[1] The aortic valve is the last structure in the heart the blood travels through before stopping the flow through the systemic circulation.

The term "semilunar" refers to an approximate half-moon shape of the valve leaflets.

When ventricular systole ends, pressure in the left ventricle rapidly drops.

The closure of the aortic valve contributes the A2 component of the second heart sound (S2).

[6] Closure of the aortic valve permits maintaining high pressures in the systemic circulation while reducing pressure in the left ventricle to permit blood flow from the lungs to fill the left ventricle.

This compensation is through dilation of the left ventricle and return to normal filling pressures.

Dysfunctional aortic valves often present as heart failure by non-specific symptoms such as fatigue, low energy, and shortness of breath with exertion.

Common causes of aortic regurgitation include vasodilation of the aorta, previous rheumatic fever, infection such as infective endocarditis, degeneration of the aortic valve, and Marfan's syndrome.

[9] The choice between SAVR and TAVR often relies on the open-heart surgical risk and indications for other open heart surgeries (etc., coronary bypass, other valve dysfunction).

The first minimally invasive aortic valve surgery took place at the Cleveland Clinic in 1996. .

It contributes the A2 component to the second heart sound and changes with inspiration ("splitting") Transthoracic echocardiography (TTE) is used as the first test because it is non-invasive.

Using TTE, the degree of stenosis and insufficiency can be quantified to grade the valve dysfunction.