THERE is good news for heart patientsrequiring bypass surgery on the aorta,the main artery which carries oxygenated blood from the heart to the rest of thebody. British researchers have recentlydeveloped a technique that uses plastictubes, called catheters, to insert synthetic grafts into the blood vessel, thus eliminating the 'need for a bypass surgery(New Scientist, Vol 146, No 198 1).
Thousands of people are known todie each year due torupture of aorta, thebody's main artery.The walls of aorta tendto become weak withold age and often tendto balloon out. Whenthe diameter of theballoon reaches a certain critical size -which is usually about6 centimetres - thedoctors say that thereis a big risk that it mayburst. These weakspots, also known asaneurysms, have to be relieved by abypass surgery before they reach the critical size.
Anthony Fox, a vascular surgeonwith the University of Bath's department of surgery now claims to havedeveloped a prototype which he says willbe ready for tests on people in a few months.
Fox's system is unique because thepolyester graft is reinforced by a 'shapememory alloy' callednitinol - a mixture ofnickel and titanium.When the graft isplaced at the desiredlocation and thecatheter removed, thenitinol comes in contact with the bloodwhose temperaturehelps the graft toexpand its endsagainst the wall of themain artery, thus stationing it at the neck and cuff.