Tuesday, December 13, 2011
4:00 – 5:00 pm
1504 GG Brown
The seminar for Tuesday, December 13, features Alison Marsden. Marsden is currently an assistant professor in the Mechanical and Aerospace Engineering department at UCSD. She graduated with a bachelor’s degree in mechanical engineering from Princeton University in 1998, a PhD in mechanical engineering from Stanford in 2005, and did postdoctoral work at Stanford University in bioengineering and pediatric cardiology from 2005-07. She has been the recipient of an American Heart Association postdoctoral fellowship, an AHA beginning grant in aid award, a Burroughs Wellcome Fund Career Award at the Scientific Interface, and is a member of an international Leducq Foundation Network of Excellence comprised of clinicians and engineers. Her work focuses on the application of optimization to fluid mechanics with particular emphasis on cardiovascular surgery and congenital heart disease. Marsden will discuss “Optimization and Multiscale Modeling for Single Ventricle Heart Patients.”
Abstract: Single ventricle heart patients are among the most challenging for pediatric cardiologists to treat, and these patients typically undergo a series of three open heart surgeries starting within the first few days of life. The final anatomy (a total cavopulmonary connection, or Fontan) directly connects the venous return to the pulmonary arteries, separating the systemic and pulmonary circulations. We will present our recent work combining shape optimization and multiscale modeling to test surgical designs of the first and third stages of the single ventricle repair, the BT shunt and the Fontan surgery. The optimization algorithm we present is an efficient derivative-free surrogate pattern search method with well established convergence theory. The optimization routine is coupled to a finite element flow solver in a fully-automated loop. Multiscale modeling couples the 3D Navier Stokes solution with a 0D lumped parameter network to model the systemic and pulmonary circulations. The use of a multiscale method allows us to capture changes in global circulatory response resulting from changes in local anatomy. A new implicit coupling algorithm for this system will be presented. Issues of numerical stability for the coupled system will be discussed, and methods for preventing divergence will be quantified and compared. Optimization results for the BT shunt will be presented, and the effect of shunt size, and anastomosislocation on coronary and systemic perfusion will be presented. Similar methods were also applied to model the third stage Fontan surgery. We will present a novel Y-graft design for the Fontan surgery that has been developed and tested in simulations on multiple patient models. Optimization of the design has led to improvements in hepatic flow distribution, an important clinical parameter related to lung development. Issues and goals related to clinical translation of the Y-graft design will be discussed.
For more information on future department seminars, visit the ME Seminar Series page.