The variant associations of aortic isthmic coarctation.

The term "coarctation" necessarily calls attention to a specific morphologic abnormality of the aortic isthmus. However, in this report, the author seeks to dispel the simplistic notion that coarctation is best characterized by isthmic obstruction, which is only 1 of an assemblage of abnormalities that include the proximal paracoarctation aorta, the distal paracoarctation aorta, the ascending aorta, the transverse aorta, the coronary arteries, the conduit arteries (radial, brachial, and carotid), the retinal vascular bed, dissecting aneurysms, cerebral aneurysms, vascular rings, systemic hypertension, and a decrease in left ventricular interpapillary muscle distance. Some of these abnormalities are secondary to the coarctation, such as collateral arteries and dissecting aneurysms. Others frequently or invariably coexist but are not secondary, such as bicuspid aortic valve and aneurysm of the circle of Willis. Still other abnormalities are seemingly contradictory, such as aneurysmal dilatation of the low-pressure distal paracoarctation aorta, while the high-pressure proximal segment does not dilate significantly. In conclusion, coarctation should be regarded as an assemblage of cardiovascular abnormalities rather than as isolated obstruction of the aortic isthmus.