Circle of Willis variations in migraine patients with ischemic stroke

Assessment of Primary Collateral Grades Based on the Integrity of Willis' Circle: Predicting the Prognosis of Acute Intracranial Internal Carotid Artery Occlusion Before Thrombectomy

OBJECTIVE

Endovascular mechanical thrombectomy (EVMT) has shown significant efficacy in improving neurological functions in patients with intracranial internal carotid artery occlusion (IICAO), but its clinical outcomes are variable. We examined the relationship between favorable clinical outcomes after EVMT in IICAO and a set of predictors.

METHODS

In this retrospective study, 189 patients with IICAO treated by EVMT at 3 centers from November 2015 to December 2020 were included and analyzed. Non-contrast computed tomography and computed tomography angiography were evaluated on admission. The morphology of IICAO was categorized into Ia, Ib, L, or T types, depending on the involvement of the posterior communicating artery origin, proximal anterior cerebral artery, and middle cerebral artery. The Willis' circle was categorized as integrated or compromised Willis' circle. In combination with the involvement of the IICAO and the integrity of Willis' circle, we used the primary collateral grade (PCG) to describe the presence of functional Willisian collaterals. Baseline data including demographics, characteristics, vascular risk factors, and initial National Institutes of Health Stroke Scale scores were collected. Hemorrhagic transformation was evaluated using the 24-hour non-contrast computed tomography after EVMT. Favorable outcomes based on modified Rankin scale, were defined as 0-2 at 90 days.

RESULTS

A total of 189 patients were included (median age, 69 years; 126 male [66.7%]). 104 patients [55.0%] showed reperfusion after EVMT, but 72 patients [38.1%] achieved favorable outcomes at 90 days. The mortality rate of type Ib was significantly higher than that with type Ia (χ2 = 14.21, P = 0.001). The outcome with different structure of Willis' circle was not statistically different between the 2 groups. A multivariate logistic regression analysis showed that IICAO T-type (odds ratio, 0.028 [95% confidence interval: 0.323-3.829], P = 0.042) and PCG 2 (odds ratio 9.427[95% confidence interval:1.863-47.698], P = 0.007) were predictors of favorable outcomes.

CONCLUSIONS

Evaluation of PCG by determining the type of IICAO and the integrity of Willis' circle may serve as a valuable indicator for the prognosis and as an essential reference for screening patients before EVMT.

Validation of an Oscillation Test for the Sonographic Assessment of Fetal-Type Posterior Cerebral Artery Variants in Migraine Patients with Visual Aura

Anatomic variants of the posterior circle of Willis, including the fetal-type posterior cerebral artery (FPCA), may contribute to the formation of visual aura in migraine. We sought to validate an oscillation test to investigate FPCA frequency in migraine using transcranial color-coded duplex ultrasonography (TCCS). First, the diagnostic accuracy of the oscillation test used to identify FPCA variants by TCCS was assessed in stroke patients with available computed tomography angiography (CTA) as the set gold standard. Second, in a cross-sectional study, patients with migraine with visual aura (MWVA) and migraine without aura (MWOA), as well as healthy controls, were prospectively recruited for sonographic assessment of FPCA variants. We compared FPCA frequency between migraine patients and controls using χ²-testing and performed logistic regression analysis to investigate a potential association between MWVA and the presence of FPCA variants. Specificity, sensitivity and positive and negative predictive values for sonographic identification of FPCA with CTA as the set gold standard were 93%, 77%, 63% and 96% (partial FPCA) and 99%, 78%, 88% and 98% (complete FPCA), respectively. One hundred forty-two migraine patients (39 ± 12 y, 90 MWVA and 52 MWOA) and 49 healthy controls (31 ± 12 y) were recruited. The χ² testing did not reveal significant differences in FPCA frequency as assessed by TCCS (unilateral or bilateral, partial and/or complete) between migraine patients and controls (MWVA: 40/90 or 44.4%, MWOA: 22/52 or 42.3%, controls: 24/49 or 49%, p = 0.79). Similarly, the frequencies of partial FPCA (p = 0.61) and complete FPCA (p = 0.27) did not vary significantly among groups. Logistic regression analysis revealed no interaction effect between migraine diagnosis and FPCA prevalence (any FPCA), when adjusted for age and sex. The sonographic oscillation test can be used as a non-invasive method to identify partial and complete FPCA variants with high specificity and reasonable sensitivity. Our findings suggest that FPCA variants do not contribute to the formation of visual migraine aura.

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

Background

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.

Methods

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.

Results

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.

Conclusion

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

Migraine and risk of stroke

Migraine and stroke are two common and heterogeneous neurovascular disorders responsible for a significant burden for those affected and a great economic cost for the society. There is growing evidence that migraine increases the overall risk of cerebrovascular diseases. In this review, based on available literature through a PubMed search, we found that ischaemic stroke in people with migraine is strongly associated with migraine with aura, young age, female sex, use of oral contraceptives and smoking habits. The risk of transient ischaemic attack also seems to be increased in people with migraine, although this issue has not been extensively investigated. Although migraine appears to be associated with haemorrhagic stroke, the migraine aura status has a small influence on this relationship. Neuroimaging studies have revealed a higher prevalence of asymptomatic structural brain lesions in people with migraine. They are also more likely to have unfavourable vascular risk factors; however, the increased risk of stroke seems to be more apparent among people with migraine without traditional risk factors. The mechanism behind the migraine-stroke association is unknown. In light of the higher risk of stroke in people with migraine with aura, it is important to identify and modify any vascular risk factor. There is currently no direct evidence to support that a migraine prophylactic treatment can reduce future stroke in people with migraine.

Circle of Willis variations in migraine patients with ischemic stroke

OBJECTIVES

Migraine is a risk factor for stroke, which might be explained by a higher prevalence in anatomical variants in the circle of Willis (CoW). Here, we compared the presence of CoW variants in patients with stroke with and without migraine.

MATERIALS AND METHODS

Participants were recruited from the prospective Dutch acute Stroke Study. All participants underwent CT angiography on admission. Lifetime migraine history was assessed with a screening questionnaire and confirmed by an interview based on International Classification of Headache Disorders criteria. The CoW was assessed for incompleteness/hypoplasia (any segment <1 mm), for anterior cerebral artery asymmetry (difference > 1/3), and for posterior communicating artery (Pcom) dominance (Pcom-P1 difference > 1/3). Odds ratios with adjustments for age and sex (aOR) were calculated with logistic regression.

RESULTS

We included 646 participants with stroke, of whom 52 had a history of migraine. Of these, 45 (87%) had an incomplete or hypoplastic CoW versus 506 (85%) of the 594 participants without migraine (aOR: 1.47; 95% CI: 0.63-3.44). There were no differences between participants with and without migraine in variations of the anterior or posterior CoW, anterior cerebral artery asymmetry (aOR: 0.86; 95% CI: 0.43-1.74), or Pcom dominance (aOR: 0.64; 95% CI: 0.32-1.30). There were no differences in CoW variations between migraine patients with or without aura.

CONCLUSION

We found no significant difference in the completeness of the CoW in acute stroke patients with migraine compared to those without.