Chronic Obstruction of the Superior Vena Cava due to Histoplasmosis

Selective angiography and indicator-dilution curves were employed to illustrate the fuctional anatomy of the collateral circulation in two patients with chronic obstruction of the superior vena cava. In both, clinical and laboratory evidence favored an etiologic diagnosis of histoplasmosis.In case 1, the transit time via the main collateralvenous pathway, which comprised the left superior intercostal, accessory hemiazygos and azygos veins, was found to be a little greater than 25 seconds.In case 2, the superior vena caval obstruction was incomplete, but there was an associated severe narrowing of the right pulmonary artery. Distortion of the indicator-dilution curves provided evidence for an increased bronchopulmonary anastomotic circulation to the right lung.These observations illustrate how radiographic and hemodynamic technics may usefully be combined to assess the effects of acquired diseases of the major blood vessels.