Correspondence on ‘Low-dose thrombolysis for submassive pulmonary embolism’ by Yilmaz and Uzun

Thirty-day results have shown that patients with COVID-19 and PE received no significant benefit from empirically administered prophylactic anticoagulants at moderate doses against venous thrombosis or mortality.3 In submassive PE, the specific role of TT remains under scrutiny.4–9 The PEITHO trial (Fibrinolysis for patients with intermediate-risk pulmonary embolism) aimed to test the benefit of single bolus weight-based tenecteplase in a stratum of patients with submassive PE.6 The authors have reported a correlation between TT and significantly decreased hemodynamic decompensation and collapse risk, although with higher risk of severe extracranial and intracranial bleeding.6 Additionally, this trial included the efficacy and safety results of standard-dose TT.6 In a prospective study, Yilmaz et al demonstrated significant elimination of major bleeding complications, along with optimal clinical outcomes using a half-dose thrombolysis strategy (50 mg/2 hours).1 Moreover, Rothschild et al reported risks of major bleeding (11%) and 30-day mortality (4.4%) involved with the application of half-dose systemic TT against acute submassive PE, similar to a previous study on systemic TT.7 Interestingly, Sharifi et al showed good clinical outcomes and no bleeding in patients with submassive PE using a different half-dose TT strategy, which involved the administration of a 10 mg intravenous (IV) bolus within 1 min followed by 40 mg IV bolus infusion within 2 hours.8 Considering the evidence regarding systemic TT, use of this therapeutically effective systemic drug (tissue plasminogen activator) seems to be correlated with significant bleeding risks, regardless of the administration route or dose. [...]for managing deteriorating PE cases with moderate-high bleeding risk, we suggest administering low-dose TT (50 mg/6 hours) over a prolonged period. Effect of intermediate-dose vs standard-dose prophylactic anticoagulation on thrombotic events, extracorporeal membrane oxygenation treatment, or mortality among patients with COVID-19 admitted to the intensive care unit: the INSPIRATION randomized clinical trial.