BAV cases, results in larger right than left cusp, with one coronary artery arising from each cusp, according to the European Heart Journal 1

The European Heart Journal notes that in adults, stenosis of BAV typically results from superimposed calcific changes, and extensive calcification often obscures the number of cusps, making determination of bicuspid vs. tricuspid valve difficult 1

The European Heart Journal states that when images are adequate, 2D echocardiography has high sensitivity and specificity for BAV diagnosis, and 3D echocardiography can provide better visualization of valve morphology, showing the valve "en face" from the aortic perspective 3
Transesophageal echocardiography (TOE) may be helpful when transthoracic image quality is suboptimal, as noted by the European Heart Journal 1

The European Heart Journal recommends distinguishing BAV from tricuspid aortic valve, which shows three cusps with a stellate-shaped systolic orifice, and from rheumatic aortic valve, which shows commissural fusion with a triangular systolic orifice and thickening/calcification along the edges of the cusps 1