AN AUTOMATED SIMULATION PROTOCOL FOR EXERCISE PHYSIOLOGY IN FONTAN PATIENTS USING A CLOSED-LOOP LUMPED-PARAMETER MODEL

摘要

Single ventricle physiology is one of the most severe forms of congenital heart disease in which an infant is born with only one functional pumping chamber. These patients must go through a series of surgical procedures concluding with the Fontan procedure, which connects the superior and inferior vena cavae to the pulmonary arteries, bypassing the right side of the heart entirely. Reduced exercise capacity is a common morbidity in Fontan patients, leading to decreased quality of life, and the etiology of lowered exercise performance remains unclear. Exercise conditions place high demands on the cardiovascular system; any good surgical design must consider the behavior of the system at stress. Invasive clinical measurements during exercise pose many challenges and are typically not standard of care. There is a need to better understand Fontan exercise physiology and to predict clinical outcomes using computational tools. Modeling efforts to describe Fontan physiology have mainly focused on the effects of variations in Fontan geometry, and typically have not considered the range of hemodynamic conditions that can occur within the patient population. A few exceptions have used open loop models to simulate exercise conditions, however numerous assumptions were required for increasing flow rates, changing waveform shapes, and prescribing changes in pulmonary vascular resistances. In addition, there has been essentially no validation of exercise simulations against clinical data.