Vascular Risk in Migraineurs: Interaction of Endothelial and Cortical Excitability Factors

Evaluation of vascular risk in patients with migraine with and without aura treated with erenumab: Post hoc analysis of pooled long-term clinical trial data

OBJECTIVE

To assess cardiovascular (CV) safety of erenumab in clinical trial patients associated with degree of CV risk.

BACKGROUND

Hypertension has been considered a theoretical risk associated with the inhibition of the calcitonin gene-related peptide pathway in migraine management, particularly in a patient population with pre-existing CV risk factors.

METHODS

Data pooled from four double-blind, randomized trials were used to assess blood pressure (BP) changes and CV safety in patients grouped based on 10-year risk of cardiac, cerebrovascular, and peripheral artery disease as no-risk-factors, low-risk (>0% to ≤10%), moderate-risk (>10% to ≤20%), and high-risk (>20%) categories. CV safety was assessed as ischemic cardiovascular and cerebrovascular adverse events (ICCAE).

RESULTS

There was no apparent difference between placebo- (N = 1032) and erenumab-treatment groups (70 mg, N = 885; 140 mg, N = 504) in clinical worsening of BP category from baseline to Months 1-3 (14% [143/1032] placebo vs. 13% [114/885] and 14% [71/504] for erenumab 70 and 140 mg, respectively) regardless of baseline BP category. The adverse event (AE) profile of erenumab was similar across CV risk categories throughout the long-term analysis. Erenumab-treated patients with high and moderate 10-year CV risk (N = 107) did not experience any ICCAEs during the double-blind treatment period; there was a single ICCAE (a cerebral dural venous sinus thrombosis) observed in the low-risk erenumab group (N = 273). There were no increases in AEs during the long-term extensions of up to 5 years (N = 2499; 3482 patient-years of exposure to erenumab) with exposure-adjusted incidence rates of cardio/cerebrovascular disorder AEs of 0.4, 0.5, 0.0, and 1.1 (per 100 patient-years) for no risk factor (N = 1805), low (N = 492), moderate (N = 121), and high (N = 81) 10-year CV risk groups, respectively.

CONCLUSIONS

Ischemic CV and cerebrovascular AEs were uncommon and the incidence rates were similar across the 10-year CV risk categories. This analysis helps provide more detail on the CV safety of erenumab.

Profiling cerebrovascular function in migraine: A systematic review and meta-analysis

Previous studies have investigated whether migraine is a circulatory disorder, as migraineurs are at heightened risk of cerebrovascular disease. However, in most cases, systemic vascular function was evaluated, which may not reflect abnormalities in the cerebral circulation. Therefore, we aimed to determine whether cerebrovascular function differs between migraineurs and controls. A systematic literature search was conducted across three electronic databases to search for studies that compared cerebrovascular function in migraineurs to controls. Where applicable, meta-analyses were used to determine standardised mean differences (SMD) between migraineurs and controls. Seventy articles were identified, 40 of which contained quantitative data. Meta-analyses showed pulsatility index (PI) was higher (SMD = 0.23; 95%CI = 0.05 to 0.42, P = 0.01) and cerebrovascular responsiveness (CVR) to hypercapnia was lower (SMD=-0.34; 95%CI=-0.67 to -0.01, P = 0.04) in the posterior circulation of migraineurs, particularly those without aura. The meta-analyses also indicated that migraineurs have higher resting mean blood flow velocity in both anterior (SMD = 0.14; 95%CI = 0.05 to 0.23, P = 0.003) and posterior circulations (SMD = 0.20; 95%CI = 0.05 to 0.34, P = 0.007). Compared to healthy controls, migraineurs have altered cerebrovascular function, evidenced by elevated PI (representing arterial stiffness) and impaired CVR to hypercapnia (representing cerebral vasodilator function). Future studies should investigate whether improvement of cerebrovascular function is able to alleviate migraine.

