Luo Wanjun, Li Bei, Chen Ri, Huang Rimao, Lin Guoqiang
Department of Cardiothoracic Surgery, Xiang Ya Hospital, Central South University, Changsha, Hunan, 410008, PR China.
Eur J Cardiothorac Surg. 2008 Feb;33(2):203-8. doi: 10.1016/j.ejcts.2007.11.010. Epub 2007 Dec 19.
Ischemic postconditioning (POC) by brief episodes of ischemia performed just at the time of reperfusion can reduce infarct size in animal models and clinical settings of percutaneous coronary intervention. However, the clinical applicability of postconditioning in cardiac surgery remains to be determined. We investigated the effect of postconditioning on myocardial protection in patients undergoing valve replacement.
Fifty adult patients scheduled for elective valve replacement under cold blood cardioplegic arrest were randomly assigned to postconditioning (n=25) or control treatment (n=25). Postconditioning was performed by three cycles of 30s ischemia and 30s reperfusion using aortic re-clamping and de-clamping started 30s after cardioplegic arrest. The creatine kinase-MB, troponin I, transcardiac release of lactate were assayed. Measurements of clinical results were recorded during the study.
The types of procedure, age, bypass and aortic cross-clamping times were similar in both groups. The postoperative peak creatine kinase-MB was lower after aortic de-clamping in the postconditioning patients compared with the control group (66+/-24 U/l vs 84+/-20 U/l, p=0.02) and peak cTnI was similar in both groups. The required inotropes were reduced in postconditioning group compared with the control group (2.3+/-1.8 vs 4.1+/-2.2 microg/min/kg, p=0.03). There were reduction trends with regard to transcardiac release of lactate in postconditioning group compared with the control group (0.10+/-0.17 mmol/l vs 0.24+/-0.16 mmol/l, p=0.08). The transcardiac neutrophil count during reperfusion was less in POC group compared with the control group (7.8+/-6.3% vs 14.0+/-8.7%, p=0.04).
The present study demonstrated that postconditioning may protect adult myocardium undergoing cold blood cardioplegic arrest. These data support the need for a further clinical trial of postconditioning in cardiac surgery.
在再灌注时通过短暂缺血进行的缺血后处理（POC）可在动物模型以及经皮冠状动脉介入治疗的临床环境中减小梗死面积。然而，后处理在心脏手术中的临床适用性仍有待确定。我们研究了后处理对接受瓣膜置换术患者心肌保护的作用。
50例计划在冷血心脏停搏下行择期瓣膜置换术的成年患者被随机分为后处理组（n = 25）和对照组（n = 25）。后处理通过在心脏停搏30秒后开始进行3个周期的30秒缺血和30秒再灌注来实施，采用主动脉再夹闭和松开的方式。测定肌酸激酶-MB、肌钙蛋白I、经心脏的乳酸释放量。在研究期间记录临床结果的测量值。
两组患者的手术类型、年龄、体外循环和主动脉阻断时间相似。与对照组相比，后处理组患者主动脉松开后术后肌酸激酶-MB峰值较低（66±24 U/l对84±20 U/l，p = 0.02），两组肌钙蛋白I峰值相似。与对照组相比，后处理组所需的血管活性药物减少（2.3±1.8对4.1±2.2微克/分钟/千克，p = 0.03）。与对照组相比，后处理组经心脏的乳酸释放量有降低趋势（0.10±0.17毫摩尔/升对0.24±0.16毫摩尔/升，p = 0.08）。与对照组相比，后处理组再灌注期间经心脏的中性粒细胞计数较少（7.8±6.3%对14.0±8.7%，p = 0.04）。
本研究表明，后处理可能对接受冷血心脏停搏的成年心肌起到保护作用。这些数据支持有必要在心脏手术中进一步开展后处理的临床试验。
