The Role of Endothelial Dysfunction in the Pathophysiology and Cerebrovascular Effects of Migraine: A Narrative Review

Background and Purpose

Migraine is a complex neurovascular disorder whose triggers are not entirely understood. Endothelial dysfunction might play a role in migraine, and there have been numerous reports on endothelium dysfunction and migraine pathophysiology, but their reciprocal cause–effect relationship remains unclear. This review reports the current evidence on endothelium dysfunction, its link with migraine, and its possible consequences for cerebral hemodynamics.

Methods

We performed a systematic literature search of PubMed up to March 2020. We included 115 articles in a narrative review.

Results

Several studies have demonstrated that endothelium dysfunction may play an important role in migraine. Despite the lack of specific biomarkers, there is evidence of oxidative stress and inflammation—two of the primary causes of endothelial damage—in migraine. The main consequences of endothelial dysfunction are increased vascular tone, thrombosis, inflammation, and increased vascular permeability. As a consequence of oxidative stress, the activity of endothelin-1 is not counterbalanced by nitric oxide (NO), whose levels decrease to lead to vasoconstriction and a possible contribution to cortical spreading depression. NO is involved in pain perception via the cyclic guanosine monophosphate (cGMP) pathway and the induction of calcitonin gene-related peptide. Oxidative stress may induce a hypercoagulable state that mainly affects platelet function through different mechanisms. Endothelial dysfunction seems to be particularly pronounced in migraine with aura (MA). Endothelial dysfunction in migraine particularly involves intracranial vessels, since flow-mediated dilation cannot detect overt peripheral vascular dysfunction.

Conclusions

Endothelial dysfunction is a vascular risk marker. How it impacts migraine, and particularly MA, needs to be understood better by defining its possible role in increasing the stroke risk in migraine patients.

Paradoxical association between age and cerebrovascular reactivity in migraine: A cross-sectional study

BACKGROUND

Previous studies reported an increased risk of ischemic stroke in younger migraineurs. We aimed to investigate the association between age and cerebrovascular reactivity (CVR) to vasodilatory stimuli in cerebral arteries in patients with migraine and normal controls.

METHODS

In this cross-sectional study, we recruited 248 patients with migraine and 105 normal controls at Samsung Medical Center between October 2015 and July 2018. CVR was measured interictally by using the transcranial Doppler breath-holding test. For the arteries which showed a correlation between age and CVR, we conducted univariable and multivariable linear regression analysis to assess the independent effect of age on CVR. The path analysis was performed to assess mediating effects of the age of onset and disease duration on the age-CVR association.

RESULTS

Patients had reduced CVR in all tested arteries compared to normal controls. A correlation between age and CVR was present in the posterior cerebral artery (PCA) only in patients (Pearson's correlation coefficient = 0.160, p = 0.012). In patients, younger age was independently associated with lower CVR in the PCA (multivariable B = 0.003, 95% CI = 0.0002-0.005, p = 0.033 adjusted for sex, migraine subtype, and headache frequencies). The path analysis showed that the age of onset fully mediated the effect of age on PCA CVR, while longer disease duration negatively modified the effect of age of onset (p for interaction = 0.018).

CONCLUSIONS

In migraineurs, younger age was associated with CVR reduction in the PCA. Younger age of onset may be a hidden risk factor mediating the paradoxical association between age and CVR. This association might explain an increased risk of stroke in younger migraineurs.

Cerebrovascular reactivity as a determinant of deep white matter hyperintensities in migraine

OBJECTIVE

To evaluate the association between the cerebrovascular reactivity to carbon dioxide (CO₂-CVR) and the deep white matter hyperintensity (WMH) burden in patients with migraine.

METHODS

A total of 86 nonelderly patients with episodic migraine without vascular risk factors and 35 headache-free controls underwent 3T MRI. Deep WMHs were quantified with a segmentation method developed for nonelderly migraineurs. The interictal CO₂-CVR was measured with transcranial Doppler with the breath-holding method. The mean breath-holding index of the bilateral middle cerebral arteries (MCA-BHI) was square root transformed and analyzed with univariate and multivariate logistic regression models to determine its association with the highest tertiles of deep WMH burden (number and volume).

RESULTS

A low MCA-BHI was independently associated with the highest tertile of deep WMH number in patients with migraine (adjusted odds ratio [OR] 0.02, 95% confidence interval [CI] 0.0007-0.63, p = 0.026). In controls, the MCA-BHI was not associated with deep WMH number. Interaction analysis revealed that migraine modified the effect of MCA-BHI on deep WMH number (p for interaction = 0.029). The MCA-BHI was not associated with increased deep WMH volume in both patients and controls. Age was independently associated with deep WMH volume in patients (adjusted OR 1.07, 95% CI 1.004-1.15, p = 0.037).

CONCLUSIONS

In this study, we found a migraine-specific association between a reduced CVR to apnea and increased number of deep WMHs in healthy, nonelderly patients with migraine. A dysfunctional vascular response to apnea may predispose migraineurs to an increased risk of WMHs.

Cardiovascular Risk Factors in Cluster Headache

Background

Patients with cluster headache tend to have a dysregulation of systemic blood pressure such as increased blood pressure variability and decreased nocturnal dipping. This pattern of nocturnal nondipping is associated with end-organ damage and increased risk of cardiovascular disease.

Objective

To determine if cluster headache is associated with a higher risk of cardiovascular disease.

Methods

Cross-sectional study of 33 cluster headache patients without evidence of cardiovascular disease and 30 age- and gender-matched healthy controls. Ambulatory blood pressure monitoring was performed in all subjects. We evaluate anthropometric, hematologic, and structural parameters (carotid intima-media thickness and ankle-brachial index).

Results

Of the 33 cluster headache patients, 16 (48.5%) were nondippers, a higher percentage than expected. Most of the cluster headache patients (69.7%) also presented a pathological ankle-brachial index. In terms of the carotid intima-media thickness values, 58.3% of the patients were in the 75th percentile, 25% were in the 90th percentile, and 20% were in the 95th percentile. In the control group, only five of the 30 subjects (16.7%) had a nondipper pattern ( P  =   0.004), with 4.54% in the 90th and 95th percentiles ( P  =   0.012 and 0.015).

Conclusions

Compared with healthy controls, patients with cluster headache presented a high incidence (48.5%) of nondipper pattern, pathological ankle-brachial index (69.7%), and intima-media thickness values above the 75th percentile. These findings support the hypothesis that patients with cluster headache present increased risk of cardiovascular disease.