Bicuspid aortic valve--ethiopathogenesis and natural history

Bicuspid aortic valve is a disease with autosomal dominant inheritance with small penetration. The population of patients with bicuspid aortic valve is heterogenous. In the absence of dilatation of ascending aorta, valvular lesion or degenerative changes of valve leaflets patients are considered to belong to the low risk population. On the other hand patients with the above mentioned characteristics compose a high risk group. Dilatation of the ascending aorta in patients with bicuspid aortic valve has a progressive feature and continues even after replacement of the aortic valve. With progression of aortic dilatation the risk of aortic dissection and rupture increases. The main reasons for aortic dilatation are changes in quality of aortic wall and possibly mechanical stress of aortic wall during asymmetrical and turbulent flow. The progression of aortic dilatation or aortic valve disease is not essentially influenced by farmacologic treatment. Surgery is the treatment of choice. Physiology and pathophysiology of bicuspid and tricuspid aortic valves, prevalence of bicuspid aortic valve in general population and in the group of patients operated on for aortic valve disease, phenotypes of bicuspid aortic valve and follow-up of asymptomatic patients with normal bicuspid valve are reviewed in this article. Indications for operation of dilated ascending aorta according to american, european and czech guidelines are discussed.