[Transcatheter-based aortic valve implantation. Present and future technologies]

The calcified aortic stenosis is the dominating valve disease. Patients affected are most common elderly people in the 8th or 9th decade of their life who often show associated comorbidities like reduced left ventricular function, impaired renal function, pulmonary hypertension, and further diseases (diabetes mellitus, stroke, chronic obstructive pulmonary disease). In many cases perioperative morbidity and mortality are too high for surgical valve replacement and patients are rejected. Nevertheless, prognosis of aortic stenosis is worse, if the typical symptoms like dyspnea on exertion, syncope, and angina occur. The transcatheter aortic valve implantation is an alternative treatment for this particular group of patients. The aortic valve bioprosthesis consists of a balloon-expandable stent or a self-expandable frame, in which a valve of bovine or porcine pericardium is incorporated. The implantation is performed by retrograde access via the femoral artery; the balloon-expandable prosthesis can also be implanted by transapical approach. Alternatively, the subclavian artery is chosen for access. More frequently, the implantation is performed in analgosedation with the patient awake that favors the transfemoral approach. A further reduction of the available prosthesis and new types of valves which are under current experimental tests and clinical evaluation contribute to this development.