J.Jpn. Surg. Soc.. 80(5): 451-465, 1979
Original article
INTRAOPERATIVE MYOCARDIAL PROTECTION DURING AORTIC CROSS-CLAMPING
(I) EXPERIMENTAL STUDY
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1st Department of Surgery, School of Medicine, Kanazawa University (Director : Prof. T. Iwa) Atsushi Hashiba |
As the method of protection, intermittent coronary perfusion with hypothermic coronary perfusate was used. The perfusate consisted of hyperkalemic (30 mEq/L) solution for potassium arrest, hypo-natremic (47 mEq/L) and hyperosmotic (380 mOsm.) solution for prevention of tissue edema and weakly alkalotic (pH 7.5) solution for reducing acidosis.
The perfusate was injected from the aortic root after the ligation of the ascending aorta. The heart was arrested within 10ｰ20 sec. and kept in a relaxed and flaccid state. The myocardial temperature was monitered at the interventricular septum and was kept at about 20°C with intermittent (about erery 30 min.) re-perfusion.
After anoxia for 30 min. with this method, the myocardial ultrastructural changes were very slight, limited to the mitochondriae, and these hearts were almost the same as normal hearts. On the other hand, in the anoxic hears that had been arrested for 30 min., the ultrastructural changes were very severe. Even after anoxia for 180 min. with this method, ischemic changes were mild, and it was shown that this method was effective for myocardial protection.
The mild hypo-osmotic (280 mOsm.) perfusate, regulated with reducing glucose was not effective for myocardial protection because of tissue edema even after anoxia for only 60 min.
In the hearts arrested with Young's solution and perfused with cold lactate Ringer's solution, a specific abnormality of the intercalated disc was seen and mitochondrial ischemic changes were advanced.
As the semiquantitative evaluation of the ischemic changes, it was found that the mitochondrial changes, named "Mitochondrial Score", was the most sensitive index.
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