Effects of habitual cigarette smoking on higher cortical function in patients with unruptured cerebral aneurysms

Postoperative changes in higher cortical function and cerebral blood flow (CBF) were investigated in patients with unruptured cerebral aneurysms to assess the effect of habitual smoking on the known transient changes after aneurysm surgery. Fifty-six adults with unruptured cerebral aneurysms, including 11 heavy smokers (smoking index > or = 600) and 45 non-smokers, were evaluated using three neuropsychological examinations, the Mini-Mental State Examination, the Maze test, and the Kana-hiroi test, and single photon emission computed tomography to measure CBF before and after surgery. Neuropsychological changes were assessed by reliable change indices to take into account the practice effects. The scores of at least one examination decreased in 15 of 56 patients 1 month after surgery. On the Maze test, five of 11 heavy smokers and five of 45 non-smokers deteriorated after surgery, showing a significant difference (p = 0.018). The CBF in heavy smokers often decreased after surgery, but there was no statistically significant difference in logistic regression. Three months after surgery, the neuropsychological scores of 13 of the 15 deteriorated patients recovered to the preoperative level. Higher cortical function in heavy smokers with unruptured cerebral aneurysms often decreases transiently after operation, compared to non-smokers. Therefore, surgery planning for heavy smokers with unruptured cerebral aneurysms should consider this outcome.