[Tissue plasminogen activator (alteplase) in acute massive pulmonary embolism. A pilot study].

Twenty six patients with acute (less than 5 days) pulmonary embolism (PE) confirmed by bilateral pulmonary angiography with a Miller index greater than 15 were given tissue plasminogen activator (Alteplase) (rt-PA) intravenously (n = 20) or directly into the pulmonary artery (n = 6). The dosage was 100 mg/7 hours (bolus 10 mg + 40 mg/2 hours + 50 mg/5 hours). Heparin (5000 IV as a bolus and 1000 IV/hour) was associated in all cases. The Miller index decreased from 24 +/- 1 (n = 26) before treatment to 12 +/- 1 (n = 25) (p less than 0.001) after 100 mg of Alteplase, and from 25 +/- 0.4 (n = 14) to 22 +/- 0.5 (n = 14) (p less than 0.001) after 50 mg. The mean pulmonary arterial pressures fell from 30 +/- 2 mmHg to 21 +/- 2 mmHg after 50 mg (n = 26) (p less than 0.001) and to 14 +/- 1 (n = 25) (p less than 0.001) after 100 mg of Alteplase. A decrease in mean pulmonary artery pressures (-22%, p less than 0.001) and total pulmonary resistances (-29%, p less than 0.001) was obtained after one hour of thrombolysis in 12 monitored patients. There were no fatalities. Severe haemorrhage occurred in 6 cases. Therefore, Alteplase induced a rapid dissolution of recent intrapulmonary thrombi without inacceptable haemorrhagic complications. Its action could be particularly beneficial in patients with right ventricular failure due to life threatening pulmonary embolism.