Compromised dynamic cerebral autoregulation in patients with a right-to-left shunt: a potential mechanism of migraine and cryptogenic stroke

Changes in cerebral autoregulation, stroke-related blood biomarkers, and autonomic regulation after patent foramen ovale closure in severe migraine patients

AIMS

This study aimed to investigate changes in dynamic cerebral autoregulation (dCA), 20 stroke-related blood biomarkers, and autonomic regulation after patent foramen ovale (PFO) closure in severe migraine patients.

METHODS

Patent foramen ovale severe migraine patients, matched non-PFO severe migraine patients, and healthy controls were included. dCA and autonomic regulation were evaluated in each participant at baseline, and within 48-h and 30 days after closure in PFO migraineurs. A panel of stroke-related blood biomarkers was detected pre-surgically in arterial-and venous blood, and post-surgically in the arterial blood in PFO migraineurs.

RESULTS

Forty-five PFO severe migraine patients, 50 non-PFO severe migraine patients, and 50 controls were enrolled. The baseline dCA function of PFO migraineurs was significantly lower than that of non-PFO migraineurs and controls but was rapidly improved with PFO closure, remaining stable at 1-month follow-up. Arterial blood platelet-derived growth factor-BB (PDGF-BB) levels were higher in PFO migraineurs than in controls, which was immediately and significantly reduced after closure. No differences in autonomic regulation were observed among the three groups.

CONCLUSION

Patent foramen ovale closure can improve dCA and alter elevated arterial PDGF-BB levels in migraine patients with PFO, both of which may be related to the preventive effect of PFO closure on stroke occurrence/recurrence.

Neglected intrapulmonary arteriovenous anastomoses: A comparative study of pulmonary right-to-left shunts in patients with patent foramen ovale

Objective

Pulmonary right-to-left shunt (P-RLS) and patent foramen ovale right-to-left shunt (PFO-RLS) often appear in combination, and there are often differences and connections between them. Intrapulmonary arteriovenous anastomoses (IPAVAs), as part of P-RLS, are often overlooked because there are no technologies to detect and identify them. This study aimed to further clarify the incidence and characteristics of P-RLS with the help of contrast transesophageal echocardiography (c-TEE) and contrast transthoracic echocardiography (c-TTE), providing a reference for clinically relevant research and patent foramen ovale (PFO) management disposal decisions.

Methods

We retrospectively investigated 414 subjects who came to our hospital for c-TEE from October 2021 to July 2022, and all subjects completed c-TTE simultaneously. 7 Patients who were newly diagnosed with an atrial septal defect were excluded. Eventually, 407 patients were included in this study. Among them, 157 patients with PFO (58 patients were treated with PFO closure subsequently) and 250 patients without PFO confirmed by c-TEE were finally enrolled. In the process, we observed and analysed the presence of P-RLS.

Results

A total of 407 patients were included in the final analysis and divided into PFO group (N = 157) and non-PFO group (N = 250) according to the results of c-TEE. Whether at rest or after Valsalva maneuver, the incidence of P-RLS was significantly higher under c-TEE than under c-TTE in the two groups (P < 0.001). For both c-TTE and c-TEE, the incidence of P-RLS was slightly higher after Valsalva maneuver than at rest, but the difference was not significant (c-TTE: rest vs. Valsalva maneuver, P = 0.214; c-TEE: rest vs. Valsalva maneuver, P = 0.076). The Valsalva maneuver increased the incidence of P-RLS in the group without PFO, which was more significant in c-TEE (c-TTE: rest vs. Valsalva maneuver, P = 0.591; c-TEE: rest vs. Valsalva maneuver, P = 0.008). In both groups, the P-RLS semiquantitative grading was statistical significance under different states and examinations (P < 0.001).

Conclusion

The vast majority of P-RLS are grade 1–2 and are derived from physiological IPAVAs. Even so, attention should be given to the differentiation between P-RLS and PFO-RLS. c-TEE is an effective method to detect P-RLS; however, the recruitments of c-TEE and Valsalva maneuver to P-RLS should be noted.

