University of Queensland researchers have developed a new surgical technique that may greatly improve the effectiveness of heart bypass operations.
The 17,000 Australians who undergo heart bypass surgery every year need to have arteries or veins removed from a part of their bodies and transferred to their heart. As this is not always possible, some form of artificial artery would be a major advance.
The new technique, which is the subject of pending patent applications, may eventually allow surgeons to grow artificial arteries inside the patients' body.
These "grow-your-own" arteries mimic the functioning of actual arteries and will not be rejected by the body's immune system like other artificial arteries. They can be grown ready for use within weeks.
Chief researcher behind the artificial artery discovery, Professor Julie Campbell of UQ's Centre for Research in Vascular Biology says the new technique uses the principles of granulation in which immune cells known as macrophages build a capsule around a foreign body to segregate it from the rest of the body.
"The process is similar to the way an oyster builds a pearl around a foreign body - in its case a tiny granule of sand," she said.
The artificial artery harvesting procedure begins with the insertion of a small length of plastic tubing in an abdominal cavity for two to three weeks. This surgery is done laparoscopically, meaning minimal disruption to the patient and a tiny scar afterwards. The body then sets to work coating the tube with two layers of tissue which resembles an artery wall inside out.
"During heart bypass surgery, the tube of tissue is removed from the plastic tubing and turned inside out like a sock. The plastic is discarded and the artificial artery then cut to size and inserted to replace the blocked artery of the patient's heart. In this way, the procedure provides us with a guaranteed supply of artificial artery to whatever length we require," Professor Campbell said.
"So far, the artificial arteries have been shown to last at least 12 months in animal models."
Studies to test the longevity of the artificial arteries are in progress in rabbits and researchers estimate it will be at least one year before it is tested in human patients.
The research team consists of Professor Julie Campbell, Professor Gordon Campbell, Dr Robert MacGinley, Anita Thomas and Johnny Efendy, all of the Centre for Research in Vascular Biology in UQ's Anatomical Sciences Department. Dr MacGinley will present a paper on the research project's progress at the Australian Biotechnology Association (ABA) 2000 conference at the Brisbane Convention Centre on Thursday, July 6, between 1.30pm and 3.30pm.
For more information, contact Peter McCutcheon at UQ Communications on 3365 1088 or 0413 380012.
Enquiries can also be directed to communications@mailbox.uq.edu.au
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