Can a relatively cheap carbon dioxide ‘flush’ reduce the risk of strokes during blood vessel surgery?
Mr Oliver Lyons, a Vascular Endovascular and Transplant surgeon at Te Whatu Ora – Waitaha Canterbury has been granted $90,902 from the Canterbury Medical Research Foundation to find out.
When someone has an artery disease such as an aortic aneurysm or aortic dissection, the only way to repair the aorta (the major blood vessel) in the chest is by keyhole surgery, but that comes with a risk of stroke and ‘silent stroke’.
“When undertaking these operations the risk of stroke is unavoidable at present however we believe there’s a simple process that could potentially reduce this risk, and that’s what this research is looking into. It’s important work and we’re so thankful the Canterbury Medical Research Foundation is enabling it to happen,” says Oliver.
Vascular surgery patients who experience stroke or ‘silent stroke’ can suffer delirium and significant decline in brain function – impacts which can be long-lasting. It’s thought the main cause of strokes in aortic surgery patients is tiny air bubbles trapped within the fabric of the stents used for the keyhole operation.

“Currently we use liquid to flush the stents prior to inserting them into the patient. This research will look at whether flushing the stents with carbon dioxide gas and then liquid, before insertion, will more effectively remove any trapped air bubbles, therefore reducing the number of strokes.”
The research is being supported by a team from Older Persons Health, and Canterbury Geriatric Medical Research Trust.
“If our research outcomes are positive we will have identified a cheap and readily accessible way of reducing the risk of stroke in these patients, which will have significant impacts worldwide.”
Originally from London, Oliver has always had an interest in cardiovascular biology and was recently awarded a Hunterian medal by the Royal College of Surgeons of England for his research. Since moving to New Zealand in 2020 Oliver has transitioned to clinical research. More information can be found here.