Anticoagulant drugs in the treatment of pulmonary embolism (1960)


Treatment of PE and prophylaxis for recurrence

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To to measure the effect of anticoagulant tretament in patients with PE, both on the course of the first embolism and on the risk of further attacks

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Trial design

Open study with parallel groups; a non protected interim analysis was performed after the first 35 cases
Active treatment: heparin 10,000 IU i.v. every 6 hours for 6 doses without laboratory control, or nicoumalone (= acenocoumarol) 16 mg, followed at 12-hourly intervals by 8, 8, and 4 mg adjusted for prothrombin time between 2–3 times control (n=16 before interim analysis + 38 after interim analysis)
Control treatment: no anticoagulant treatment (n=19 before and after interim analysis)

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Primary efficacy endpoint: death from PE
Secondary endpoints: non-fatal recurrence, other deaths

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Trial participants

73 patients with PE (documented acute right heart failure or pulmonary infarction or both) and no contraindication to anticoagulant therapy

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Efficacy outcome: After enrollment of 35 patients, an interim analysis showed that the difference in the 2 groups was unlikely to be due to chance. Of the 19 untreated patients 5 had died from PE and 5 others had non-fatal recurrences of PE, as compared with no death from PE and no recurrence in the treated group (p=0.0005). Thereafter all patients were admitted to the treated group. At the end of the study, in the treated group no patient has died from PE, and only 1 patient had a non-fatal recurrence. The 2 deaths in the treated group were due to other causes than PE

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In patients with PE, treatment with heparin or nicoumalone significantly reduced the risk of mortality. The likelihood of recurrent embolism was also diminished significantly

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Barritt DW, Jordan SC. Anticoagulant drugs in the treatment of pulmonary embolism. A controlled trial. Lancet 1960;1:1309-1312

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Corresponding author

D. W. Barritt, MD, Departments of Medicine and Cardiology, United Bristol Hospitals, Bristol, England

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