Graduate Students Receive American Heart Association Fellowships

February 13, 2023

Two UT Austin Biomedical Engineering graduate students received the prestigious American Heart Association (AHA) Predoctoral Fellowship Award. 

Andrew Robinson is a fourth-year graduate student in the Cosgriff-Hernandez Lab and Natalie Simonian is a third-year graduate student working in the Michael Sacks Willerson Center for Cardiovascular Modeling and Simulation.  

The purpose of the fellowship is to enhance the training of promising students in pre-doctoral or clinical health professional degree training programs and recognize students who intend careers as scientists, physician-scientists or other clinician-scientists, or related careers aimed at improving global health and wellbeing.

Andrew Robinson:

Robinson’s research focuses on the development of electrospun materials for cardiovascular applications, specifically the development of synthetic vascular grafts and heart valves with improved mechanical properties. 

His proposal for the American Heart Association predoctoral fellowship is titled "Model-directed Fabrication of a Durable Synthetic Heart Valve” that aims to design and optimize a polymer-based synthetic replacement valve.

Current clinically used bioprosthetic replacement heart valves have a high rate of failure within 10-15 years due to limited durability. Unfortunately, these biological-based materials have seen little advancement in durability over the last few decades leading to the desire for a synthetic heart valve.

Polymeric valves enable a large design space to develop the next generation of heart valves. However, current fabrication methods of polymeric materials often result in isotropic materials—meaning the valve has the same mechanical properties in all directions.

This can cause a potential problem considering the native heart valve has a highly anisotropic structure. Previous modeling work by collaborators in the Sacks Lab demonstrated that even small changes toward a native fiber structure significantly improves the function and may lend toward enhanced durability of the valve.

Applying the electrospinning procedures that Robinson refined over the last few years, he can fabricate materials with curvilinearly aligned fibers, where fibers are aligned in an arc, like the colors of a rainbow, and wavy fibers over a wide range.

A model of electrospun fibers

Utilizing computational simulations in collaboration with the Sacks Lab, the wide range of fiber structures that Robinson can produce will be explored rapidly using computer models. The combination of advanced material fabrication and computational simulation provides a promising route to rapidly identify fiber structures that optimize the durability of the heart valve.

Inside and outside of the Cosgriff-Hernandez lab, Robinson is dedicated to improving the lives of others.

“Beyond being a tenacious and brilliant researcher, Andrew is always willing to help fellow lab members and has worked to build a more diverse and inclusive engineering community here at UT,” said Cosgriff-Hernandez.

Natalie Simonian:

Simonian’s research focuses on patient-specific, image-based models of the mitral valve to predict surgical outcomes and optimize treatment planning.

The mitral valve is the largest of four valves in the heart, and its function is to ensure the correct direction of blood flow in the left side of the heart. Sometimes, the valve can no longer close properly and blood leaks backwards, a condition known as Mitral Regurgitation. One method to fix a leaky valve is to surgically implant a ring around the edge of the valve.

Unfortunately, this method is unsuccessful in approximately 33 percent of patients.

Another treatment option is the MitraClip procedure which closes the valve by pinning the leaflets together with a clip. The procedure is a safe option even for patients who cannot handle surgery. However, this procedure also does not work well for everyone and improved testing to find the most beneficial method is essential.

Her proposal for the American Heart Association predoctoral fellowship is titled "In-Vivo Patient-Specific Optimization of MitraClip Repair in Mitral Regurgitation" and focuses on developing computer models of a patient’s heart to predict if the MitraClip procedure would be beneficial

Working with clinical images of a patient’s heart, Simonian creates a 3D computer model and simulate its movement before and after surgery. Examining differences in size, shape, and behavior between valves that function well after treatment can tell researchers more about how the disease damages the valve and how the clip impacts the valve.

"Multi-center registries and randomized trials would be necessary to prove which procedure is superior for a given patient. Given the number of proposed procedures and the complexity and duration of such studies, it is highly unlikely that MV repair procedure optimization will be achieved by prospective clinical trials alone. Our goal is the development of high-speed computational methods for patient specific pre-surgical TEER simulations to determine optimal repair strategies in clinically relevant timeframes," said Michael Sacks, professor of biomedical engineering and director of The Oden Institute James T. Willerson Center for Cardiovascular Modeling and Simulation.

The overall goal of Simonian's research is to provide physicians with improved, patient-specific knowledge about the efficacy of each treatment option for patients with leaky mitral valves.