Remote ischaemic preconditioning: the current best hope for improved myocardial protection in cardiac surgery?

Ischaemic preconditioning has been recognised as a major cardioprotective phenomenon for many years.1 2 Cycles of non-lethal ischaemia and reperfusion applied to the heart before a potentially lethal ischaemic insult have the ability to reduce infarct size by >50%. More recently, it became apparent that the protection generated by this classical form of direct ischaemic preconditioning could be replicated when the non-lethal ischaemia was applied to one segment of the heart and the lethal ischaemia applied to a separate segment.3 Thereafter, it became established that the same protection could also occur even if the preconditioning ischaemic stimulus was applied completely distant from the target organ requiring protection—that is, transient ischaemia of a remote organ or limb could still generate protection for the organ being subsequently challenged by lethal ischaemia.4 There is now clinical evidence, suggesting that this remarkable remote ischaemic preconditioning (RIPC) phenomenon may represent a simple, inexpensive, easily applied method of increasing cardioprotection during an array of interventional procedures that require a period of cardiac ischaemia to allow repair or intervention. Moreover, as it is now recognised that such protection may be achieved by starting the cyclical remote ischaemia and reperfusion after the period of injurious cardiac ischaemia has started—so-called remote post- or peri-conditioning—the possibility arises of enhancing protection in other situations, including transplantation.5 Several clinical reports of RIPC in cardiovascular surgery have now been published. In children undergoing congenital heart defect repairs using cardiopulmonary bypass, lower limb RIPC has been shown to reduce troponin release and inotrope requirements.6 In adults undergoing coronary artery bypass (CABG) surgery, intermittent upper limb ischaemia has been followed by reductions in postoperative release of lactate dehydrogenase7 and troponin T.8 In abdominal aortic aneurysm surgery, RIPC, induced by unilateral …