Aortic stenosis is a common valvular heart disease, affecting mainly people over age 60. It is characterized by years to decades of slow progression followed by rapid clinical deterioration and a high death rate once symptoms develop. The onset of symptoms confers a poor prognosis: patients die within an average of five years after the onset of angina, three years after the onset of syncope, and two years after the onset of heart failure symptoms. The overall mortality rate is 75% at three years without surgery. Drug therapy for it remains ineffective, and aortic valve replacement is the only recommended long-term treatment.