<P>Background: The incidence of thromboembolic events following traditional open heart surgery has not been clinically significant. However, with beating heart surgery, for which cardiopulmonary bypass (CPB) is not required, the incidence of spontaneous intravascular thrombosis may be similar to that encountered after general surgeries. Compounding this risk is that many cases of off-pump coronary artery bypass (OPCAB) surgery are reserved for the elderly patient with multiple comorbidities. The few studies to date that have assessed the coagulation profile in OPCAB patients have been limited to the first 24 hours after surgery. </P><P>Methods: We prospectively studied 17 OPCAB and 6 on-pump patients over 4 days (hospital course) with daily thromboelastography. A coagulation index (CI) (reflecting R and K times, a angle, and maximum amplitude [MA]) was calculated for the patients, who served as their own controls. </P><P>Results: The OPCAB patients demonstrated 3 days postoperatively a 17% increase in coagulation compared with the baseline. Specifically, the CI consistently revealed an elevation in the a angle and the MA, both of which reflect increased fibrinogen and platelet activity. On the other hand, 3 days following surgery the CI of the CPB group was tightly clustered around their respective baseline CI values, which had recovered from a significant decrease immediately after surgery. </P><P>Conclusion: A state of hypercoagulability, as measured by thromboelastography, exists in the OPCAB patient beyond the first postoperative day, and this finding suggests that prophylactic postoperative anticoagulation therapy targeting fibrinogen and platelet activity may be indicated for these patients.</P>
