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According to these methods, the hemi-Fontan and bidirectional Glenn procedures performed equally well, but important differences in energy losses and flow distribution were found after the completion Fontan procedures. The superior hydraulic performance of the lateral tunnel Fontan operation after the hemi-Fontan procedure relative to any other method may be due to closer to optimal caval offset achieved in the surgical reconstruction.

Edge-to-edge mitral valve repair consists in suturing the free edge of the leaflets to re-establish coaptation in prolapsing valves. The leaflets are frequently sutured at the middle and a double orifice valve is created. In order to study the hemodynamic implications, a parametric model of the left heart has been developed. Different valve areas and shapes have been investigated. Results show that the simplified Bernoulli formula provides a good estimation of the pressure drop and that the pressure drop may be predicted on the basis of the pre-operative geometric and hemodynamics data by means of customized models.

Although patients undergoing dialysis have a complex illness, there are compelling reasons to believe that the inadequate removal of organic waste is an important contributing factor to the illness itself. This paper focuses on the transport phenomena that occur within a dialyser. An attempt is made to clarify how transport phenomena are related to the performance of a dialysis session and how they depend on the membrane characteristics. Our study offers some discussion points on the complex issue of defining what the best parameters could be in comparing the efficiency of different membranes. The new high-flux dialysers have improved larger-molecule clearance and biocompatibility. Membrane performance is a very hard process to evaluate, and different membranes can only be compared by establishing adequate points of comparison. At the same time, the points of comparison themselves may change depending on the type of co-morbidities of the specific patient who is considered for membrane selection. This editorial (together with all the papers presented in this issue) seeks to focus on the membrane's own merits in improving the dialysis therapy.