UQ researchers give moggies an extra life
A unique operating technique, developed by University of Queensland researchers to extract potentially fatal heartworms from cats, has proven successful in a clinical trial.
Dr Rick Atwell from the School of Veterinary Science and Animal Production said the technique was a world-first.
"The heart of a cat is only about three to four centimetres long and in the past to remove heartworms we have had to surgically open the chest, expose the heart and then open up the heart itself," Dr Atwell said.
"In this new technique we insert the catheter, which has a protective tip, through the anaesthetised cat's jugular and down into the heart itself.
"The first two centimetres of the catheter has filaments on it and when twisted in both directions they entrap the heartworms. We then extract both the catheter and the entangled heartworms."
Dr Atwell said the catheter was twisted an exact number of times in each direction
He said the cat in the clinical trial had been diagnosed through lung X-rays after a confusing clinical history "as it often is in the case of feline heartworm".
"After the first heartworm was extracted we did an ultrasound and saw another worm and inserted the catheter again. You can actually feel the heart beating against the catheter before you begin the extraction process," he said.
Both extracted heartworms were male, about 15 centimetres long and if left untreated, would have caused the cat's death through thrombosis (clotting of the blood).
Dr Atwell said the "negative side effects" of an anaesthetic regime which lowered the blood pressure also helped the technique by allowing the worms to be "washed" to the top of the heart and into a more accessible position.
The research was funded through seeding grants from the University's URG program and the operation was carried out at the Manly Road Veterinary Clinic, which carries out clinical research trials for the University.
Dr Atwell said while dogs were able to survive the presence of heartworms, cats were much more vulnerable.
"Currently research among Brisbane cats suggests about 11 percent of the population have evidence of being exposed to heartworms but only about one percent of local cats become infected with worms," he said.
"This new technique is very simple and cost-effective. We can produce the catheter locally for use by practitioners."
Dr Atwell said the data would be presented at an international forum in the U.S.A in 1999.
For further information contact Dr Rick Atwell (telephone 3365 2551).