Cerebral vascular reactivity and the migraine-stroke relationship: A narrative review

Migraine, and especially migraine with aura, is associated with an increased risk of stroke and vascular events; however, the reasons for this association are unclear. Several studies evaluated cerebral autoregulation and vasomotor reactivity in patients with migraine compared with non-migraineurs, with conflicting results. Our narrative review aimed at summarizing their results to find the most reliable evidence in the field. Studies which used visual stimuli to evoke vascular responses consistently showed an increased vascular reactivity in migraineurs compared with non-migraineurs, while studies which used systemic stimuli such as hyper- or hypocapnia showed inconsistent results. Therefore, central neural mechanisms might be more important than peripheral vascular mechanisms in determining the cerebral vascular responses of patients with migraine. However, a large body of evidence supports the existence of peripheral vascular dysfunction in patients with migraine. Further studies are needed to explain the complex interactions between central neural and peripheral vascular mechanisms in determining migraine and its vascular risk. Migraine preventive treatments, and especially the most recent ones with a peripheral action, might provide important insights in this field.

Vascular safety of erenumab for migraine prevention

Objective

To examine the cardiovascular, cerebrovascular, and peripheral vascular safety of erenumab across migraine prevention studies.

Methods

Vascular adverse events (AEs) and blood pressure data were integrated across 4 double-blind, placebo-controlled studies of erenumab and their open-label extensions in patients with chronic or episodic migraine. Subgroup analyses were conducted by acute migraine-specific medication use and number of vascular risk factors at baseline. Standardized search terms were used to identify vascular AEs (cardiovascular, cerebrovascular, or peripheral). An independent committee adjudicated whether targeted events were vascular in origin.

Results

In placebo-controlled studies, 2,443 patients received placebo (n = 1,043), erenumab 70 mg (n = 893), or erenumab 140 mg (n = 507) subcutaneously once monthly. Regardless of acute migraine-specific medication use or vascular risk factors at baseline, AE incidence was similar across the placebo and erenumab treatment groups. Hypertension AEs were reported for 0.9% (placebo), 0.8% (erenumab 70 mg), and 0.2% (erenumab 140 mg) of patients. Vascular AEs, which were similar across double-blind and open-label treatment, generally were confounded, with plausible alternative etiologies. In 18 patients with events reviewed by the independent committee, 4 events were positively adjudicated as cardiovascular in origin: 2 deaths and 2 vascular events. All 4 positively adjudicated cardiovascular events occurred during open-label erenumab treatment.

Conclusion

Selective blockade of the canonical calcitonin gene-related peptide receptor with erenumab for migraine prevention had a vascular safety profile comparable to that of placebo over 12 weeks, with no increased emergence of events over time. Further study of long-term safety of erenumab in patients with migraine is needed.

Clinicaltrials.gov identifiers

NCT02066415, NCT02456740, NCT01952574, NCT02483585, NCT02174861, and NCT01723514.

Classification of evidence

This analysis provides Class II evidence that for patients with migraine, erenumab does not increase the risk of vascular AEs.

Tooth Clenching Induces Abnormal Cerebrovascular Responses in Migraineurs

Prevalence of masticatory parafunctions, such as tooth clenching and grinding, is higher among migraineurs than non-migraineurs, and masticatory dysfunctions may aggravate migraine. Migraine predisposes to cerebrovascular disturbances, possibly due to impaired autonomic vasoregulation, and sensitization of the trigeminovascular system. The relationships between clenching, migraine, and cerebral circulation are poorly understood. We used Near-Infrared Spectroscopy to investigate bilateral relative oxy- (%Δ[O₂Hb]), deoxy- (%Δ[HHb]), and total (%Δ[tHb]) hemoglobin concentration changes in prefrontal cortex induced by maximal tooth clenching in twelve headache-free migraineurs and fourteen control subjects. From the start of the test, migraineurs showed a greater relative increase in right-side %Δ[HHb] than controls, who showed varying reactions, and right-side increase in %Δ[tHb] was also greater in migraineurs (p < 0.001 and p < 0.05, respectively, time-group interactions, Linear mixed models). With multivariate regression model, migraine predicted the magnitude of maximal blood pressure increases, associated in migraineurs with mood scores and an intensity of both headache and painful signs of temporomandibular disorders (pTMD). Although changes in circulatory parameters predicted maximal NIRS responses, the between-group differences in the right-side NIRS findings remained significant after adjusting them for systolic blood pressure and heart rate. A family history of migraine, reported by all migraineurs and four controls, also predicted maximal increases in both %Δ[HHb] and %Δ[tHb]. Presence of pTMD, revealed in clinical oral examination in eight migraineurs and eight controls, was related to maximal %Δ[HHb] increase only in controls. To conclude, the greater prefrontal right-side increases in cerebral %Δ[HHb] and %Δ[tHb] may reflect disturbance of the tooth clenching-related cerebral (de)oxygenation based on impaired reactivity and abnormal microcirculation processes in migraineurs. This finding may have an impact in migraine pathophysiology and help to explain the deleterious effect of masticatory dysfunctions in migraine patients. However, the role of tooth clenching as a migraine trigger calls for further studies.

