Stroke risk and prognostic factors of asymptomatic middle cerebral artery atherosclerotic stenosis.

BACKGROUND AND PURPOSE

Stroke risk of asymptomatic atherosclerotic middle cerebral artery (MCA) stenosis has not been well studied. This study was designed to investigate stroke risk and prognostic factors of asymptomatic atherosclerotic MCA stenosis.

MATERIALS AND METHODS

A total of 200 consecutive patients who visited the transcranial Doppler ultrasound (TCD) laboratory of our hospital and who met the following criteria were prospectively enrolled in this study: diagnosed as MCA stenosis due to atherosclerosis by TCD, age above 40 years old, no history of ischemic stroke or transient ischemic attack (TIA), no ipsilateral carotid artery stenosis. The mean follow-up time was 38.3 ± 9.9 (range 4 to 60) months.

RESULTS

Thirteen patients were lost to follow up. Seven patients (3.8%) developed ischemic stroke or TIA during the follow-up period, with an occurrence rate of 0.5% in the first year and 1.6% in the second year. Three were in the blood supply region of diseased vessels, three were in the contralateral hemisphere and one case of TIA occurred in the posterior circulation. Univariate analysis showed that diabetes mellitus (DM) (X²=9.168, p=0.002) and carotid atherosclerotic plaque (X²=4.403, p=0.036) were associated with higher risk of stroke occurrence in this cohort.

CONCLUSIONS

The stroke risk in patients with asymptomatic atherosclerotic MCA stenosis was low and remained stable during follow up. Higher risk of stroke occurrence is associated with DM and carotid atherosclerotic plaque.