Post-conditioning reduces infarct size in an open-chest porcine acute ischemia-reperfusion model

• Published in: Acta anaesthesiologica Scandinavica Vol. 52; no. 9; pp. 1188 - 1193
• Main Authors: LIE, R. H., HASENKAM, J. M., NIELSEN, T. T., POULSEN, R., SLOTH, E.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-10-2008; Blackwell
• Subjects: Acute Disease; Anesthesia; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Biological and medical sciences; Disease Models, Animal; Female; Hemodynamics; Ischemic Preconditioning, Myocardial - methods; Medical sciences; Myocardial Ischemia - blood; Myocardial Ischemia - pathology; Myocardial Ischemia - surgery; Risk Factors; Sus scrofa; Vertebrata; Mammalia; Infarct; Ischemia reperfusion; Anesthesia; Artiodactyla; Conditioning; Ungulata; Pig
• ISSN: 0001-5172; 1399-6576
• DOI: 10.1111/j.1399-6576.2008.01756.x

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.
Conclusion: 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.