Hemodynamic effects of nonionic contrast bolus injection and oxygen inhalation during pulmonary angiography in patients with chronic major-vessel thromboembolic pulmonary hypertension

Background Pulmonary angiography is the gold standard for the diagnosis of chronic thromboembolic pulmonary hypertension; however, major complications have been reported. This study evaluates the hemodynamic effects of direct pulmonary nonionic contrast bolus injection and oxygen inhalation in patients with chronic thromboembolic pulmonary hypertension. Methods and Results In 33 patients, hemodynamic parameters were measured after oxygen inhalation and during bolus injection of nonionic contrast medium in a control group (group 1, n=11), in a group of patients with moderately severe pulmonary hypertension (group 2, n=9), and in a group with severe pulmonary hypertension (group 3, n=13). Oxygen inhalation significantly improved oxygen supply. Pulmonary artery pressure and heart rate were reduced, but pulmonary vascular resistance and total pulmonary resistance were not significantly affected. One hundred ninety-eight angiograms were performed selectively on both pulmonary arteries in the posterior-anterior, oblique, and lateral views. Before contrast bolus injection, RAP and PAP significantly increased because of initial inspiration. Contrast bolus injection caused only a minor pressure increase (Delta PA systolic, 2.3+/-1.4, 2.5+/-1.8, and 5.0+/-5.2 mm Hg, groups 1, 2, and 3, respectively) without significance between the groups. After the angiography, pulmonary artery pressure was moderately increased, predominantly in group 3, but pulmonary vascular resistance was not significantly changed. Systemic vascular resistance was decreased. Cardiac index increased in groups 1 and 2 but was unchanged in group 3. Systemic pressure there fore decreased in group 3. Conclusions We concluded that bolus injection of nonionic contrast medium causes no major hemodynamic effects even in patients with severe chronic thromboembolic pulmonary hypertension. Oxygen contributes to safety during the procedure.