The nurse is conducting an admission assessment of an infant with heart failure who is scheduled for repair of restenosis of coarctation of the aorta that was repaired 4 days after birth. Findings include blood pressure higher in the arms than the lower extremities, pounding brachial pulses, and slightly palpable femoral pulses. Which pathophysiologic mechanism supports these findings?

C The pulmonic valve prevents adequate blood volume into the pulmonary circulation. A The lumen of the aorta reduces the volume of blood flow to the lower extremities. D An opening in the atrial septum causes a murmur due to a turbulent left to right shunt. B The aortic semilunar valve obstructs blood flow into the systemic circulation.