Abstract
This experimental and clinical study evaluates the degree of myocardial protection afforded by coronary perfusion with cold lactated Ringer's solution plus mannitol. In the experimental study, diluted blood at 30°C (Control G.), lactated Ringer's solution at 4°C (G.A), 1, 000ml lactated Ringer's solution plus 200ml of 20% mannitol at 4°C (G.B), and 1, 000ml lactated Ringer's soultion plus 500ml of 20% mannitol at 4°C (G.C) were used for coronary perfusion. The myocardial-protecting effect of each perfusate was evaluated by examining serum isoenzymes (CPK-MB, LDH1+2, ), left ventricular function (Vmax, LVEDP, CO), and the ultrastructure of myocardium. There were no significant differences in myocardial changes between the control group, G.A and G.B. Left ventricular enddiastolic pressure increased significantly in G.A and a significant increase in CPK-MB was seen in G.C. Mitochondrial scores for each group were 98 (Control G.), 86 (G.A), 93 (G.B), and 51 (G.C). Minimal myocardial change was seen in G.B.
In the clinical study aortic root perfusion with cold lactated Ringer's solution (400m Osm) under aortic cross clamping (27-144min) was employed in 25 patients. They all survived and CPK-MB returned to preoperative values within 49 hours after operation. In 6 cases, the ultrastructure of left ventricular papillary muscle was examined. It was confirmed that no significant mitochondrial changes developed during aortic cross-clamping.
