Post-conditioning reduces infarct size in an open-chest porcine acute ischemia-reperfusion model.
BACKGROUND
Timely reperfusion is a prerequisite for myocardial salvage; however, re-oxygenation of the ischemic myocardium initiates reperfusion injury. Post-conditioning diminishes the detrimental aftermath of an acute myocardial infarction through alleviation of reperfusion injury. Ischemic post-conditioning consists of a series of brief interruptions in the coronary blood supply that has to be applied within the first minutes after re-establishing the coronary flow.


METHODS
Sixteen female mixed Danish Landrace and Yorkshire pigs weighing 20 kg were included. The heart was exposed through a midline sternotomy. A snare was positioned around the left anterior descending coronary artery downstream of the second diagonal branch. After randomization to either no treatment (control group) or treatment by ischemic post-conditioning (post-conditioning group), the pigs underwent 45 min of ischemia and 180 min of reperfusion. The post-conditioning group had a post-conditioning algorithm applied consisting of 15 s of reperfusion alternating with 15 s of re-occlusion repeated 10 times.


RESULTS
The groups were comparable with regard to body weight, hemodynamics and the size of the area at risk. The post-conditioning group had an absolute reduction in infarct size of 18.1% [confidence interval (CI): 6.2: 30.0%] compared with the control group (P=0.0056). In the post-conditioning group, infarction developed in 39.6+/-12.0% (1 SD) of the area at risk compared with 57.8+/-10.2% (1 SD) in the control group.


CONCLUSIONS
When ischemic post-conditioning was applied at reperfusion, we found an absolute reduction in infarct size of 18.1% presumably attributable to a diminished reperfusion injury. The model we have developed is suitable for further studies of this promising intervention.
Lie
R H
RH
Department of Anaesthesiology and Intensive Care, Aarhus University Hospital, Skejby, Aarhus, Denmark. rasmus.lie@ki.au.dk
Hasenkam
J M
JM
Nielsen
T T
TT
Poulsen
R
R
Sloth
E
E
D000208:Acute Disease; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006439:Hemodynamics; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D017202:Myocardial Ischemia / Q000097:blood / Q000473:pathology* / Q000601:surgery*; D012307:Risk Factors; D034421:Sus scrofa