Perioperative aspirin therapy in non-cardiac surgery: A systematic review and meta-analysis of randomized controlled trials

International Journal of Cardiology 2018;258:59–67 

doi: 10.1016/j.ijcard.2017.12.088 0167-5273

 Presented by: Dr L Jones

Background

  • Cardiovascular and bleeding events are amongst the leading complications during surgery
  • Aspirin is the cornerstone of secondary prevention of cardiovascular disease
  • As an irreversible cyclooxygenase-I inhibitor, aspirin poses a bleeding risk
  • For non-cardiac surgery aspirin’s benefits and bleeding risks remain unclear

Design & Setting

  • A systematic review and meta-analysis of randomised controlled trials
  • Aspirin v no aspirin in non-cardiac surgery
  • All cause mortality, cardiovascular mortality, arterial ischaemic events, venous thromboembolic events and bleeding events separately evaluated

Subjects

  • 7 relevant prospective randomised controlled trials
  • 28302 patients
  • Intermediate risk cardiovascular-risk surgery

Intervention

  • Different for every trial but a variation on aspirin at various doses v no aspirin

 Outcomes

  • All cause mortality (All trials)
  • Cardiovascular mortality (All trials)
  • Perioperative MI (All trials)
  • Major Bleeding (All trials)
  • Cerebrovascular events (6 trials)
  • Peripheral arterial events (3 trials)
  • Venous thromboembolic events (4 trials)

 Results

  • All-cause mortality (3.7% vs. 3.8%; odds ratio (OR) 0.97, CI 0.86–1.10) and cardiovascular mortality (2.0% vs. 2.1%, OR 0.92; CI 0.78–1.09) were not different in aspirin vs. no aspirin groups.
  • Arterial ischemic events showed no differences, including myocardial infarction (2.5% (aspirin) vs. 2.5% (no aspirin)), cerebrovascular events (0.6% (aspirin) vs. 0.6% (no aspirin)) and peripheral arterial events (0.2% (aspirin) vs. 0.3% (no aspirin)).
  • Aspirin significantly reduced the risk for venous thromboembolic events (VTE; 1.5% (aspirin) vs. 2.0% (no aspirin); OR 0.74, CI 0.59–0.94, p = 0.02).
  • Perioperative major bleeding was significantly more frequent in aspirin groups (4.4% vs. 3.7%; OR 1.18, CI 1.05 to 1.33, p = 0.007).

 Conclusions

  • Aspirin showed no difference in terms of mortality v no aspirin for intermediate risk non cardiac surgery
  • Aspirin significantly reduced the risk for VTE but also had a significantly higher major bleeding risk

 Strengths

  • Meta-analysis of RCTs
  • High sample size
  • Easy to measure primary outcomes

 Weaknesses

  • Not all trials included secondary outcome measures eg. VTE risk
  • Variance in doses of aspirin per study
  • Some studies (PEP, POISE-II and STRATEGEM) used other anticoagulants as well as aspirin

 Implications

  • Aspirin showed no mortality benefit therefore the initiation/ continuation of aspirin in the perioperative period for intermediate risk surgery is not recommended.
  • Aspirin showed a 25% risk reduction in VTE for orthopaedic surgery and therefore should be considered as prophylaxis alongside other anticoagulants

 Potential for impact

  • Conclusive evidence for stopping aspirin in the preoperative period for intermediate risk surgery. This helps in decision making in the pre assessment clinic.
  • Consideration for adding aspirin to VTE prophylaxis protocols