CEREBRAL METABOLISM OF PATIENTS WITH STENOSIS OF THE INTERNAL CAROTID-ARTERY BEFORE AND AFTER ENDARTERECTOMY

Occlusion or severe stenosis, with a reduction in the diameter of more than 70% of the extracranial arteries may lead to hypoperfusion of th e brain with an increased risk of cerebral infarction. The aim of this study was to investigate whether endarterectomy of stenosed internal carotid arteries leads to alterations in cerebral metabolism in region s in which no infarcts were visible with magnetic resonance imaging (M RI). We studied 10 healthy control subjects and 20 patients with trans ient or nondisabling cerebral ischemia with MRI and H-1 magnetic reson ance spectroscopic imaging. All patients underwent carotid endarterect omy. Patients were examined 1 week before and 3-6 months after carotid endarterectomy. The N-acetyl aspartate (NAA)/choline ratio in the sym ptomatic hemisphere before endarterectomy (2.29 +/- 0.42) was signific antly (p < 0.001) lower than for control subjects (3.18 +/- 0.32). In five of the patients lactate was detected preoperatively in regions th at were not infarcted. The NAA/choline ratio in the symptomatic hemisp here of these five patients did not increase significantly after endar terectomy (1.99 +/- 0.22 vs. 2.23 +/- 0.48). The NAA/choline ratio in patients without lactate preoperatively increased significantly (p < 0 .01) after endarterectomy to a normal level (from 2.39 +/- 0.42 to 2.9 2 +/- 0.52). These results indicate that the presence of cerebral lact ate may predict whether the NAA/choline ratio increases after carotid endarterectomy.