Stopping vs. Continuing Aspirin before Coronary Artery Surgery

Le Trac, Mercer University College of Pharmacy

According to the 2011 American College of Cardiology Foundation (ACCF)/ American Heart Association (AHA) guideline for coronary artery bypass graft (CABG), aspirin (100 mg to 325 mg daily) should be administered to CABG patients preoperatively. It was also recommended that aspirin should be initiated within six hours postoperatively and then continued indefinitely to reduce the occurrence of saphenous vein graft (SVG) closure and adverse cardiovascular events. [1]

According to the 2012 American College of Chest Physicians (“CHEST”) guideline, aspirin should be continued around the time of CABG surgery instead of stopping it for seven to ten days before surgery. [2]

It was suggested that preoperative aspirin may cause postoperative bleeding, which leads to the need for transfusion and re-exploration. These interventions were thought to be associated with increased morbidity, mortality, length of stay, and cost to the healthcare system. [3]

Title: Stopping vs. Continuing Aspirin before Coronary Artery Surgery [4]
Design Multicenter, double-blind, randomized; N= 2,100
Objective To determine whether aspirin would reduce the occurrence of death and thrombotic complications in at-risk patients who were undergoing coronary artery surgery
Study Groups Aspirin (n= 1,047); placebo (n= 1,053)
Methods Patients who were scheduled to undergo coronary artery surgery and were at increased risk for complications were randomly assigned to receive 100 mg of aspirin or placebo and tranexamic acid or placebo.
Duration 30 days
Primary Outcome Measure Composite of death and thrombotic complications (nonfatal myocardial infarction, stroke, pulmonary embolism, renal failure, or bowel infarction) within 30 days after surgery
Baseline Characteristics Characteristic Aspirin (n= 1,047) Placebo (n= 1,053)
Age (year) 66.5±9.7 66.2±10.2
Male (%) 88.3 81.5
New York Heart Association (NYHA) classification (%)
I 15.6 17.5
II 55.4 54.9
III 26.4 25.8
IV 2.7 1.8
Preexisting medication condition (%)
Diabetes 33.1 34.9
Hypertension 80.9 80.2
Angina 71.1 71.8
Heart failure 13.0 12.6
Myocardial infarction within 90 days 7.2 7.9
Previous cardiac surgery 1.6 1.3
Tranexamic acid received (%) 49.8 50.0
Postoperative aspirin within 24 hours (%) 78.4 76.0
Results Event (%) Aspirin (n= 1047) Placebo (n= 1053) Risk ratio (95% confidence interval) p value
Composite primary outcome 19.3 20.4 0.94 (0.80–1.12) 0.55
Death 1.3 0.9 1.56 (0.68–3.60) 0.30
Myocardial infarction 13.8 15.8 0.87 (0.71–1.07) 0.20
Stroke 1.3 1.1 1.17 (0.55–2.52) 0.70
Renal failure 4.7 3.9 1.20 (0.80–1.80) 0.39
Pulmonary embolism 0.8 1.0 0.81 (0.32–2.03) 0.81
Bowel infarction 0 0.2   0.50
Adverse Events Common Adverse Events: N/A
Serious Adverse Events: N/A
Percentage that Discontinued due to Adverse Events: N/A
Study Author Conclusions Among patients undergoing coronary artery surgery, the administration of preoperative aspirin resulted in neither a lower risk of death or thrombotic complications nor a higher risk of bleeding than that with placebo.

The benefits of preoperative aspirin before CABG were thought to reduce mortality rate and the rate of serious complications such as myocardial infarction, stroke, pulmonary embolism, renal failure, and bowel infarction. However, these study results suggest that administering aspirin before CABG does not provide benefits or cause serious complications. Thus, the decision for preoperative aspirin should be made based on whether the increased bleeding risk outweighs potential benefits.

References

  1. Hills LD, Smith PK, Anderson JL, et al. 2011 ACCF/AHA Guideline for Coronary Artery Bypass Graft Surgery: A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2011;124:e652– e735
  2. Guyatt GH, Akl EA, Crowther M, et al. Executive Summary: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. 2012;141(2_suppl):7S-47S. doi:10.1378/chest.1412S3.
  3. Sun JC, Crowther MA, Warkentin TE, et al. Should aspirin be discontinued before coronary artery bypass surgery? Circulation 2005; 112:e85.
  4. Myles PS, Smith JA, Forbes A, et al. Stopping vs. Continuing Aspirin before Coronary Artery Surgery. N Engl J Med. 2016; 374:728-737
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