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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
192
3 cycles of 5 minutes to arm and legs
Normal saline IV started prior to knife to skin at a rate of 2-5 mls/h and stopped just after weaning off bypass.
IV GTN given during surgery started prior to knife to skin and stopped after weaning off cardiopulmonary bypass.
The Heart Hospital, UCL Hospitals NHS Trust
London, United Kingdom
Troponin T area under the curve
Troponin T area under the curve will be calculated using blood samples collected at 0,6,12,24,48 and 72 hours plotting it against time to calculated AUC.
Time frame: 72 hours
Inotrope/Vasopressor requirements peri-operatively
The inotrope score will be calculated as follows: Dosages (in μg/kg/min) of \[Dopamine + Dobutamine\] + \[(Adrenaline + Noradrenaline + Isoproterenol + Isoproterenol) x 100\] + \[(Enoximone + Milrinone) x 15\]
Time frame: Post-operative day 1,2,3 and 4
Ventilator dependence post operatively
The duration of endotracheal intubation will be noted in hours. Re-intubation rates will be calculated by noting down the number of patients requiring re-intubation and comparing this amongst the 4 groups.
Time frame: Post-operative day 1,2,3 and 4
Incidence of Acute Kidney Injury assessed using biomarkers
Serum creatinine levels will be noted in the first 3 days postoperatively. If a patient requires renal replacement therapy, this will be recorded and comparisons made amongst the groups. Hourly urine output and daily urine volumes for the duration of ITU stay will be recorded.
Time frame: Post-operative day 1,2,3 and 4
Length of ITU stay
A record of stay in days will be noted
Time frame: Average 4 days
Length of hospital stay
Duration of hospital stay will be recorded in days
Time frame: Average 14 days
Incidence of post-operative atrial fibrillation
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Atrial fibrillation will be diagnosed using ECG. A record of the number of patients developing AF post operatively, the intervention used to treat it and whether or not the patient reverted to sinus rhythm prior to ITU discharge will be documented
Time frame: Post-operative day 1,2,3 and 4