Certified Surgical Technologist (CST) Practice Exam

A congenital defect in which the fetal blood vessel between the pulmonary artery and aorta does not close is called?

1. Coarctation of the aorta

2. Patent ductus arteriosus

3. Tetralogy of Fallot

4. Ventricular septal defect

The correct answer is: Patent ductus arteriosus

The condition described is a congenital defect where the ductus arteriosus, a blood vessel that connects the pulmonary artery to the aorta during fetal development, fails to close after birth. This vessel is critical for fetal circulation because it allows blood to bypass the non-functioning lungs. After birth, the ductus arteriosus typically closes within the first few days of life, as the newborn begins to breathe air and the circulatory system adapts to support lung function. When this closure does not occur, the condition is referred to as patent ductus arteriosus (PDA). As a result, blood can flow from the aorta back into the pulmonary artery, leading to increased blood flow to the lungs and potentially causing complications such as heart failure or pulmonary hypertension if left untreated. Other conditions listed, such as coarctation of the aorta, tetralogy of Fallot, and ventricular septal defect, involve different anatomical defects and do not specifically refer to the failure of the ductus arteriosus to close, making patent ductus arteriosus the correct term for this particular situation. Understanding these differences highlights the significance of proper anatomical closure at birth and its implications for cardiovascular health.