Low-Dose Aspirin Is the Safest Prophylaxis for Prevention of Venous Thromboembolism After Total Knee Arthroplasty Across All Patient Risk Profiles

Abstract

Background: The International Consensus Meeting on Venous Thromboembolism (ICM-VTE) in 2022 proclaimed low-dose aspirin as the most effective agent in patients across all risk profiles undergoing joint arthroplasty. However, data on large patient populations assessing trends in chemoprophylactic choices and related outcomes following total knee arthroplasty (TKA) remain scant. The present study was designed to characterize the clinical use of various chemoprophylactic agents in patients undergoing TKA and to determine the efficacy of aspirin compared with other agents in patient groups stratified by VTE risk profiles.

Methods: This study utilized a national database to determine the proportion of patients undergoing TKA who received low-dose aspirin versus other chemoprophylaxis between 2012 and 2022. VTE risk profiles were determined on the basis of comorbidities established in the ICM-VTE. The odds ratios (ORs) and 95% confidence intervals (CIs) between various classes of thromboprophylaxis in patients with high and low risk of VTE were calculated. The odds of deep-vein thrombosis (DVT), pulmonary embolus (PE), bleeding events, infections, mortality, and hospitalizations were also assessed in the 90-day postoperative period for propensity-matched cohorts receiving low-dose (81 mg) aspirin only versus other prophylaxis, segregating patients by VTE risk profile.

Results: A total of 126,692 patients undergoing TKA across 60 health-care organizations were included. The proportion of patients receiving low-dose aspirin increased from 7.65% to 55.29% between 2012 and 2022, whereas the proportion of patients receiving other chemoprophylaxis decreased from 96.25% to 42.98%. Low-dose-aspirin-only use increased to approximately 50% in both high-risk and low-risk populations but was more likely in low-risk populations (OR, 1.17; 95% CI, 1.15 to 1.20) relative to high-risk populations. Both low-risk and high-risk patients in the low-dose-aspirin-only cohorts had decreased odds of DVT, PE, bleeding, infections, and hospitalizations compared with other prophylaxis regimens.

Conclusions: The findings of the present study on a very large population of patients undergoing TKA support the recent ICM-VTE statement by showing that low-dose aspirin is a safe and effective method of prophylaxis in patients across various risk profiles.

Level of evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Fig. 1

STROBE flow diagram depicting patient selection.

Fig. 2

Trends in usage rates of aspirin (ASA) and other chemical thromboprophylaxis from 2012 to 2022.

Fig. 3

Rates of DVT and PE within 90 days postoperatively among all patients managed with TKA from 2012 to 2022.

Fig. 4

Use of low-dose-aspirin-only regimens in patients at high and low risk for VTE from 2012 to 2022.

Fig. 5

Forest plot depicting the relative odds of receiving various classes of chemical thromboprophylaxis based on the patient risk profile. A ratio of >1.0 denotes a higher proportion of patients with a low-risk profile, compared with high-risk patients, receiving the particular anticoagulant. UF = unfractionated.