Cardiac Protection by Volatile Anaesthetics: A Review

Abstract

Ischaemic preconditioning, a response to brief sublethal episodes of ischaemia leading to a pronounced protection against subsequent lethal ischaemia, is mimicked by some pharmacological agents. Halogenated anaesthetics alone exhibit cardioprotective properties at therapeutic doses, independent of their anaesthetic and haemodynamic effect, leading to the concept of anaesthetic preconditioning. Only recently has research turned to clinical application of preconditioning protocols, and anaesthetic preconditioning has indeed been demonstrated in randomised clinical trials conducted in patients undergoing cardiac surgery - mostly coronary artery bypass graft. Most of these trials demonstrate cardiac protection by assessing postprocedural release of cardiac troponin or early postoperative cardiac function. Few studies focus on clinical outcomes, and none demonstrates an advantage in terms of mortality or cardiac morbidity. A recent meta-analysis, pooling data regarding the use of desflurane and sevoflurane, found significant reductions of in-hospital mortality, myocardial infarction rate, intensive care unit and hospital stay, time on mechanical ventilation and incidence of long term cardiac events. In conclusion, the use of desflurane and sevoflurane appears to yield a better outcome, in terms of mortality and cardiac morbidity, in patients undergoing cardiac surgery. A definitive demonstration of this concept represents a difficult task because of the low mortality rate in modern cardiac surgery and because of the number of interfering factors. Whether these cardioprotective properties also exist in non-coronary surgery settings is still controversial owing to the scarce available data.