Transfer function analysis of dynamic cerebral autoregulation: A CARNet white paper 2022 update

Cerebral autoregulation (CA) refers to the control of cerebral tissue blood flow (CBF) in response to changes in perfusion pressure. Due to the challenges of measuring intracranial pressure, CA is often described as the relationship between mean arterial pressure (MAP) and CBF. Dynamic CA (dCA) can be assessed using multiple techniques, with transfer function analysis (TFA) being the most common. A 2016 white paper by members of an international Cerebrovascular Research Network (CARNet) that is focused on CA strove to improve TFA standardization by way of introducing data acquisition, analysis, and reporting guidelines. Since then, additional evidence has allowed for the improvement and refinement of the original recommendations, as well as for the inclusion of new guidelines to reflect recent advances in the field. This second edition of the white paper contains more robust, evidence-based recommendations, which have been expanded to address current streams of inquiry, including optimizing MAP variability, acquiring CBF estimates from alternative methods, estimating alternative dCA metrics, and incorporating dCA quantification into clinical trials. Implementation of these new and revised recommendations is important to improve the reliability and reproducibility of dCA studies, and to facilitate inter-institutional collaboration and the comparison of results between studies.

The Patent Foramen Ovale and Migraine: Associated Mechanisms and Perspectives from MRI Evidence

Migraine is a common neurological disease with a still-unclear etiology and pathogenesis. Patent foramen ovale (PFO) is a kind of congenital heart disease that leads to a right-to-left shunt (RLS). Although previous studies have shown that PFO has an effect on migraine, a clear conclusion about the link between PFO and migraine is lacking. We first summarized the PFO potential mechanisms associated with migraine, including microembolus-triggered cortical spreading depression (CSD), the vasoactive substance hypothesis, impaired cerebral autoregulation (CA), and a common genetic basis. Further, we analyzed the changes in brain structure and function in migraine patients and migraine patients with PFO. We found that in migraine patients with PFO, the presence of PFO may affect the structure of the cerebral cortex and the integrity of white matter, which is mainly locked in subcortical, deep white matter, and posterior circulation, and may lead to changes in brain function, such as cerebellum and colliculus, which are involved in the processing and transmission of pain. In summary, this paper provides neuroimaging evidence and new insights into the correlation between PFO and migraine, which will help to clarify the etiology and pathogenesis of migraine, and aid in the diagnosis and treatment of migraine in the future.

Compromised cerebrovascular reactivity in migraineurs with right-to-left shunts: a potential mechanism of white matter hyperintensities

OBJECTIVE

Our study aims to explore the changes of cerebrovascular reactivity (CVR) in migraineurs with right-to-left shunts (RLS), and further evaluate the association between CVR and the occurrence of the white matter hyperintensities (WMHs).

METHODS

RLS was diagnosed based on a contrast enhancement transcranial Doppler (c-TCD) examination. The breath holding index (BHI), which represents CVR, was measured from the middle cerebral artery (MCA) using a TCD with the breath-holding method. WMHs was defined as clearly hyperintense areas in 3 T magnetic resonance imaging (MRI). All migraineurs underwent a standardized questionnaire for family and personal history and detailed migraine features.

RESULTS

Three hundred and ninety-seven migraineurs and 100 controls were included in our study. The BHI was significantly lower in migraineurs than controls (0.527 ± 0.709 vs. 0.674 ± 0.489, P = 0.016). Moreover, migraineurs with RLS had lower BHI than those without RLS (0.504 ± 0.671 vs. 0.674 ± 0.721, p = 0.024). Migraineurs with WMHs had lower BHI than those without (0.47 ± 0.71 vs. 0.75 ± 0.49, p = 0.035). The reduced BHI was an independent influencing factor for WMHs in our study (OR = 0.338; 95% CI = 0.142-0.806, p = 0.014).

