Should aspirin (acetylsalicylic acid) be held prior to total knee arthroplasty in patients with a history of cardiovascular disease or at high risk for thromboembolic events?

Should Aspirin Be Held Prior to Total Knee Arthroplasty?

Aspirin should NOT be routinely held prior to total knee arthroplasty in patients with cardiovascular disease or at high risk for thromboembolic events—continuation is safe and may reduce cardiovascular complications without significantly increasing clinically important bleeding. 1, 2

Evidence-Based Recommendation Framework

For Patients WITHOUT Coronary Stents

Continue aspirin through the perioperative period for patients with established cardiovascular disease (coronary artery disease, prior stroke, peripheral arterial disease), as the thrombotic risk outweighs bleeding concerns in total knee arthroplasty. 1, 3

• The American College of Chest Physicians supports continuing aspirin when thrombotic risk outweighs bleeding concerns, and total knee arthroplasty is classified as intermediate bleeding risk surgery. 1
• Discontinuing antiplatelet therapy increases the absolute risk of stroke recurrence or cardiovascular events by approximately 2% within 30 days. 1, 3
• A retrospective study of 739 patients undergoing total hip or knee arthroplasty found that blood loss and local bleeding complications were comparable between patients who continued versus discontinued aspirin, with a trend toward increased cardiac complications (6.5% vs 0.0%, p=0.107) in those who discontinued. 2

For Patients WITH Coronary Stents

Aspirin MUST be continued throughout the perioperative period regardless of stent type—this is non-negotiable. 1, 3

• Premature discontinuation markedly increases risk of catastrophic stent thrombosis, death, and myocardial infarction. 1
• For drug-eluting stents, aspirin should be continued perioperatively whenever possible, and if thienopyridines must be discontinued, aspirin continuation is mandatory. 1, 3
• Elective surgery should ideally be delayed until at least 30 days after bare-metal stent placement and 12 months after drug-eluting stent placement. 1

Bleeding Risk Analysis

Quantified Bleeding Outcomes

The bleeding risk from continuing aspirin in total knee arthroplasty is modest and manageable:

• A study of 1655 patients showed calculated blood loss was slightly higher with continued aspirin (969.1 vs 904.0 ml), with transfusion rates of 53.0% vs 40.2%, but no significant difference in deep vein thrombosis rates and only 0.3% pulmonary embolism in the non-aspirin group. 4
• Continuing aspirin may increase the frequency of procedural bleeding (relative risk 1.5) but does not increase the severity of bleeding complications or perioperative mortality. 5, 1
• A prospective study of 139 patients found that TKA patients who continued aspirin more frequently showed marked knee swelling at 1 week (81.3% vs 35.1%, p=0.001), but orthopaedic outcomes did not differ significantly. 2
• A study of 3473 consecutive TKA patients using aspirin as primary chemoprophylaxis demonstrated fatal pulmonary embolism rates of 0.06-0.14% and reoperation for hematoma in only 0.4%. 6

Safety Profile

Low-dose aspirin (81-100 mg daily) continued perioperatively is safe as part of multimodal venous thromboembolism prophylaxis. 7

• A prospective study of 139 patients found no significant differences in blood loss, operative time, surgical wound healing, or hemoglobin drop between aspirin continuation and control groups. 7
• The NEJM trial comparing aspirin to rivaroxaban after initial 5-day rivaroxaban prophylaxis showed venous thromboembolism rates of 0.64% with aspirin vs 0.70% with rivaroxaban (non-inferior), with major bleeding at 0.47% vs 0.29% respectively (not significantly different). 8

Practical Management Algorithm

Decision Pathway

1. Identify cardiovascular risk status:

   • High risk: coronary stents, established CAD, prior stroke, peripheral arterial disease → Continue aspirin 1, 3
   • Moderate risk: cardiovascular disease without stents → Continue aspirin 1
   • Low risk: primary prevention only → May discontinue 3

2. For patients requiring discontinuation (rare):

   • Stop aspirin ≤7 days (not the traditional 7-10 days) before surgery, with 3 days being acceptable for most cases. 1
   • Resume within 24 hours postoperatively once adequate hemostasis is achieved. 1, 3

3. Dosing recommendations:

   • Continue usual maintenance dose of 75-100 mg daily perioperatively. 1, 3
   • Do not reduce dosage before surgery in patients on long-term aspirin up to 300 mg/day. 1

Critical Caveats and Pitfalls

Common Errors to Avoid

• Do not routinely discontinue aspirin for 10 days—this is excessive and increases thrombotic risk unnecessarily; 7 days or less is sufficient if discontinuation is truly needed. 1
• Do not stop aspirin in patients with coronary stents under any circumstances unless the bleeding risk is catastrophic (e.g., intracranial surgery), and even then, restart immediately postoperatively. 1, 3
• Perform thorough medication reconciliation—patients may not report over-the-counter NSAIDs with antiplatelet effects that can increase bleeding risk. 1, 3
• Avoid combining multiple antiplatelet or anticoagulant medications without careful risk assessment, as bleeding risk increases significantly with combination therapy. 3

Guideline Controversies

There is divergence among guideline societies regarding aspirin as sole thromboprophylaxis:

• The AAOS, SIGN, and Brazilian guidelines recommend aspirin as sole thromboprophylaxis (Grade A-B), arguing that it causes less bleeding and that the link between DVT and pulmonary embolism is unproven. 5
• The ACCP and French guidelines advise against aspirin as the sole method of thromboprophylaxis (Grade A-B), stating it is less effective than other regimens. 5
• For patients already on aspirin for cardiovascular indications, this controversy is irrelevant—continuation is recommended for cardiovascular protection, not as primary VTE prophylaxis. 1, 3

Special Considerations

• For patients on dual antiplatelet therapy (aspirin + clopidogrel), if clopidogrel must be stopped, aspirin should be continued and clopidogrel restarted as soon as possible postoperatively. 5, 1
• Transient knee swelling is more common with continued aspirin but does not affect functional outcomes. 2
• The thrombotic risk clusters early after discontinuation, with highest risk in the first 30 days. 3