Cardiovascular Fluid Mechanics
July 1, 2002 — July 5, 2002
Coordinators:
- Karl Perktold (Technical University of Graz, Graz, Austria)
- Gianni Pedrizzetti (Università di Trieste, Trieste, Italy)
Arteriosclerosis and heart diseases represent the major cause of death in the western world. The dramatic increase in the number of symptomatic and asymptomatic patients has provoked increased attention in the development of systematic approaches to improve diagnostic and therapeutic techniques. The role of fluid dynamics derives from the fact that the onset and development of arteriosclerosis that is observed in proximity of curved and branching arteries is associated with the irregularities of the local hemodynamic pattern; at the same time most heart diseases correspond to specific variations of the flow in the heart chambers. Fluid dynamics has contributed significantly in the recent past years and most diagnoses are now made using a combination of ultrasonic imaging and Doppler measurements of flow velocity, however its role is still destined to grow with the growing capabilities of numerical and diagnostic tools.
The course presents recent advances in the interdisciplinary field represented by the application of fluid mechanics to cardiovascular problems. The progress in such field closely follows the growing computational capabilities that allow the direct numerical simulation of fluid flows in complex sites and conditions. Nevertheless much care and experience must be taken when evaluating the accuracy of these results that are affected either by the numerical approximations or by the model idealisation of the actual physiological conditions. The rapid advancement of diagnostic techniques allows a closer link and a completion between in vivo data and numerical models. Given the differences between singular applications of the same pathology, it is also important to build relatively simple conceptual models able to interpret the qualitative information available.
The course is addressed to doctoral students and experienced researchers in fluid mechanics and biological fluid mechanics. The course will extensively treat recent advances in the computational aspects and theoretical modelling of cardiovascular fluid mechanics; the course also covers some basic elements on the relevant physiology and discusses open problems for the clinical applications.
The course is planned in 32 lectures given by with 6 different lecturers:
• 4 lecturers (22 lectures), from the field of bio fluid mechanics, will present the physical aspects and discuss recent advances in the mathematical models of flow phenomena in large blood vessels. The lectures will cover numerical simulations, conceptual models, and applications. The different aspects, new techniques, and perspectives of direct numerical simulations are covered in the course. These include advanced solution methods for complex domains, their efficiency and accuracy, the problem of grid generation for realistic geometries, and the implementation of reliable boundary conditions at the walls and at the in-outlets. Conceptual models, as well as approximate or simplified numerical models, will also cover a part of the course. These topics, which include complex geometry, boundary-layer separation and vorticity dynamics, interaction between flow and elastic walls, allow qualitative syntheses of phenomena and improve interpretation of numerical results. Applications to realistic cases will be presented in connection to the different approaches presented.
• 2 lecturers (10 lectures), from the applied medical research, who will introduce relevant physiology and pathological aspects, and actual in vivo measurements. Non-invasive ultrasound techniques are introduced to assess mechanical properties of the blood and vessel/heart walls in humans, as well as flow characteristics and wall motion. Topics regarding the relation between intima-media thickness and wall shear stress, modifications with ageing and pathologies, and the structure-function relation of arteries and heart valves are presented. Emphasis is put on advanced diagnostic tools, related outcomes, and possible crosschecks. Several applications will be shown in detail. Discussions are reserved to relevant open problems, these represent a crucial element in the development of such an interdisciplinary field, that is the clear identification of the fluid dynamical problem to be analysed for an effective physiological aim.