Cerebrovascular reactivity after treatment of unruptured intracranial aneurysms--A transcranial Doppler sonography and acetazolamide study.

BACKGROUND

Cerebrovascular reactivity (CVR) is defined as the change in cerebral blood flow, or blood velocity, in response to a vasoactive stimulus. There is a possible association between impaired CVR and vasospasm after aneurysmal subarachnoid hemorrhage. Most studies on CVR and vasospasm have used healthy subjects as reference. However, due to potential different vascular features, CVR in persons with intracranial aneurysms may differ from CVR in healthy subjects. Therefore, our aim was to examine CVR in patients with unruptured intracranial aneurysms (UIA).

METHODS

CVR was examined in 37 patients in the first postoperative week after treatment for UIA, using acetazolamide (AZ) test with transcranial Doppler monitoring of blood flow velocities.

RESULTS

Mean blood flow velocity in the middle cerebral arteries was 58.5 (SD 12.8) cm/s at baseline, and 94.3 (SD 19.5) cm/s after stimulation with AZ. Mean CVR was 62.6 (SD 16.8) %. There was no significant difference when comparing right and left sides, and treated and untreated sides. A simple regression analysis suggested that CVR increased with 0.7% points for each year a patient aged (p=0.004). However, the significance disappeared in a multiple analysis (increase of 0.6% points per year, p=0.055). Other possible influencing factors (gender, smoking, hypertension, body mass index, aneurysm location and treatment modality) were not significantly associated with CVR.

CONCLUSIONS

CVR in patients with UIA is not different from normal values reported in healthy subjects, and does not indicate a systemically impaired vascular system in patients with UIA. We suggest that CVR in age and gender matched healthy controls can be used as reference for persons with intracranial aneurysms.