Sustained cognitive benefit 5 years after carotid endarterectomy.

Objectives: This study investigated the long-term effect of carotid endarterectomy (CEA) on cognitive brain function by means of P300 evoked potentials.

Methods: Twenty-five consecutive patients (36% women) with a median age of 68 years underwent CEA with a median degree of stenosis of 90%. Cognitive brain function was objectively measured by means of P300 auditory evoked potentials (peak latencies in milliseconds [ms]) before CEA, at discharge, and at 1 and 5 years. Values were compared with 25 age- and sex-matched healthy individuals.

Results: Cognitive P300 evoked potentials were prolonged (ie, impaired) in patients before CEA compared with controls (vertex [Cz], 384 +/- 52 vs 357 +/- 16 ms, P = .020]. At 1 year, P300 evoked potentials were significantly shortened (ie, improved) in patients after CEA compared with baseline values [Cz, 371 +/- 38 vs 384 +/- 52 ms, P = .010]. Furthermore, no difference between patients after CEA and controls was observed [Cz, 371 +/- 38 vs 360 +/- 14 ms, P = .21]. This effect was sustained at 5 years, and P300 evoked potentials continued to be significantly shortened (ie, improved) in patients after CEA compared with baseline values [Cz, 367 +/- 39 vs 384 +/- 52 ms, P = .040]. Continuing, no difference between patients after CEA and controls could be observed [Cz, 367 +/- 39 vs 362 +/- 17 ms, P = .58]. These results could be confirmed in repeated measures analysis of variance for Cz (P = .025) and frontal (Fz) results (P = .018).

Conclusions: CEA improves previously impaired cognitive brain function as shown by P300 measurements similar to normal cognitive brain function of age- and sex-matched healthy individuals. This beneficial effect is sustained up to 5 years after treatment.