The left atrioventricular valve is structurally different from the aortic valve in the following ways.:
The Left atrioventricular valve is bicuspid valve while the Aortic valve is the semilunar valve.
The Left atrioventricular valve has irregular leaflets that regulate the opening and closing of the atrioventricular orifice, while the aortic valve has cusps like structure folded like half moon shaped structure.
Specialized supporting structures are needed to support the AV valve to the heart while the semilunar shape of aortic valve is self supportive.
Explanation:
Atrioventricular valves maintain the unidirectional flow of blood from atria to ventricles while the aortic valve maintains unidirectional flow of blood from left ventricle to the aorta.
