Objective:To investigate the changes of blood plasma endothelin-1(ET-1)

thromboxane A2(TXA2)

prostacyclinI2(PGI2) and TXA2/PGI2(T/P) as well as their relationship with vascular lesions in patients with ateriosclerosis obliterans(ASO) before and after interventional therapy. Methods:Totally 42 cases with ASO were divideed into group A

B and C based on transatlantic inter society consensus(TASC). The levels of ET-1

TXA2

PGI2in plasma in all cases were measured by method of enzyme-linked immunosorbent assay (ELISA) before and after interventional treatment

then the value of T/P were calculated. Results: The levels of ET-1

T/P were increased in all groups after interventional therapy compared with those before the operation with statistical differences(F=44.34

P<0.01; F=109.09

P<0.01). The level of ET-1 in group B and C before and after the operation was significant higher than in group A with statistical differences(P<0.05). Statistical differences was observed in the value of T/P between group A

B and C(P<0.05). The value of T/P was increased as the vascular lesion become more and more severe. Negative correlation was obseved between postoperative T/P value and postoperative PGI2 value (r=-0.638

P<0.01) while no correlation was found between postoperative T/P value and postoperative TXA2 value(r=0.099，P>0.05). Conclusion: The levels of ET-1 and T/P in blood plasma are incresed in patients with ASO after all interventional therapy

the cause of which is the damage of endothelial cell. The levels of ET-1

T/P and the changes of T/P value are incresed as the vascular lesion become more and more severe. The formation of postoperative thrombus is positively associated with the severity of vascular lesion.