Vasomotor reactivity in middle cerebral artery stenosis.
OBJECTIVE
Vasomotor reactivity (VMR) represents the autoregulatory capacity of cerebral vessels and its clinical significance has been reported in steno-occlusive diseases of internal carotid artery (ICA). However, it has yet to be studied in intracranial steno-occlusive diseases.


METHODS
Consecutive patients with middle cerebral artery (MCA) stenosis diagnosed by MR angiography were compared with age-matched controls. Patients with ipsilateral ICA stenosis or advanced small vessel disease were excluded. Degree of stenosis was graded as mild (< 50%), moderate (50-90%), or severe (> 90%). VMR was measured by a semi-closed rebreathing method with monitoring of end-expiratory CO₂ level and calculated by percentage change of mean flow velocity of MCA.


RESULTS
Fifty-eight MCAs with stenosis among 44 patients were compared with 38 MCAs without stenosis among 19 controls. VMR was reduced in patients with stenosis as compared with controls (41.6% vs 57.1%, p < 0.001). VMR was more reduced in patients with previous stroke compared with those without previous stroke (27.5% vs 53.1%, p < 0.001). Decrement of VMR was well correlated with degree of stenosis (p < 0.001). Multivariate logistic regression analysis adjusting for age, hypertension and diabetes revealed moderate to severe stenosis as an independent determinant of reduced VMR (odds ratio 10.2, 95% CI 3.35-30.96, p < 0.001).


CONCLUSIONS
TCD measurement of VMR is feasible in MCA stenosis and VMR is reduced in a dose-responsive manner. These pilot results need to be replicated and further clinical significance of VMR in MCA stenosis remains to be determined.
Department of Neurology, Seoul National University Boramae Hospital, College of Medicine, Seoul National University, Republic of Korea.
Jee-Young
JY
Lee
Yong-Seok
YS
Lee
D000368:Aged; D001160:Arterioles / Q000000981:diagnostic imaging / Q000503:physiopathology; D001944:Breath Tests; D002245:Carbon Dioxide / Q000032:analysis; D015897:Comorbidity; D003251:Constriction, Pathologic; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology; D006973:Hypertension / Q000453:epidemiology; D020244:Infarction, Middle Cerebral Artery / Q000453:epidemiology / Q000473:pathology / Q000503:physiopathology*; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D016037:Single-Blind Method; D020521:Stroke / Q000453:epidemiology; D017585:Ultrasonography, Doppler, Transcranial; D014661:Vasoconstriction / Q000502:physiology; D014664:Vasodilation / Q000502:physiology; D014666:Vasomotor System / Q000503:physiopathology*
D002245:Carbon Dioxide