Porcine stented xenograft has been less favorable hemodynamic function in aortic position.
In 5 cases of AVR using porcine xenograft, preoperative and postoperative hemodynamics has been evaluated. The transvalvular pressure gradients were significant and calculated valve areas were small.
In order to investigate the cause of these disadvantageous properties of porcine stented xenograft, we have made the analysis of opening characteristics of normal aortic valve using isolated heart-lung preparations and hydraulic simmulation using tri-leaflet valve hearing aortic root model.
In the opening phase of aortic valve, increase in the radius of comnissure perimeter, distension of free margins of leaflets and circular orifice of the valve were observed. Therefore, the valve area was larger than the aortic area at three commissures in closing phase.
Stented xenograft, however, dose not have these mechanism. It is the reason why stented xenografts show hemodynamically disadvantageous properties, especially in small sizes. So, porcine stented xenograft must not be used in aortic position when the valve size is small.
