Investigation of the Ability of the MECC System to Provide Reduced Risk Over the Existing CECC System and Equivalent Risk to Off-Pump CABG Surgery: The IMPROVE TRIAL

Off-pump coronary artery bypass grafting (OPCAB) and the use of minimal extracorporeal circulation system (MECC) have both been proposed as alternatives to avoid the harmful effects of conventional cardiopulmonary bypass (CPB). However, with the technically more demanding nature of off-pump CABG, the potential short-term benefits of off-pump surgery may not translate into long-term benefits in providing optimal revascularization. In this prospective cohort study, it is our goal to evaluate short term outcomes as demonstrated by blood loss, transfusion need, and systemic inflammatory response during CABG surgery using MECC or conventional CPB or OPCAB.

In addition to the technical challenges posed during off-pump CABG surgery, it is also known that a significant systemic inflammatory response is mounted in patients who undergo conventional CPB. This inflammatory response is a combined effect of 1) the placement of required tubes and lines for connection with the heart/lung machine, 2) hemodilution, and 3) hypothermia. In this study, we will measure levels of tissue inflammation through the use of specialized laboratory tests (C Reactive Protein, C5 complement activation and Interleukin 6), and we will correlate these inflammation levels to the three different cardiopulmonary bypass options. It is our hypothesis that MECC will provide the stable operating environment of conventional CPB and the patient benefits of less blood loss, decreased transfusion rate, and decreased inflammation levels seen in patients with OPCAB.