THOUSANDS of stroke victims worldwide could stand a greater chance of survival because of a ground-breaking study by a Prince of Wales Hospital medical team. The study, led by associate professor Richard Kay Li-chi, was hailed as a 'major breakthrough' by Chinese University Dean of Medicine Professor Arthur Li Kwok-cheung yesterday. 'It is a major work on stroke rehabilitation and the treatment of strokes and this is going to affect a lot of people in Hong Kong,' Professor Li said. 'People with strokes will have a greater chance of recovery.' The study was published yesterday in the United States-based New England Journal of Medicine, as part of a major package on stroke treatment. More than 15,000 people are admitted to hospital and 2,000 die each year from ischemic strokes in Hong Kong. A stroke results when build-up in the lining of blood vessels detaches and is pumped through the bloodstream until it becomes clogged in a part of the brain. A medical source said neurologists had studied stroke victims - Hong Kong people aged mainly in their 60s - who were treated by one of three methods. Stroke victims who were injected with a blood-thinner called heparin within 48 hours of their collapse had shown a remarkable recovery rate. 'We had groups of patients who have thrombosis - strokes due to clotting of the vessels to the brain,' the source said. 'We have had patients treated with low-molecular weight heparin, high-molecular weight heparin and those who receiving nothing. 'For those on low-molecular weight heparin, it works extremely well and they have fewer complications.' Heparin, a naturally occurring substance in blood platelets, was released into the bloodstream to maintain the blood's consistency and prevent clotting. 'Women who are on the pill, for example, have a greater chance of blood clotting, so when they come for operations you give them some supplementary heparin,' the source said. But doctors had to gauge the dose carefully. Too much heparin would not only prevent blood clots - it would induce bleeding which was difficult to stop. The substance, carefully measured, could limit or prevent brain damage from blood clotting in stroke patients. 'It's very logical,' the doctor said. 'And we have not just done it on a few patients - we've recruited patients from all over Hong Kong for this.' But Hong Kong neurological society past president Dr Patrick Li Chung-ki said the results should be viewed carefully. 'I think this is the first-ever study which shows benefits in terms of giving anti-coagulants to patients with strokes,' Dr Li said. 'There is a difference in outcome, but not survival. 'I think the questions were more whether the patient required assistance, whether they were still in hospital, whether they were independent,' he said. 'It involved a large number of patients.' Professor Arthur Li said members of the team had been bound by an agreement with the New England Journal of Medicine to refrain from discussing their work until the article was published. 'When we showed our article to them [the journal's editors], they came back to us and said: 'This is a major breakthrough. No one has submitted this to us before,' ' he said.