CONCLUSION

Our results indicated that BHI was reduced in migraineurs, and the reduced BHI was associated with RLS. Moreover, the reduced CVR in migraineurs with RLS might be related to the occurrence of WMHs.

Different patterns of white matter lesions among patent foramen ovale, atherosclerotic cerebral small vessel disease and cerebral venous thrombosis

None of studies are available on the predictive ability of white matter lesions (WMLs) among patent foramen ovale (PFO), atherosclerotic cerebral small vessel disease (aCSVD) and cerebral venous thrombosis (CVT). Herein, we aimed to uncover the difference of the WML patterns among the three disease entities in a real-world setting to provide clinical references for predicting probable WML etiologies. We retrospectively reviewed data from consecutive patients with imaging-confirmed PFO, aCSVD, or CVT enrolled from 2014 through 2020. WMLs presented on fluid-attenuated inversion recovery (FLAIR) maps were compared among the three groups based on visual evaluation, Fazekas and modified Scheltens scales. Propensity score matching (PSM) was implemented to correct age and hypertension differences among groups. A total of 401 patients were entered into final analysis, including PFO (n = 112, 46.5 ± 12.8 years), aCSVD (n = 177, 61.6 ± 11.8 years) and CVT (n = 112, 37.4 ± 11.4 years) groups. In this study, WMLs occurred in all of the involved patients in the three groups (100%), which were independent to age, symptom onset and disease durations. On visual evaluation, PFO-WMLs were multiple spots distributed asymmetrically around bilateral subcortex and peri-ventricles. aCSVD-WMLs were dots or sheets distributed symmetrically in subcortex and peri-ventricles, and often coexisted with lacunar infarctions. CVT-WMLs were cloud-like around bilateral peri-ventricles, and enabled to attenuate after recanalization. Fazekas and modified Scheltens scores of PFO-WML vs. aCSVD-WML were significantly different even after being matched by 1:2 PSM (all p < 0.05), meaning that the WML burden in aCSVD was considerably heavier than that in PFO. WML patterns induced by PFO, aCSVD and CVT were obviously different, and were therefore of great clinical significance to preliminarily predict and differentiate the three diseases entities.

Pathogeneses and Imaging Features of Cerebral White Matter Lesions of Vascular Origins

White matter lesion (WML), also known as white matter hyperintensities or leukoaraiosis, was first termed in 1986 to describe the hyperintense signals on T2-weighted imaging (T2WI) and fluid-attenuated inversion recovery (FLAIR) maps. Over the past decades, a growing body of pathophysiological findings regarding WMLs have been discovered and discussed. Currently, the generally accepted WML pathogeneses mainly include hypoxia-ischemia, endothelial dysfunction, blood-brain barrier disruption, and infiltration of inflammatory mediators or cytokines. However, none of them can explain the whole dynamics of WML formation. Herein, we primarily focus on the pathogeneses and neuroimaging features of vascular WMLs. To achieve this goal, we searched papers with any type published in PubMed from 1950 to 2020 and cross-referenced the keywords including “leukoencephalopathy”, “leukoaraiosis”, “white matter hyperintensity”, “white matter lesion”, “pathogenesis”, “pathology”, “pathophysiology”, and “neuroimaging”. Moreover, references of the selected articles were browsed and searched for additional pertinent articles. We believe this work will supply the robust references for clinicians to further understand the different WML patterns of varying vascular etiologies and thus make customized treatment.

Prevalence and grade of RLS in migraine: A prospective study of 251 migraineurs by synchronous test of c-TTE and c-TCD

BACKGROUND

Right-to left shunt (RLS) is regarded as a risk factor resulting in migraine, but the relevance between the RLS and migraine remains controversial. This paper aims at investigating the prevalence and RLS grade of patent foramen ovale (PFO) in cases of migraine (including migraine with and without aura) and evaluate the relationship between PFO and migraine.

