Low dose acetylsalicylic acid and thromboxane release at the site of plug formation in vivo in elderly patients with cardiovascular disease.

Abstract

Thromboxane B2 (TXB2) levels in bleeding time blood and in serum were measured in 13 elderly patients with cardiovascular disease, seven of whom were receiving continuous treatment with low dose acetylsalicylic acid (ASA, 125 mg every second day--250 mg daily) for prevention of stroke. Blood sampling was performed openly, but assays of TXB2 were performed by a blinded investigator. In patients treated with ASA, median serum TXB2-levels were 4% and TXB2-levels in bleeding-time blood were less than 16% of the corresponding levels in patients without ASA (P less than 0.01). The results show that in elderly atherosclerotic patients very low doses of ASA substantially suppress TXB2 formation, not only in serum but also at the site of local haemostasis. The extent of suppression is comparable to that previously reported from young healthy subjects.