Aspirin may not provide optimum anti-coagulation for all patients

Treatment failures occur with any drug and aspirin is no exception. Evidence is growing that some people will not respond to the anti-coagulant action of aspirin and the drug will not protect against cardiovascular events despite its regular intake.

Professor Andrew Szczeklik from Poland and Professor Graeme Hankey from Western Australia will present the latest findings on aspirin resistance at the XXth Congress of the International Society of Thrombosis and Haemostasis today.

"There are at least two possible explanations for the aspirin-resistance phenomenon," said Professor Szczeklik. "One is high levels of blood cholesterol, which can in itself promote coagulation events in the blood stream. In patients with high cholesterol levels, aspirin in in normal doses has hardly any anti-clotting effects, whereas treatment with a statin (inhibitor of cholesterol) significantly reduces blood clotting. In patients with coronary heart disease, aspirin exerts it anti-coagulant effects only when blood cholesterol is in the 'normal' range."

Szczeklik went onto say, "A patients genetic make-up may alter their response to aspirin resistance.. For example, in coronary heart disease patients carrying one particular gene are resistant to the anti-coagulant action of aspirin and are at increased risk of an acute coronary event."