Clopidogrel and Aspirin After Surgery for Coronary Artery Disease - Clopidogrel and Aspirin After Surgery for Coronary Artery Disease

Nov 01, 2010
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Author/Summarized by Author:
Anthony A. Bavry, MD, MPH, FACC
Summary Reviewer:
Deepak L. Bhatt, MD, MPH, MBA, FACC
Trial Sponsor:
Key Project in the National Science & Technology Pillar Program
Date Published:
01/01/2010
Date Updated:
11/01/2010
Original Posted Date:
11/01/2010
References

Description:

The goal of the trial was to compare treatment with aspirin plus clopidogrel compared with aspirin alone among patients undergoing coronary artery bypass grafting (CABG).

Hypothesis:

Aspirin plus clopidogrel will be more effective in improving early bypass graft patency.

Study Design

  • Randomized
  • Parallel

Patient Populations:

  • Patients undergoing elective CABG

    Number of enrollees: 249
    Duration of follow-up: 3 months
    Mean patient age: 58 years
    Percentage female: 18%
    Ejection fraction: 60%

Exclusions:

  • Thrombocytopenia (<100 x 109/L) or polycythemia (>300 x 109/L)
  • Previous CABG or cardiac surgery
  • Need for concomitant valve or aorta surgery
  • Renal insufficiency
  • Left ventricular systolic dysfunction (<30%)
  • Aspirin or clopidogrel within 7 days of surgery
  • Liver disease
  • Need for perioperative warfarin
  • Active gastroduodenal ulcer or gastrointestinal bleeding
  • Large postoperative pleural effusion
  • Reoperation for tamponade due to bleeding
  • Postoperative low cardiac output syndrome or need for inotropic support and/or intra-aortic balloon pump
  • Clinical instability

Primary Endpoints:

  • Graft occlusion assessed by multi-slice computed tomography at 3 months

Secondary Endpoints:

  • Major adverse cardiac events, defined as cardiovascular death, myocardial infarction, and repeat revascularization

Drug/Procedures Used:

After successful CABG, Chinese patients were randomized to aspirin (100 mg) plus clopidogrel (75 mg; n = 124) versus aspirin (100 mg) alone (n = 125) when chest tube drainage was ≤30 cc/h for 2 hours.

Principal Findings:

Overall 249 patients were randomized. There was no difference in baseline characteristics among the participants. In the aspirin plus clopidogrel group, the mean age was 58 years, 18% were women, mean body mass index was 26 kg/m2, 40% were diabetics, preoperative left ventricular ejection fraction was 60%, off-pump CABG was performed in 64%, and the mean number of grafts was 3.2 per patient.

The primary outcome, overall graft occlusion at 3 months, occurred in 6.5% of the aspirin plus clopidogrel group versus 10.3% of the aspirin alone group (p = 0.073). Saphenous vein grafts occluded in 8.4% versus 14.3% (p = 0.043), internal mammary artery grafts occluded in 1.8% versus 0.9% (p = 0.58), and radial artery grafts occluded in 25% versus 33% (p = 0.81), respectively.

Interpretation:

Among Chinese patients undergoing CABG, the use of aspirin plus clopidogrel may be beneficial compared with aspirin alone. Dual antiplatelet therapy was associated with a nonsignificant reduction in overall graft occlusion and a significant reduction in saphenous vein graft occlusion at 3 months. These findings contrast with the smaller, though placebo-controlled CASCADE trial, which found no difference in overall graft patency at 1 year. The definitive study on this topic has yet to be conducted.

References:

Gao G, Zheng Z, Pi Y, et al. Aspirin plus clopidogrel therapy increases early venous graft patency after coronary artery bypass surgery: a single-center randomized controlled trial. J Am Coll Cardiol 2010;56:1639-43.

Keywords: Platelet Aggregation Inhibitors, Radial Artery, Ticlopidine, Purinergic P2Y Receptor Antagonists, Body Mass Index, Saphenous Vein, Drainage, Mammary Arteries, Stroke Volume, Chest Tubes, Coronary Artery Bypass, Diabetes Mellitus


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