[The intrapulmonary metabolism of prostaglandin E1 in patients with pulmonary hypertension].

We investigated the intrapulmonary metabolism of prostaglandin E1 (PGE1), hemodynamics, oxygenation indexes (OI) and intrapulmonary shunt ratios (QS/QT) in patients with pulmonary hypertension (PH group, n = 7) and those with normal pulmonary artery pressure (N group, n = 5). PGE1 at a concentration of 20 approximately 60 ng.kg-1.min-1 was continuously administered intravenously to the patients in both groups for treatment. The intrapulmonary metabolism of PGE1 was calculated as 100 x (1--the concentration ratio of PGE1 in radial/pulmonary artery) %. The concentrations of PGE1 were measured by radioimmunoassay (DCC method) with the specific anti-PGE1 antibodies supplied by Ono Pharmaceutical Co. Hemodynamics were measured using a Swan-Ganz catheter, and OI and QS/QT were calculated from blood gas analyses. In the PH group, the intrapulmonary metabolisms of PGE1 decreased significantly compared with the N group. In addition, mPAP/mSAP in the PH group increased significantly compared with the N group regardless of PGE1 administration. There were no significant differences in OI and QS/QT between the two groups in spite of PGE1 administration. We concluded that the intrapulmonary metabolisms of PGE1 in patients with pulmonary hypertension were significantly decreased compared to the patients with normal pulmonary artery pressure. For this reason, it is important to monitor hypotension more carefully whenever we administer PGE1 to patients for the treatment of pulmonary hypertension.