Tian Ganghong, Xiang Bo, Dai Guangping, Li Gang, Sun Jiankang, Summers Randy, Deslauriers Roxanne
Institute for Biodiagnostics, National Research Council of Canada, Winnipeg, Manitoba, Canada.
J Thorac Cardiovasc Surg. 2003 Apr;125(4):872-80. doi: 10.1067/mtc.2003.109.
This study was undertaken to compare the efficacy of retrograde cardioplegia for myocardial perfusion with that of antegrade cardioplegia at the same flow rate.
Colored microspheres were used in rat hearts to assess the capillary flow of cardioplegia solution. Myocardial perfusion was evaluated with magnetic resonance imaging in pig hearts. Phosphorus 31 magnetic resonance spectroscopy was used to determine the efficacies of the cardioplegic techniques in sustaining myocardial energy metabolism.
At the same flow rate, the number of colored microspheres delivered to the capillaries by retrograde cardioplegia (15 +/- 1 microspheres/mm2) was significantly lower than that delivered by antegrade cardioplegia (29 +/- 2 microspheres/mm2). Furthermore, only 19% +/- 3% of the colored microspheres delivered to the capillaries by retrograde cardioplegia were found in the arteriolar portions of the capillaries, whereas most (80% +/- 3%) remained in the venular portions. Moreover, magnetic resonance images showed that contrast-enhanced signal-time courses obtained from different regions of the myocardium during retrograde cardioplegia varied significantly. Localized phosphorus 31 spectra showed that retrograde cardioplegia required a higher flow rate than did antegrade cardioplegia to sustain normal myocardial energy metabolism.
We conclude that retrograde cardioplegia provides significantly less capillary flow than does antegrade cardioplegia. Its microvascular perfusion varies significantly among the various small areas of the myocardium. As a result, its efficacy in sustaining normal myocardial energy metabolism is lower than that of antegrade cardioplegia.
本研究旨在比较相同流速下逆行心脏停搏与顺行心脏停搏对心肌灌注的效果。
在大鼠心脏中使用彩色微球来评估心脏停搏液的毛细血管流量。在猪心脏中用磁共振成像评估心肌灌注。采用磷31磁共振波谱法来确定心脏停搏技术在维持心肌能量代谢方面的效果。
在相同流速下，逆行心脏停搏输送至毛细血管的彩色微球数量（15±1个微球/mm²）显著低于顺行心脏停搏（29±2个微球/mm²）。此外，逆行心脏停搏输送至毛细血管的彩色微球中，只有19%±3%出现在毛细血管的小动脉部分，而大部分（80%±3%）留在小静脉部分。而且，磁共振图像显示，逆行心脏停搏期间从心肌不同区域获得的对比增强信号-时间曲线有显著差异。局部磷31波谱显示，逆行心脏停搏比顺行心脏停搏需要更高的流速来维持正常的心肌能量代谢。
我们得出结论，逆行心脏停搏提供的毛细血管流量明显少于顺行心脏停搏。其微血管灌注在心肌的各个小区域之间有显著差异。因此，其在维持正常心肌能量代谢方面的效果低于顺行心脏停搏。