METHODS

Synchronous test of contrast transthoracic echocardiography and contrast transcranial Doppler ultrasonography was performed in 251 cases of migraine, which contains 62 cases of migraine with aura (MA) and 189 cases without aura (MO) and 275 healthy adults. Among these cases, 25 cases with migraine and 14 healthy adults were evaluated through transesophageal echocardiography.

RESULTS

(1). The prevalence of permanent RLS, total RLS, and large RLS in migraine was 11.16%, 39.04%, and 17.13%, respectively, which was significantly higher than that of the controls (P = .042, <.001, and.001, respectively). (2). Permanent RLS was detected as 7.93% of the cases in MO, 20.96% in MA, and 6.18% in controls. Total RLS was detected as 35.98% of the cases in MO, 48.38% in MA, and 23.64% in controls. Large RLS was detected as 13.76% of the cases in MO, 27.41% in MA, and 7.27% in controls. Compared with controls, the positive rate of total RLS and large RLS in MO increased (P = .004 and.022, respectively), the that of permanent RLS, total RLS, and large RLS in MA also increased (P < .001 for each of the comparisons). The positive rate of permanent RLS and large RLS in MA was remarkably higher than that in MO (P = .005 and.013, respectively). (3) The presence of large-size PFO (≥2.0 mm) of migraine showed higher than that of the controls (P = .048).

CONCLUSIONS

PFO is associated with the migraine (especially with aura), when it is permanent RLS, large RLS, and large-size PFO (≥2.0 mm).

Cerebral vasomotor reactivity in migraine: effect of patent foramen ovale and aerogenic microembolism

OBJECTIVE

The first data on the effect of presence of patent foramen ovale (PFO) with high-volume right-to-left shunt (RLS) on cerebral vasomotor reactivity (CVMR) in migraineurs are herein presented. In addition, the immediate effect of air microbubbles on CVMR has been determined.

METHODS

Breath-holding index (BHI) and percent velocity decrease during hyperventilation (HPV) tests were performed before and after agitated saline injections in bilateral middle and posterior cerebral arteries (MCA and PCA) in 38 migraineurs (19 with aura) and 18 control subjects.

RESULTS

Presence of PFO correlated with a significant decrease of MCA BHI (1.43 ± 0.39 vs 1.04 ± 0.67, p = 0.032) and marginal reduction of PCA BHI (1.25 ± 0.46 vs. 1.01 ± 0.39, p = 0.090) in migraineurs. After agitated saline injection, PCA BHI significantly decreased from 1.03 to 0.78 (p = 0.007) in patients with PFO, from 1.15 to 0.91 (p = 0.014) in those without PFO, and from 1.01 to 0.76 (p = 0.023) in subjects with migraine and PFO. No significant MCA BHI difference was noted soon after bubble injection.

CONCLUSIONS

The presence of high grade RLS is associated with reduced vasodilatory CVMR in migraineurs. Further decrease of CVMR of PCA upon aerogenic microemboli passage may support the mechanism of 'facilitation with subclinical cerebral ischemia caused by microembolism', hypothesis explaining the onset of migraine.

ABBREVIATIONS

BHI: Breath-holding index; BHT: Breath Holding Test; CVMR: Cerebral vasomotor reactivity; EDV: End-diastolic velocity; HIT-6: Headache Impact Test; HPV: Hyperventilation; MCA: Middle cerebral artery; MIDAS: migraine disability Assessment score; PCA: Posterior cerebral artery; PFO: Patent foramen ovale; PI: Pulsatility index; PSV: Peak systolic velocity; RLS: Right-to-left shunt; TCD: Transcranial Doppler; Vmean: Mean velocity.

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.

Migraine Genetic Variants Influence Cerebral Blood Flow

Objective

To investigate the association of migraine genetic variants with cerebral blood flow (CBF).

Background

Migraine is a common disorder with many genetic and non‐genetic factors affecting its occurrence. The exact pathophysiological mechanisms underlying the disease remain unclear, but are known to involve hemodynamic and vascular disruptions. Recent genome‐wide association studies have identified 44 genetic variants in 38 genetic loci that affect the risk of migraine, which provide the opportunity to further disentangle these mechanisms.

