Tissue plasminogen activator in acute pulmonary embolism.

The use of thrombolytic therapy to treat AMI has reawakened interest in thrombolysis for acute pulmonary embolism (PE). We have investigated the use of recombinant human tissue-type plasminogen activator (rtPA) in patients with acute PE. In an open label study, rtPA achieved more than 90% efficacy and safety. In a trial comparing rtPA with an FDA-approved dose of urokinase (UK), rtPA appeared more rapid and safer. We are now conducting a comparative trial of rtPA with a novel dosing regimen of UK. In addition, a concurrent trial is comparing rtPA vs heparin for improvement in right ventricular function, assessed by echocardiography, among PE patients. However, the greatest challenge in PE research is to undertake a large-scale trial that compares thrombolysis and heparin for reduction of clinically relevant end points such as mortality and recurrent PE.