Aortic stenosis restricts the blood flow from the left ventricle to the aorta and may also affect the pressure in the left atrium. Watch an animation of aortic valve stenosis. Aortic valve plays a key role in getting oxygen-rich blood to your body. Aortic valve stenosis is a common and serious heart problem. Aortic stenosis mainly occurs due to the buildup of calcium deposits that narrow the valve. Patients with aortic stenosis can live full and rewarding lives. However, they may need to be monitored by a heart specialist with office visits and periodic testing. Aortic valve stenosis occurs when the aortic valve narrows and doesn't open as it should. This limits the amount of blood pumped from your heart . The most common cause of aortic stenosis in a person under age 70 years is a congenital bicuspid aortic valve. Approximately 2% of the population is born with a bicuspid aortic valve, and about half of these individuals develop at least mild aortic stenosis by the age of 50 years. Rheumatic valvular disease is responsible for aortic stenosis on occasion.