Myocardial Protection: What the Surgeon Does

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Abstract
With changing patient demographics resulting in greater risk of myocardial ischemia, avoidance of low-output states must begin with patient selection. From that point, a variety of well-established surgical techniques can be used to provide myocardial protection. Hypothermia and cardioplegia are fundamental among these; however, it should be recognized that alternate approaches must be considered. The well-documented deleterious effects of overdistension and hypoperfusion must be borne in mind. To this is added the complex formulation of contemporary cardioplegic solutions based on thorough understanding of the pathophysiology of ischemic injury. Specific deleterious consequences of ischemia and/or hypothermia are abnormalities of tissue volume regulation, lack of high-energy substrate availability, reduced capacity for postischemic oxidative metabolism, depressed availability of high-energy phosphate precursors, and the potential damage done by oxygen-induced free-radical-mediated oxidant injury.