Subcarinal Angle Research Articles

Relationship of lung geometry to the development of pleural abnormalities in insulation workers exposed to asbestos

The relationship of respiratory airway and airspace geometry to radiographic evidence of pleural abnormality consistent with asbestos exposure was studied in 178 construction insulators. Lung geometry was assessed from tracings of radiographic shadows, and the measures taken were tracheal length and diameter, subcarinal angle, right and left lung lengths, and upper, middle, and lower lung widths. Important modifying variables--age, height, weight, exposure estimates, and smoking history--were included in a logistic regression model to test the significance of the lung geometry measurements as predictors of the presence or absence of pleural abnormality. No such relationships were found. Neither were there any differences in prevalence or severity of pleural disease between the right and left sides which might have been found if airway geometry were a significant determinant of asbestos pleural disease. These results do not support the hypothesis that lung geometry is a host risk factor for the development of asbestos-related pleural disease.

Widening of the subcarinal angle by pericardial effusion

The subcarinal angle and transverse diameter of the cardiopericardial silhouette were measured on inspiratory posteroanterior radiographs of 54 patients (average age, 43.1 years) with pericardial effusion. The subcarinal angle was significantly greater (p less than 0.001) during effusion (81.0 degrees, n = 54) than either before (62.3 degrees, n = 14) or after (56.7 degrees, n = 21) effusion. A significant (p less than 0.05) positive correlation (r = 0.60, n = 118) was found between the magnitude of the subcarinal angle and the transverse diameter. This suggested that pericardial fluid accumulation displaces the heart and, in turn, splays the main bronchi. When pericardial fluid is not suspected clinically, a widened subcarinal angle, without other evidence of left atrial enlargement, may be a clue suggesting pericardial effusion.