Bioengineers at the University of Limerick have discovered a new way of connecting severed blood vessels, reports Claire O'Connell.
Joined-up thinking is often the key to a good result. That's why a team in Limerick is applying engineering solutions to medicine, coming up with an improved device to make artificial connections between blood vessels.
They hope their vascular graft design, which smooths the flow of blood through the connection, will benefit patients needing bypass grafts for blocked arteries, and they believe it could also help people undergoing kidney dialysis.
"You need a vascular graft in a few situations, and one is where you have a blocked artery, especially in the leg where poor circulation could result in amputation," explains Prof Tim McGloughlin, a director of the centre for applied biomedical engineering research at the University of Limerick (UL).
To treat the condition, surgeons take blood vessels from elsewhere in the patient and use them to create a bypass around the blocked artery. But blood flow through the resulting new connections may not be ideal, notes Prof McGloughlin. "When you do a bypass procedure, you end up putting a non-physiological junction into the vessel, and that changes the flow conditions. It creates a local fluid stress which the vessel wouldn't normally have experienced."
At UL, Prof McGloughlin and Dr Michael Walsh used computer modelling to develop a new geometry for a graft junction, while vascular surgeon Prof Pierce Grace from HSE Mid-Western Regional Hospital worked with them to ensure it would be feasible in practice. Then by running water and glycerin through experimental models in the lab, the researchers looked at how blood flow would be affected by the new design.
The result was Prolong, a graft that crucially allows the blood to re-enter the host vessel though two inlets, as Prof McGloughlin describes: "The two inlets smooth the flow and reduce the likelihood of restenosis, or re-blocking, which is one of the major causes of clinical failures with present grafts."The researchers are also looking at another application for Prolong - to provide blood vessel access in patients undergoing kidney dialysis.
"This graft is used to provide needle access for the patient for the dialysis machine, so you have an in and an out through the graft. They join the artery to the vein using a synthetic material. So you now have high- velocity fluid coming out of the artery going into the vein, which normally experiences low velocity fluids. Prolong improves the flow regime going into the vein, reducing the velocity, which is important."
With preclinical trials of the kidney application scheduled for this year, the developers are in discussion with major companies in the field about licensing the technology.
The work is funded by Enterprise Ireland.