Which condition is characterized by a narrowing of the aorta?

Coarctation of the aorta is specifically defined as a constriction or narrowing of the aorta, typically occurring just distal to the left subclavian artery. This condition can lead to various complications, including hypertension in the upper body and decreased perfusion to the lower body. It is often identifiable by differences in blood pressure readings between the upper and lower extremities and can be associated with other cardiovascular anomalies. The clinical presentation can vary, with some patients being asymptomatic, allowing the condition to go unnoticed for some time.

Other conditions listed do not involve narrowing of the aorta. Ventricular septal defect refers to an abnormal opening in the interventricular septum, leading to shunting of blood between the left and right ventricles. Pulmonary stenosis is a narrowing of the outflow tract from the right ventricle to the pulmonary artery, typically affecting blood flow to the lungs. Atrial septal defect, on the other hand, involves an opening in the atrial septum, allowing blood to flow between the left and right atria. Thus, coarctation of the aorta is the only condition among the options that specifically describes a narrowing of the aorta itself.