Laboratory efficacy testing of acetylsalicylic acid treatment in secondary prevention of ischemic stroke
Abstract
Aim: To assess the efficacy of antiplatelet therapy with acetylsalicylic acid (ASA) in secondary prevention in a strictly selected group of patients after ischemic stroke. Patients and methods: The group included 106 patients with a minimum of factors potentially affecting the effect of ASA.
While compliance was verified by laboratory determination of ASA levels in plasma, presence of previous embolic events was minimized by thorough examination of the heart and carotid arteries. All patients taking 100 mg of ASA daily had their serum 11-dehydrotromboxane B2 levels determined.
Results: Even in this strictly selected set of patients, effective thromboxane suppression (95% and higher) was only achieved in 76 patients, with suppression levels of 80-94.9% determined in 24 patients, and lower in another six patients. Patients with inadequate thromboxane suppression had statistically higher body mass index, cholesterol and LDL cholesterol, and uric acid levels.
Conclusion: While ASA use led to marked thromboxane suppression in all patients, the required level of suppression was not achieved in over a fourth of our patients. Consistent with latest reports, it is likely that the seemingly inadequate suppression of thromboxane is due to its production from sources other than platelets.