Wedge Pulmonary Arteriography

Abstract

The association of pulmonary arterial lesions with congenital and acquired cardiac defects has been recognized for a number of years. These arterial lesions can be considered of two general types. In one, muscular hypertrophy, thickened elastic layers of pulmonary arteries of all sizes, and a thickened muscular layer of arterioles are encountered. In the other type, obliterative intimal proliferation and fibrosis involving muscular arteries of 300–500 micra are associated with thin-walled and dilated smaller arteries and arterioles (1, 2). Cardiac catheterization technics have permitted measurements of pulmonary artery pressure and flow and, thus, calculation of pulmonary vascular resistance. Such hemodynamic studies, when correlated with the histopathological changes in the pulmonary vessels, have clarified the functional significance of these vascular lesions. Since it is the smaller pulmonary arteries and arterioles that are involved, clinically applicable methods of visualizing the smaller branches of the pulmonary arterial tree should prove useful in the study of the occurrence, pathogenesis, and differentiation of these lesions and should be helpful in the investigation of their relationship to the hemodynamic pattern and in the selection of candidates for repair of the associated cardiac defects. Pulmonary arterial lesions are at present defined by lung biopsy. Indirectly, their presence can be deduced either from plain radiographs of the chest or from hemodynamic data obtained at cardiac catheterization, indicating an increased pulmonary resistance. Some workers have visualized the main pulmonary arterial trunk and its major branches by venous angiography and pulmonary arteriography (3–5), although certain studies were concerned with pulmonary disease (6, 7). Others have defined the x-ray appearance of the pulmonary vascular lesions by postmortem dye injection technics (5, 8–12). It is the purpose of this report to describe a clinical technic for visualizing radiographically the small pulmonary arteries and to outline the preliminary results of the application of this technic in 38 patients with congenital or acquired heart disease, studied between April 1957 and May 1958. Methods During right heart catheterization, a No. 7 Cournand catheter is manipulated into a pulmonary artery “wedge” position. Care is taken to wedge the catheter tip in an area of clear lung field free from mediastinal shadow, diaphragm, or scapula. After the wedge position is confirmed by a pressure tracing, and while the patient holds his breath at full inspiration, 2 or 3 c.c, of 70 per cent sodium 3-acetamido-2,4,6-triiodobenzoate (Urokon) is introduced through the catheter at an injection pressure of approximately 100 mm. Hg, as measured at the proximal end of the catheter. During the injection, an x-ray exposure is made. The catheter is immediately flushed with 5 to 10 c.c, of physiologic saline and a repeat pressure tracing is obtained.