Hypercoagulability in patients undergoing coronary artery bypass grafting: prevalence, patient characteristics and postoperative outcome.

OBJECTIVES To investigate the prevalence of preoperative hypercoagulability assessed by thromboelastography (TEG), to identify patient characteristics associated with hypercoagulability and to explore whether hypercoagulability is associated with a greater risk for myocardial infarction (MI), stroke and mortality 30 days after coronary artery bypass grafting (CABG) surgery. METHODS This is a prospective, observational study of 200 consecutive CABG surgery patients. Hypercoagulability was defined as TEG maximum amplitude >69 mm. RESULTS Eighty-seven out of 200 (43.5%) CABG patients were TEG-hypercoagulable. In univariate regression analysis, age, female gender, hypertension, severe chronic obstructive pulmonary disease, platelet count and fibrinogen level were significantly associated with TEG-hypercoagulability. Multivariate regression analysis revealed higher age, platelet count and fibrinogen levels as variables independently associated with TEG-hypercoagulability. Thirty-day outcome data: MI (TEG-hypercoagulable 6.9% vs. TEG-normocoagulable 3.7%, NS), stroke (8.0 vs. 2.8%, NS) and mortality (4.6 vs. 0.9%, NS). There was a significant difference in 30-day combined event rate of MI, stroke and mortality (17.2 vs. 6.6%, P = 0.019). In univariate analysis, only female gender and TEG-hypercoagulability were significantly associated with 30-day combined event rate. In multivariate analysis, only female gender was significantly associated with 30-day outcome (P = 0.014), whereas TEG-hypercoagulability demonstrated a trend (P = 0.065). CONCLUSIONS Hypercoagulability identified by TEG was preoperatively found in 43.5% of CABG patients, and the findings of this study support the notion that TEG-hypercoagulable patients have a higher risk for a combination of thromboembolic complications and death after surgery.