title: The circle of Willis predicts the antihypertensive effects of carotid artery stenting.
abstract: OBJECTIVE Carotid artery stenting (CAS) has antihypertensive effects, but the durability and degree of this response remain variable. The authors propose that this clinical variability is a function of the presence or absence of a complete circle of Willis (COW). Incomplete COWs perfuse through a higher-resistance pial collateral pathway, and therefore patients may require a higher mean arterial pressure (MAP). Carotid artery revascularization in these patients would reduce the end-organ collateral demand that has been hypothesized to drive the MAP response. METHODS Using a retrospective, nonrandomized within-subject case-control design, the authors compared the postoperative effects of CAS in patients with and without a complete COW by using changes in MAP and antihypertensive medication as end points. They recorded MAP and antihypertensive medications 3 months prior to surgery, preoperatively, immediately postoperatively, and at the 3-month follow-up. RESULTS Data were collected from 64 consecutive patients undergoing CAS. Patients without a complete COW (25%) were more likely to demonstrate a decrease in BP response to stenting (i.e., a drop in MAP of 10 mm Hg and/or a reduction or cessation of BP medications at 3 months postoperatively). Of the patients in the incomplete COW cohort, 75% had this outcome, whereas of those in the complete COW cohort, only 41% had it (p < 0.041). These findings remained statistically significant in a logistic regression analysis for possible confounders (p < 0.024). A receiver operating curve analysis of preoperative data indicated that a MAP > 96.3 mm Hg was 55.5% sensitive and 57.4% specific for predicting a complete COW and that patients with a MAP > 96.3 mm Hg were more likely to demonstrate a good MAP decrease following CAS (p < 0.0092). CONCLUSIONS CAS is associated with a significant decrease in MAP and/or a reduction/cessation in BP medications in patients in whom a complete COW is absent.
authors.affiliation: Department of Neurosurgery, University of California, San Diego, California.
authors.forename: David R
authors.initials: DR
authors.lastname: Santiago-Dieppa
authors.affiliation: Department of Neurosurgery, University of California, San Diego, California.
authors.forename: Brian R
authors.initials: BR
authors.lastname: Hirshman
authors.affiliation: Department of Neurosurgery, University of California, San Diego, California.
authors.forename: Arvin
authors.initials: A
authors.lastname: Wali
authors.affiliation: Department of Neurosurgery, University of California, San Diego, California.
authors.forename: J
authors.initials: J
authors.lastname: Scott Pannell
authors.affiliation: Department of Neurosurgery, University of California, San Diego, California.
authors.forename: Yasaman
authors.initials: Y
authors.lastname: Alam
authors.affiliation: Department of Neurosurgery, University of California, San Diego, California.
authors.forename: Scott
authors.initials: S
authors.lastname: Olson
authors.affiliation: Department of Neurosurgery, University of California, San Diego, California.
authors.forename: Vincent J
authors.initials: VJ
authors.lastname: Cheung
authors.affiliation: Department of Neurosurgery, University of California, San Diego, California.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Steinberg
authors.affiliation: Department of Neurosurgery, University of California, San Diego, California.
authors.forename: Mihir
authors.initials: M
authors.lastname: Gupta
authors.affiliation: Department of Neurosurgery, University of California, San Diego, California.
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Khalessi
mesh_terms: D001794:Blood Pressure / Q000502:physiology; D016893:Carotid Stenosis / Q000150:complications / Q000628:therapy*; D016022:Case-Control Studies; D002941:Circle of Willis / Q000503:physiopathology*; D015331:Cohort Studies; D016208:Databases, Factual / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D006973:Hypertension / Q000209:etiology / Q000628:therapy*; D008297:Male; D011237:Predictive Value of Tests
keywords: ACoA = anterior communicating artery; BP = blood pressure; CAS = carotid artery stent; COW = circle of Willis; MAP = mean arterial BP; PCoA = posterior communicating artery; ROC = receiver operating characteristic; TIA = transient ischemic attack; angioplasty and stenting; blood pressure; carotid artery stenosis; carotid artery stent; circle of Willis; hypertension; pial collaterals