Open BAV

The opening of a BAV resembles the open mouth of a fish, leading to the term “fish mouth” valve.

BAV and the Aorta Aortic Aneurysm and Dissection At one time it was thought that the abnormal blood flow from a bicuspid aortic valve was the main cause of enlargement of the ascending aorta. However, development of an ascending aortic aneurysm has been observed in the presence of a normally functioning bicuspid aortic valve. Also, the aneurysmal progression of the ascending aorta following replacement of the bicuspid aortic valve indicates the intrinsic aortic wall abnormality present in this syndrome. In addition, family members with normal-appearing tricuspid aortic valves may also experience aortic aneurysm and dissection. Bicuspid aortic disease is increasingly being understood as degeneration of the medial layer of the aorta, resulting in an aortic wall that gradually loses its strength. This condition causes the aorta to over stretch with each beat of the heart, eventually leading to formation of an aneurysm. Secondary to the anatomical nature of the ascending aorta (which is relatively free inside the pericardium), and its exposure to maximal blood flow from the heart, the aortic root and ascending aorta are the most common sites of aneurysm formation. This weak aortic tissue is prone to dissection and rupture. Given that many also develop labile hypertension, this combination of high pressure and weak aortic tissue potentially can result in a life-threatening situation.

Closed BAV

When closed, it may be difficult to distinguish a BAV from an aortic valve with all three leaflets.

Tricuspid Aortic Valve

Closed TAV

A normal aortic valve has three leaflets or cusps. Pictured here is a TAV with the leaflets closed. The opening of a TAV is shaped like a triangle.

Aortic Aneurysm The aorta in those from BAV families may be enlarged and balloon out, which is called an aneurysm.