A normal human heart has four chambers: two upper chambers called atria, which receive blood into the heart, and two lower chambers called ventricles, which pump blood out of the heart. A single ventricle defect, also called single defect anomaly or single ventricle physiology, refers to a variety of cardiac defects where only one of the heart’s two ventricles functions properly. A single ventricle defect is a congenital (meaning it is present at birth) condition and is among the most complex of heart defects. This condition occurs in five of every 100,000 live births as the heart develops during the first eight weeks of the mother’s pregnancy. Current surgical correction, which has been practiced over the past five decades, shows poor outcome with mortality rates as high as 30 percent. This is complicated by the fact that the condition requires multiple, complex surgeries and while survival rates continue to improve, the condition still carries some of the highest morbidity and mortality rates related to congenital heart surgery.
That’s where Stanford Researcher and Assistant Professor at Cornell, Dr. Mahdi Esmaily, comes in. Dr. Esmaily, or Dr. Braveheart, as some of us like to call him, has been conducting research that is nothing short of ground breaking and lifesaving. Dr. Esmaily, Postdoctoral scholar at the Center for Turbulence Research – Stanford University, has applied his engineering expertise to a long standing problem in the medical field. He has conducted computational simulations of blood flow to evaluate an innovative new surgical procedure. The outcome is that infant cardiac surgeons may be able to use a radical new surgery by adopting a frankly engineering concept. This is accomplished by constructing an anatomy that is inspired by an ejector pump, a device that is typically found in industrial power plants. In this operation, the high-energy flow from the systemic circulation is injected into the low-energy flow from the upper body, assisting its drainage into the pulmonary arteries. This is counter to the current surgery which is known to cause inadequate pulmonary blood flow in already stressed patients ‒ particularly true in tiny infants.
The High Performance Computing Center (HPCC) at Stanford University was founded to provide high performance computing resources and services that enable computationally-intensive research within the School of Engineering and to support the efforts of scientists performing sponsored research. The High Performance Computing Center leverages Mellanox InfiniBand in their High Performance Computing research to enable larger simulations, analyses and faster computation times than are possible using computers available to individual researchers.
Dr. Esmaily used high performance computing resources to simulate realistic 3-dimensional models of neonatal circulations. These simulations predicted that his proposed surgery provides significantly higher oxygen delivery at a lower single-ventricular workload in comparison to the conventional operation, meaning that part of the heart will not have to work as hard. The conclusion is that while there is more research to be done, the use of an ejector pump, augmented by Dr. Esmaily’s technique, holds the promise of giving surgeons a brand new, less risky option, for newborns undergoing this kind of surgery and with it, hope for the families of infants born with heart defects.