浅低温心脏不停跳人工瓣膜置换过程中心肌保护与局部炎症反应

Relationship between myocardial inflammatory response and the myocardial protective effect of on-pump beating-heart technique with mild hypothermia

背景:人工心脏瓣膜置换过程中心脏不停跳技术对机体的保护效果可能与减轻体外循环心脏手术诱发的炎症反应有关。目的:观察浅低温心脏不停跳手术对体外循环人工机械瓣膜置换患者心肌的保护作用与心肌局部炎症反应的关系。方法:将二尖瓣机械瓣膜置换患者随机分为对照组和实验组,对照组在中度低温心脏停跳下完成心脏瓣膜置换手术,实验组在浅低温心脏跳动下完成心脏瓣膜置换手术。结果与结论:两组瓣膜置换过程中心肌局部白细胞介素6、白细胞介素8、肿瘤坏死因子а、肌钙蛋白Ⅰ水平均较置换前显著升高;实验组白细胞介素6、白细胞介素8和肿瘤坏死因子а、肌钙蛋白Ⅰ水平升高程度显著低于对照组,表明心脏不停跳手术可减少体外循环期间心肌局部促炎性细胞因子的生成,减轻心肌局部炎症反应,保护心肌。两组体外循环结束时核转录因子κB表达增加,实验组较对照组增加幅度较小,说明浅低温心脏跳动手术有利于抑制心肌组织释放促炎性细胞因子。提示浅低温心脏不停跳手术在一定程度上减轻心肌的局部炎症反应,可能是该手术方式保护心肌的重要机制。

BACKGROUND： On-pump beating-heart technique has been promoted as better systemic protection compared with the technique of cardioplegic arrest, and the attenuated inflammatory response may play an important role in the protective effect of the on-pump beating-heart technique. OBJECTIVE： To investigate the relationship between local inflammatory response and the myocardial protective effect of on-pump beating-heart technique with mild hypothermia in patients with artificial mechanical heart valve replacements. METHODS： Forty patients undergoing elective mechanical mitral valve replacements with cardiopulmonary bypass （CPB） were eligible for inclusion in the study. The patients were randomly divided into control group and beating group with 20 patients in each group. The conventional approach was used in control group, while the heart was kept empty and beating throughout the operation in beating group. In all patients, blood samples withdrawn from the right atrium or the coronary sinus before the CPB, 30 minutes after the start of CPB, or before the right atrium was closed, were assayed for plasma levels of interleukin （IL）-6, IL-8, tumor necrosis factor-alpha （TNF-α）, and cardiac troponin I（cTnI） levels. Meanwhile, the right atrial myocardial tissue samples were taken to detect myocardial cell nuclear transcription factor kappa B （NF-κB） expression when the right atrium was opened and closed. RESULTS AND CONCLUSION： There were no significant differences between control and beating groups in terms of demographic, pre-operative or operative parameters. In both groups, compared with the baseline values, plasma levels of IL-6, IL-8, TNF-α and cTnI were gradually increased during CPB. Compared with the control group, the increasing degrees of IL-6, IL-8, TNF-α, and cTnI were significantly lower in the beating group （P 0.05）. The increased expression of NF-κB was lower in beating group than that in control group （P 0.05）. These results suggest that the attenuated myocardial inflammatory response plays an important role in myocardial protection of on-pump beating-heart technique with mild hypothermia.