Chest roentgenograms in primary pulmonary hypertension.

The characteristics of 59 chest roentgenograms of patients with primary pulmonary hypertension were investigated and compared with roentgenograms of 100 healthy control subjects. The relationship with pulmonary hemodynamics was also examined. In primary pulmonary hypertension, there was remarkable protrusion of the main pulmonary artery; the DPA (T/2) and the PL/T index (see text) had high values. These indices depend mainly on pulmonary hypertension, but are partially determined physically by the size of the individual heart. The width of the descending branch of the right pulmonary artery (dPA) was about double the control value (P less than 0.001). The cardiothoracic ratio was significantly increased in primary pulmonary hypertension and there was a positive correlation between the ratio and the mean right atrial pressure (r = 0.37, P less than 0.01). However, there was no correlation with pulmonary arterial pressure or other pulmonary hemodynamic parameters. These results indicate that the increase in the cardiothoracic ratio in primary pulmonary hypertension is caused mainly by right heart failure.