Radiologic assessment of pulmonary arterial pressure and blood volume in chronic, diffuse, interstitial pulmonary diseases.

Chronic, diffuse, interstitial pulmonary diseases may cause an increase in mean pulmonary arterial pressure (PAP) and a decrease in pulmonary blood volume (PBV). We compared 12 cardiovascular and three parenchymal assessments on plain chest radiographs with values of PAP and PBV obtained during cardiac catheterization in 29 patients with such diseases (progressive systemic sclerosis 20, sarcoidosis six, miscellaneous three) and normal pulmonary venous pressures. PAP ranged from 10 to 40 torr (mean 19, SD +/- 7), PBV from 6.4 to 10.8% of total blood volume (mean 8.4, SD +/- 1.2). PBV was significantly related to eight radiologic variables. PAP was significantly related to the severity of parenchymal disease and size of the central pulmonary arteries, both of which were assessed radiologically. Diversion of blood flow to upper zones was significantly related to restriction of the pulmonary vascular bed, but was not necessarily a sign of increased PAP. In general, pulmonary hemodynamic abnormalities appeared proportional to the radiologic severity of parenchymal disease.