Joint AAGBI/ACTACC Research Grant
Comparison between Propofol and Isoflurane Anaesthesia (COPIA) on Cardiovascular Outcomes following Cardiac Surgery - a Randomised Controlled Feasibility Trial
Dr Gudrun Kunst
The most common cause of death in the United Kingdom in people younger than 75 years is heart vessel disease (coronary heart disease, CHD) with about 82,000 deaths (in 2009) from CHD and about 124,000 heart attacks per year in the UK. The overall economic cost is estimated to be about £9.0 billion per year in the UK. These individuals are normally treated with a bypass graft (coronary artery bypass graft, CABG) surgery with about 20,000 of these procedures performed yearly in the UK (in 2015). These operations are very successful for most people, but about 4 people in every hundred die over the year after surgery. In addition, as an increasing number of older and frailer individuals are undergoing CABG surgery, possible risks such as heart damage, kidney damage and stroke are increasing. These complications occur in at least 10 out of every 100 people having bypass surgery over the first year after surgery. Therefore, new treatment strategies to improve health outcomes in these high-risk individuals undergoing bypass surgery have the potential to improve health and wellbeing. Interestingly, evidence from recent preliminary studies suggests that maintenance of general anaesthesia with an anaesthetic gas (volatile anaesthetic) alone has the potential to reduce complications such as heart muscle damage. This effect can result in improved clinical outcomes after CABG surgery when compared with the anaesthetic agent propofol, which is given as an infusion. However, most of these results are based on small studies and they have been inconclusive and conflicting. In addition, in all of these studies the volatile anaesthetic has been administered in addition to the infusion anaesthetic propofol, and recent evidence suggests that propofol can induce stress for the heart muscle. We therefore propose this study to assess, a volatile anaesthetic as the only agent for maintenance of anaesthesia during heart surgery, compared with propofol, for the first time.
The objective of this research proposal is to assess feasibility of the study protocol and of recruitment targets. Subsequently, a larger clinical study is planned to find out whether the anaesthetic maintenance technique with the volatile anaesthetic isoflurane can improve health outcomes in the United Kingdom, when compared with the anaesthetic propofol, in adult patients undergoing CABG surgery. The volatile anaesthetic isoflurane is given as a gas through the lungs whereas the anaesthetic agent propofol is a liquid, which is given as a continuous infusion into the patients' veins. Interestingly, management of general anaesthesia has remained unchanged over the last 20 years. We showed recently that about half of anaesthetists use propofol for maintenance, and the other half the volatile anaesthetic isoflurane. Therefore, there is the potential for improved outcomes following surgery if one anaesthetic agent is shown to be more protective than another, especially as this could easily be implemented in clinical practice in the UK. This is important as so far the evidence that volatile anaesthetics may be beneficial in people undergoing heart surgery is only based on small preliminary studies.
