THE GENERATION OF BY-PRODUCTS OF LIPID-PEROXIDATION FOLLOWING CAROTIDENDARTERECTOMY

The aim of this study was to determine whether free radical-induced li pid peroxidation occurs following transient carotid clamping. Jugular vein plasma levels of malondialdehyde (MDA) and diene conjugates (DC) were estimated in 24 patients undergoing carotid endarterectomy, at th e beginning of the operation (To), just prior to clamping the carotid artery before the shunt was removed for closure of the arteriotomy (Ts ), and at 30 (T30)), 60 (T60)), 120 (T120)), 180 (T180)), and 300 (T30 0)) seconds after the clamps were released. Carotid clamp times were r ecorded. Significant elevations in the concentrations of both MDA and DC were observed at T60 after clamp release (MDA = 559 +/- 64 pmol/ml, DC = 428 +/- 32 units/ml), in comparison to concentrations at To (MDA = 408 +/- 34 pmol/ml, p < 0.01; DC = 374 +/- 28 units/ml, p < 0.05), returning to baseline at T300. There was a significant correlation bet ween the percentage rise in MDA concentration and the duration of clam p-induced ischaemia (r = 0.45, p = 0.03). The significance of this bur st of MDA and DC is unclear especially as the one patient who sustaine d a postoperative neurological deficit displayed no rise in the concen tration of either. If this rise is related to free radical generation following ischaemia-reperfusion injury it may play an important role i n influencing the clinical outcome in the patients.