The bicuspid aortic valve.

The bicuspid aortic valve affects 1 to 2% of the population and may be complicated by aortic stenosis or aortic insufficiency and infective endocarditis. The bicuspid aortic valve is associated with abnormalities of the aortic wall such as coarctation of the aorta, aortic dissection, and aortic aneurysm. Most patients with a bicuspid aortic valve will develop some complication during life. Individuals with a bicuspid valve may be unaware of its presence and are at risk for unsuspected complications. Aortic wall abnormalities associated with bicuspid aortic valve are due to cystic medial necrosis. This process is associated with increased metalloproteinase activity and apoptosis of vascular smooth muscle cells. The clinical correlates of aortopathy in the bicuspid aortic valve include significant enlargement of the ascending aorta with aneurysm formation and dissection. This process continues after valve replacement. The person with bicuspid aortic valve requires continuous surveillance to treat associated lesions and prevent complications.