Although aspirin therapy has been touted for several years as a preventative measure when it comes to people at increased risk for heart attack, research now suggests that this may not be the case for some people.
According to Professors Andrew Szczeklik (Poland) and Graeme Hankey (Western Australia) some people are simply not responsive to the anti-coagulant effects of the drug. The scientists will present these latest findings on aspirin resistance at the XXth Congress of the International Society of Thrombosis and Haemostasis.
One possible reason for the diminished effectiveness of aspirin as a protection against heart attack in certain individuals is high levels of blood cholesterol which can, in itself, promote coagulation events in the blood stream.
In patients with high cholesterol levels, the normally recommended dose of aspirin has hardly any anti-clotting effect, whereas treatment with a statin cholesterol inhibitor significantly reduces blood clotting.
In patients with coronary heart disease, aspirin is seen to exert its anti-coagulant effects only when blood cholesterol is in the “normal” range.
In addition, according to Professor Szczeklik: "A patient’s 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."
Professor Hankey believes that, since the use of aspirin as an anti-coagulant therapy has risen significantly, it is essential to study the issue of aspirin resistance. This is even more important with respect to patients who have had a heart attack, unstable angina, bypass surgery, or high cholesterol.
The drug Clopidogrel has been shown to have anti-clotting and anti-inflammatory effects in patients with diseased arteries and seems to be most effective in patients who do not respond to aspirin