Methods

We included 4665 participants of the population‐based Rotterdam Study (mean age 65.0 ± 10.9 years, 55.6% women). Cross‐sectional area (mm²), flow velocity (mm/s), and blood flow (mL/min) were measured in both carotids and the basilar artery using 2‐dimensional phase‐contrast magnetic resonance imaging. We analyzed 43 previously identified migraine variants separately and calculated a genetic risk score (GRS). To assess the association with CBF, we used linear regression models adjusted for age, sex, and total brain volume. Hierarchical clustering was performed based on the associations with CBF measures and tissue enrichment.

Results

The rs67338227 risk allele was associated with higher flow velocity and smaller cross‐sectional area in the carotids (P_minimum = 3.7 × 10⁻⁸). Other variants were related to CBF with opposite directions of effect, but not significantly after multiple testing adjustments (P < 1.4 × 10⁻⁴). The migraine GRS was not associated with CBF after multiple testing corrections. Migraine risk variants were found to be enriched for flow in the basilar artery (λ = 2.39).

Conclusions

These findings show that genetic migraine risk is complexly associated with alterations in cerebral hemodynamics.

Right-to-left shunts and hormonal therapy influence cerebral vasomotor reactivity in patients with migraine with aura

Patent Foramen Ovale and impaired cerebral hemodynamics were proposed among the pathophysiological mechanisms explaining the increased risk for stroke in patients with Migraine with Aura (MA). Our study aimed at comparing the vasomotor reactivity (VMR) of the anterior and the posterior cerebral circulation in patients with Migraine with Aura, in patients with acute vascular ischemic accidents, and in controls. We hypothesized that VMR in MA patients is preserved in the anterior circulation and reduced in the posterior circulation. We prospectively assessed with Transcranial Doppler the vasomotor reactivity to breath holding of the Middle and Posterior Cerebral Arteries (MCA, PCA) in MA patients, in acute vascular patients and healthy controls. We also evaluated the possible effect of clinical characteristics of MA (attack frequency, aura length or type, disease history), vascular factors and the presence of right-to-left shunt on VMR. Diverging from our hypothesis, MA patients displayed a higher breath-holding index (BHI) than controls in the MCA (1.84±0.47%/s vs 1.53±0.47%/s, p = .001) as well as in the PCA (1.87±0.65%/s vs 1.47±0.44%/s, p < .001). In MA patients, MCA BHI was higher in those with large right-to-left shunts (2.09±0.42 vs 1.79±0.47, p = .046) and lower in those taking estrogens (1.30±0.30%/s vs 1.9±0.45%/s, p = .009). We did not observe an effect of MA characteristics on BHI. The increased BHI in MA patients with large right-to-left shunts could be explained by the vasoactive effect in the cerebral circulation of substances bypassing the deactivating pulmonary filters or by a constitutional trait of the vascular system associating persistent right-to-left shunts and hyper-reactive hemodynamics. Our results discourage the hypothesis that altered hemodynamics contribute to increasing the stroke risk in all MA patients. However, estrogens can lower VMR, curtailing the hemodynamic resources of MA patients.

