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This study tests the hypothesis that improved myocardial salvage following regional ischemia occurs when attention is directed toward the duration of blood cardioplegic reperfusion rather than the reperfusate "dose". Pilot studies after global ischemia established the postischemic oxygen use pattern consistent with normal and impaired recovery; the best(More)
In seven dogs on cardiopulmonary bypass, a critical stenosis (75% to 90%) of the left anterior descending coronary artery (LAD) was produced. Alternate 250 ml/min infusions of asanguineous and blood cardioplegic (4 degrees C) solutions were made for 3 to 5 minutes. Poststenotic flow (flowmeter), intramyocardial temperature, and aortic pressure were(More)
This study tests the hypothesis that immediate functional recovery is possible after 2 to 3 hours of regional ischemia by control of the conditions of reperfusion (i.e., total vented bypass) and the composition of the reperfusate (substrate-enriched blood cardioplegic solution) by either central cannulation with thoracotomy or peripheral cannulation without(More)
This study tests the hypothesis that failure to minimize left ventricular oxygen demands by venting during reperfusion diminishes recovery after controlled blood cardioplegic reperfusion. Of 25 dogs undergoing 2 hours of left anterior descending coronary occlusion, nine were reperfused with normal blood without bypass and five were reperfused with normal(More)
This study tests the hypothesis that irreversible muscle damage does not occur after as long as 6 hours of ischemia before reperfusion, immediate functional recovery is possible by controlling the conditions of reperfusion during total vented bypass and the composition of the reperfusate with substrate-enriched blood cardioplegic solution, and such control(More)
This study tests the hypothesis that surgical revascularization (i.e., simulating coronary artery bypass grafting) with control of reperfusion conditions (total vented bypass) and of reperfusate composition (substrate-enriched blood cardioplegic solution) produces better recovery than is possible in the non-surgical setting (i.e., normal blood in beating,(More)
This study tests the hypothesis that improved muscle salvage is possible by markedly reducing the ionic calcium (Ca++) of the reperfusate (less than 250 mumol/L) and adding a calcium channel-blocking drug (diltiazem). Preliminary pilot studies showed that a 20-minute infusion of markedly hypocalcemic substrate-enriched blood cardioplegic solution (less than(More)
This study evaluates the capacity of regional substrate-enriched blood cardioplegic reperfusion (without bypass) to salvage cardiac muscle subjected to 40 minutes of regional ischemia. Results are compared with those obtained by normal blood reperfusion at either systemic or reduced perfusion pressure (i.e., simulating acute angioplasty or streptokinase(More)
This study assesses the regional oxygen requirements of muscle segments that are beating and working, beating and empty, arrested and decompressed, and nonischemic that move dyskinetically. Regional oxygen demands were evaluated by producing a dyskinetic segment by infusing regional cardioplegic solution through a left anterior descending coronary artery(More)