Simulations Reveal Optimal Strategy for Surgery
by Adrienne Mueller, PhD
August 14, 2024
The aorta is the primary vessel for blood flow from your heart to your body – and that blood flow is controlled by the aortic valve. Some babies are born with a congenital heart defect of the aortic valve, and patients with a particularly severe heart defect are sometimes treated by a new surgical procedure called bicuspidization. In bicuspidization, the surgeon cuts the diseased valve and sews in patches to construct a new valve. However, one problem that frequently occurs after the surgery is stenosis: narrowing of the valve that causes the heart to work harder to pump blood. Overall, outcomes of bicuspidization surgeries are variable and there is limited knowledge on the cause of poor results.
In order to address this need, first author Alexander Kaiser, PhD and senior author Michael Ma, MD, led a study to develop computational models to simulate bicuspidization surgeries that was recently published in the Journal of Thoracic and Cardiovascular Surgery. Computational models allow researchers to prototype new surgical geometries without putting patients at risk.
Aortic valve viewed from above. A model of bicuspidization showing restricted flow due to inadequate free edge length (left) and unrestricted forward flow with added free edge length (right).
The investigators used their simulations to predict the optimal postoperative surgical geometry, specifically a parameter called free edge length, for bicuspid valves. They found that valves with longer free edge lengths had less stenosis. However, valves with too long of a free edge length had shapes that could impair their function when the valve is closed. These results pave the way for future laboratory, animal and human research that will improve this surgery and yield better outcomes for individuals with diseased aortic valves. Overall, this study suggests surgeons should consider increasing valve free edge length relative to current practice to reduce stenosis and improve surgical outcomes.
Additional Stanford Cardiovascular Institute-affiliated investigators who contributed to this study include Moussa A. Haidar, Perry S. Choi, Amit Sharir, and Alison Marsden.
Dr. Alexander Kaiser
Dr. Michael Ma