The Impact of Variational Primary Collaterals on Cerebral Autoregulation

The influence of the anterior and posterior communicating artery (ACoA and PCoA) on dynamic cerebral autoregulation (dCA) is largely unknown. In this study, we aimed to test whether substantial differences in collateral anatomy were associated with differences in dCA in two common types of stenosis according to digital subtraction angiography (DSA): either isolated basal artery and/or bilateral vertebral arteries severe stenosis/occlusion (group 1; group 1A: with bilateral PCoAs; and group 1B: without bilateral PCoAs), or isolated unilateral internal carotid artery severe stenosis/occlusion (group 2; group 2A: without ACoA and with PCoA; group 2B: with ACoA and without PCoAs; and group 2C: without both ACoA and PCoA). The dCA was calculated by transfer function analysis (a mathematical model), and was evaluated in middle cerebral artery (MCA) and/or posterior cerebral artery (PCA). Of a total of 231 non-acute phase ischemic stroke patients who received both dCA assessment and DSA in our lab between 2014 and 2017, 51 patients met inclusion criteria based on the presence or absence of ACoA or PCoA, including 21 patients in the group 1, and 30 patients in the group 2. There were no significant differences in gender, age, and mean blood pressure between group 1A and group 1B, and among group 2A, group 2B, and group 2C. In group 1, the PCA phase difference values (autoregulatory parameter) were significantly higher in the subgroup with patent PCoAs, compared to those without. In group 2, the MCA phase difference values were higher in the subgroup with patent ACoA, compared to those without. This pilot study found that the cross-flow of the ACoA/PCoA to the affected area compensates for compromised dCA in the affected area, which suggests an important role of the ACoA/PCoA in stabilizing cerebral blood flow.

Compromised dynamic cerebral autoregulation in patients with generalized anxiety disorder: a study using transfer function analysis

BACKGROUND

Patients with generalized anxiety disorder (GAD) usually present with various neurological symptoms, but the mechanisms remain unclear. We aimed to analyze the characteristics of dynamic cerebral autoregulation (dCA) in patients with GAD.

METHODS

Patients (aged ≥18 years) who were diagnosed with GAD were enrolled in this study. Medically and psychiatrically healthy volunteers were recruited as controls. Subjects received the Hamilton Rating Scale for Anxiety (HAMA) and 17-item Hamilton Depression Rating Scale (HAMD) evaluation. Noninvasive continuous arterial blood pressure and bilateral middle cerebral artery blood flow velocity were recorded simultaneously from each subject. Transfer function analysis was used to derive the autoregulatory parameters, including phase difference, gain, and coherence function.

RESULTS

A total of 57 patients with GAD and 40 healthy volunteers were enrolled. We found that the phase difference values were significantly compromised in patients with GAD. In the Spearman correlation analysis, the phase difference values were negatively correlated with the HAMA scores and the HAMD scores. In the multiple linear regression analysis, GAD is negatively correlated with the phase difference values, whereas age is positively correlated with the phase difference values.

CONCLUSIONS

Our results suggested that the dCA was compromised in patients with GAD and negatively correlated with the score of anxiety. Improving the dCA may be a potential therapeutic method for treating the neurological symptoms of GAD patients.

Right-to-left shunt and subclinical ischemic brain lesions in Chinese migraineurs: a multicentre MRI study

Background

Migraine is considered as a risk factor for subclinical brain ischemic lesions, and right-to-left shunt (RLS) is more common among migraineurs. This cross-sectional study assessed the association of RLS with the increased prevalence of subclinical ischemic brain lesions in migraineurs.

Methods

We enrolled 334 migraineurs from a multicentre study from June 2015 to August 2016. Participants were all evaluated using contrast-enhanced transcranial Doppler, magnetic resonance imaging (MRI), and completed a questionnaire covering demographics, the main risk factors of vascular disease, and migraine status. RLS was classified into four grades (Grade 0 = Negative; Grade I = 1 ≤ microbubbles (MBs) ≤ 10; Grade II = MBs > 10 and no curtain; Grade III = curtain). Silent brain ischemic infarctions (SBI) and white matter hyperintensities (WMHs) were evaluated on MRI.

Results

We found no significant differences between migraineurs with RLS and migraineurs without RLS in subclinical ischemic brain lesions.SBI and WMHs did not increase with the size of the RLS(p for trend for SBI = 0.066, p for trend for WMHs = 0.543). Furthermore, curtain RLS in migraineurs was a risk factor for the presence of SBI (p = 0.032, OR = 3.47; 95%CI: 1.12−10.76). There was no association between RLS and the presence of WMHs.

