Balloon aortic valvuloplasty (BAV) plays a crucial role in transcatheter aortic valve implantation (TAVI). However, data on morphology during BAV are lacking. During surgical aortic valve replacement, open BAV was performed as a non-therapeutic in-vivo model prior to aortic valve excision. Twenty-six patients with severe aortic stenosis were included in the study after ethics committee approval. A valvuloplasty balloon was advanced from the open aorta, across the stenotic aortic valve and was rapidly inflated and deflated. All patients except for one had tricuspid aortic valves with severe visible calcification on the aortic side of leaflets. All valves were successfully dilated. Only in the presence of severe central calcific noduli, fractures occurred in the middle portion of the leaflets in three and in the commissural part in four patients. No embolization of valvular debris occurred, however, ten coronary leaflets partially reached coronary orifices, resulting in three near-obstructions. The present study visualized for the first time the behaviour of bulky leaflet calcifications during valvuloplasty. Fractures in the middle portion of the free edge may occur whenever a huge calcification completely affects the whole leaflet area. No signs of embolization were observed, possibly explaining low stroke rates during TAVI procedures.