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.

Adult↗

PubMedDate not supplied

Redistribution of pulmonary blood flow in interstitial lung diseases: the chest radiograph as a physiologic tool.

Posteroanterior radiographs of the chest showed enlargement of vessels in the upper lung fields in 18 of 29 patients with interstitial lung diseases, despite normal pulmonary wedge pressures and normal or reduced pulmonary blood volumes. The degree of such redistribution ("diversion") did not correlate either with the severity of pulmonary hypertension observed at cardiac catheterization or with radiologic assessment of predominance of disease at the lung bases. Diversion did correlate with several indices of disease severity: reduction in vital capacity, reduction in diffusing capacity, reduction in pulmonary blood volume and radiographic severity of parenchymal abnormalities. Furthermore, diversion correlated with lung height, a variable which was not statistically related to the other indices of disease severity. Distension of upper lung vessels occurs in interstitial lung diseases as the result of a decreased hydrostatic gradient over which the lung is perfused (decreased lung height), partial obliteration of the vascular bed (decreased pulmonary volume), and, more speculatively, decreased extravascular pressure (increased lung recoil).

Arthritis, Rheumatoid↗