Comparison of Warm and Tepid Re-perfusion Temperature for Myocardial Protection by Ischemic Preconditioning.
10.4326/jjcvs.30.237
- VernacularTitle:Ｉｓｃｈｅｍｉｃ ｐｒｅｃｏｎｄｉｔｉｏｎｉｎｇの心筋保護効果 微温再潅流と常温再潅流との比較検討
- Author:
Hiroyuki Hirose
- Publication Type:Journal Article
- Keywords:
ischemic preconditioning
- From:Japanese Journal of Cardiovascular Surgery
2001;30(5):237-241
- CountryJapan
- Language:Japanese
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Abstract:
Recently, ischemic preconditioning (IPC) for myocardial protection in heart surgery, has been used intensively. However, no data are available concerning the effect and influence of reperfusion temperature during IPC. To estimate the effectiveness of re-perfusion temperature during IPC, we performed an experiment using pigs. Twenty male pigs (40-50kg in body weight) were used. After establishing cardiopulmonary bypass (CPB), IPC was made, cross-clamping the ascending aorta twice for 3min and performing re-perfusion for 5min. According to the re-perfusion temperature, we divided this model into four groups as follows; 37°C of the re-perfusion temperature with IPC (warm IPC, n=5), 37°C without IPC (warm NIPC, n=5), 32°C with IPC (tepid IPC, n=5) and 32°C without IPC (tepid NIPC, n=5). After the IPC procedure, all the hearts underwent global ischemia by cross-clamping for 15min under ventricular fibrillation, and re-perfusion with 32°C blood temperature was done for half hour. We measured myocardial levels of adenosine triphosphate, troponin-T, serum nitrous oxide, and other myocardial enzymes. After sacrificing animals, biopsy of the left ventricular free wall was made, and its histological changes were evaluated by scanning electron microscopy (SEM). Blood sampling was made before CPB, at the end of IPC, end of global ischemia, 10 and 30min after re-perfusion. In warm IPC, adenosine significantly increased, and serum troponin-T was significantly lower than other groups. The myocardium of warm IPC showed a normal SEM image, while ischemic damage was revealed in other groups. These results suggested that warm IPC induced effective myocardial protection. however tepid IPC did not protect the myocardium.
