Aortic valve

Function

The aortic valve's three semilunar cusps — left, right and posterior — face the hardest workload in the circulation, opening and closing against 120 mmHg some 3 billion times in an average life. Behind each cusp, the aorta bulges into a sinus of Valsalva; the coronary arteries branch from the left and right sinuses, feeding the myocardium during diastole when the valve is closed.

Its closure sound (A2) normally precedes the pulmonary (P2); the split widens in right bundle branch block and pulmonary stenosis, and reverses (paradoxical splitting) in left bundle branch block and severe aortic stenosis.

Blood supply

Left and right coronary ostia arise from its sinuses.

Nerve supply

Passive hydraulic closure.

Clinical relevance

Aortic stenosis

Calcific degeneration of a trileaflet (or congenitally bicuspid) aortic valve narrows the orifice — angina, syncope and heart failure in the elderly, now treatable by TAVI without open surgery.

Aortic regurgitation

Diastolic leak widens the pulse pressure — a collapsing (water-hammer) pulse and visible carotid pulsation (Corrigan's sign).

Related conditions

• Aortic stenosis
• Infective endocarditis
• Rheumatic heart disease