Safety of Therapeutic Anticoagulation with Low-Molecular-Weight Heparin or Unfractionated Heparin Infusion during Catheter-Directed Thrombolysis for Acute Pulmonary Embolism
Is there a significant difference in complication profile in use of therapeutic dosed low-molecular-weight heparin versus unfractionated heparin infusion during catheter directed thrombolysis?
No significant difference was found in complication rates between use of therapeutic dosed low-molecular-weight heparin and heparin infusion during catheter directed thrombolysis for acute pulmonary embolism
Assaf Graif et al. Safety of Therapeutic Anticoagulation with Low-Molecular-Weight Heparin or Unfractionated Heparin Infusion during Catheter-Directed Thrombolysis for Acute Pulmonary Embolism. Journal of Vascular and Interventional Radiology. April, 2020: 31; 4, 537-543.
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Figure 3. Complications
Anticoagulation dosing during catheter directed thrombolysis for pulmonary embolism (PE) remains controversial with no clear consensus between cessation of systemic anticoagulation versus therapeutic dosing versus subtherapeutic dosing. Similarly, there is no clear data to differentiate use of low-molecular-weight heparin (LMWH) versus unfractionated heparin. This study aimed to evaluate safety of therapeutic-dose anticoagulation. With a focus on hemorrhagic complications, during catheter directed thrombolysis for acute pulmonary embolism.
156 patients were identified who underwent catheter directed thrombolysis for submassive of massive acute pulmonary embolism. All patients were treated with therapeutic anticoagulation, either unfractionated heparin infusion (ptt every 6 hours with target range of 50-80 seconds) or LMWH (weight based, BID 1 mg/kg) based on physician preference. Primary endpoints were hemorrhagic complications and all complications. No significant difference in hemorrhagic complication or all complications was found between heparin infusion and LMWH groups.
Based on this study, there does not appear to be a significant difference in complication rate between therapeutic LMWH and heparin infusion during catheter directed thrombolysis for acute pulmonary embolism. The authors compared their complication rates to those of other studies using sub-therapeutic anticoagulation without major differences. While this may suggest no increased complication rate with use of therapeutic dosing, it does not prove any benefit either.
As is often the difficulty in retrospective reviews, there is significant heterogeneity in treatments performed. While the paper focused on heparin infusion versus LMWH, there was also significant variability in the catheter directed thrombolysis procedures (unilateral versus bilateral, infusion catheter choice, clot fragmentation, thrombectomy, plasty). Additionally, 5% of patients received systemic tPA prior to thrombolysis.
Further research is necessary in this realm, specifically comparing therapeutic dosing to subtherapeutic dosing of anticoagulation while minimizing heterogeneity between treatments.
David M Mauro, MD
Department of Radiology, Vascular and Interventional Radiology
University of North Carolina