Prostacyclin and thromboxane A2 synthesis are increased in acute lower limb ischaemia

Abstract Prostacyclin (PGl 2 ) and thromboxane A 2 (TXA 2 ) play an important role in the pathophysiology of various cardiovascular diseases. The balance between PGl 2 and TXA 2 regulates the interaction between platelets and the vessel wall in vivo. In this study we measured PGl 2 and TXA 2 synthesis by analysing their urinary index metabolites 2,3-dinor-6-keto-PGF 1α and 11-dehydro-TXB 2 , respectively, in acute (10 patients) and chronic (10 patients) lower limb ischaemia. Both PGl 2 and TXA 2 synthesis were increased about two-fold in patients with acute lower limb ischaemia compared to chronic lower limb ischaemia. However, the PGl2TXA2 ratio was more or less the same in acute and chronic lower limb ischaemia. In patients with acute lower limb ischaemia caused by thrombotic occlusion, PGl 2 and TXA 2 formation were about two times higher than in patients with acute lower limb ischaemia caused by embolic occlusion. Elevation of PGl 2 and TXA 2 synthesis in acute lower limb ischaemia may reflect increased platelet-vascular wall interactions without changing the PGl2TXA2 ratio.