cardiovascular disorders
Aortic Stenosis
Etiology of Aortic Stenosis
In older patients,the most common precursor to aortic stenosis is Aortic sclerosis The cause of aortic sclerosis and stenosis is not yet known but is mediated by an inflammatory process that is similar to but distinct from Atherosclerosis . Genetic, anatomic, fluid dynamic, and environmental risk factors include hypertension, smoking, high cholesterol, and presence of a bicuspid valve. Lipid deposition and inflammation lead to thickening of aortic valve structures by fibrosis and calcification initially without causing significant obstruction. Over years, aortic sclerosis progresses to stenosis in as many as 15% of patients. Lipoprotein (a) is implicated in the pathogenesis of both aortic stenosis and atherosclerosis. Elevated lipoprotein (a) levels also predict faster hemodynamic progression of AS. Patients with Psoriasis are at increased risk for atherosclerosis, and more recently, psoriasis has been tied to an increased risk of aortic stenosis. In patients<70 years,the most common cause of aortic stenosis is A congenital Bicuspid Aortic Valve None Congenital aortic stenosis occurs in 3 to 5/1000 live births and affects more males; it is associated with Coarctation of the Aorta and progressive dilatation of the ascending aorta, causing In medically underserved countries,the most common cause of aortic stenosis in all age groups is Rheumatic Fever None caused by a discrete congenital membrane or hypoplastic constriction just above the sinuses of Valsalva is uncommon. A sporadic form of supravalvular AS is associated with a characteristic facial appearance (high and broad forehead, hypertelorism, strabismus, upturned nose, long philtrum, wide mouth, dental abnormalities, puffy cheeks, micrognathia, low-set ears). When associated with Neonatal Hypercalcemia , this form is known as Williams syndrome. Subvalvular AScaused by a congenital membrane or fibrous ring just beneath the aortic valve is uncommon. 