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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
| To Clot or Not – Risk of Hospital-Acquired Venous Thromboembolism in Patients Prescribed Aspirin After Total Hip Arthroplasty/Total Knee Arthroplasty Amy N.Cruz1, Josh Roberts1, Jeremiah Duby1, James Chhen1, Michelle Krichevsky2, Tiffany Pon1, 2. 1University of California Davis, Sacramento, CA, USA.2University of California San Francisco, San Francisco, CA, USA |
Abstract
Background Aspirin (ASA) is a common agent utilized for venous thromboembolism (VTE) prophylaxis following total hip arthroplasty (THA) and total knee arthroplasty (TKA) procedures. Yet, there has been varying guidance on which agent is most appropriate for VTE prophylaxis in this population, and there is no consensus on the recommended dose of ASA. Objectives The primary objective of the study is to compare ASA dosing of 81 mg twice daily versus 325 mg daily on the rate of hospital-acquired VTE in TKA or THA patients at UC Davis Health (UCDH). Secondary outcomes include characterizing the types of HA-VTE that occurred (e.g., proximal, distal, other), identifying any continued ASA use beyond the intended prophylactic period, and assessing whether patients required transition to therapeutic anticoagulation for HA-VTE. Methods This is a retrospective cohort study of adult patients (≥ 18 years) who underwent THA/TKA procedures between Jan 1, 2017, to September 16, 2025, and were prescribed ASA 81 mg BID or 325 mg daily for VTE prophylaxis. Patients were excluded if they received any other dosing regimen of ASA, were on any other anticoagulation, had documented nonadherence, were pregnant, or did not follow up with an orthopedic surgeon within 90 days of discharge from the hospital. Based on an estimated effect size of 12% from a pilot study conducted at UCDH, a total sample size of 486 participants (243 in each arm) is required to achieve 80% power at a significance level (alpha) of 0.05. Results Preliminary results found no significant difference between VTE rates in the two dosing regimens. VTE was 28.9% in the ASA 81 mg BID group and 40% in the 325 mg daily group (OR = 0.61, p = 0.40). Data collection is ongoing, and results are pending. Conclusion In this THA/TKA surgery population, there was a numerically higher rate of VTE in patients receiving aspirin 325 mg daily vs 81 mg twice daily. The overall rate of VTE in this population also exceeds what has previously been reported in literature.
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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.