Flow Simulation of Cardiac Defects to Evaluate Effectiveness of Occlusion Devices

摘要

Cardiac occlusion devices are used to close abnormal openings in the heart. Most popularly known congenital heart defects (CHD) are atrial septal defect (ASD), patent ductus arteriosus (PDA), ventricular septal defect, and patent foramen ovale. ASD is between a heart's two upper chambers which results in movement of oxygenated blood from left atrium to right atrium and hence increases the load on lungs and can cause heart arrhythmias and stroke. Ductus arteriosus is a connection between the pulmonary artery and aorta in a fetus and gets closed after birth. The condition in which ductus arteriosus does not close after birth is PDA and causes pulmonary hypertension. According to the Center for Disease Control and Prevention, congenital heart defects are the most common type of birth defect in the United States, affecting nearly 1% of or about 40,000 births per year. Nearly one-third to one-half of these CHDs are critical and require intervention in the first year of life. In minimally invasive surgical techniques used to treat CHDs, a physical barrier to flow of blood in the duct is introduced by implanting an occlusion device in the duct which facilitates thrombogenesis and occludes the duct. We have used the finite element method (FEM) and computational fluid dynamics (CFD) to simulate flow condition in a heart with and without defect. This study is further extended to simulate flow condition after placing a device in defect. Although flow simulation has been used for many vessel flows [1,2], these specific cases of cardiac defects are not addressed.