Paper of the Week: Aspirin Is an Effective Prophylaxis for Venous Thromboembolism in Ambulatory Patients with Femoral Neck Fracture Undergoing Hip Arthroplasty

Emanuele Chisari, MD, Timothy L. Tan, MD, Roshan Shah, MD, Matthew Levitsky, MD, Nicolas Piuzzi, MD, Carlos Higuera, MD, Daniel Santana, BS, Syona Satwah, BS, Javad Parvizi, MD, FRCS

Chisari E, Tan TL, Shah R, et al. Aspirin Is an Effective Prophylaxis for Venous Thromboembolism in Ambulatory Patients with Femoral Neck Fracture Undergoing Hip Arthroplasty [published online ahead of print, 2022 Jan 14]. J Bone Joint Surg Am. 2022
doi: 10.2106/JBJS.21.00168

Summary by Irfan A. Khan, ATC

Venous thromboembolism (VTE) can be a catastrophic postoperative complication in patients undergoing hip fracture repair, having the potential to be fatal.¹ Due to this, the study of interventions aimed at ameliorating the development of deep vein thrombosis (DVT) and pulmonary embolism (PE) is essential. While aspirin is established as an effective VTE prophylactic agent in patients undergoing primary total joint arthroplasty,² there is a paucity of evidence supporting its use in patients undergoing hip fracture repair.

Chisari et al. retrospectively compared the risk of developing symptomatic VTE in patients who received aspirin or other anticoagulants after being treated with total hip arthroplasty (THA) or hemiarthroplasty (HA) for femoral neck fractures.³ The primary outcomes were development of symptomatic PE, symptomatic DVT, and overall symptomatic VTE. A total of 1,127 patients were included in this study, with 612 patients being treated with total hip arthroplasty and 515 patients being treated with hip hemiarthroplasty.

Among the 1,127 patients in this study, 40.1% received aspirin and 59.9% of patients received other anticoagulants for VTE prophylaxis. The rate of overall VTE was significantly lower in patients who received aspirin, compared to those who did not receive aspirin (1.98% vs. 6.7%; p < 0.001). A risk calculator was utilized to identify patients at high-risk for VTE,⁴ and they were excluded. After that, patients undergoing THA who received aspirin were propensity score matched to patients undergoing THA who were treated with other anticoagulants. This revealed no significant difference in VTE development amongst patients who received aspirin or other anticoagulants (1.64% vs. 3.28%; p = 0.684). After propensity score matching, similar findings were obtained in patients treated with HA who received aspirin or other anticoagulants (2.0% vs. 8.0%; p = 0.362). 

Chisari et al. concluded that in regular-risk patients undergoing hip arthroplasty for femoral neck fractures, aspirin is an effective VTE prophylactic agent,³ and is not inferior to other anticoagulant medications such as low-molecular-weight heparin (LMWH) and Warfarin. One potential limitation of the study is that when conducting propensity score matching, the number of patients in each cohort decreased significantly, which may have decreased the power of the statistical analysis. Despite this, the aspirin cohorts had lower rates of overall VTE, so increased power would have likely favored patients who received aspirin, further supporting its efficacy.

References:

1. Rosencher N, Vielpeau C, Emmerich J, Fagnani F, Samama CM; ESCORTE group. Venous thromboembolism and mortality after hip fracture surgery: the ESCORTE study. J Thromb Haemost. 2005;3(9):2006-2014. doi:10.1111/j.1538-7836.2005.01545.x
2. Matharu GS, Kunutsor SK, Judge A, Blom AW, Whitehouse MR. Clinical Effectiveness and Safety of Aspirin for Venous Thromboembolism Prophylaxis After Total Hip and Knee Replacement: A Systematic Review and Meta-analysis of Randomized Clinical Trials. JAMA Intern Med. 2020;180(3):376-384. doi:10.1001/jamainternmed.2019.6108
3. Chisari E, Tan TL, Shah R, et al. Aspirin Is an Effective Prophylaxis for Venous Thromboembolism in Ambulatory Patients with Femoral Neck Fracture Undergoing Hip