Influence of transluminal angioplasty on the prostanoid release from the arterial wall

Vasospasm and thrombosis complicate percutaneous transluminal angioplasty (PTA). To study if the release of the prostanoids PGI2 and TxA2 are affected by PTA, the following experiment was undertaken: In ten rabbits, the upper or lower half of the aorta was randomised either to transluminal angioplasty or control segment. After excision the segments were simultaneously but separately perfused ex vivo with Hank's balanced salt solution for five consecutive 15 min periods. Arachidonic acid was added to the perfusate for the last 15 min period. PGI2 and TxA2 were measured by radioimmunoassay in the perfusate as the stable degradation products 6-keto-PGF1 alpha and TxB2. After perfusion, the two aortic segments were prepared for scanning electron microscopy (SEM). Angioplasty decreased the basic release of PGI2 as well as the response to arachidonic acid. This is likely to be due to endothelial denudation as seen by SEM. The release of TxA2 from the vessel wall was very low and was not increased by dilatation. The influence of angioplasty on the prostanoid system may be of importance in the complications of vasospasm and thrombosis.