DOES INTERMITTENT CORONARY PERFUSION OFFER GREATER MYOCARDIAL PROTECTION THAN CONTINUOUS AORTIC CROSS-CLAMPING

  • 1 January 1977
    • journal article
    • research article
    • Vol. 82  (1) , 51-59
Abstract
Considerable controversy exists concerning the relative merits of intermittent coronary perfusion vs. continuous aortic cross-clamping for cardiac procedures requiring ischemic arrest. Using the isovolumic ventricular balloon model and stop-freeze biopsy techniques, myocardial contractility (LV dp/dt max [left ventricular maximum change in pressure with time], length-tension and force-velocity relationships) and metabolism (adenine nucleotides, creatine phosphate and glycogen) were studied in 46 intact dogs supported by normothermic cardiopulmonary bypass and subjected to either 60 min of continuous ischemic arrest or to four 15-min intervals of ischemia each followed by 5 min of reperfusion. Following ischemia the hearts were reperfused for 30 min and defibrillated after the first 20 min. There were no significant differences in either metabolic parameters or contractile function between the groups. Although partial regeneration of ATP and glycogen occurred during reperfusion, only creatine phosphate achieved normal values and the end result was no difference between the 2 techniques. Five minutes of coronary reperfusion between consecutive episodes of ischemic arrest affords no greater intraoperative protection of the myocardium than does continuous aortic cross-clamping.