RETEPLASE
The double bolus administration of reteplase appears to induce faster hemodynamic improvement in patients with massive pulmonary embolism compared with intravenous alteplase infusion, according to a report in the July 1999 issue of the American Heart Journal.
Dr Ulrich Tebbe, a physician at the Medizinische Klinik in Lippe-Detmold and a team from other German clinics, carried out the first study of the use of reteplase – a nonglycosylated plaminogen activator produced by recombinant DNA technology – in the treatment of massive pulmonary embolism. [page 39,col 2, par 2]
In the study, 36 patients who had shown recent clinical symptoms of massive pulmonary embolism were treated. 23 received reteplase as two intravenous bolus injections 30 minutes part while the remaining 13 received alteplase as an intravenous infusion of 100mg over two hours. [p39, Methods] All patients receive concomitant therapy with heparin. [p41, col 1, par 2]
The study measured the change in total pulmonary resistance for 24 hours after drug administration. Total pulmonary resistance was chosen as it takes into account both the mean pulmonary artery pressure, which can be taken as a measure of the severity of pulmonary embolism, and the cardiac index. [p43,col 1,par 2] Other hemodynamic, clinical and safety parameters were used as secondary variables. [p41, col 1, par3]
According to the report, a primary objective in the treatment of massive pulmonary embolism is improvement of hemodynamic disturbances in the very early phase of treatment. “A thrombolytic regimen resulting in a faster reduction in total pulmonary resistance may lead to a rapid clinical hemodynamic improvement and may decrease the early mortality rate in acute massive pulmonary embolism,” the authors write. [p43, col1, par4]
Dr Tebbe and his colleages found that double bolus of reteplase appears to be at least as effective at reducing pulmonary vascular resistance as treatment with the two-hour alteplase infusion. [p43,col2, par 3] “The decrease in pulmonary vascular resistance under reteplase treatment tended to be greater, and occurred earlier, compared with alteplase...”, they report. [p43, col 2, par 1]
The authors conclude that “...double bolus reteplase therapy for pulmonary embolism appears to induce faster hemodynamic improvement compared with a two-hour infusion of alteplase.” [p43, col 2, par 1].