**4. Valve choice**

Currently, the types of valves most implanted are balloon-expandable and selfexpanding valves.

Basically, the choice of valve depends on anatomical considerations and available valve sizes. Attention should be paid to annulus dimension and its geometry, bicuspid/tricuspid valve, amount and distribution of calcifications in LVOT and proximal aorta, sino-tubular and ascending aorta dimensions, and coronary height [11].

Usually, in the case of extensive calcifications with an increased risk of rupture, in extreme oval-shape annulus or in the presence of iliofemoral diameter between 5.0 and 5.5 mm, a self-expanding valve is preferred [29–31].

Instead, when we are in the presence of dilated ascending aorta (> 43 mm), very angulated aorta (particularly for transfemoral approach), or in the presence of an elevated preoperative risk of postprocedural pacemaker implant, the choice can fall on the balloon-expandable valves.

Anyway, most of the time the choice depends on operator experience and confidence [3].
