Myocardial protection by pre- and post-anesthetic conditioning.

BACKGROUND AND OBJECTIVES Perioperative myocardial ischemia is commonly observed, and it can increase significantly postoperative morbidity and mortality. The cardioprotective properties of volatile anesthetics and opioids have been studied during several decades and currently constitute powerful tools in the management of patients with ischemic coronariopathy. The objective of this review was to provide the fundaments of myocardial protection by preconditioning. CONTENTS The concepts of cellular damage secondary to ischemia and reperfusion, ischemic preconditioning (IPC), and anesthetic preconditioning (APC), as well as the mechanisms of myocardial protection, are discussed. Recent studies in cardiac surgery demonstrated that the use of short periods of ischemia during reperfusion can reduce the area of myocardial infarction. Volatile anesthetic can also have a protective effect in myocardial reperfusion. Independently of the signaling pathway that leads to preconditioning, both anesthetic and ischemic, mitochondrial dependent KATP channels are considered the final mediators of cardioprotection by controlling the mitochondrial influx of calcium and, therefore, preventing the induction of necrosis and apoptosis. Although IPC and APC effectively reduce the area of myocardial infarction and improve postoperative ventricular function, it is important to stress that those treatments should be instituted before ischemic events to justify their clinical applicability. CONCLUSIONS Phenomena known as myocardial ischemic preconditioning and anesthetic preconditioning are well known, and the mechanism of protection is similar in both situations; however, not every step that leads to this protection has been fully explained. Further studies are necessary to increase the clinical applicability of the cardioprotective properties of anesthetics.