Unusual Roentgen Manifestations of Patent Ductus Arteriosus

In February 1939, Gross and Hubbard (1) reported the first successful ligation of a patent ductus arteriosus. Subsequent experiences have demonstrated the safety and desirability of the procedure in virtually all patients with this abnormality. Although in the majority of cases the condition can be recognized by physical examination alone, in some instances simple roentgen methods may offer important contributory evidence. In others, additional contrast studies may be required for diagnosis. The 7 cases to be reported here illustrate a number of infrequent and less familiar roentgen features. Physical Findings The characteristic continuous “machinery murmur” in the pulmonary area in an acyanotic individual is the most important diagnostic sign of patent ductus arteriosus. When present, it is virtually pathognomonic of the lesion. The character of the murmur depends on a continuous flow of blood through the patent ductus from the aorta to the pulmonary artery. In infancy (2) and in the presence of pulmonary hypertension, only a systolic murmur may be heard, making the diagnosis more difficult and sometimes dependent upon other studies. As a rule, there is a wide systemic pulse pressure, especially after exercise. In only 14 of 62 patients studied by Shapiro (3) was this pressure normal. Other less specific features in the history and physical examination have been fully recorded elsewhere (2, 4). Cardiac Catheterization Cardiac catheterization, by demonstrating a significant increase in the oxygen content of the pulmonary artery blood over that in the right ventricle, suggests the diagnosis. Aortic-pulmonary septal defect, while rare, may present a similar finding. At times the examiner is fortunate enough to guide the catheter through the ductus into the descending aorta. Determinations of pressure and blood oxygen content of the left heart circulation are then obtained. Such passage is undeniable evidence of a patent ductus, but it is not accomplished in the majority of cases. In patients with reversed flow due to pulmonary hypertension, recognition by this procedure requires that the ductus be catheterized (5). Roentgen Findings Several papers have analyzed comprehensively the roentgen findings in patent ductus arteriosus (6). It is to be stressed that, with the exception of special angiographic studies, the usual roentgen examination is seldom diagnostic. The characteristic findings are: slight to moderate enlargement of the pulmonary artery, left auricle, and left ventricle; an increased amplitude of pulsation in the aorta, pulmonary artery, and left ventricle; an increase in caliber of the peripheral pulmonary vessels, which may show “hilar dance.” This latter observation is more frequently made in intracardiac shunts. Except in cases in which congestive heart failure is present, the heart is seldom greatly enlarged. Two types of contrast examination are available: angiocardiography and thoracic aortography.