Low-dose systemic thrombolytic therapy for treatment of submassive pulmonary embolism: Clinical efficacy but attendant hemorrhagic risks.

OBJECTIVES: The purpose of the present study is to evaluate the safety and efficacy of "low-dose" systemic thrombolytic therapy (TT) for treatment of patients with intermediate-high risk submassive pulmonary embolism (PE).

BACKGROUND: TT is increasingly utilized in acute submassive PE. Strategies for TT include catheter-directed administration as well as traditional IV systemic therapy. Regardless of the route, most studies document the attendant significant bleeding complication rates expected from induction of a systemic lytic state. To mitigate bleeding, "low-dose" systemic TT (Alteplase 50 mg) has been advocated, based on recent studies which demonstrated clinical efficacy with elimination of any significant bleeding complications.

METHODS: Over a 24-month period, our institutional PE Response Team treated 45 acute submassive PE patients with "Low Dose" IV Alteplase 50 mg. Clinical outcomes and bleeding complications were assessed.

RESULTS: Overall clinical outcome was excellent, with 97.8% of patients surviving to discharge and a 30-day, all-cause mortality of 4.4%. Despite no patients having a HAS-BLED score > 2 (average score = 0.8 +/-), ISTH major and GUSTO moderate bleeding was observed in 11% (n = 5) of cases.

CONCLUSIONS: The present observations document that low-dose systemic TT is associated with excellent clinical outcome for intermediate-high risk submassive PE, but with attendant risk for bleeding. These findings are consistent with the concept that induction of a therapeutic lytic state carries inextricable bleeding risk.