Artificial arteries designed like gun barrels could revolutionise heart bypass surgery and save health services millions, researchers claim.
Scientists are working on synthetic grafts with a twist and internal "rifling" - helical grooves - that causes blood to spiral through them in much the same way a bullet fired from a gun is made to spin.
The smoother flow is expected to reduce wear and tear at the junction points where the graft is attached, thereby increasing its life span.
Bypass surgery involves patching in a healthy blood vessel to route blood around a length of artery narrowed or clogged by disease.
Coronary artery bypass operations to supply heart muscle with sufficient blood are the most common form of heart surgery in England, with 20,000 performed each year.