Heart attack and stroke patients could soon avoid potentially risky drugs like Warfarin and aspirin, thanks to the discovery of a blood-clotting enzyme by a team of scientists at Sydney's Heart Research Institute.

The new research, led by Professor Shaun Jackson, has the potential to protect thousands of Australians from heart attacks and strokes and has revealed for the first time a particular enzyme plays a vital role in controlling clotting of the blood.

"We've discovered this enzyme has the very special ability to reduce build-up of blood clots that clog arteries while also sticking blood firmly to the site of blood vessel injury," Professor Jackson said.

"This is an exciting area of research as new medicines represent one of the most promising new ways of treating disease."

Researchers discovered the new enzyme, then developed new therapies that had not been tested before.

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"We believe they are going to be more effective than current therapies we use in the clinic," Professor Jackson said.

"In the long term this could be a game changer in the management of cardiovascular disease."

Heart Disease and Blood Clots Cardiovascular disease affects 3.72 million Australians

Cardiovascular disease affects 3.72 million Australians It causes 520,000 hospitalisations a year and kills about 45,000 people

It causes 520,000 hospitalisations a year and kills about 45,000 people Blood clots play a key role in heart attacks and strokes by blocking supply of blood to the heart or brain

The breakthrough was made by a team of researchers from Monash University, University of Melbourne, Walter and Eliza Hall Institute of Medical Research, University of Strasbourg, France and the Scripps Research Institute, United States.

Blood-thinning medications like Warfarin and aspirin are used by thousands of Australians to reduce the risk of heart attack and stroke.

But they can cause side-effects, and patients on Warfarin need to be carefully monitored.

Professor Jackson said the discovery of the enzyme and the new therapy was made all the more exciting by the element of surprise.

"The function of this enzyme has been a mystery for decades so to discover what its role is and realise its importance is a thrill," he said.

Heart attacks and stroke are the leading causes of death and long-term disability in Australia.

Both conditions are typically caused by blood clots in the circulation of the heart or brain.

The findings have been published in the prestigious journal Nature Communication.

New drug a lifesaver: patient

Daman Brahimi had rheumatic fever as a child which damaged his heart.

He had to have a stent put in his heart and suffered two strokes in 1997 and has had to take Warfarin ever since.

"I have to have blood taken twice a week," he said.

"If I didn't have to have the tests, my life would be 100 times better. I have rashes on my arm. It's not pleasant at all."

Mr Brahimi said he is keen to try the new drug.

"If it works, it will be great. Oh god, a lifesaver," he said.