Abstract: The invention relates to a device for testing the functioning of an aortic valve by placing the device on the free end of a cylindrical tubular prosthesis inserted into the aorta, said tubular prosthesis being connected, with its other end, to the aortic wall in the region of the aortic valve. According to the invention, the device consists of a multi-part housing provided with at least one through-flow channel for a control liquid, the housing being provided, on its lower side facing the free end of the tubular prosthesis, with a peripheral sealing device that can be placed around the edge of the tubular prosthesis, and at least one pressure-measuring sensor and at least one optical sensor element for video recording being arranged on the lower side.