Department of Cardiac Surgery, University of Rostock, Rostock, Germany.
J Thorac Cardiovasc Surg. 2012 Sep;144(3):677-83. doi: 10.1016/j.jtcvs.2012.05.037. Epub 2012 Jun 12.
Minimal extracorporeal circulation (MECC) has been introduced in coronary artery bypass graft (CABG) surgery, offering clinical benefits owing to reduced hemodilution and no blood-air interface. Yet, the effects of MECC on the intraoperative microvascular perfusion in comparison with conventional extracorporeal circulation (CECC) have not been studied so far.
The current study aimed to analyze alterations in microvascular perfusion at 4 predefined time points (T1-T4) during on-pump CABG using orthogonal polarization spectral imaging. Forty patients were randomized for being operated on with either MECC or CECC. Changes in functional capillary density (FCD), blood flow velocity, and vessel diameter were analyzed by a blinded investigator.
After start of extracorporeal circulation (ECC) and aortic crossclamping (T2), both groups showed a significant drop of FCD, with a significantly higher FCD in the MECC group (206.8 ± 33.6 cm/cm² in CECC group versus 217.8 ± 35.3 cm/cm² in MECC group; P = .034). In the late phase of the ECC (T3), FCD in the MECC group was already recovered, whereas FCD in the CECC group was still significantly depressed (223.1 ± 35.6 cm/cm² in MECC group; P = .100 vs T1; 211.1 ± 36.9 cm/cm² in CECC group; P = .017 vs T1). After termination of ECC (T4), FCD recovered in both groups to baseline. Blood flow velocity tended to be higher in the MECC group, with a significant intergroup difference after aortic crossclamping (T2).
Orthogonal polarization spectral imaging data reveal an impairment of microvascular perfusion during on-pump CABG. Changes in FCD indicate a faster recovery of the microvascular perfusion in MECC during the reperfusion period. Beneficial recovery of microvascular organ perfusion could partly explain the perioperative advantages reported for MECC.
微创体外循环（MECC）已应用于冠状动脉旁路移植术（CABG）中，因其可减少血液稀释且不存在血-气界面，故具有临床优势。然而，目前尚未研究 MECC 对与常规体外循环（CECC）相比的术中微血管灌注的影响。
本研究旨在使用正交偏振光谱成像术分析 4 个预设时间点（T1-T4）在体外循环泵辅助 CABG 期间的微血管灌注变化。40 例患者随机接受 MECC 或 CECC 手术。由一位盲法研究员分析功能毛细血管密度（FCD）、血流速度和血管直径的变化。
在体外循环（ECC）和主动脉阻断（T2）开始后，两组的 FCD 均显著下降，MECC 组的 FCD 明显更高（CECC 组为 206.8±33.6 cm/cm²，MECC 组为 217.8±35.3 cm/cm²；P=.034）。在 ECC 的晚期（T3），MECC 组的 FCD 已经恢复，而 CECC 组的 FCD 仍明显降低（MECC 组为 223.1±35.6 cm/cm²；P=.100 与 T1 相比；CECC 组为 211.1±36.9 cm/cm²；P=.017 与 T1 相比）。ECC 终止后（T4），两组的 FCD 均恢复至基线水平。MECC 组的血流速度趋于较高，在主动脉阻断后（T2）有显著的组间差异。
正交偏振光谱成像数据显示，体外循环泵辅助 CABG 期间存在微血管灌注受损。FCD 的变化表明，在再灌注期间 MECC 中微血管灌注的恢复更快。MECC 围手术期优势的部分原因可能是微血管器官灌注的有益恢复。
