Bicuspid Aortic Valve Review


bicuspid_aortic_valveA bicuspid aortic valve is the most common cardiac congenital anomaly and is considered a connective tissue disorder. The incidence is 1-2% in the general population and it is the most common cause of aortic valve stenosis in people age 70 or less. Aortic regurgitation can also result from a bicspid aortic valve.

The aortic valve is normally tricuspid or trileaflet. When two of the cusps are fused together, the valve becomes functionally “bicuspid”. Most commonly, the right and left coronary cusps are fused and least commonly the left and noncoronary cusps are fused. This results over time in increased wear of the leaflets since the hemodynamic stress is distributed to only two cusps instead of three. Aortic valve stenosis or aortic valve regurgitation result. An ascending aortic aneurysm frequently develops concomitantly.

A systolic ejection click frequently indicates a bicuspid aortic valve. This sound is heard just after the 1st heart sound (S1). Usually, the opening of the aortic valve is not audible, however with a bicuspid aortic valve the leaflets “dome” suddenly prior to opening which creates a systolic ejection click. The click may be difficult to hear in the presence of significant aortic stenosis.

The treatment is surgical replacement when symptoms from aortic stenosis or aortic regurgitation develop. Also, an ascending aortic aneurysm has a lower threshold for repair in the setting of a bicuspid aortic valve and should be performed if the diameter reaches > 5.0 cm.

Related Links:

Topic Review: Aortic Stenosis

Topic Review: Aortic Regurgitation

Multiple Choice Questions: Aortic Stenosis

Multiple Choice Questions: Aortic Regurgitation

Case Questions: Aortic Stenosis

Case Questions: Aortic Regurgitation

References:

1. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine

2. Hurst's the Heart, 13th Edition

3. Siu S et al. Bicuspid Aortic Valve Disease. J Am Coll Cardiol. 2010;55(25):2789-2800.

Image: CC Patrcik J Lynch and C. Carl Jaffe, Yale University, 2006.

By Steven Lome