Why does the Aortic Valve start to open even when the pressure difference is not favorable?

Study on the Physiology of the Aortic Valve

The aortic valve is a one-way valve situated between the aorta and the left ventricle. One-way valves open when the pressure on one side is more than on the other side. Do you know aortic valve starts to open even when the pressure difference is not favourable? Why is this important?

Aortic valve disease affects 5 to 7 % of the elderly population. Understanding the mechanics of the aortic valve is critical to cardio thoracic surgical procedures.

Simulation of the Opening and Closing of a Normal Valve