Announcement
Thank you for attending THSNA 2026. The virtual meeting is now closed.
Thank you for attending THSNA 2026. The virtual meeting is now closed.
Presentation Details
| Characterizing Low Molecular Weight Heparin-Associated Bleeding Risk in Thrombolysis or Thrombectomy for Venous Thromboembolism Natasha Jolakoski, Lisa Koselke, Allison Burnett. University of New Mexico Hopsital, Albuqerque, NM, USA |
Abstract
Background
Management of acute venous thromboembolism (VTE) may require prompt reperfusion strategies (e.g., catheter-directed thrombolysis [CDT], mechanical thrombectomy [MT]) for patients with high-risk features such as hemodynamically unstable pulmonary embolism (PE), right ventricular dysfunction, or limb-threatening deep vein thrombosis (DVT). All acute VTE requires immediate therapeutic anticoagulation, typically with intravenous (IV) unfractionated heparin (UFH) or subcutaneous (SQ) low-molecular-weight heparin (LMWH). Current guidelines favor SQ LMWH over IV UFH for initial therapy due to lower recurrence and major bleeding rates, though no specific recommendations exist for patients undergoing CDT or MT. IV UFH is commonly used because of its short half-life, reversibility, and perceived procedural safety, including when thrombolytics are used. However, IV UFH often fails to achieve therapeutic targets promptly. LMWH may offer advantages such as predictable pharmacokinetics, simpler administration, no routine monitoring, and lower risk of heparin-induced thrombocytopenia (HIT). Evidence comparing LMWH and UFH in VTE patients undergoing advanced intervention remains limited, largely retrospective, and uncertain regarding comparative bleeding risk. In April 2023, our institution implemented a multidisciplinary acute VTE protocol recommending LMWH as preferred initial parenteral anticoagulation, including for CDT and MT, unless contraindications exist (e.g., severe renal impairment, massive PE, potential ECMO need). This study aims to evaluate the safety of this practice change by comparing clinically relevant bleeding in LMWH-treated patients following protocol implementation with historically published UFH-treated cohorts undergoing similar procedures. We hypothesize that LMWH will demonstrate similar or lower bleeding rates compared with UFH. Methods
This is an ongoing single-center, retrospective, descriptive cohort study with a historical comparator at a tertiary academic medical center. Adults ≥18 years with acute intermediate-risk PE or iliofemoral DVT who received pre-procedural LMWH and underwent CDT or MT from 5/1/23–9/1/25 will be evaluated. Exclusions include severe renal impairment (CrCl <20 mL/min), pregnancy, incarceration, heparin allergy, or transfer from outside facilities. Encounters are identified through diagnostic and procedural codes cross-referenced with pharmacy data to confirm LMWH as initial anticoagulation. Data abstraction includes demographics, comorbidities, labs, procedural details, and bleeding events defined by International Society on Thrombosis and Haemostasis (ISTH) criteria. The primary outcome is the incidence of clinically relevant bleeding (major or clinically relevant non-major) within 72 hours post-procedure or before discharge. Rates will be compared with contemporary meta-analyses and randomized trials of similar IV UFH-treated populations. Secondary outcomes include LMWH utilization trends, hospital length of stay, 30-day mortality, and time from diagnosis to LMWH initiation. Baseline characteristics will be summarized descriptively. Adjusted relative risks with 95% confidence intervals will be estimated using multivariable regression. Statistical significance is defined as p <0.05. Final analyses are anticipated in early 2026. Results
Data collection in progress. Final results, including rates or clinically relevant bleeding events, to be presented upon conclusion of study. Conclusion
Findings will be analyzed and presented in Spring 2026.
No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.
Management of acute venous thromboembolism (VTE) may require prompt reperfusion strategies (e.g., catheter-directed thrombolysis [CDT], mechanical thrombectomy [MT]) for patients with high-risk features such as hemodynamically unstable pulmonary embolism (PE), right ventricular dysfunction, or limb-threatening deep vein thrombosis (DVT). All acute VTE requires immediate therapeutic anticoagulation, typically with intravenous (IV) unfractionated heparin (UFH) or subcutaneous (SQ) low-molecular-weight heparin (LMWH). Current guidelines favor SQ LMWH over IV UFH for initial therapy due to lower recurrence and major bleeding rates, though no specific recommendations exist for patients undergoing CDT or MT. IV UFH is commonly used because of its short half-life, reversibility, and perceived procedural safety, including when thrombolytics are used. However, IV UFH often fails to achieve therapeutic targets promptly. LMWH may offer advantages such as predictable pharmacokinetics, simpler administration, no routine monitoring, and lower risk of heparin-induced thrombocytopenia (HIT). Evidence comparing LMWH and UFH in VTE patients undergoing advanced intervention remains limited, largely retrospective, and uncertain regarding comparative bleeding risk. In April 2023, our institution implemented a multidisciplinary acute VTE protocol recommending LMWH as preferred initial parenteral anticoagulation, including for CDT and MT, unless contraindications exist (e.g., severe renal impairment, massive PE, potential ECMO need). This study aims to evaluate the safety of this practice change by comparing clinically relevant bleeding in LMWH-treated patients following protocol implementation with historically published UFH-treated cohorts undergoing similar procedures. We hypothesize that LMWH will demonstrate similar or lower bleeding rates compared with UFH. Methods
This is an ongoing single-center, retrospective, descriptive cohort study with a historical comparator at a tertiary academic medical center. Adults ≥18 years with acute intermediate-risk PE or iliofemoral DVT who received pre-procedural LMWH and underwent CDT or MT from 5/1/23–9/1/25 will be evaluated. Exclusions include severe renal impairment (CrCl <20 mL/min), pregnancy, incarceration, heparin allergy, or transfer from outside facilities. Encounters are identified through diagnostic and procedural codes cross-referenced with pharmacy data to confirm LMWH as initial anticoagulation. Data abstraction includes demographics, comorbidities, labs, procedural details, and bleeding events defined by International Society on Thrombosis and Haemostasis (ISTH) criteria. The primary outcome is the incidence of clinically relevant bleeding (major or clinically relevant non-major) within 72 hours post-procedure or before discharge. Rates will be compared with contemporary meta-analyses and randomized trials of similar IV UFH-treated populations. Secondary outcomes include LMWH utilization trends, hospital length of stay, 30-day mortality, and time from diagnosis to LMWH initiation. Baseline characteristics will be summarized descriptively. Adjusted relative risks with 95% confidence intervals will be estimated using multivariable regression. Statistical significance is defined as p <0.05. Final analyses are anticipated in early 2026. Results
Data collection in progress. Final results, including rates or clinically relevant bleeding events, to be presented upon conclusion of study. Conclusion
Findings will be analyzed and presented in Spring 2026.
No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.