Evaluation of closed cardiopulmonary bypass circuit for aortic valve replacement

Since 2005, we have used a novel technique based on the closed cardiopulmonary bypass system without cardiotomy suction (minimal cardiopulmonary bypass [mini-CPB]) for aortic valve replacement (AVR). In this study, we investigated the clinical advantages of this approach. We prospectively studied 32 patients who underwent isolated AVR using the mini-CPB (group M, n = 13) or conventional CPB (group C, n = 19). We compared the hemodilution ratio, serum interleukin (IL)-6 and IL-8 levels, and blood transfusion volume between the two groups. The characteristics, duration of CPB, and aortic cross-clamping time did not differ between the two groups. The hemodilution ratio was significantly lower in group M just after starting CPB (M vs. C: 14% +/- 2% vs. 25% +/- 3%, p = 0.0009). IL-6 levels increased significantly after surgery in both groups, but the postoperative levels were significantly lower in group M at 6 (84.9 +/- 24.9 pg/ml vs. 152 +/- 78 pg/ml, p = 0.042) and 12 (72.7 +/- 36.1 pg/ml vs. 123 +/- 49.6 pg/ml, p = 0.029) hours after CPB. There were no differences in IL-8 or blood transfusion volume after CPB. Mini-CPB offers an alternative to conventional CPB for AVR and has some advantages regarding hemodilution and serum IL-6 levels. However, it is unlikely to become the standard approach for AVR because there are no marked clinical advantages of mini-CPB.