Conclusion

Overall, RLS is not associated with increased SBI or WMHs in migraineurs. However, when RLS is present as a curtain pattern, it is likely to be a risk factor for SBIs in migraineurs.

Trial registration

No. NCT02425696; registered on April 21, 2015.

Electronic supplementary material

The online version of this article (10.1186/s12883-018-1022-7) contains supplementary material, which is available to authorized users.

Prevalence and extent of right-to-left shunt on contrast-enhanced transcranial Doppler in Chinese patients with migraine in a multicentre case-control study

Background

The association between RLS and migraine is still debated. The aim of this study is to investigate the prevalence and grade of RLS in Chinese patients with migraine and to evaluate the relationship between RLS and migraine.

Methods

A multi-center case-control study of contrast-enhanced transcranial Doppler was conducted in 931 consecutive patients with migraine (240 of 931 had migraine with aura and 691 of 931 were in the migraine without aura group) and 282 were healthy adults. Clinical trial no. NCT02425696.

Results

The prevalence of RLS was 63.8% and 39.9% in the migraine with aura group (MA+) and migraine without aura group (MA−), respectively, significantly higher than that of the healthy group (29.4%, p < 0.001; p < 0.001). The positive rate of large RLS in the MA+ group and MA− group was 32.1% and 16.5%, respectively, significantly higher than healthy group (6.4%, p < 0.001; p < 0.001). There was no difference among groups in terms of positive rate of permanent RLS ( p = 0.704).

Conclusion

This multi-centre case-control study suggested that there is an association between RLS and migraine with and without aura, especially when the shunt is large.

Effectiveness and Safety of Transcatheter Patent Foramen Ovale Closure for Migraine (EASTFORM) Trial

We evaluated the safety and effectiveness of transcatheter patent foramen ovale (PFO) closure for the treatment of migraine in a Chinese population. This non-randomized clinical trial enrolled 258 consecutive substantial or severe migraineurs with a right-to-left shunt (RLS) (grade II–IV) and grouped subjects according to their election or refusal of PFO closure. Migraine was diagnosed according to the International Classification of Headache Disorders III-beta and evaluated using the Headache Impact Test-6 (HIT-6). In total, 241 participants (125 in the transcatheter closure group and 116 in the control group) were included in the study. In general, the PFO closure procedure was found to be safe. At 1 month after closure, 76.1% of patients returned for c-TCD evaluation; of these, 85.7% were downgraded to negative status or a grade-I shunt. Residual shunts and placebo effects were thought to resolve by 12 months post-procedure, when migraine impact was reported to decrease by 73.6%. Transcatheter PFO closure was demonstrated to be effective for the treatment of migraine by comparing HIT-6 scores between the transcatheter closure and control groups (p < 0.001). Our results suggest that transcatheter PFO closure is a safe and effective approach for the treatment of migraine in the Chinese population, especially in females with constant RLS. Clinical trial no. NCT02127294 (registered on April 29, 2014).

Migraine with aura and patent foramen ovale: myth or reality?

Several observational studies report that subjects with migraine with aura have a higher prevalence of right-to left shunt, commonly due to patent foramen ovale, and that patent foramen ovale is more prevalent in subjects with migraine with aura. Although migraine without aura has been less extensively studied, it does not seem to be associated with an increased prevalence of right-to left shunt. The mechanism that underlies the possible relationship between patent foramen ovale and migraine with aura remains speculative. The proposed mechanisms are migraine-triggering vasoactive chemicals bypassing the pulmonary filter and reaching the cerebral circulation and paradoxical microembolization. However, it is unclear, at this time, if there is a causal or comorbid association between the two conditions. In some families atrial shunts show a dominant inheritance that seems to be linked to inheritance of migraine with aura. Migraine with aura is an independent risk factor for ischemic stroke, and patent foramen ovale is present more frequently in patients with cryptogenic stroke than in controls. At this moment, there is no convincing evidence that excess stroke risk of migraine is simply mediated by patent foramen ovale through paradoxical embolism. Several non-controlled studies suggest that closure of the foramen ovale significantly reduces attack frequency in migraine patient, but the only prospective placebo-controlled trial does not support these results. Patent foramen ovale closure, at present, is not indicated as a treatment for migraine in clinical practice.

