Efficacy and safety of low-dose thrombolysis in acute intermediate-high risk pulmonary thromboembolism complicated by PaO2/FiO2 < 300

Objective: ratio < 300 mmHg. Methods: ratio and NT-proBNP were assessed at baseline, 24 h, 3 days, and 7 days, while mPAP was measured at baseline, 24 h, and 7 days. Safety endpoints included mortality, hemodynamic decompensation, and bleeding within 7 days. Secondary outcomes included hospital and ICU stay, costs, and 3-month outcomes. Conclusion: ratio <300 mmHg, low-dose thrombolysis yielded early improvements in oxygenation, mPAP and right ventricular function, with efficacy similar to conventional-dose thrombolysis. We found a numerical reduction in minor bleeding events and no major bleeding across groups. However, the study lacked sufficient statistical power to confirm a true difference in bleeding risk between groups. Further large-sample studies with adequate power are warranted to verify the clinical value of low-dose alteplase for this patient population.