A COMPARATIVE STUDY OF THE MAIN PULMONARY ARTERY AND ASCENDING AORTA BIOMECHANICAL BEHAVIOR

摘要

During the prenatal period a state of physiologic pulmonary hypertension exists due to the equalization of pressures by the patent ductus arteriosus, resulting in similar wall thickness of the ascending aorta (AA) and main pulmonary artery (MPA). After birth, as the ductus arteriosus closes and pulmonary arterial pressure decreases, attenuation of medial smooth muscle occurs such that the ratio of medial thickness to external diameter decreases from about 25% in fetuses to less than 10% in infants 3 to 6 months of age.