Importance of hemodynamic factors in the prognosis of symptomatic carotid occlusion.
BACKGROUND
The relative importance of hemodynamic factors in the pathogenesis and treatment of stroke in patients with carotid artery occlusion remains controversial.


OBJECTIVE
To test the hypothesis that stage II cerebral hemodynamic failure (increased oxygen extraction measured by positron emission tomography [PET]) distal to symptomatic carotid artery occlusion is an independent risk factor for subsequent stroke in medically treated patients.


METHODS
Prospective, blinded, longitudinal cohort study of patients referred from a group of regional hospitals between 1992 and 1996.


METHODS
From 419 subjects referred, 81 with previous stroke or transient ischemic attack in the territory of an occluded carotid artery were enrolled. All were followed up to completion of the study, with average follow-up of 31.5 months.


METHODS
Telephone contact every 6 months recorded the subsequent occurrence of all stroke, ipsilateral ischemic stroke, and death.


RESULTS
Stroke occurred in 12 of 39 patients with stage II hemodynamic failure and in 3 of 42 patients without (P = .005); stroke was ipsilateral in 11 of 39 patients with stage II hemodynamic failure and in 2 of 42 patients without (P = .004). Six deaths occurred in each group (P = .94). The age-adjusted relative risk conferred by stage II hemodynamic failure was 6.0 (95% confidence interval [CI], 1.7-21.6) for all stroke and 7.3 (95% CI, 1.6-33.4) for ipsilateral stroke.


CONCLUSIONS
Stage II hemodynamic failure defines a subgroup of patients with symptomatic carotid occlusion who are at high risk for subsequent stroke when treated medically. A randomized trial evaluating surgical revascularization in this high-risk subgroup is warranted.
Department of Neurology and Neurological Surgery, the Edward Mallinckrodt Institute of Radiology, Washington University, St Louis, MO, USA.
R L
RL
Grubb
C P
CP
Derdeyn
S M
SM
Fritsch
D A
DA
Carpenter
K D
KD
Yundt
T O
TO
Videen
E L
EL
Spitznagel
W J
WJ
Powers
D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging; D016893:Carotid Stenosis / Q000175:diagnosis / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D002561:Cerebrovascular Disorders / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D006439:Hemodynamics; D006801:Humans; D002546:Ischemic Attack, Transient / Q000209:etiology / Q000503:physiopathology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D016019:Survival Analysis; D014055:Tomography, Emission-Computed