PROSTACYCLIN AND THROMBOXANE-A, SYNTHESIS ARE INCREASED IN ACUTE LOWER-LIMB ISCHEMIA

Prostacyclin (PGI(2)) and thromboxane A(2) (TXA(2)) play an important role in the pathophysiology of various cardiovascular diseases. The ba lance between PGI(2) and TXA(2) regulates the interaction between plat elets and the vessel wall in vivo. In this study we measured PGI(2) an d TXA(2) synthesis by analysing their urinary index metabolites 2,3-di nor-6-keto-PGF(1 alpha) and 11-dehydro-TXB(2), respectively, in acute (10 patients) and chronic (10 patients) lower limb ischaemia. Both PGI (2) and TXA(2) synthesis were increased about two-fold in patients wit h acute lower limb ischaemia compared to chronic lower limb ischaemia. However, the PGI(2)/TXA(2) ratio was more or less the same in acute a nd chronic lower limb ischaemia. In patients with acute lower limb isc haemia caused by thrombotic occlusion, PGI(2) and TXA(2) formation wer e about two times higher than in patients with acute lower limb ischae mia caused by embolic occlusion. Elevation of PGI(2) and TXA(2) synthe sis in acute lower limb ischaemia may reflect increased platelet-vascu lar wall interactions without changing the PGI(2)/TXA(2) ratio.