B64-04 Step-wise Systemic Thrombolysis (50 + 50 Mg) for Intermediate-high and High-risk Pulmonary Embolism: A Case Series

Abstract Introduction Systemic thrombolysis is a treatment strategy that may be employed for high-risk pulmonary embolism (PE). Prior studies have shown a reduction in mortality and recurrent PE when compared with anticoagulation alone; however, there is a significantly increased risk of bleeding complications. Half-dose thrombolysis may be given with comparable outcomes but decreased bleeding risk; however, there is a paucity of studies looking at a stepwise administration of 50 mg of alteplase followed by continued instability and subsequent dosing of an additional 50 mg. We found several cases in our institution’s pulmonary embolism response team (PERT) database that utilized this strategy with varying outcomes. Case The above table summarizes five cases in the PERT database where an initial 50 mg of alteplase was administered to patients with high risk or intermediate-high risk PE with decompensation. After initial administration, patients were re-assessed, and if there were signs of continued hemodynamic compromise attributed to pulmonary embolism, a second dose of 50 mg of alteplase was administered. Each dose of 50 mg was administered over 1 hour or as a 10 mg bolus followed by 40 mg over 55 minutes. The table also highlights two cases in which the patients only received the initial 50 mg dose due to immediate hemodynamic improvement. Discussion Pulmonary embolism remains a leading cause of cardiovascular mortality, and the optimal dosing strategy for systemic thrombolysis continues to evolve. Prior studies have suggested that reduced-dose thrombolysis may lower bleeding risk while maintaining clinical benefit. Risk stratifying and finding the appropriate patients to administer thrombolytics is also an ongoing area of study. The ideal approach balancing efficacy and safety remains uncertain. In this case series, we describe the use of a step-wise thrombolysis strategy (50 mg tPA followed by reassessment, with an additional 50 mg given only if needed) in patients with intermediate-high risk with clinical decompensation and high-risk pulmonary embolism. These are compared with two cases from our institution in which there was an observed hemodynamic improvement after the initial 50 mg dose alone. In this cohort of patients, only three demonstrated bleeding during their hospitalization, with a range of hematuria to hemorrhagic shock observed. These findings suggest that a 50 + 50 mg dosing protocol may allow clinicians to evaluate response before administering the full thrombolytic dose, thereby potentially reducing bleeding risk while preserving therapeutic benefit. Larger prospective studies are warranted to further evaluate outcomes and define standardized criteria for escalation. This abstract is funded by: None