Circle of Willis variants and their association with outcome in patients with middle cerebral artery-M1-occlusion stroke.

Westphal, Laura P; Lohaus, Niklas; Winklhofer, Sebastian; Manzolini, Christian; Held, Ulrike; Steigmiller, Klaus; Hamann, Janne M; El Amki, Mohamad; Dobrocky, Tomas; Panos, Leonidas D.; Kaesmacher, Johannes; Fischer, Urs; Heldner, Mirjam R.; Luft, Andreas R; Gralla, Jan; Arnold, Marcel; Wiest, Roland; Wegener, Susanne (2021). Circle of Willis variants and their association with outcome in patients with middle cerebral artery-M1-occlusion stroke. European journal of neurology, 28(11), pp. 3682-3691. Wiley 10.1111/ene.15013

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An incomplete circle of Willis (CoW) has been associated with a higher risk of stroke and might affect collateral flow in large vessel occlusion (LVO) stroke. We aimed to investigate the distribution of CoW variants in a LVO stroke and transient ischemic attack (TIA) cohort and analyze their impact on 3-month functional outcome.


CoW anatomy was assessed with time-of-flight magnetic resonance angiography (TOF-MRA) in 193 stroke patients with acute middle cerebral artery (MCA)-M1-occlusion receiving endovascular treatment (EVT) and 73 TIA patients without LVO. The main CoW variants were categorized into four vascular models of presumed collateral flow via the CoW.


82.4% (n = 159) of stroke and 72.6% (n = 53) of TIA patients had an incomplete CoW. Most variants affected the posterior circulation (stroke: 77.2%, n = 149; TIA: 58.9%, n = 43; p = 0.004). Initial stroke severity defined by the National Institutes of Health Stroke Scale (NIHSS) on admission was similar for patients with and without CoW variants. CoW integrity did not differ between groups with favorable (modified Rankin Scale [mRS]): 0-2) and unfavorable (mRS: 3-6) 3-month outcome. However, we found trends towards a higher mortality in patients with any type of CoW variant (p = 0.08) and a higher frequency of incomplete CoW among patients dying within 3 months after stroke onset (p = 0.119). In a logistic regression analysis adjusted for the potential confounders age, sex and atrial fibrillation, neither the vascular models nor anterior or posterior variants were independently associated with outcome.


Our data provide no evidence for an association of CoW variants with clinical outcome in LVO stroke patients receiving EVT.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Neurology
04 Faculty of Medicine > Department of Radiology, Neuroradiology and Nuclear Medicine (DRNN) > Institute of Diagnostic and Interventional Neuroradiology

UniBE Contributor:

Dobrocky, Tomas, Panos, Leonidas, Kaesmacher, Johannes, Fischer, Urs Martin, Heldner, Mirjam Rachel, Gralla, Jan, Arnold, Marcel, Wiest, Roland Gerhard Rudi


600 Technology > 610 Medicine & health








Chantal Kottler

Date Deposited:

30 Sep 2021 16:36

Last Modified:

03 Nov 2023 07:48

Publisher DOI:


PubMed ID:


Uncontrolled Keywords:

TOF-MRA anatomical variants circle of Willis collaterals stroke




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