Lipid peroxidation as a cause of lower limb swelling following femoro-popliteal bypass grafting.

We examined the role of free radical induced lipid peroxidation in lower limb swelling in patients following femoro-popliteal bypass grafting. In 20 patients undergoing this operation blood samples were taken from the femoral vein via a cannula before the femoral artery clamp was applied, just prior to and immediately after clamp release and at 10 min intervals thereafter for 1 h for measurements of malondialdehyde (MDA) and vitamin E. The concentration of MDA was significantly elevated at 40 min after reperfusion (mean ± S.E.M., 573 ± 83 pmol/ml) compared to just before clamp release (359 ± 41 pmollml; p μ mol/m m cholesterol, p p = 0.0001) while that in the five, whose swelling was less than 10%, was 344 ± 40 to 559 ± 243 pmol/ml ( p = 0.25). A significant fall in vitamin E was found only in the group with greater than 10% lower limb oedema (5.90 ± 0.33 to 5.40 ± 0.34 μ mol/m m cholesterol, p μ mol/m m cholesterol). These results suggest that free radical induced peroxidation occurs following femoro-popliteal bypass grafting and that there is more free radical damage in those who subsequently develop significant lower limb oedema. Oxygen-derived free radicals may play a significant role in causing lower limb oedema in this situation.