|University of Houston mathematician Sunica Canic and her colleagues build computer models to study stents. Their simulations could lead to better designs and also help doctors select the right stents for specific procedures. Computer scientists usually model stents in three dimensions, keeping track of about 200,000 mesh points points Together with her collaborator Josip Tambaca of the University of Zagreb in Croatia, and her Ph. D. student Mate Kosor, Canic wrote a much simpler program that approximates stents with only 400 mesh points.|
Scientists Use Math to Build Better Stents
Emily Carlson, August 16, 2010
University of Houston mathematician Sunica Canic and her colleagues build computer models to study stents; their simulations could lead to better designs and also help doctors select the right stents for specific procedures
"I realized we could provide them with a fluid dynamics and mechanics point of view to help them make decisions…for example, about which stent grafts they use in their procedures," she said.
Stents are tiny mesh tubes made from metal alloys that hold blood vessels open after they've been clogged with disease-causing plaque. Even though stents are designed to be compatible with the human body, they sometimes cause unwanted reactions, such as blood clots and scar tissue formation. So scientists have tried to coat stents with cells that make the tiny tubes even more compatible.
But these, too, aren't yet perfect, said Canic. Blood flowing over a coated stent can still clot or tear cells away. This is, as Canic put it, "not good." A professor of mathematics at the University of Houston, Canic makes computer models to guide the search for a better stent coating.
Congressional Briefing: December 6, 2011 "Mathematics:
Leading the Way For New Options in the Treatment of Coronary Artery Disease"
She also uses computer models to study the strengths and weaknesses of different stent structures. Her work could help manufacturers optimize stent design and help doctors choose the right stents for their patients, ultimately improving patient outcomes.
Computer scientists usually model stents in three dimensions. Keeping track of about 200,000 points, or nodes, along the stent mesh, the models are massive.
Together with her collaborator Josip Tambaca of the University of Zagreb in Croatia, and her Ph. D. student Mate Kosor, Canic wrote a much simpler program that approximates stents as meshes of one-dimensional rods. This program let them achieve the same result using just 400 nodes.
Professor Sunčica Čanić was born in the city of Pula, Croatia.
Using their simplified model, the researchers have examined the designs of several stents on the market to see which structures seem to be best for specific blood vessels or procedures. For instance, they found that stents with an "open design" — where every other horizontal rod is taken out — bend easily, which makes them good to put in curvy coronary arteries.
Canic has also used the model to design a stent with mechanical properties specifically tailored to an experimental heart-valve replacement procedure. She found that this specialized stent works best for the procedure when it's stiff in the middle and less stiff at the ends. In addition, she has found that combining bendiness with radial stiffness — where you can bend the stent into a U shape, but you can’t squeeze the tube shut — produces a stent with less chance of buckling than those that are currently in use.
The most rewarding part of her work, said Canic, is that "we can use mathematics for something useful, connected to real-world problems." She reports that her collaborators are already putting the results of her simulations into practice.
Meanwhile, her greatest challenge is serving as an ambassador of mathematics to the medical and bioengineering communities.
Professor Sunčica Čanić studied mathematical sciences
at the University of Zagreb, Croatia, where she earned her Master's degree.
In the beginning, she said, it was difficult to collaborate with people from different disciplines who speak different scientific languages. "But once they saw that there is a lot of information there that could be helpful, it has been much easier," she said. "Now people want to talk to us from the medical center. They come to us and ask questions, and that's good."
Today, Canic is collaborating with Prof. Boris Muha (University of Zagreb), Prof. Martina Bukac (University of Pittsburgh), Prof. Annalisa Quaini (University of Houston), and Dr. Stephen Little (Methodist Hospital in Houston) on modeling a novel experimental procedure for heart valve replacement, called Transcatheter Aortic Valve Replacement (TAVR).
Since only a few years ago, patients with failing aortic valves no longer need to have open-heart surgery. All that is needed is a small cut in the patient's groin area, where a catheter, holding a bioartificial valve, is placed and guided through the patient's arteries, all the way to the location of the failing aortic valve. The valve, which is mounted on a stent, is then pushed out of the catheter, and a self-expanding stent anchors the valve in the location of the failing valve.
