Activation of coagulation and fibrinolysis during coronary artery bypass grafting: a comparison between on-pump and off-pump techniques.

Coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) is associated with intense activation of hemostatic mechanisms. But the precise knowledge of the effects of eliminating CPB in patients undergoing off-pump coronary artery bypass grafting (CABG) are not well established. The present study was carried out to compare and document the changes in selected coagulation and fibrinolysis variables in patients undergoing on-pump and off-pump CABG (OPCAB). A total of 42 patients of on-pump and 31 patients of off-pump CABG were selected for the study. Platelet count, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), Fibrinogen and D-dimer levels were measured immediately, 24 h and 7 days after operation and compared with the baseline preoperative values. Statistical analysis was done by mixed ANOVA for repeated measures and Post-hoc tests using the Bonferroni correction, Chi square and unpaired t test. All the parameters were significantly changed (P < 0.05) with the time. Platelet counts, fibrinogen and D-dimer levels were significantly different between on-pump and off-pump CABG patients on immediate and 24 h postoperative period and attained almost same level after 7 days of operation. Fibrinogen level and platelet counts were increased after a sharp fall in the immediate post-operative period whereas D-dimer levels were persistently increased with a sharp peak of rise in the immediate post-operative period in on-pump group. On-pump surgery was associated with excessive fibrinolytic activity immediately after operation. The off-pump group demonstrated less activation of coagulation and fibrinolysis and delayed postoperative response that became almost equal to the on-pump group in the later postoperative period.