Prospects of cardioprotection by volatile anesthetics

Abstract

Myocardial ischaemia is followed by some reversibile or ireversibile changes. The aim of cardioplegia is to protect numerous intracellular processes: to spare the intracellular energy stores, to reduce the free oxygen radicals synthesis, to protect the function of the endothelium and myocardial oxygen balance as well as ionic balance. The crystalloid or blood cardioplegia, with anterograde or retrograde infusion, is a basic procedure of the intraoperative cardiac protection. Glucose-insulin-potassium solution was primarily used in a myocardial infarction. After the first promising results, some surgical teams started to use the high glucose-insulin-potassium solution, as a metabolic modulation approach, during a coronary surgery as addition to cardioplegia. During ischaemia, a number of intracellular mechanisms deteriorate with bioenergy misbalance and decrease of cellular functional reserve. In particular, the regulation of contractility in response to loading, alteration in autocrine or paracrine regulation in metabolically stressed hearts and acquired, ?learned? tolerance of muscle to deteriorate perfusion (preconditioning) are examples of a variety of the cardiac adaptation. The further improvement in the metabolic modulation during a coronary surgery was made with fluorine ion halogenated volatile aneasthetics used for anaesthesia. The results of some experimental and first clinical studies induced a new approach to the modulation of the intracellular metabolic mechanisms and announced a new concept of anaesthetic preconditioning in coronary surgery. Large, randomized studies are needed to evaluate anaesthetic preconditioning and dependence of its efficiency on type and dose of volatile anaesthetics as well as the role of gene regulation in cardioprotection.