腺苷预处理对缺血心肌保护作用的临床研究

Myocardioprotective effect of adenosine preconditioning on open heart surgery

目的:探讨腺苷预处理在心内直视手术中对缺血心肌的保护效果及其机制。方法:将23例不伴有重度肺动肺高压的先天性心脏病患者随机分为腺苷预处理组(腺苷组,n=12)和对照组(n=11)。对照组在升主动脉阻断后采用常规改良冷St.Thomas液使心脏停跳行心肌保护(20 ml/kg),每30 min重复1次。腺苷组在体外循环(CPB)前缓慢静脉推注腺苷2 mg/kg行预处理,30 min内推完,此后施行和对照组相同的CPB和心肌保护方法。心脏停跳后行心内畸形纠治,完成心内操作后恢复心脏血供。观察心脏自动复跳率及术后心律变化、术后2、6、24和48 h血清肌酸激酶(CK)及其同工酶(CK-MB)、乳酸脱氢酶(LDH)水平和缺血末心肌组织细胞形态学变化。结果:两组均无手术死亡者。腺苷组心脏自动复跳率为91.6%,而对照组为54.5%(P<0.05),对照组1例术后偶发室性早搏,2例需短时应用小剂量血管活性药物。两组血清CK、CK-MB和LDH水平均有升高,但腺苷组在术后不同时点明显低于对照组(P<0.05或P<0.01);对照组心肌组织形态学可见心肌纤维变性、横纹模糊及间质水肿明显,而腺苷组变化较轻。结论:腺苷预处理可减少心肌细胞缺血引起的心肌酶释放,减轻缺血心肌的组织形态学变化,有利于再灌注后减少心律失常的发生和心功能的恢复。

Objective： To explore the myocardioprotective effect and mechanism of adenosine preconditioning in patients undergoing open heart surgery. Methods： Twenty-three patients with simple congenital heart defects were randomly divided into two groups：adenosine preconditioning group （adenosine group, n = 12） and control group （ n = 11 ）. The hearts suspended with cool improved St. Thomas cardioplegia （20 ml·kg^-1 ） which was perfused every thirty minutes after aortic-clamping in both groups. Adenosine was administered intravenously to the patients slowly in adenosine group at a dose of 2 mg·kg^-1 before beginning of cardiopulmonary bypass（CPB）. The serum concentration of creatine kinase（CK）, creatine kinase MB isoenzyme （CK-MB） and lactic dehydrogenase（LDH） from venous blood were measure at different time points after operation. Myocardial tissues were taken from right atrial appendage at the end of the myecardial ischemia time, and the cyto - histo - morphological changes were observed. Results ： After heart reperfusion,the proportion of spontaneous returned heartbeat was 91.6% in adenosine group, but 54.5% in control group （P 〈 0.05）. The levels of serum CK, CK-MB and LDH in adenosine group were mueh less than those in control group at different time points（ P 〈 0.05 or P 〈 0.01 ）. The myocardial histo-morphologieal observation showed very metamorphie ehanges in eontrol group, but slighter ehanges in adenosine group. Conclusion： Adenosine precon- ditioning can reduce the release of myocardial enzyme and the isehemie injury of myocardium, which may be. one of the mechanisms of adenosine preconditioning.