Physical Modeling and Computer Simulation of Balloon Angioplasty

START project Y 74 Physical and Numerical Modeling of Balloon Angioplasty Gerhard HOLZAPFEL 20.06.1997 Objective: To improve computer simulation and physical modeling of balloon angioplasty which is an important mechanical treatment in clinical practice. Background: Balloon angioplasty is a major treatment in atherosclerotic diseases at almost every vessel site (coronary, peripheral, supraaortic, renal, mesenteric and aorta). Therefore it has enormous epidemiological and economical importance. However, clinical success is not satisfying. Finite element method basically is appropriate to simulate the highly-individual nonlinear mechanisms of balloon angioplasty. It is a helpful computational tool and the approximation technique of choice. To do so, appropriate finite element codes as well as refined physical models for plaque and media damage have to be developed. Nonlinear continuum mechanics provides the suitable theoretical framework. Purpose: To simulate balloon angioplasty in a clinically relevant way. This would,. be helpful in developing lesion- specific performances of balloon angioplasty, in predicting dilation success for effective treatment planning, in developing new catheter designs, in training of interventional. physicians (to list only the most important items). International Cooperation: In order to better understand the mechanical process and to improve the clinical success rate of balloon angioplasty the expertise and cooperation of a team of professionals belonging to different scientific research fields is indispensable. The research program proposed is supported by: 1) Prof. Dr. Kozaburo Hayashi, Department of Mechanical Engineering, Faculty of Engineering Science, Oskaka University, Toyonaka, Osaka, 560 Japan. 2) Prof. Dr. Jean H. Heegaard, Department of Mechanical Engineering, Faculty of Biomechanical Engineering Division, Stanford University, Stanford, USA. 3) Prof. Dr. Peter Wriggers, Institute for Mechanics, TH Darmstadt, Hochschulstraße 1, 63289 Darmstadt, Germany. 4) Prof. Dr.h.c.Dr. Thomas Kenner, Institute of Physiology, Karl-Franzens-University Graz, Harrachgasse 21/V, 8010 Graz, Austria. 5) Prof. Dr. Ernst Pilger and Dr. C. Schulze-Bauer, Division of Angiology, Department of Internal Medicine, Karl- Franzens-University Graz, 8036 Graz, Austria. Influence of the proposed work on the development of the field Computational (Bio)mechanies and Finite-Element-Methods: Finite-Element and software development. Development of an appropriate program environment which efficiently enables numerical simulations of balloon angioplasty procedures. Implementation of nonlinear material models into new finite element technologies. Continuum damage model -for the media. Development of arterial continuum damage, models for the inner media. Identification of material parameters. Intravascular ultrasound imaging (IVUS). Coupling of IVUS-images with finite element methods. Generation of 3D-finite element meshes based upon ultrasound images. Parameter studies. Large scale structural analyses of balloon angioplasty for developing a catalog of configurations with particular features that could guide therapeutic decisions. Clinical Applications: Besides these computational concerns for basic research and engineering there are a lot of promising clinical applications. => Development of new catheter designs and sophisticated performance techniques of balloon angioplasty, find optimal performance parameters (balloon diameter, balloon length ...). => Prediction of long term results - more insights in the biomechanical individual processes could bring new (mechanical) concepts of restenosis. => Insights in balloon angioplasty process - a finite element model could help to understand the complex mechanisms of angioplasty (rupture, dissection, plaque, fracture ...). => Clinical applications to stenotic non-atherosclerotic lesions in other organs (ureter, gut ...)