Genetic and biochemical changes of the serotonergic system in migraine pathobiology

Migraine is a brain disorder characterized by a piercing headache which affects one side of the head, located mainly at the temples and in the area around the eye. Migraine imparts substantial suffering to the family in addition to the sufferer, particularly as it affects three times more women than men and is most prevalent between the ages of 25 and 45, the years of child rearing. Migraine typically occurs in individuals with a genetic predisposition and is aggravated by specific environmental triggers. Attempts to study the biochemistry of migraine began as early as the 1960s and were primarily directed at serotonin metabolism after an increase of 5-hydroxyindoleacetic acid (5-HIAA), the main metabolite of serotonin was observed in urine of migraineurs. Genetic and biochemical studies have primarily focused on the neurotransmitter serotonin, considering receptor binding, transport and synthesis of serotonin and have investigated serotonergic mediators including enzymes, receptors as well as intermediary metabolites. These studies have been mainly assayed in blood, CSF and urine as the most accessible fluids. More recently PET imaging technology integrated with a metabolomics and a systems biology platform are being applied to study serotonergic biology. The general trend observed is that migraine patients have alterations of neurotransmitter metabolism detected in biological fluids with different biochemistry from controls, however the interpretation of the biological significance of these peripheral changes is unresolved. In this review we present the biology of the serotonergic system and metabolic routes for serotonin and discuss results of biochemical studies with regard to alterations in serotonin in brain, cerebrospinal fluid, saliva, platelets, plasma and urine of migraine patients.

A Case of Migraine With Aura Resolving on Warfarin But Not on Apixaban

Several case reports have associated anticoagulants such as heparin and vitamin K antagonists with reduced symptoms in migraine, but no data exist for direct acting oral factor Xa inhibitors. We report the case of a 55-year-old female who experienced complete remission of migraine with aura for 12 years while on warfarin, with return of symptoms within 3 weeks of switching to apixaban, and resolution of symptoms once again within days of warfarin resumption. Our case suggests that anticoagulation alone is not sufficient to improve migraine symptoms. Further study of vitamin K-dependent proteins not involved in anticoagulation, such as the relatively novel growth arrest-specific gene 6, may clarify the link between warfarin and migraine symptoms.

The relationship between levels of plasma-soluble urokinase plasminogen activator receptor (suPAR) and presence of migraine attack and aura

Migraine is one of the most common types of pain associated with sterile inflammatory conditions. Soluble urokinase plasminogen activator receptor (suPAR) is a potential novel inflammatory marker. We aim to determine the association between serum values of suPAR, procalcitonin, fibrinogen, and high-sensitivity C-reactive protein (hs-CRP) and migraine disease characteristics. The study involved a total of 60 migraine patients (33 patients in the interictal period, 27 patients in the attack period) and 30 healthy individuals. The serum values of suPAR were found to be significantly higher in migraine patients in the attack period than in migraine patients in the interictal period, and in healthy individuals (p < .01 for both). In addition, levels of suPAR were determined to be higher in migraine with aura patients than in migraine without aura patients. When we subdivided migraine patients according to frequency of attack (attacks/month), significant differences were found between the suPAR and procalcitonin levels (measured during the attack period) of those in the frequent-attack group (4-5 or more) versus those in the less frequent attack group (less than 4). Serum levels of procalcitonin were shown to be significantly higher in migraine patients during the attack period compared with migraine patients in the interictal period and in control subjects (p = .001 for both). Significant differences were found between plasma levels of fibrinogen in migraine patients versus control subjects (p < .01). No statistically significant difference was found between levels of hs-CRP in migraine patients versus the control group. These findings may show that presenting a high level of suPAR in migraine patients with attack and aura results to predisposition to occurring on the symptoms and that high levels of suPAR, procalcitonin and fibrinogen in patients with migraine result in neurogenic inflammation during migraine headaches.

Association between use of short-acting benzodiazepines and migraine occurrence: a nationwide population-based case-control study

AIM

To evaluate the association between using benzodiazepines (BZDs) with short- or long-acting durations and migraine occurrence.

