**4. Features of perceval-S prosthesis implantation in bicuspid aortic valve**

Bicuspid aortic valve can pose a significant challenge during the implantation of a sutureless valve. The most common variants encountered are Sievers 1 or 2. Abnormal distribution of leaflets and commissures around the fibrous annulus circumference may lead to improper positioning of guiding sutures. Improper positioning of the valve frame can result in the formation of paravalvular fistulas. It is also essential to pay attention to the coronary artery ostia, which may have non-standard origins.

For correct valve seating, it is necessary to create guiding sutures around the circumference at points of 120–120-120 degrees and pre-calculate the position of the valve struts relative to the coronary artery ostia. The valve should not be implanted in case of aortic root dilatation. Isolated dilation of the ascending aorta above the sinotubular ridge is not a contraindication for implantation.
