Pulmonary artery systolic pressures estimated by echocardiogram vs cardiac catheterization in patients awaiting lung transplantation

Background: At many lung transplant centers, right heart catheterization and transthoracic echocardiogram are part of the routine pre-transplant evaluation to measure pulmonary pressures. Because decisions regarding single vs bilateral lung transplant procedures and the need for cardiopulmonary bypass are often made based on pulmonary artery systolic pressures, we sought to examine the relationship between estimated and measured pulmonary artery systolic pressures using echocardiogram and catheterization, respectively. Methods: We retrospectively reviewed all patients in our program who had measured pulmonary hypertension (n = 57). Patients with both echocardiogram-estimated and catheterization-measured pulmonary artery systolic pressures performed within 2 weeks of each other were included (n = 19). We analyzed results for correlation and linear regression in the entire group and in the patients with primary pulmonary hypertension (n = 8) and pulmonary fibrosis (n = 8). Results: In patients with primary pulmonary hypertension, pulmonary artery systolic pressure was 94 ± 27 and 95 ± 15 mm Hg by echocardiogram and catheterization, respectively, with r² = 0.11; in patients with pulmonary fibrosis, 57 ± 23 and 58 ± 12 mm Hg with r² = 0.22; and in the whole group, 76 ± 29 and 75 ± 23 mm Hg with r² = 0.50. Thirty-two additional patients had mean pulmonary artery systolic pressure = 48 ± 16 mm Hg by catheterization but either had no evidence of tricuspid regurgitation by echocardiogram (n = 22) or the pulmonary artery systolic pressure could not be measured (n = 10). Conclusions: In patients with pulmonary hypertension awaiting transplant, pulmonary artery systolic pressures estimated by echocardiogram correspond but do not serve as an accurate predictive model of pulmonary artery systolic pressures measured by catheterization. Technical limitations of the echocardiogram in this patient population often preclude estimating pulmonary artery systolic pressure.