What does coarctation of the aorta lead to in terms of blood flow patterns?

Coarctation of the aorta is a congenital condition characterized by a narrowing of the aorta, usually occurring distal to the left subclavian artery. This anatomical abnormality creates a significant impact on blood flow dynamics in the body.

When coarctation occurs, the segment of the aorta below the coarctation (including branches supplying the lower body) experiences lower pressure and, therefore, reduced blood flow. In contrast, the blood vessels supplying the upper body (head and arms, especially the branches from the aorta before the coarctation) continue to receive normal or increased flow due to the pressure gradient created by the narrowing. This results in classic clinical signs such as hypertension in the upper body and hypotension in the lower body.

The increased flow to the upper body and decreased flow to the lower body can lead to various complications and symptoms, including blood pressure discrepancies in different extremities, chest pain, or heart failure in severe cases. Recognizing this blood flow pattern is critical for diagnosis and treatment, including surgical intervention or balloon angioplasty, aimed at relieving the obstruction to normalize blood flow distribution.