Investigation Into the Role of GTN & RIPC in Cardiac Surgery

The Effect of Remote Ischaemic Preconditioning and Glyceryl Trinitrate on Peri-operative Myocardial Injury in Cardiac Bypass Surgery Patients (ERIC-GTN Study)

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).

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.

Inclusion Criteria:

• Age > 18 years all patients admitted for on- pump CABG and/or valve surgery
• Able to give consent

Exclusion Criteria:

• Allergies to excipients of IMP and placebo
• Chronic Renal failure (eGFR<30 ml/min/kg)
• Severe liver disease
• Peripheral arterial disease
• Pregnant or lactating women