Guidelines-recommend thrombolytic therapy for pulmonary embolism in patients with severe hemodynamic compromise and low risk of bleeding. Thrombolytics in submassive pulmonary embolism have an unfavorable risk/benefit ratio and remain controversial. Based on our experience with extensive, lower extremity thrombi, nine patients with symptomatic, submassive pulmonary embolisms (five medical, four surgical) were treated with low-dose alteplase (<10 mg/day, infused over 6 h per treatment). Alteplase was delivered by pulse spray and/or directed or undirected central venous catheters depending on clot size and location. All patients improved symptomatically and as determined objectively by pulmonary artery pressures and/or imaging, though acute benefits ranged from substantial to modest. One surgical patient required re-exploration for bleeding at the site of a recent retroperitoneal lymph node dissection. This experience may help guide the design of a randomized controlled trial to determine the safety and efficacy of low-dose alteplase for submassive pulmonary embolism.
aOffice of Tissues and Advanced Therapies, FDA Center for Biologics Evaluation and Research, Silver Spring
bCritical Care Medicine Department, National Institutes of Health Clinical Center
cCardiovascular Branch, National Heart, Lung, and Blood Institute
dSurgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
eUrologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
fDivision of Urology, Department of Surgery, Howard University Hospital, Washington, District of Columbia
gDepartment of Radiologic Diagnostics, National Institutes of Health Clinical Center, Bethesda, Maryland, USA
Correspondence to Jay N. Lozier, MD, PhD, FACP, Office of Tissues and Advanced Therapies, FDA Center for Biologics Evaluation and Research, Building 71, Room 5270, 10903 New Hampshire Avenue, Silver Spring, MD 20993, USA Tel: +1 240 402 5605; fax: +1 301 402 1213; e-mail: Jay.Lozier@fda.hhs.gov
Received 12 April, 2018
Accepted 31 August, 2018
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