Psychological testing, cerebral blood flow (CBF) measurement, and computed tomographic scan were performed before and 3 months after operation in 31 patients subjected to endarterectomy of the internal carotid artery (ICA) because of transient ischemic attacks and in 11 control patients operated on for atherosclerosis of the lower extremities. In preoperative psychological testing both carotid surgery patients and controls performed somewhat below the normal level for their age group. Postoperatively, cognitive functions improved in the carotid surgery group but not in the control group. The improvement was related to the laterality of the operation, being more marked in verbal tests in patients with left ICA operation and in visuospatial tests in patients with right ICA operation. Postoperatively regional CBF improved in 2 patients only. Hence the intellectual improvement could not be related to changes in CBF. Intellectual deterioration in patients with internal carotid atherosclerosis may be delayed or terminated by surgical abolition of the source of multiple cerebral embolizations.

Serial measurements of cerebral blood flow (CBF) were performed in 56 patients before and one to four times after uncomplicated carotid endarterectomy. The findings were related to the ratio between internal carotid artery (ICA) and common carotid artery (CCA) mean pressures. Within the 1st postoperative day CBF increased by a median of 37% in the ipsilateral and 33% in the contralateral hemisphere. Later recordings showed a gradual return of CBF toward the preoperative level. Sixteen patients with an ICA/CCA pressure ratio below 0.7 showed a significantly more pronounced and longer-lasting flow increase than did 40 patients with a ratio above this level. On Day 1, the median CBF increase in the ipsilateral hemisphere was 61% and 24% in the two groups, respectively (p less than 0.01). A significant improvement in side-to-side asymmetry, resulting from a higher gain in the ipsilateral hemisphere, occurred in the low pressure ratio group, while the hemispheric asymmetry on average was unchanged in the high pressure ratio group. This relative hyperemia was most pronounced 2 to 4 days following reconstruction. The marked hyperemia, absolute as well as relative, in patients with a low ICA/CCA pressure ratio suggests a temporary impairment of autoregulation. Special care should be taken to avoid postoperative hypertension in such patients, who typically have preoperative hypoperfusion, to avoid the occurrence of cerebral edema or hemorrhage.

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Psychological testing was performed in 25 patients (mean age 56 years) with transient ischaemic attacks and/or minor strokes and with angiographically verified internal carotid artery stenosis. The effects of carotid endarterectomy on intellectual functions were evaluated postoperatively at 2 weeks and 8 months respectively. Preoperatively the mean test values were below the normal level for all tests indicating a general intellectual impairment for the group as a whole. This may reflect multi-infarct dementia in statu nascendi. At the early postoperative test session some test results were statistically significantly worse than the preoperative. 8 months postoperatively the mean values for all tests had improved as compared with the preoperative values. This improvement reached a statistically significant level in 6 tests. When the side of operation was considered a pattern emerged: in the 12 patients with left-sided endarterectomies improvement was significant for tests mainly related to left-hemisphere function (Word Pairs Test, Story Recall, Trail Making B, Similarities) and in the 13 patients with right-sided endarterectomies significant improvement occurred in the functions mainly related to the right hemisphere (Visual Gestalts, Block Design, Digit Span backwards). This relationship between side of operation and improvement in lateralized functions cannot be explained by retest effects. It is concluded that TIA's and minor strokes per se may impair intellectual function, and that reversal of deterioration and even improved mental state may follow carotid endarterectomy.

SUMMARY Cerebral blood flow CBF was studied in 14 patients with transient ischemic attacks TIA and arteriosclerotic neck vessel disease. CBF was measured by a rapidly rotating single photon emission computerized tomograph using Xenon-133 inhalation. This method yields images of 3 brain slices depicting CBF with a spatial resolution of 1.7 cm. Based primarily on the clinical evidence and on the angiographical findings embolism was considered the pathogenetic factor in 10 cases, whereas chronic hemodynamic insufficiency rendered symptomatic by postural factors probably accounted for the symptoms in 4 patients.Of the 14 patients, all studied days to weeks after the most recent TIA, four showed hypoperfused areas on the CBF-tomograms and with roughly the same location hypodense areas on CT-scanning, i.e. areas of complete infarction. However, an additional five patients showed reduction of CBF in areas with no abnormality on the CT-scan. The abnormal blood flow pattern was found to be unchanged after clinically successful reconstructive vascular surgery. This suggests the presence of irreversible ischemic tissue damage without gross emollition (incomplete infarction).It is concluded, that TIAs are often harmful events, as no less than 9 of the 14 patients studied had evidence of complete and/or incomplete infarction. Thorough examination and rational therapy should be instituted as soon as possible to prevent further ischemic lesions. Stroke Vol 14, No 6, 1983AS A TRANSIENT ISCHEMIC ATTACK TIA per definition leaves the patient without a neurological deficit, irreversible damage to brain tissue was former ly thought not to occur. However, neuropsychological studies of patients with TIA and arteriosclerotic neck vessel disease have revealed intellectual impairments in many of these patients, presenting either as lateralized deficits or as diffuse signs of cortical dysfunc tions.12 Despite the lack of psychometric tests prior to the first TIA these findings are thought to be the result of the repetitive ischemic episodes leading to deterio ration of complex integrated cerebral function and eventually to "multiinfarct dementia," a term intro duced primarily by Hachinski et al in 1974.3 Further, as prospective studies of CT-scannings in patients with TIAs have revealed infarcted areas in 35% of patients studied, it has become accepted that some TIAs are in fact minor strokes with definite areas of ischemic tis sue necrosis, although the patients recover neurologically. 45Only few studies of CBF in patients with TIA have been undertaken, and in none of these were the find ings compared to the results of CT-scanning. 6-8Single photon emission computerized tomography with inha lation of Xenon-133 has been shown to be a valid method for determination of alterations in CBF in stroke often revealing areas of low flow larger than the CT-scan defects, a discrepancy possibly reflecting par tial neuronal loss (incomplete infarction). method is safe, atraumatic and by its three-dimension al approach to CBF circumvents tissue layer ...