Translational approach to aortic valve repair techniques: "in silico","in vitro","in vivo" data merging

Introduction Aortic Valve Repair procedures have not good long term results but in dedicated centers due to a lack of standardization. The minor tissue quantity compared to the mitral valve reduce the errors margins in each techniques applied. Translational approach means merging data from different research methodology. Our aim is to apply such an approach to the aortic valve repair procedure in order to obtain different information from different methodology ranging from bioengineering to medical research tools to analyze , improve and standardize different surgical techniques. Material and Methods The Research has been divided in 4 steps First step has been the project on a new self designed pulse duplicator platform in order to reduce during root surgery any modification induced by root repositioning and permitting a deep control both on hydrodynamic parameters and on the surgical field. This set-up has been used to compare differences between tricuspid and bicuspid aortic valve. Second step has been the information and anatomical data gathering to build different finite elements models able to simulate different pathologies and different surgical repairs. Third step was the cross - validation of these “in vitro” and “in silico” models and the application of two different aortic valve repair techniques on them. The Interleaflet Triangles Reshaping , a simple and widely used surgical procedure in order to try to predict the final result from pre-op measurements and the NeoChordae technique, a very new , not standardized , rarely used procedure in order to try to optimize results before the clinical experience. Forth step was the merging between “in silico”, “in vitro” and “in vivo” results. Results This new approach permitted : the definitions of which is the physiologic interleaflet triangle dimension and where is better to perform the reshaping procedure in order to achieve a annular reduction, increased coaptation and not hampering the normal leafets kinematics increasing the pressure drop accros the valve. The error margin was defined as the 60% of the triangles height.These data were validated by the clinical experience “in vivo”. The best place where to insert a Neocordae was discovered and the range of the applied force was defined as well as the results of some errors in performing the technique. Conclusions Our translational research approach seems to succeed in refining surgical techniques already considered standardized, in defining the consequence of a sub-optimal technique application and in studying new techniques reducing the “acute” model, often represented by the animal model, according to the 3R research guidelines.

Approccio transnazionale alla riparazione della valvola atroci attraverso il merging dei dati ottenuti da 3 diversi ambiti di ricerca: in silico mediante modelli ad elementi finiti, in vitro mediante analisi su banco prova appositamente progettato, in vivo attraverso l'analisi della esperienza clinica. Questa metodica di ricerca è stata applicata a 2 diverse tecniche chirurgiche: il reshaping dei triangoli subcommissurali e l'applicazione di neocorde sui foglietti aortici.