二尖瓣置换术中心脏跳动与停跳对降钙素基因相关肽及心肌细胞超微结构的影响

Effect of mitral valve replacement between beating heart and arrested heart on calcitonin gene-related peptide and myocardial ultrastructure

目的：为进一步评价心内直视术中心脏跳动的作用。方法：２０例风湿性心脏瓣膜病二尖瓣置换者，随机分为心脏不停跳组及停跳组。应用放射免疫法测定血浆和心肌组织中的降钙素基因相关肽（ＣＧＲＰ）含量和进行心肌细胞超微结构观察。结果： １、血浆ＣＧＲＰ，与术前比较，均有明显升高（Ｐ ＜０．０１）。两组间比较，在主动脉开放后１５ｍｉｎ、３０ｍｉｎ，术后２ｈ、６ｈ等４个时点的含量，不停跳组均低于停跳组（Ｐ ＜０．０５或Ｐ ＜０．０１）。２、心肌ＣＧＲＰ含量，两组内各时点与其术前比较，均有明显下降（Ｐ＜０．０１）；两组间比较，术后含量不停跳组高于停跳组（Ｐ ＜０．０５）。３、不停跳组心肌细胞超微结构术前、术后无明显变化，而停跳组术后较术前心肌损害加重Ｉ－ＩＩ级。结论：提示浅低温体外循环心脏跳动中心内直视术对心肌损伤较轻，推测并非主要是由于增加了保护性细胞因子的产生而且还减少了心肌缺血再灌注（Ｉ／Ｒ）损伤，为一种值得推广的具有较好心肌保护作用的手术方式。

Objective: To estimate further myocardial protective effect between beating heart with mild hypothermia and arrested heart with cold blood cardioplegia perfusion. Methods: Twenty cases were randomly divided into two groups. The samples of plasma and myocardium were measured by radioimmunoassay, Myocardial ultrastructure were observed and analysed. Results: (1). The contents of CGRP in plasma were increased significantly when compared with their basic levels at pre-operation in two groups. Levels of CGRP in the beating heart group were significantly lower than that of the arrested heart group at 15min and 30min after aortic de-clamping, 2h and 6h post-operation. (2). The content of CGRP in myocardium was decreased significantly in both groups. CGRP levels in the beating heart group were significantly higher than those of the arrested heart group at post-operation. (3). For myocardium sample of electron microscopy: there were no significant differences between pre-operation and post-operation in the beating heart group. The degree of post-operation myocardial injury is more severe (I to II degree more) than that of pre-operation in the arrested heart group. Conclusion:Myocardial ischemic injury and reperfusion injury in the beating heart group is less severe than that in the arrested heart group. It decreased myocardial I/R injury and might not increase the protective factor mainly. Thereby, the technology of the beating heart with mild hypothermia and CPB is worth popularizing for myocardial protective effect during open-heart operation.