Association between vertebral artery dominance and basilar artery curvature in migraineurs: an anatomical magnetic resonance imaging study

BACKGROUND AND PURPOSES

Numerous studies demonstrate a link between cerebrovascular alterations and migraine pathogenesis. We investigated the association between migraine and vertebral artery dominance (VAD), basilar artery (BA) curvature, and elongation.

MATERIALS AND METHODS

This cross-sectional MRI study included 74 migraine patients and 74 control subjects aged between 18 and 55 years. Diameters of the intracranial part of the vertebral artery (VA) and BA, height of the BA bifurcation, and total lateral displacement of the BA were measured. In addition, we investigated the directional relationship between VAD and BA curvature.

RESULTS

There were no statistically significant differences between the groups regarding VA and BA diameters and total lateral displacement of the BA. The height of the BA bifurcation was found to be significantly higher in migraine patients compared to controls (p = 0.002). The left-side VAD was more frequent in migraine patients compared to control subjects (60.8% (45/74) vs 41.9% (31/74), p = 0.001). In migraine patients, particularly those with aura (MwA) patients, with left-side VAD, the rate of BA displacement to the right side is significantly higher than those with right-side VAD or non-VAD (p = 0.022). Also, we found that total lateral displacement of the BA is correlated with VA asymmetry in patients with MwA (r = 0.538, p = 0.007).

CONCLUSION

VAD and its opposite-directional relationship with the lateral displacement of the BA may be associated with migraine pathophysiology. Together with aging, this association may contribute to changes in the vertebrobasilar system (VBS) geometry which may result in increased risk for posterior circulation infarction (PCI) in migraineurs.

Vertebral artery hypoplasia and chronic migraine: is there an association or just an incidental finding?

We describe a 29-year-old woman with chronic migraine and psychiatric comorbidities that presented with new transient left-sided hemiparesis and hemi-hypoesthesia and were found to have right vertebral artery hypoplasia (VAH). We briefly review the association of VAH and migraine and the influence of psychiatric disorders and VAH as possible risk factors for chronification of episodic migraine. Despite uncertain mechanisms, VAH may be one of thecontributing factors for the chronicity of migraine.

Vertebral artery hypoplasia as an independent risk factor of posterior circulation atherosclerosis and ischemic stroke

ABSTRACT

Vertebral artery hypoplasia (VAH) is a frequent anatomical variation of vertebral arteries, with emerging evidence suggesting that it contributes to posterior circulation ischemia. However, the relationship between VAH and ischemic stroke remains unknown. Hence, this study aimed to determine the prevalence of VAH in patients diagnosed with acute ischemic stroke who were followed up in a neurology clinic and to determine if it can potentially be a risk factor for atherosclerotic stenosis in vertebrobasilar circulation.This retrospective study included 609 patients diagnosed with acute ischemic stroke between January 1, 2019 and January 1, 2020. Demographic of patients, risk factors, radiological and clinical characteristics were evaluated.Posterior circulation was very common in patients with VAH, and the most common locations of atherosclerotic stenosis were V1 and V4 segments of the vertebral artery and the middle segment of basilar artery. Analysis of the risk factors for atherosclerotic stenosis in patients with posterior circulation acute ischemic stroke suggested that VAH was an independent risk factor.Findings of the study suggest that VAH pre-disposes atherosclerotic stenosis in vertebrobasilar circulation, although its mechanism remains unknown. Hemodynamic parameters associated with atherosclerosis could not be measured in vivo. Thus, to better understand the underlying mechanism, conducting studies that examine blood flow parameters with high-resolution magnetic resonance angiography in patients diagnosed with acute cerebral ischemia patients with VAH is warranted.

Vertebral Artery Diameter and Flow: Nature or Nurture

BACKGROUND AND PURPOSE

In contrast with the carotid arteries, the vertebral arteries (VAs) show considerable variation in length, caliber, and vessel course. This study investigated whether the variation in diameter and flow characteristics of the VAs might be inherited.

