PB0932 - Safety and efficacy of low molecular weight heparin in patients with acute venous thromboembolism post-thrombolytic therapy as compared to unfractionated heparin: A systematic Review and Meta-analysis

Background: Low molecular weight heparin (LMWH) is a proven treatment for patients with venous thromboembolism (VTE) with a lower risk of VTE recurrence and lower rates of major hemorrhage, when compared to unfractionated heparin (UFH). It has largely replaced the use of UFH in many indications, but its use around thrombolysis remains controversial.

Aims: To evaluate the currently available evidence on LMWH use in post-thrombolysis as compared to UFH.

Methods: EMBASE and MEDLINE were searched up to 2022. We included studies that assessed the use of LMWH as compared to UFH in patients with massive and submissive PE in the acute post-thrombolysis phase. Data were pooled to estimate odds ratios (OR), with 95% confidence intervals (CIs) for VTE recurrence, bleeding complications and 30-day mortality.

Results: Three studies were included in this systematic review: one randomized controlled trial (RCT), and two cohort studies. A total of 299 patients were treated with UFH, and 227 patients were treated with LMWH. Patients treated with LMWH had a statistically significant lower risk of major bleeding with OR 0.41 [0.17, 0.97] P value .04 and 30-day mortality with OR 0.44 [0.23, 0.85] P value .01. On the other hand, though the risk of VTE recurrence and clinically relevant major bleeding (CRNMB) were lower, this was not statistically significant with OR of 0.18 [0.03, 1.07] P value 0.06 for VTE recurrence, and OR of 0.75 [0.39, 1.42] P value 0.38 for CRNMB.

Conclusion(s): In patients with massive and submissive PE post-thrombolysis, the study shows low certainty evidence to suggest that LMWH is a reasonable option for anticoagulation with lower risk of VTE recurrence, bleeding complications and 30-day mortality when compared to UFH. However, this conclusion is largely influenced by observational data and the very limited evidence available. Certainly, more RCTs with robust methodology are needed to evaluate this clinical question.