Modeling the function of the new valve, and of the stent holding the valve, is what Canic and her team are investigating these days. In their medical collaborator's lab, 3D printing of human organs, and parts of the patient's cardiovascular system surrounding the aortic valve, combined with mathematical modeling and computer simulations, are being used for patient-specific simulations of this procedure. "What was science fiction yesterday, is reality today," says Canic.
Cullen Distinguished Professor
Department of Mathematics
622 PGH Building
University of Houston
Houston, Texas 77204-3476
Phone: (713) 743-3466
Fax: (713) 743-3505
University of Zagreb, Croatia, BA, 1984
University of Zagreb, Croatia, MA, 1986
State University of New York at Stony Brook, PhD, 1992
2008-present, Cullen Distinguished Professor, University of Houston
2008-present, Director, Center for Mathematical Sciences, Houston
2011-2015, Member of College of CSR Reviewers at NIH (Center for Scientific Review)
2013-2015, Program Director for the SIAM Analysis of PDEs Activity Group
2013-2015, Associate Editor for SIAM J Numerical Analysis
2003-2008, Full Professor of Mathematics, University of Houston
2003 Aug./Sep., Invited Visiting Professor, University of Lyon1, France
1998-2003, Associate Professor of Mathematics, University of Houston
2001 May, Invited Visiting Professor, University of Lyon1, France
1998-1999, Associate Professor of Mathematics, Iowa State University
1992-1998, Assistant Professor of Mathematics, Iowa State University
1997-1997, Visiting Assistant Professor of Mathematics, SUNY Stony Brook
1996-1996, Visiting Assistant Professor of Mathematics, University of Houston
1993-1993, Fields Institute Fellow, The Fields Institute, Waterloo, Canada
1992-1992, Visiting Assistant Professor of Mathematics, University of Houston
1989-1992, Research Assistant, SUNY Stony Brook
Awards and Recognitions
Public Rockwell Lecture at the University of Iowa, October 3, 2012.
Congressional Briefing, US Congress, Washington DC, December 2011. Invited by AMS to present a Congressional Briefing. Title: ``Mathematics: Leading the way for new options in the treatment of coronary artery disease."
Coalition for National Science Funding: Singled out to Represent AMS (American Mathematical Society) research at the Research Exibition, US Congress, Capitol Hill, 6/26/2008.
National Science Foundation, Mathematical and Physical Sciences Distinguished Lecture ``Mathematics and Cardiology: Partners for the Future" 9/17/2007.
US Congressional Recognition ``Top Women in Technology" 2006.
Association for Women in Computing: Winner of the Top Woman In Technology Award 2005.
University of Houston Research and Scholarship Award 2001 (Associate Prof.)
Selected Honors and Professional Service
Director of Programs, Society for Industrial and Applied Mathematics (SIAM) APDE Activity Group (2013-2015).
Invited member of NIH's College of CSR (Center for Scientific Review) Reviewers (by invitation only). Since 2010.
Member of the Committee of the AMS (American Mathematical Society) National Meetings; Since 2009.
Editor for the SIAM Journal on Numerical Analysis (2013-present);
Editor for the Proceedings of the AMS since 1997;
Editor for Glasnik Matematicki;
Editor for Networks and Heterogeneous media
Editor for Journal of Inequalities
Editor for Frontiers in Computational Physiology and Medicine
Member of Scientific Committee for HYP2006 Bi-annual International Conference on Hyperbolic Problems (to be held in Lyon, FR)
Organizer of a Session on Cardiovascular Flows at the Houston Society for Engineering in Medicine and Biology Annual Meeting 2005.
Organizer (co-organizer) of numerous SIAM (Society for Industrial and Applied Mathematics) conference minisymposia;
Organizer of several American Mathematical Society special sessions;
Organizer of a Symposium for the American Association for the Advancement of Sciences (AAAS)
Co-organizer of the conference in honor of Olga Oleinik at Iowa State University 1997;
Mentor for AWM Princeton 1995;
Formated for CROWN by Darko Žubrinić
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