If the aortic valve leaflets are thickened or calcified, or if there is prolapse or perforation of the valve leaflets, blood from the aorta may regurgitate through the aortic valve into the left ventricle. Mild regurgitation means that only a small amount of blood regurgitates into the left ventricle and does not cause serious problems for the person, which means that mild aortic regurgitation usually has no obvious symptoms and does not cause heart failure, etc. The aortic valve is a one-way valve located between the ascending aorta and the heart, which under physiological conditions prevents the aortic blood from backflowing into the heart and causing damage. In normal people, there are generally three aortic valve leaflets, and in diastole the three leaflets are very tightly matched to prevent backflow of blood from the ascending aorta to the heart.