Objective: Comparing peri-operative activation of the coagulation and fibrinolytic systems and platelet function in patients receiving CABG operation by means of on pump or off pump techniques. Methods: 32 consecutive patients requiring elective CABG were enrolled in the study and assigned in a randomized fashion to: on pump group or off pump group. Heparin was given at the same dose (300 U/kg) and antifibrinolytic drugs were not administered. Activation of the coagulation system was evaluated by means of Prothrombin Fragment 1.2 (PF-1.2) and Tissue Factor (TF) measurements; fibrinolysis was evaluated measuring Tissutal Plasminogen Activator (TPA), Plasminogen Activator Inhibitor-1 (PAI-1) and D-Dimer (D-D) formation. Platelets function was evaluated by means of the Platelet Function Analyzer (PFA-100®). Blood samples were collected at T0 (during induction of anesthesia), T1 (45 min after heparin administration), T2 (15 min after protamine administration), T3 (3 h after the end of the operation), T4 (postoperative day (POD) 1), T5 (POD4), and T6 (POD6). Results were corrected for haemodilution. Results: No statically significative differences were found in pre, peri and post-operative clinical characteristics between the two groups, except for heparinization time (on pump group 159.6±40.4 min; off pump group 121.6±35.7; P<0.05) and hemoglobin value at POD6 (on pump group 9.3±2.34 g/dl; off pump group 10.9±1.35 g/dl; P<0.05). The coagulation system was activated during cardiopulmonary bypass (CPB) and highest levels of PF-1.2 were measured at T1, T2 and T3 (P<0.05 compared with off pump group); a trend towards increased levels of PF-1.2 was observed in both groups at T4,T5 and T6. TF production was similar in the two groups and no statistically significative differences were found at any sample time. The fibrinolytic system was more activated in the on pump group as demonstrated by TPA levels at T1 (P<0.05), PAI-1 levels at T2 (P<0.05) and D-D levels at T2 and T3 (P<0.05). Not surprisingly, CPB induces platelet dysfunction; PFA-100 bleeding times were significantly elevated in on pump group at T1, T2 and T3 (P<0.05). PFA-100 bleeding postoperative times were not prolonged in both groups despite aspirin administration. Conclusions: Off-pump patients produce less activation of the coagulation system and do not activate fibrinolysis during the operation; their platelet function is preserved during and after the operation. This may explain the reported reduced rate of postoperative bleeding associated with this technique. The absence of fibrinolysis together with functioning platelets and increased thrombin formation postoperatively suggest that off pump patients may experience a pro-thrombotic state.
|Titolo:||Activation of the coagulation system in coronary artery bypass grafting operation: comparison between on-pump and off-pump techniques|
|Data di pubblicazione:||2005|
|Appare nelle tipologie:||01.05 Abstract in rivista|