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Activation of the coagulation system during coronary artery bypass grafting: comparison between on-pump and off-pump
Domenico Paparella1, Antonella Galeone, Maria Teresa Venneri
1Division of Cardiac Surgery, Dipartimento d'Emergenza e Trapianti di Organo, University of Bari, Italy. paparella@tin.it
Insights
On-pump coronary artery bypass grafting leads to greater thrombin formation and fibrinolytic activation compared to off-pump surgery. Off-pump procedures preserve platelet function, showing a weaker fibrinolytic response.
Area of Science:
- Cardiovascular Surgery
- Hemostasis and Thrombosis
Background:
- Coronary artery bypass grafting (CABG) involves complex physiological responses.
- Understanding the impact of on-pump versus off-pump techniques on coagulation and fibrinolysis is crucial for patient outcomes.
Purpose of the Study:
- To compare the activation of coagulation, fibrinolysis, and platelet function during on-pump and off-pump CABG.
- To elucidate the hemostatic differences between the two surgical approaches.
Main Methods:
- A randomized trial of 32 patients undergoing on-pump or off-pump CABG.
- Evaluation of coagulation and fibrinolytic markers and in vitro bleeding time.
- Blood sampling at multiple time points up to postoperative day 6.
Main Results:
- On-pump CABG showed significantly higher thrombin formation and D-dimer release.
- In vitro bleeding time was prolonged in the on-pump group, indicating impaired platelet function.
- Tissue factor production and tissue-plasminogen activator levels were similar between groups.
Conclusions:
- On-pump CABG results in more pronounced thrombin generation and fibrinolytic activation.
- Off-pump CABG preserves platelet function and shows a less active fibrinolytic system.
- Both techniques lead to preserved platelet function at discharge, but with increased thrombin formation.
Objective:
The activation of the coagulation and fibrinolytic systems and platelet function in patients undergoing coronary artery bypass surgery on-pump or off-pump techniques was compared.
Methods:
Thirty-two patients were randomly assigned to on-pump or off-pump coronary artery bypass grafting. Heparin was given at the same dose. Activation of the coagulation and fibrinolytic systems was evaluated by measurement of several markers. Platelet function was evaluated by in vitro bleeding time test. Blood samples were collected at 7 different times, up to postoperative day 6.
Results:
Overall tissue factor production was similar in the two groups. Thrombin formation was more elevated in the on-pump group (P < .001), particularly during the operation; prothrombin fragment 1.2 discharge values were higher than the preoperative ones (P = .002). Levels of tissue-plasminogen activator showed no difference between the groups (P = .1). D-dimers release was higher in the on-pump group (P = .0002). In vitro bleeding time was longer in the on-pump group (P < .0001), particularly in the first 24 hours; it was not prolonged in the off-pump group. In both groups, regardless of aspirin treatment, discharge in vitro bleeding times were lower than the preoperative ones (P < .01).
Conclusion:
Although the extrinsic coagulation pathway is similarly activated, thrombin formation is more pronounced in patients having on-pump bypass grafting. Patients subjected to off-pump bypass grafting have normally functioning platelets and a weak activation of the fibrinolytic system. At discharge, both groups have preserved platelet function and increased thrombin formation. Further studies with angiographic evaluation are needed to establish a correlation between coagulation parameters, platelet function, and graft patency.
