Risk factors for re-exploration due to bleeding after coronary artery bypass grafting

OBJECTIVE: The study aimed to investigate relevant clinical risk factors for re-exploration due to bleeding after primary coronary artery bypass graft (CABG) surgery, and to evaluate the influence of antiplatelet and antifibrinolytic drugs. DESIGN: Three retrospective analyses were performed on patients who underwent CABG: (1) Logistic regression was used to identify clinical risk factors for re-exploration (n = 3000). (2) A case-control study (n = 228) was used to obtain information on exposure of antithrombotic and hemostatic therapy. (3) Based on exposure to antiplatelet and antifibrinolytic therapy, and odds ratios (ORs) in multivariate logistic models, the proportion of re-explorations attributed to these drugs was calculated. RESULTS: A receiver operating characteristic curve was created for clinical risk factors. The C-index was 0.64, indicating limited ability to predict re-exploration for bleeding. Clopidogrel was the only drug influencing the risk of re-exploration (OR 3.2, 95% CI 1.7-5.9). The harmful effect of clopidogrel was confirmed in multivariate model (OR 4.7, 95% CI 2.2-9.9), and aprotinin had a protective effect of the same magnitude (OR 0.2, 95% CI 0.1-0.6). CONCLUSIONS: Clopidogrel is an essential risk factor for re-exploration due to bleeding, and attributable to at least one-quarter of surveyed cases. Aside from pharmaceuticals, there are no strong clinical risk factors.