Mechanisms of oxidative stress and myocardial protection during open-heart surgery

Abstract

Cold heart protection via cardioplegia administration, limits the amount of oxygen demand. Systemic normothermia with warm cardioplegia was introduced due to the abundance of detrimental effects of hypothermia. A temperature of 32–33°C in combination with tepid blood cardioplegia of the same temperature appears to be protective enough for both; heart and brain. Reduction of nitric oxide (NO) concentration is in part responsible for myocardial injury after the cardioplegic cardiac arrest. Restoration of NO balance with exogenous NO supplementation has been shown useful to prevent inflammation and apoptosis. In this article, we discuss the “deleterious” effects of the oxidative stress of the extracorporeal circulation and the up-to-date theories of “ideal” myocardial protection.

Atrial Septal Defect Surgery With Normothermic Cardiopulmonary Bypass and Normothermic Blood Cardioplegia in the Pediatric Age Group

“…In CPBP, whole body hypothermia is used for organ protection, especially in the brain, kidneys, lungs and heart by reducing metabolic activity and reducing the oxygen requirement (1, 2). Decreased brain blood flow and autoregulation during hypothermia have been shown to cause changes in neural tissue oxygen and glucose uptake, cellular membrane stability, and the use and production of ATP (1). It was determined that there was no increase in the probability of a neurological disorder with normothermic CPBP in the brain tissue that was protected by hypothermia and autoregulation was preserved (1).…”

“…Decreased brain blood flow and autoregulation during hypothermia have been shown to cause changes in neural tissue oxygen and glucose uptake, cellular membrane stability, and the use and production of ATP (1). It was determined that there was no increase in the probability of a neurological disorder with normothermic CPBP in the brain tissue that was protected by hypothermia and autoregulation was preserved (1). No cerebrovascular event was detected in the early postoperative period or in the follow-up period in the patient group included in the study.…”

“…No cerebrovascular event was detected in the early postoperative period or in the follow-up period in the patient group included in the study. The increase in plasma viscosity and decrease in erythrocyte elasticity during hypothermic CPBP and the increase in hemoglobin oxygen affinity with hypothermia decrease oxygen delivery at the tissue level, which leads to increased circulatory disturbance at the microcapillary level (1). Both the direct effect of hypothermia and the temporary deterioration that occurs in NO synthesis at the endothelium level and the increase in serum norepinephrine level lead to an increase in peripheral vascular resistance, which increases the afterload of the heart and results in further deterioration of peripheral vascular circulation (1).…”

“…Blood cardioplegia, which can be hypothermic, tepid or normothermic, is the preferred method because it can carry oxygen to the tissues during cardiac arrest and can meet the metabolic needs of myocardial tissue. Decreasing the metabolic needs by reducing myocardial heat during cardiac arrest is an advantage of hypothermic cardioplegic solutions, but the negative effects of hypothermia on cell metabolism and coronary artery endothelium are also known (1). The metabolic activity decrease provided by hypothermia cannot be achieved with tepid or normothermic cardioplegia, and repetitive cardioplegia applications are used to alleviate this adverse event (1,(3)(4)(5)(6).…”

“…Decreasing the metabolic needs by reducing myocardial heat during cardiac arrest is an advantage of hypothermic cardioplegic solutions, but the negative effects of hypothermia on cell metabolism and coronary artery endothelium are also known (1). The metabolic activity decrease provided by hypothermia cannot be achieved with tepid or normothermic cardioplegia, and repetitive cardioplegia applications are used to alleviate this adverse event (1,(3)(4)(5)(6). The use of normothermic CPBP and normothermic blood cardioplegia is the method of choice for ASD closure operations requiring short term CPBP and aortic clamping.…”