Is Thrombolytic Therapy Effective for Pulmonary Embolism? -- American Family Physician

www.aafp.org/afp AMERICAN FAMILY PHYSICIAN 1097 160 patients with angiographically documented PE were divided into two groups, each of which received standard heparin or urokinase. Lung scans, pulmonary angiograms and measurements of right heart pressures and blood flow dynamics performed at 24 hours showed significant improvement only in the urokinase group. However, lung scans performed seven days, 14 days, three months and six months later showed no difference between the two groups. The phase II Urokinase-Streptokinase Pulmonary Embolism Trial (USET) followed four years later and compared both urokinase and streptokinase with standard anticoagulation. A total of 167 patients were divided into groups receiving heparin only, streptokinase and heparin, or urokinase and heparin. The effects on lung scans were similar between the streptokinase/heparin group and urokinase/ heparin only group. Again, compared with the heparin group, improvement occurred only within the first 24 hours; over a longer period of time, no differences were apparent between the groups. More recently, Levine and associates divided 58 patients with PE into two groups; 33 received thrombolysis and 25 received standard anticoagulation with heparin. Lung scans performed 24 hours, seven days and P ulmonary embolism (PE) is a common disorder that is associated with significant morbidity and mortality. The primary cause of death in fatal PE is right-sided heart failure. The most serious long-term complication of PE is pulmonary hypertension. Earlier studies have reported that the mortality rate associated with pulmonary embolism has remained the same for the last 40 years. A more recent study, however, found a significant decline in mortality from 1979 to 1996. Anticoagulation remains the standard of treatment for PE and has clearly been shown to reduce mortality and the rate of recurrent PE. Anticoagulation does not directly contribute to clot lysis. It prevents the propagation of the thrombus while allowing endogenous fibrinolytic activity to dissolve the clot. The lytic process may take several days to several months to develop, and in many patients it is incomplete and may lead to the occurrence of pulmonary hypertension.