异氟烷预处理对心脏瓣膜置换术病人血肌红蛋白、vWF和心肌细胞显微结构的影响

Effects of isoflurane preconditioning on plasma level of myoglobin and von Willebrand factor and myocardial microstructure in patients undergoing cardiac valve replacement

目的观察异氟烷预处理对心脏瓣膜置换术病人血浆肌红蛋白(Mb)、血管假性血友病因子(vWF)浓度和心肌细胞显微结构的影响,以证实异氟烷预处理对心肌的保护作用。方法择期心肺转流术下行心脏瓣膜置换术病人30例,年龄18～60岁,随机分为2组,每组15例。试验组在麻醉诱导后吸入1.1%～1.2%(呼气末浓度)异氟烷30min,洗脱15min。对照组不吸入异氟烷,其余用药2组无区别。分别于吸入异氟烷前(T0),主动脉开放30min(T1)、6h(T2)、12h(T3)及24h(T4)经桡动脉取血测血浆Mb和vWF浓度。分别于主动脉阻断前(上腔静脉插管时)和主动脉开放后(上腔静脉退管时)取部分右心耳组织观察其显微结构。结果与T0比较,对照组血浆Mb浓度在T1～T3时升高、在T4时下降,试验组在T1～T4时均降低,2组在T1～T4均有显著差异(P<0.05)。与T0比较,对照组血浆vWF浓度在T1、T3及T4时降低,试验组在T1～T4时均降低,试验组下降幅度大于对照组,2组在T1及T2时差异有显著意义(P<0.05)。光镜和电镜下可见试验组主动脉开放后心肌细胞显微结构损伤明显轻于对照组。结论异氟烷预处理能降低心脏瓣膜置换术病人主动脉开放后一段时间内血浆Mb和vWF浓度,减轻心肌细胞显微结构损伤,对心肌有一定的保护作用。内皮功能的改善可能是其保护机制之一。

AIM To verify the protection of isoflurane preconditioning on myocardium against ischemia/reperfusion injury in patients undergoing cardiac valve replacement by measuring plasma concentration of myoglobin （Mb） and yon Willebrand factor （vWF） and observing myocardial microstructure and ultramicro- structure. METHODS Thirty patients at the age of 18 - 60 years undergoing elective valve replacement were randomly assigned into control group （n = 15） and trial group （n = 15）. The patients in the trial group were administered with isoflurane （end-tidal concentration 1.1% - 1.2%） for 30 min followed by a 15 min washout period after anesthesia induction based on conventional therapy. The patients in the control group only received conventional therapy. Blood samples were taken from radial artery and the concentration of Mb and vWF were measured before inhalation of isoflurane （T0）, and at 30 min （T1）, 6 h （T2）, 12 h （T3） and 24 h （T4） after aorta opening. Right atrial biopsies were collected to observe myocardial microstructure and ultramicro-structure at the times when inserting catheter into superior vena cava （SVC） and pulling out the catheter from SVC, respectively. RESULTS In the control group, compared with T0, a significant increase of mean Mb level was detected at T1 - T3, and a significant decrease of mean vWF level was detected at T1, T3 and T4. While in the trial group, compared with T0, mean Mb and vWF levels were significantly decreased at T1- T4. Compared with the control group, mean Mb level at T1 - T4 and mean vWF level at T1 - T2 in the trial group decreased significantly （P 〈 0.05）. The degree of myocardial injury was slighter in the trial group than that in the control group. CONCLUSION Isoflurane preconditioning could decrease plasma level of Mb and vWF after aorta opening, reduce myocardial injury, and has protective effects on myocardium in patients undergoing cardiac valve replacement. Improving endothelial function of myocardial blood vessel may be one of its protection mechanisms.