METHODS

The migraine group comprised 9616 subjects older than 20 years and newly diagnosed with migraine between 2005 and 2011, and the comparison group comprised 38,464 subjects without migraine. The BZDs used in the subjects were dichotomously defined as short-acting (half-life ≤24 h) and long-acting substances. A logistic regression model was used to calculate the odds ratio (OR) of migraine associated with BZD exposure and other diseases.

RESULTS

The adjusted OR of migraine associated with BZD exposure was 1.73 (95% confidence interval [CI] = 1.63-1.84). Either exposure to a short-acting BZD alone or using it combining with a long-acting BZD had significant higher risks of migraine (adjusted OR = 1.69, 95% CI = 1.59-1.80; adjusted OR = 2.06, 95% CI = 1.91-2.24, respectively), whereas only long-acting BZD use was not associated with an increase of migraine. Meanwhile, sleep disorders, anxiety, and stroke were strongly associated with migraine (adjusted OR = 2.00, 1.91, and 1.57, respectively).

CONCLUSIONS

We observed a significant increase of migraine occurrence in subjects using short-acting BZDs, either alone or in combination with long-acting ones.

Associations Between Sleep Quality and Migraine Frequency: A Cross-Sectional Case-Control Study

Migraine has been associated with sleep disturbances. Relationship between sleep quality and migraine frequency is yet to be determined. The present study aimed to investigate sleep disturbances among low-frequency, moderate-frequency, high-frequency, and chronic migraineurs, with and without auras, with well-controlled confounding variables.This cross-sectional controlled study included 357 subjects from an outpatient headache clinic in Taiwan. Standardized questionnaires were utilized to collect demographic, migraine, sleep, depression, anxiety, and restless leg syndrome characteristics in all participants. According to frequency of migraine attacks, patients were divided into 4 groups: with 1 to 4 migraine days per month, 5 to 8 migraine days in a month, 9 to 14 migraine days in a month, and >14 migraine days per month. The Pittsburgh Sleep Quality Index (PSQI) and subgroup items were used to evaluate sleep quality. The association between migraine frequency and sleep quality was investigated using multivariable linear regression and logistic regression.The PSQI total score was highest in patients with high frequent migraine (10.0 ± 3.4) and lowest in controls (7.0 ± 3.4) with a significant trend analysis (P for trend = 0.006). Migraine frequency had an independent effect on the items "Cannot get to sleep within 30 minutes" (P < 0.001), "Wake up in the middle of the night or early morning" (P < 0.001), "Bad dreams" (P = 0.001), "Pain" (P = 0.004), and "Quality of sleep" (P < 0.001). The result showed the effect of migraine frequency in both the aura-present (P for trend = 0.008) and the aura-absent subgroups (P for trend = 0.011).High migraine frequency correlates with poor sleep quality and a higher prevalence of poor sleepers. These associations occur in migraine with aura and without aura.

Migraine with aura: which patients are most at risk of stroke?

The complex association between migraine (M) and ischemic stroke (IS) is discussed. Epidemiological studies and meta-analyses show that M with aura (MA) and not M without aura, doubles the risk of IS. The risk is higher for female gender, young age and higher headache attacks frequency. Smoking habit and oral contraceptives, especially if associated, increase stroke risk. The underlying pathogenetic mechanisms are not completely understood, but it is hypothesized that a particular brain susceptibility to cortical spread depression could explain the association between MA and IS. The absolute risk of IS in migraineurs is relatively low and an antithrombotic primary prevention is not indicated, but it is mandatory to investigate and treat associated risk factors for IS and, in young MA women, consider only progestinic oral contraceptives, if needed, and smoking cessation.

Hemiplegia and headache: a review of hemiplegia in headache disorders

The most common scenario wherein the practicing neurologist is likely to encounter a patient with headache and hemiplegia will vary depending on his/her specific type of practice. A neurologist providing consultative service to an emergency department is far more likely to see patients with "secondary" headache and hemiplegia in the setting of either ischemic or hemorrhagic stroke than hemiplegia as a transient feature of a primary headache disorder. Neurologists subspecializing in headache medicine who practice in a tertiary referral headache clinic are more likely to encounter hemiplegic migraine, but even in that clinical setting hemiplegic migraine is by no means a frequent diagnosis. The acute onset of hemiplegia can be very frightening not only to the patient but also to the medical personnel. Given the abundance of mimicry, practitioners must judiciously ascertain the correct diagnosis as treatment may greatly vary depending on the cause of both headache and hemiplegia. In this review, we will address the most common causes of hemiplegia associated with headache.