Characteristics of dynamic cerebral autoregulation in cerebral small vessel disease: Diffuse and sustained

Cerebral small vessel disease is a major cause of stroke and vascular dementia; however, the pathogenesis is largely unclear. In this study, we investigated the characteristics of the impairment of dynamic cerebral autoregulation (dCA) in lacunar infarction patients. Seventy-one lacunar infarction patients were enrolled in the study, including 46 unilateral middle cerebral artery (MCA) territory stroke patients and 25 unilateral posterior cerebral artery (PCA) territory stroke patients. Each group of patients was randomly divided into two subgroups. Group 1 underwent dCA assessments in the bilateral MCAs, and Group 2 underwent dCA assessments in the bilateral PCAs. All patients were followed up for 6 months. Transfer function analysis was applied to derive the autoregulatory parameters of gain and phase difference. In the unilateral MCA territory stroke patients, impairments of dCA were observed in both the MCAs and PCAs, and the same results were observed in the unilateral PCA territory stroke patients. These impairments remained unchanged during the 6-month follow-up. In lacunar infarction, which is most prevalent type of cerebral small vessel disease, though patients with unilateral MCA territory/PCA territory stroke, the impairments of dCA were global and sustained. This finding suggests that the physiological changes associated with lacunar infarction were diffuse.

Right-to-Left Shunt Does Not Increase the Incidence of Silent Lacunar Infarcts in Patients with Migraine

Right-to-left shunt (RLS) is associated with cryptogenic stroke and migraine. Herein we investigated the relationship between RLS and silent lacunar infarcts in patients with migraine. A total of 263 patients with migraine who met eligibility criteria were enrolled from January 2010 to December 2011, among which 127 subjects fell into RLS group. Baseline demographics were comparable between RLS and non-RLS groups (P > 0.05). The incidence of silent lacunar infarcts in RLS group was not significantly different from that of the non-RLS group (25.2% versus 21.3%, P > 0.05). Furthermore, we found that the incidence of silent lacunar infarcts in permanent and latent RLS subgroups was comparable with non-shunt RLS subgroup (28.6% versus 24% versus 21.3%, P > 0.05). Similarly, the incidence of silent lacunar infarcts in the non-RLS group, mild-shunt group, and large-shunt group was also comparable (21.3% versus 23.8% versus 29.3%, P > 0.05). In addition, RLS did not increase the incidence of silent lacunar infarcts in migraine patients with elder age (<50 years age group: 15.8% versus 17.9%; ≥50 years age group: 53.1% versus 37.5%, both P > 0.05). In conclusion, RLS does not increase the incidence of silent lacunar infarcts in patients with migraine. Further prospective studies are warranted to validate this finding.

Cryptogenic stroke

In about a quarter of ischaemic strokes the cause is undetermined, because the investigation is incomplete or delayed, because there are multiple causes or because the stroke is truly cryptogenic. Cryptogenic stroke can be further classified as non-embolic or embolic. Embolic stroke of undetermined source can be due to paroxysmal atrial fibrillation, minor emboligenic cardiac conditions, atheroembolism, cancer associated and paradoxical embolism through a patent foramen ovale (PFO) or less often a pulmonary fistula. Currently, risk factor control, statins and antiplatelets are the main therapeutic measures to prevent recurrent stroke. There is no evidence to implement routine closure of PFO in patients with cryptogenic stroke. Direct anticoagulants are being evaluated in randomized controlled trials including embolic stroke of undetermined source patients. Advances in high resolution ultrasound or magnetic resonance imaging of extracranial and intracranial vessels and of the heart and prolonged heart rhythm monitoring will be instrumental techniques to identify arterial and cardiac hidden causes of stroke.