Cause
Aortic stenosis is most commonly caused by age-related progressive calcification of a normal (three-leafed) aortic valve (>50% of cases) mean age 65 to 70 years old - most common cause. Other causes include calcification of a congenital bicuspid aortic valve (30-40% of cases) most common cause and acute rheumatic fever post-inflammatory (less than 10% of cases).
Normal valves have three leaves (tricuspid), but some valves have two leaves (bicuspid). Typically, aortic stenosis due to calcification of a bicuspid valve appears earlier, in the 40s and 50s, whereas that due to calcification of a normal valve appears later, in the 70s and 80s. Hypertension, diabetes mellitus, hyperlipoproteinemia and uremia may speed up the process.
Read more about this topic: Aortic Valve Stenosis