Association of Migraine and Sleep-Related Breathing Disorder: A Population-Based Cohort Study

In this nationwide population-based cohort study, we aimed to evaluate the effects of sleep-related breathing disorders (SBD) on migraine development.Patients ages 20 years or more and diagnosed with SBD between 2000 and 2009 were evaluated as the SBD cohort (n = 3411), and compared with comparison cohort (n = 13,644). The adjusted hazard ratio (aHR) for developing migraine was calculated in both cohorts by multivariate Cox proportional hazards model.The cumulative incidence of migraine was significantly higher in the SBD cohort than in the comparison cohort. In the SBD cohort, the overall aHR for developing migraine was 2.43 (95% confidence interval [CI] = 1.72-3.44). The risk of developing migraine was higher in men (aHR 2.71) than in women (aHR 2.29) with SBD. When stratifying by age, we observed increased incidence of migraine in patients ages 20 to 44 years and 45 to 64 years, with a higher aHR of 2.51 (95% CI = 1.47-4.30) and 2.68 (95% CI = 1.63-4.43), respectively. The risk of developing migraine in the patients with SBD with or without comorbidity exhibited nonsignificant differences. After stratifying by the use of hypnotics, the aHR for developing migraine was 2.39 in the patients with hypnotics use and 3.58 in the patients without hypnotics use.Our findings indicate increased risk of developing migraine in adults, but not elderly ones, with SBD.

High risk of developing subsequent epilepsy in young adults with migraine: a nationwide population-based cohort study in Taiwan

BACKGROUND AND PURPOSE

This study evaluated the effect of migraine on the subsequent development of epilepsy.

METHODS

A total of 10,016 patients diagnosed with migraine [ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification) 346] during the period between 2000 and 2009 who were aged older than 20 years were identified as the migraine cohort. A comparison cohort including 40 064 people were enrolled in this study. We calculated the adjusted hazard ratio (aHR) for developing epilepsy (ICD-9-CM 345) in the two cohorts after adjusting for age, sex and comorbidities. Kaplan-Meier analysis was used to measure the cumulative epilepsy incidence, and the log-rank test was used to estimate the differences between two curves.

RESULTS

The cumulative incidence of epilepsy was significantly high in the migraine cohort. The aHR for developing epilepsy in the migraine cohort was 1.85 (95% CI = 1.22-2.81). The aHR for developing epilepsy in the female migraineurs was significantly different compared with that of the non-migraine cohort (aHR = 2.04, 95% CI = 1.20-3.48) and male migraineurs (aHR = 1.53, 95% CI = 0.78-3.00). The incidence of developing epilepsy was increased in patients aged 20-44 years, yielding an aHR of 2.14 (95% CI = 1.24-3.68). The comorbidity-specific aHR for developing epilepsy associated with migraine was 2.33 (95% CI = 1.25-4.34) in patients without any comorbidities, and 1.73 (95% CI = 1.02-2.93) in those with comorbidities.

CONCLUSION

This population-based retrospective cohort study revealed a significant increase in subsequent epilepsy risk in young adults with migraine.

Higher risk of developing a subsequent migraine in adults with nonapnea sleep disorders: A nationwide population-based cohort study

OBJECTIVE

This nationwide population-based cohort study evaluated the effect of nonapnea sleep disorders (NSDs) on the subsequent development of a migraine.

METHODS

We identified 46,777 patients aged 20 years and older who were diagnosed with an NSD (ICD-9-CM: 307.4 or 780.5) and without coding for apnea-sleep disorders (ICD-9-CM: 780.51, 780.53, or 780.57) between 2000 and 2002 as the sleep disorder (SD) cohort. A comparison cohort of 93,552 people was enrolled. We calculated the adjusted hazard ratio (aHR) for developing a migraine (ICD-9-CM: 346) after adjusting for age, sex, comorbidity, and drug use. A Kaplan-Meier analysis was used to measure the cumulative incidence of a migraine between 2 curves until the end of 2011.

RESULTS

The cumulative incidence of a migraine was significantly higher in the SD cohort. The aHR for developing a migraine in the SD cohort was 3.52 (95% CI=3.28-3.79). The risk of developing a migraine with an NSD was higher in men (aHR=4.31) than in women (aHR=3.35). The age-stratified effect of an NSD on developing a migraine was highest among patients aged 55 years and younger. Higher risks of developing a migraine were observed among the participants without any comorbidity and without any drug treatment for their insomnia.

