Severe pulmonary hypertension accompanying patent ductus arteriosus

The patent ductus arterious was closed in 3 patients who had equilibrated pressures in the pulmonary artery and aorta, with excellent clinical and hemodynamic results. The presence of a right-to-left shunt does not contraindicate operation if there is also a left-to-right shunt. A marked decrease in pulmonary vascular resistance may occur postoperatively in spite of a lack of change in the pathology of the pulmonary arterial tree angiographically.The concomitant existence of enlargement of the left ventricle, and, consequently, enlargement of the total heart size, suggests that the pulmonary hypertension is of secondary type and thus may be influenced beneficially by the operation.With no signs of a left-to-right shunt, and with the cardiac size within normal limits, the picture resembles that of primary pulmonary hypertension. Surgical treatment could be expected to have a beneficial effect if vasoconstriction of considerable degree could be demonstrated to exist in this type of patient. This question requires further study.