Ischaemic heart disease is a leading cause of mortality in the western world. A number of patients undergo coronary artery bypass graft (CABG) surgery as treatment for ischaemic heart disease. With the rise of interventional procedures, patients who are coming to have CABG surgery are higher risk1. Remote ischaemic preconditioning (RIPC) has been shown to reduce perioperative myocardial injury (PMI) in patients having CABG even when cold blood cardioplegia or intermittent cross clamp fibrillation is used as cardioprotective measures. These patients have a general anaesthetic with multiple infusions including Glyceryl Trinitrate (GTN). The use of GTN in these patients is based on theoretical assumptions of coronary vasodilation pre operatively along with maintaining graft potency postoperatively. We intend to investigate the effect of GTN in patients undergoing cardiac surgery being subjected to RIPC in its role as a Nitric Oxide (NO) donor. Exogenous NO has been shown to be cardioprotective in animal models.
The purpose of this study is to determine whether Glyceryl Trinitrate (GTN) reduces injury to the heart during heart-lung bypass surgery in combination with the newer technique of remote ischaemic preconditioning (RIPC).