An innovative study, led by researchers at University Hospitals Plymouth NHS Trust and the University of Plymouth, is seeking to improve survival rates for patients following major surgery.
The Coronary Anatomy and Dynamic Exercise Test (CADET) study is investigating the effectiveness of different types of tests carried out prior to major surgery, to assess patient fitness, and therefore the likelihood of a good post-surgery recovery.
Funded by both local charity Bowel Cancer West and the Association of Anaesthetists of Great Britain and Ireland/National Institute of Academic Anaesthesia, the project is a world-first, due to its unique approach in combining assessments to give a fuller picture.
“Although contemporary surgery is generally regarded as safe, there is still a reasonably high chance that particularly unfit patients could develop complications afterwards,” explains Dr Gary Minto, Consultant Anaesthetist at University Hospitals Plymouth.
“This is generally because not enough oxygen is being circulated in the blood stream to support the healing process, and this can cause wound breakdown or severe infection. Less fit patients tend to be less able to circulate oxygen to parts of the body involved in the surgery that require it. We therefore want to understand how best to identify the patients that are at higher risk, so that we can improve their chances of survival, such as by using specialised monitoring and blood-flow support. Knowing who is at risk is essential.”Derriford Hospital is one of many in the UK that currently perform Cardiopulmonary Exercise Testing, CPET for short, which involves monitoring patients while using a stationary exercise bike, in order to determine patient fitness for surgery. However, it is still not clear exactly how effective the CPET is in these assessments.
“The team at Derriford Hospital currently undertakes over 700 CPET tests a year, making it one of the leading centres in the world,” adds Gary. “However, we want to make sure that we are picking everything up that is relevant to fitness for surgery, and need to find out whether the bicycle test alone is able to do this.”
Working together with Professor Carl Roobottom, Consultant Radiologist at Derriford Hospital and Chair of Radiology at the University of Plymouth, it was decided to combine the CPET test with Computed Tomography Coronary Angiography (CTCA) scans, to measure and compare the results between the two.
“We are now able to perform CT scans of the coronary arteries without exposing patients to high radiation doses, so it made sense to integrate these with the CPET,” explains Carl. “The physiological demands of surgery and recovery can be quite high, which means the heart has to pump harder, and therefore patients with coronary disease might struggle to meet these demands. It’s therefore crucial that we are able to identify whether patients are at risk of heart attack, by looking at heart structure as well as blood supply.”
Over the past two years nearly 200 patients from Devon, Cornwall and Somerset have taken part in the study, by having both the CPET and CTCA conducted before major surgery, and a follow-up with the team a year later. Now, the team are in the process of assessing the results.
“We hope that the results of the study will enable us to determine a consistent approach to pre-surgical assessments,” adds Gary. “The next step for us would then be to try to understand what particular combinations of test results might correlate with patient recovery, and then research the best ways to deal with them.”
The CADET study has benefited from over £60,000 funding provided by Bowel Cancer West, who are keen to support research that could benefit patients with bowel cancer.
“One of our aims is to select unique, locally led research projects that can make a big difference in filling a national gap, and putting the South West firmly on the map as a hotbed for lifesaving research,” said Dr Mark Coleman, Chairman of Bowel Cancer West and Colorectal Surgeon at Derriford Hospital. “Cancer patients often face having major surgery, and so a study like this that could save lives is incredibly important to us.”