The release of thromboxane B2 and 6-keto-PGF1 alpha following pulmonary embolism

It has been shown in animals that acute obstruction of pulmonary artery branches is followed by an early but shortly lived increase in blood levels of thromboxane B2 and a subsequent longer-lasting increase in blood levels of 6-keto-PGF1 alpha. Our study was conducted on twelve patients with acute pulmonary embolism. Nine were treated with urokinase; three could not be given thrombolytic or anticoagulant drugs due to bleeding peptic ulcer (2 cases) or recent cerebral hemorrhage (1 case). HPLC and RIA tests were performed on arterial blood samples at diagnosis and after 1, 6, 12 and 24 hours. Findings were compared with those in a control group of 6 healthy subjects. There was a difference in prostanoid behaviour between the untreated and urokinase treated patients. Among the former mean TxB2 was significantly raised at clinical onset and began to decline after 6-12 hours, approaching the mean level found among the controls after 24 hours. In contrast 6-keto-PGF1 alpha was raised after 1 hour and gradually declined thereafter. In the subjects treated with urokinase TxB2 was already close to the mean control level after 1 hour; 6-keto-PGF1 alpha had increased after 1 hour but had returned near the control level after 12. The behaviour of prostanoids appears to match the clinical course.