Purpose : Several factors contributes to postoperative inflammatory reaction (blood-air contact, contact of blood with foreign material, non-specific response to surgical trauma, ..) . Although introducing more technical demands, Off-pump surgery (OPCAB) is thought to offer some advantages, notably in term of reduction of the post-operative inflammatory reaction. But reduction of the "post-pump syndrome" may also be obtained by modifying some luminal and design characteristics of the CPB circuits, such in SMA circuits. The aim of this prospective study was to compare the benefit of these two approaches in terms of post-operative inflammatory response.
Methods : Ninety patients submitted CABG surgery were included. The main criteria of inclusion was the surgeon's ability to perform OPCAB surgery, based on visualisation of the coronarography. They were randomized in five groups: group I : closed SMA circuit, without pump suction (n=20); group II : open SMA circuit, with pump suction (n=20); group III : OPCAB, Heparin 3mg/kg (n=20); group IV : OPCAB, Heparin 1mg/kg (n=20) and group II' : open SMA circuit, without pump suction (n=10).
Serial pre-, per- and post-operative blood samples were taken. IL 6 and myeloperoxydase (MPO) were assayed as markers of neutrophil activation and inflammation. Intraoperative and postoperative clinical data were collected and analyzed.
Results : There were no significant differences in the mean number of bypasses between the five groups. The pattern of IL6 levels were similar for all the groups but, a significantly higher increase was observed in group II, compared to groups I and II' (p=0,0141 and 0,0086). For MPO pattern, similar results were observed. Nevertheless, although a statistically significant difference occurred between group II and groups III, IV and II'(p= 0,0184; 0,0120 and 0,0277), no significant differences was observed between group I, II', III and IV for IL6 and MPO.
Conclusion : OPCAB surgery is not associated to reduced post operative inflammatory reaction compared to coronary artery surgery with more biocompatible CPB, i.e. open or closed SMA circuits but without pump suction.