How do aortic coarctation and pseudocoarctation differ?
Aortic coarctation is a hemodynamically significant stenosis of the aorta, most commonly seen just distal to the takeoff of the left subclavian artery. Pseudocoarctation mimics coarctation because there is an apparent focal narrowing of the proximal descending aorta. This narrowing is due to buckling of a tortuous aorta, however, and does not result in a hemodynamically significant pressure gradient across the area of narrowing. Rib notching, owing to collateral intercostal arteries, is seen in true coarctation but not in pseudocoarctation.