Aortic stenosis is the most common cardiac valve lesion in the USA. Because 1% to 2% of the population is born with a biscuspid aortic valve, aortic stenosis increases with age. In contrast with aortic sclerosis, which tends to be benign and associated with leaflet thickening only, aortic stenosis is associated with measurable outflow obstruction due to decrease in functional area of the valve, with subsequent diastolic and systolic left ventricular dysfunction.