METHODS

A total of 172 Italian twins from Padua, Perugia, and Terni (54 monozygotic, 32 dizygotic) recruited from the Italian Twin Registry underwent B-mode and pulsed-wave Doppler ultrasound assessment of their VAs. VA diameters, peak systolic velocity (PSV) and end diastolic velocity (EDV) were assessed at the level of a horizontal V2 segment. Univariate quantitative genetic modeling was performed.

RESULTS

Fourteen percent of the sample had VA hypoplasia. Within pair correlation in monozygotic twins was higher than in dizygotics (.552 vs. .229) for VA diameter. Age- and sex-adjusted genetic effect, under the most parsimonious model, accounted for 54.7% (95% CI: 42.2-69.1%) of the variance of VA diameter, and unshared environmental effect for 45.3% (95% CI: 30.9-57.8%). No heritability was found for the PSV of VA, but shared (34.1%; 95% CI: 16.7-53.7%) and unshared (65.9%; 95% CI: 45.9-83.1%) environmental factors determined the variance. EDV of VA is moderately genetically influenced (42.4%; 95% CI: 16.1-64.9%) and also determined by the unshared environment (57.6%; 95% CI: 34.7-83.7%).

CONCLUSIONS

The diameter of the VAs is moderately genetically determined. Different factors influence the PSV and EDV of VAs, which may highlight the complex hemodynamic background of VA flow and help to understand the vertebral flow anomalies found by ultrasound.

Vertebral Artery Hypoplasia and Posterior Circulation Infarction in Patients with Isolated Vertigo with Stroke Risk Factors

BACKGROUND

We aimed in this study to investigate the prevalence of vertebral artery hypoplasia (VAH) in a population with isolated vertigo in association with stroke risk factors, to determine whether VAH is an independent risk factor for posterior circulation infarction (PCI).

METHODS

We sequentially enrolled 245 patients with isolated vertigo with at least 1 vascular risk factor, who were divided into PCI and non-PCI groups, according to present signs of acute infarction on diffusion-weighted magnetic resonance imaging. All patients underwent magnetic resonance angiography and cervical contrast-enhanced magnetic resonance angiography to screen for VAH. Univariate and multivariate logistic regression analyses were performed to identify the significant risk factors for PCI.

RESULTS

VAH was found in 64 of 245 patients (26%). VAH (odds ratio [OR] = 2.70, 95%confidence interval [CI] 1.17-6.23, P = .020), median stenosis of the posterior circulation (OR = 7.09, 95%CI = 2.54-19.79, P < .001), and diabetes mellitus (OR = 3.13, 95%CI 1.38-7.12, P = .006) were independent risk factors for PCI. The predominant Trial of Org 10172 in Acute Stroke Treatment subtype in our patients with isolated vertigo with PCI complicated by VAH was mainly small-artery occlusion.

CONCLUSIONS

Our findings suggest that VAH is an independent risk factor for PCI in patients with isolated vertigo with confirmed risk from stroke.

Spontaneous Thrombolysis of Multiple Thrombi at Distal Region of Hypoplastic Vertebral Artery After Stent-assisted Angioplasty on Vertebral Artery Origin Stenosis: Angiographic Follow-up

Vertebral artery hypoplasia (VAH) can be easily overlooked if the contralateral side vertebral artery is intact, because of compensation by the contralateral artery or cerebral collateral network. The clinical relevance and hemodynamic impact of VAH is still controversial. However, VAH has recently been considered a risk factor for posterior circulation ischemia. Ischemic stroke is seldom caused by free floating thrombi (FFT) in the artery. Pathophysiology of FFT has not yet been clarified. The state of reduced blood flow such as a vertebral artery origin stenosis may cause FFT. Their instability may make them sources of recurrent artery to artery embolism. Patients with FFT will require appropriate medical and endovascular treatment.

The current case illustrates a short-term angiographic change of spontaneous thrombolysis of VAH and multiple thrombi at the distal region of the stenosed lesion after stent-assisted angioplasty for a vertebral artery origin stenosis.

