Effect of ischemic postconditioning in adult valve replacement.
OBJECTIVE
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.


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Luo
Wanjun
W
Department of Cardiothoracic Surgery, Xiang Ya Hospital, Central South University, Changsha, Hunan, 410008, PR China. luowanjun@yahoo.com
Li
Bei
B
Chen
Ri
R
Huang
Rimao
R
Lin
Guoqiang
G
D000293:Adolescent; D000328:Adult; D002316:Cardiotonic Agents / Q000008:administration & dosage; D052279:Creatine Kinase, MB Form / Q000097:blood; D005260:Female; D006324:Heart Arrest, Induced / Q000009:adverse effects*; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D015425:Myocardial Reperfusion / Q000379:methods*; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D019990:Perioperative Care; D016896:Treatment Outcome; D019210:Troponin I / Q000097:blood
D002316:Cardiotonic Agents; D019210:Troponin I; D052279:Creatine Kinase, MB Form