Aortic stenosis (AS or AoS) is the narrowing of the exit of the left ventricle of the heart, such that problems result. It may occur at the aortic valve as well as above and below this level. It typically gets worse over time. Symptoms often come on gradually with a decreased ability to exercise often occurring first. If heart failure, loss of consciousness, or heart related chest pain occurs due to AS the outcomes are worse. Loss of consciousness typically occurs with standing or exercise. Signs of heart failure include shortness of breath especially when lying down, at night, or with exercise, and swelling of the legs. Thickening of the valve without narrowing is known as aortic sclerosis.
Causes include being born with a bicuspid aortic valve and rheumatic fever. A bicuspid aortic valve affects about one to two percent of the population while rheumatic heart disease mostly occurring in the developing world. A normal valve, however, may also harden over the decades. Risk factors are similar to those of coronary artery disease and include smoking, high blood pressure, high cholesterol, diabetes, and being male. The aortic valve usually has three leaflets and is located between the left ventricle of the heartand the aorta. AS typically results in a heart murmur. Its severity can be divided into mild, moderate, severe, and very severe based on ultrasound of the heart findings.
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http://www.aafp.org/afp/2016/0301/p371.html aortic stenosis: diagnosis and treatment brian h. grimard, md; robert e. safford, md, phd; and elizabeth l. burns, md, mayo medical school, jacksonville, florida am fam physician. 2016 mar 1;93(5):371-378.
university of pennsylvania school of medicine. "one-third of patients with low flow aortic stenosis do not improve with transcatheter aortic valve replacement, research finds: patients who do not improve with tavr are found to have worse clinical outcomes at one year." sciencedaily. sciencedaily, 15 june 2016. www.sciencedaily.com/releases/2016/06/160615134745.htm .
http://www.hindawi.com/journals/crp/2012/145202/ katie l. losenno, robert l. goodman, and michael w. a. chu, “bicuspid aortic valve disease and ascending aortic aneurysms: gaps in knowledge,” cardiology research and practice, vol. 2012, article id 145202, 16 pages, 2012. doi:10.1155/2012/145202
http://eurheartj.oxfordjournals.org/content/ehj/35/31/2069.full.pdf clinical update:aortic stenosis and coronary artery disease:what do we know? what don’t we know?a comprehensive review of the literature with proposed treatment algorithms by jean-michel paradis et al., european heart journal (2014) 35, 2069–2082 doi:10.1093/eurheartj/ehu247