Migraine: possible role of shear-induced platelet aggregation with serotonin release

BACKGROUND

Migraine patients are at an increased risk for stroke, as well as other thromboembolic events. This warrants further study of the role of platelets in a proportion of migraine patients.

OBJECTIVE

To extend the "platelet hypothesis" using literature data and observations made in a rat model of shear stress-induced platelet aggregation. Such aggregation causes release of serotonin, leading to vasoconstriction during sufficiently strong aggregation and to long-lasting vasodilation when aggregation diminishes. This vasodilation also depends on nitric oxide and prostaglandin formation.

RESULTS

A role for platelet aggregation in a number of migraineurs is indicated by reports of an increased platelet activity during attacks and favorable effects of antiplatelet medication. We hypothesize that in those patients, a migraine attack with or without aura may both be caused by a rise in platelet-released plasma serotonin, albeit at different concentration. At high concentrations, serotonin may cause vasoconstriction and, consequently, the neuronal signs of aura, whereas at low concentrations, it may already stimulate perivascular pain fibers and cause vasodilation via local formation of nitric oxide, prostaglandins, and neuropeptides. Platelet aggregation may be unilaterally evoked by elevated shear stress in a stenotic cervico-cranial artery, by reversible vasoconstriction or by other cardiovascular abnormality, eg, a symptomatic patent foramen ovale. This most likely occurs when a migraine trigger has further enhanced platelet aggregability; literature shows that many triggers either stimulate platelets directly or reduce endogenous platelet antagonists like prostacyclin.

CONCLUSION

New strategies for migraine medication and risk reduction of stroke are suggested.

Vertebral artery hypoplasia: prevalence and reliability of identifying and grading its severity on magnetic resonance imaging scans

OBJECTIVE

The purpose of this study is to examine the inter- and intraexaminer reliability of determining the prevalence of vertebral artery hypoplasia on magnetic resonance imaging (MRI) as well as the reliability of assigning a severity grading of mild, moderate, or marked hypoplasia.

METHODS

Two chiropractic radiologists independently evaluated the MR images of 131 adult patients retrospectively for visual vertebral artery hypoplasia. Severity of hypoplastic was graded. The side of hypoplasia and sex of the patient were recorded. The process was repeated after 1 month. Descriptive statistics were calculated for prevalence, severity, and sex distribution of hypoplasia. The kappa statistic was calculated for the reliability of detecting and grading the hypoplasia.

RESULTS

Interexaminer reliability was substantial for both readings (kappa = 0.68, 83% agreement for the first reading; kappa = 0.75, 86% agreement for the second reading). Interexaminer reliability for grading the severity of asymmetry was substantial (kappa = 0.73, 83% agreement for the first read; kappa = 0.69, 81% agreement for the second reading). Intraexaminer reliability readings provided a kappa of 0.71 (substantial) and 83% agreement for examiner 1. Examiner 2 had a kappa of 0.85 (almost perfect) with 92% agreement. Overall, 57 (43.5%) of the 131 patients demonstrated hypoplasia. Hypoplasia was more common in women (49%) than men (35.8%). Seven arteries demonstrated severe hypoplasia. Six of these 7 patients were women.

CONCLUSIONS

Vertebral artery hypoplasia is common and can be reliably diagnosed and categorized on cervical MRI scans. Vertebral artery hypoplasia was more common in women than men in this group of patients.

A case of atypical sporadic hemiplegic migraine associated with PFO and hypoplasia of vertebro-basilar system

We describe the case of a patient with atypical hemiplegic migraine and associated basilar symptoms, where a large patent foramen ovale (PFO) and hypoplasia of basilar artery were found. The longer period of 4-year remission of the headache attacks was coincident with the percutaneous PFO closure. When 5 years after, hemiplegic migraine attacks relapsed, with more relevant basilar symptoms, a mild re-opening of PFO was found. The atypical presentation of attacks with basilar symptoms and prolonged hemiplegia does not strictly fit the diagnostic criteria of ICHD-II.