Inhibition by aspirin of human arterial and venous prostacyclin synthesis.

Prostacyclin (PGI2) synthesis by human mesenteric arteries and veins was measured ex vivo in 62 patients who received either no medication or a single oral dose of aspirin 40 mg, 75 mg or 300 mg approximately 24 hrs pre-operatively. Each dose of aspirin caused a significant reduction in both arterial and venous PGI2 synthesis compared with the untreated group. Arterial PGI2 synthesis did not differ significantly from venous PGI2 synthesis whether assessed by sample weight or sample area.