Effect of minimal extracorporeal circulation compared to cardiopulmonary bypass system on organ function and inflammatory response: a prospective randomized study-interims analysis

Objectives: Cardiopulmonary bypass causes systemic inflammatory response resulting in organ failure and cerebral dysfunction. Mini-extracorporeal circulation systems including a centrifugal pump with active drainage, low prime, and a cell-saving device might reduce the inflammatory response.

Methods: In a prospective, randomized study, 80 out of 150 patients underwent coronary artery bypass grafting using either mini-extracorporeal circulation (MECC-group, n=40) or conventional cardiopulmonary bypass (CPB-group, n=40) since March 2004. Mean age was 67±8 years in the CPB-group and 65±8 years in the MECC-group. Blood levels of cytokines, creatinkinase, Troponin T, S100B, were serially measured at different time points (preoperatively, 0, 1, 6, 12, 24, and 48 hours after CPB). Neuropsychological examination (grooved pegboard Test, TAP, Syndrom Kurz Test) including functional and emotional measures (Short form 36 Test and the Hospital anxiety and Depression Scale) were performed preoperatively, two days, five days, and 3 months postoperatively.

Results: Baseline characteristics, comorbidities, number of anastomoses, CPB and cross-clamp time, ventilation time, and ICU stay were comparable. There were no significant differences in neuropsychological tests and cytokine levels. MECC-patients demonstrated significantly lower peak levels of troponin T (0.42ng/ml versus 0.85ng/ml, p<0.0001), myocardial creatinkinase (214.4U/l versus 90.2U/l, p<0.01) and S 100B (1.83ng/ml versus 0.37ng/ml, p<0.001). Blood loss (1470±1969ml versus 1077±652ml, p=0.036) and hospital stay were significantly reduced in the MECC-group (7.6±0.2 days versus 8.6±0.6 days, p=0.041). The mortality in both groups was 2.5%.

Conclusion: The MECC is a safe bypass system that reduces significantly the myocardial damage and the hospital stay. However, neuropsychological tests did not show any significant differences so far.