Case Report: Staged alteplase administration under VA-ECMO support for high-risk pulmonary embolism with severe thrombocytopenia

High-risk pulmonary embolism (PE) with severe thrombocytopenia creates competing reperfusion and bleeding risks. A 28-year-old man presented with obstructive shock and central pulmonary arterial filling defects. The last documented platelet count before alteplase was 21 × 10⁹/L; platelet transfusion intervened, and the count at infusion initiation was unknown. Venoarterial extracorporeal membrane oxygenation (VA-ECMO) and hemostatic support were instituted. With increasing vasoactive requirements, the team selected bedside systemic thrombolysis after multidisciplinary consideration of surgical and catheter-based alternatives. Unfractionated heparin was paused at the first 20-mg alteplase infusion at 17:00. Arterial cannulation-site bleeding at 17:20 was treated with compression. The progress note documented that bleeding had stopped by 19:03; despite reduced vasoactive requirements, support dependence persisted. A second 20-mg infusion began at 19:25. Each stage lasted approximately 1 h. Heparin was restarted after the second infusion. Vasopressors were stopped on Day 1 and VA-ECMO was removed on Day 7. Hemoglobin fell from 150 to 117 g/L on Day 0 and reached 75 g/L on Day 8, prompting red-cell transfusion. Major bleeding could not be excluded. The patient was discharged on Day 19; Day 103 imaging showed no obvious residual pulmonary arterial filling defect. This case describes individualized decisions during multimodal care, not a validated alteplase regimen or evidence of its safety.