CONCLUSION

The findings of this population-based cohort study indicate a higher risk of developing a subsequent migraine in patients with an NSD, which could be considered an independent, predisposing factor for developing subsequent a migraine in adulthood.

Migraine and risk of ischaemic heart disease: a systematic review and meta-analysis of observational studies

BACKGROUND AND PURPOSE

Several studies have assessed the risk of ischaemic heart diseases in migraineurs, drawing different conclusions. To define and update the issue, a systematic review and meta-analysis of the available observational studies was performed.

METHODS

PubMed and EMBASE were systematically searched up to April 2014 for observational studies dealing with the risk of any form of ischaemic heart disease in migraineurs. Studies assessing migraine as exposure and several types of ischaemic heart disease as outcomes were included in the analysis. A random effects model was used to pool the effect sizes.

RESULTS

Out of 3348 records, 15 studies (one case-control, one cross-sectional and 13 cohort studies) were identified and were included in the meta-analysis. The pooled analysis indicated an increased risk of myocardial infarction (pooled adjusted effect estimate 1.33, 95% confidence interval 1.08-1.64; P = 0.007) and of angina (pooled adjusted effect estimate 1.29, 95% confidence interval 1.17-1.43; P < 0.0001) in migraineurs compared to non-migraineurs.

CONCLUSIONS

Based on our data indicating an association of migraine with myocardial infarction and angina and on previous data showing an association of migraine, and particularly migraine with aura, with an increased risk for stroke, migraine can be appropriately considered an overall risk factor for cardiovascular diseases.

The impact of migraine on posterior ocular structures

Purpose. To investigate the thickness of the retinal nerve fiber layer (RNFL) and choroid in patients who have migraines in comparison to healthy controls. Methods. This study included 76 eyes and patients in the migraine group, 36 with aura (MWA group) and 40 without (MWoA group), and 38 eyes as control subjects. The RNFL and macular thicknesses were analysed with standard OCT protocol while choroidal thickness was analysed with EDI protocol in all subjects. Choroidal thickness was measured at the fovea, 1500 µm nasal and 1500 µm temporal to the fovea in a horizontal section. Results. The mean RNFL thickness for nasal and nasal inferior sectors was significantly thinner (P ≤ 0.018) in the migraineurs' eyes than in those of the controls, as was the mean choroid thickness at the fovea and measured points (P < 0.0001). However, the mean macular thickness was not significantly different between the groups. Conclusions. This study suggests that migraine leads to a reduction in the peripapillary RNFL thickness and to thinning in choroidal structures. These findings can be explained by a chronic ischemic insult related to migraine pathogenic mechanisms and these findings are considered supportive of the relationship between glaucoma and migraine.

Study of neurovascular coupling during cold pressor test in patients with migraine

BACKGROUND

Altered neurovascular coupling in migraineurs could be a consequence of impaired function of modulatory brainstem nuclei. The cold pressor test (CPT) should activate brainstem structures. We measured visually evoked cerebral blood flow velocity response (VEFR) to CPT in migraine.

METHODS

Twenty-three healthy volunteers and 29 migraineurs participated in the study. We measured arterial blood pressure, end-tidal CO2, heart rate and cerebral blood flow velocity in posterior and middle cerebral artery using transcranial Doppler. VEFR was calculated as cerebrovascular reactivity to photic stimulation before, during and after CPT.

RESULTS

In healthy individuals, there was a significant decrease in peak systolic VEFR from CPT phase to recovery phase (p < 0.05). There was an increase in mean VEFR from basal to CPT phase and a decrease from CPT to recovery phase, both significant (p < 0.05). End-diastolic VEFR increased from basal to CPT phase and decreased in recovery phase below the basal phase values, all changes significant (p < 0.05). In migraine, no statistically significant changes in peak systolic, mean or end-diastolic VEFRs were observed between phases (p > 0.05). The differences in phases in mean and end-diastolic VEFRs between the basal phase and the CPT phase and between the CPT phase and the recovery phase were significantly higher in healthy individuals (p < 0.05).

CONCLUSIONS

The absence of the effect of CPT on VEFR in migraine is likely to be a consequence of impaired subcortical modulation of neurovascular coupling.