Trileaflet reconstruction of the aortic valve with autologous pericardium (TriRec) is a new treatment option for diseased aortic valves and offers benefits compared to conventional valve replacement. At the moment no prospective randomized trials evaluating the role of the TriRec procedure are available and factors contributing to long- term durability are unknown.

The investigators want to examine aortic flow patterns with 4D- Flow- Magnetic Resonance Imaging (MRI) in patients after the TriRec procedure or biological prosthetic valve replacement in a prospective randomized trial. Flow patterns in the ascending aorta, examined with 4D- Flow- MRI, show nearly laminar flow patterns and no outflow obstruction in healthy subjects with tricuspid aortic valves. In contrast, helical flow patterns, turbulences and increased flow velocities are observed in diseased valves and also after valve replacement with mechanical or biological prostheses. These helical flow patterns seem to influence aortic wall remodeling and may contribute to structural valve dysfunction of biological prosthesis.

The investigators hypothesize that after TriRec procedure more physiological flow patterns will be observed, compared to biological valve prosthesis. The results can contribute to understand mechanisms for long- term performance of this technique and determine the role of this novel technique for treatment of aortic valve disease.