Relationship between pulmonary artery diameter at computed tomography and pulmonary artery pressures at right-sided heart catheterization

Rationale and Objectives. The purpose of the study was to determine the relationship between pulmonary artery (PA) size at computed tomography (CT) and PA pressures, to develop a noninvasive CT method of PA pressure measurement, and to determine a PA diameter that can enable differentiation of normal subjects from those with pulmonary hypertension. Methods. PA vessel diameters in 55 candidates for lung and heart-lung transplantation were measured at CT and correlated with PA pressures with both linear and stepwise multiple regression. The multiple regression equations were then tested prospectively in 35 pretransplantation patients. Results. Combined main and left main PA cross-sectional area corrected for body surface area showed the best correlation with mean PA pressure (r = .87), The multiple regression equations helped predict mean PA pressure within 5 mm Hg in 50% of patients with chronic lung disease and in only 8% of patients with pulmonary vascular disease. Conclusion. There was a very good correlation between main and left main PA size and mean PA pressure. At present, however, CT has not demonstrated sufficient accuracy to be used clinically.