Clinical, Pathologic, and Hemodynamic Considerations

IN COARCTATION of the aorta, the coexistence of a defect of the ventricular septum tends to prevent development of hypertension in the upper systemic circulation by permitting blood from the left ventricle to pass into the pulmonary circulation. This tendency is accentuated but not fundamentally altered if there is also a patent ductus arteriosus opening into the aorta proximal to the coarctation. A more complicated situation obtains if the ductus enters the aorta distal to the coarctation. Then systolic pressure in the descending aorta tends to approach that in the pulmonary artery, owing to the equalizing effect of the ductus, and also the pressure in the ascending aorta may approach that in the pulmonary artery, owing to the equalizing effect of the ventricular septal defect. Consequently, little or no pressure gradient may exist across the coarctation. Recognition of the existence of coarctation in these circumstances is of great practical importance, as discussed later. In this paper analysis is made of 26 cases of ventricular septal defect and coarctation of the aorta with or without patent ductus arteriosus, in which the diagnosis was fully established by pathologic, surgical, or coinplete hemodynamic data. Briefer reference, principally for purposes of classification, is made to 13 other cases in which this combination of defects formed part of more complicated malformations. Classification According to Associated Abnormalities: In the classification used, the