Migraine and circle of Willis anomalies

Department of Neurology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA 19104, United States.
Medical Hypotheses (Impact Factor: 1.15). 02/2008; 70(4):860-5. DOI: 10.1016/j.mehy.2007.05.057
Source: PubMed

ABSTRACT Several mechanisms are currently thought to contribute to migraine pathogenesis, including interictal neuronal hyperexcitability, cortical spreading depression underlying the symptom of aura, and trigeminal nerve activation at a peripheral and central level. However, these mechanistic concepts incompletely explain migraine susceptibility in individual patients and do not fully account for the well documented association between migraine and ischemic cerebrovascular disease, including increased risk of both clinical stroke and subclinical brain lesions in migraine patients. The circle of Willis is a major source of collateral blood flow supply in the human brain, and developmental morphologic variants of the circle of Willis are extremely frequent. Altered cerebral blood flow (CBF) has been demonstrated in regions supplied by variant circle of Willis vessels. Our central hypothesis is that circle of Willis anomalies correlate with alterations in cerebral hemodynamics and contribute to migraine susceptibility and ischemic complications of migraine. Dysregulation of CBF may allow relative ischemia to develop in the setting of increased metabolic demand related to neuronal hyperexcitability, may trigger cortical spreading depression, and may predispose individuals with migraine to ischemic lesions and stroke. Identification of structural alterations in the cerebral vasculature in migraine patients would have several important pathophysiological and clinical implications. First, it would provide a developmental mechanism for migraine susceptibility that may lead to further insights into genetic predisposition to migraine. Second, it would expand understanding of potential mechanisms underlying migraine aura and linking migraine with both clinical and subclinical cerebral infarction. Third, it could help to identify the subpopulation of patients at risk of progressive cerebral ischemia so as to target preventative therapies appropriately. Fourth, it would suggest a role for further diagnostic evaluation to determine migraine mechanism in individual patients, analogous to the current paradigm in ischemic stroke in which determination of stroke mechanism is critical to therapeutic decision-making.

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    ABSTRACT: The Cerebral Circle Region, also known as the Circle of Willis (CoW), is a loop of arteries that form arterial connections between supply arteries to distribute blood throughout the cerebral mass. Among the population, only 25% to 50% have a complete system of arteries forming the CoW. 3D time-varying simulations for three different patient-specific artery anatomies of CoW were performed in order to gain a better insight into the phenomena existing in the cerebral blood flow. The models reconstructed on the basis of computer tomography images start from the aorta and include the largest arteries that supply the CoW and the arteries of CoW. Velocity values measured during the ultrasound examination have been compared with the results of simulations. It is shown that the flow in the right anterior artery in some cases may be supplied from the left internal carotid artery via the anterior communicating artery. The investigations conducted show that the computational fluid dynamic tool, which provides high resolution in both time and space domains, can be used to support physicians in diagnosing patients of different ages and various anatomical arterial structures.
    Journal of Biomechanics 03/2014; 47(7). DOI:10.1016/j.jbiomech.2014.02.039 · 2.50 Impact Factor
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    ABSTRACT: Although cerebral blood flow is the crucial factor for cerebral infarction and the circle of Willis (CoW) is considered the primary control structure for cerebral hemodynamics, risk of cerebral infarction caused by the morphological variation in the CoW has never been studied due to lack of proper tools. Here, the alteration of cerebral blood flow in CoW variation was quantitatively assessed by a new analysis method using a microfluidic device that was controlled by pneumatic valves. Using this device, the occlusion of diverse major arteries was realized by closing the channel with pneumatic valves. The morphological variations of the CoW and their hemodynamics were designed and analyzed after occlusion of the major arteries. While the differences in hemodynamics of CoW variants were not statistically significant compared with a complete CoW without occlusion or with occlusion of the efferent arteries, the occlusion of afferent arteries such as common carotid artery and vertebral artery severely affected the flow rate (28.4–48.8 %) and related arterial pressure of efferent arteries (48.6 ± 6.7–36.0 ± 1.4 mmHg) in CoW variants where the posterior communicating artery and the P1 segment are absent, which is associated with cerebral ischemic infarction. The novel analysis system using microfluidics provides a robust and accurate method, in which the hemodynamics of individual morphological variation and stenosis, and occlusion of vessels can be analyzed. Thus, this method is particularly suitable for personalized analysis of hemodynamics and may find new applications in biomedical researches.
    Microfluidics and Nanofluidics 11/2014; 17(5). DOI:10.1007/s10404-014-1366-2 · 2.67 Impact Factor
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    ABSTRACT: Background The circle of Willis is an important source of collateral blood flow to maintain adequate cerebral perfusion, particularly in the posterior circulation. Some studies report a relationship between incomplete circle of Willis and migraine, whereas other studies show no difference between the prevalence of incomplete circle of Willis in migraineurs and controls. In the present study we compared the prevalence of incomplete circle of Willis in female migraine patients without aura to female healthy non-migraine controls. Using 3-Tesla magnetic resonance angiography we recorded three-dimensional time-of-flight angiograms in 85 female participants (48 migraine patients without aura [median age 28 years] and 37 healthy controls [median age 25 years]). The images were subsequently analysed blindly by a neuroradiologist to detect incomplete circle of Willis. Findings We found no difference between the prevalence of incomplete circle of Willis in patients, 20/47 (43%), and controls, 15/37 (41%), p = 0.252. Post hoc analysis showed a significant relationship between age and prevalence of incomplete circle of Willis, p = 0.003. Conclusion We found no relationship between migraine without aura and incomplete circle of Willis.
    The Journal of Headache and Pain 05/2014; 15(1):27. DOI:10.1186/1129-2377-15-27 · 3.28 Impact Factor

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