Re-evaluation of the relationship between migraine and persistent foramen ovale and other right-to-left shunts

Clinical relevance of atrial septal aneurysm and patent foramen ovale with migraine

AIM

To test the potential association between atrial septal aneurysm (ASA) and migraine in patent foramen ovale (PFO) closure patients through an observational, single-center, case-controlled study.

METHODS

We studied a total of 450 migraineurs who had right-to-left shunts and underwent PFO closure in a retrospective single-center non-randomized registry from February 2012 to October 2016 on the condition that they were aged 18-45 years old. Migraine was diagnosed according to the International Classification of Headache Disorders, 3^rd edition and evaluated using the Headache Impact Test-6 (HIT-6). All patients underwent preoperative transesophageal echocardiography, contrast transthoracic echocardiography, and computed tomography or magnetic resonance imaging examinations, with subsequent fluoroscopy-guided PFO closure. Based on whether they have ASA or not, the patients were divided into two groups: A (PFO with ASA, n = 80) and B (PFO without ASA, n = 370). Baseline characteristics and procedural and follow-up data were reviewed.

RESULTS

Compared to group B, group A had an increased frequency of ischemic lesions (11.3% vs 6.2%, P = 0.038) and migraine with aura (32.5% vs 21.1%, P = 0.040). The PFO size was significantly larger in group A (P = 0.007). There was no significant difference in HIT-6 scores between the two groups before and at the one-year follow-up after the PFO closure [61 (9) vs 63 (9), P = 0.227; 36 (13) vs 36 (10), P = 0.706].

CONCLUSION

Despite its small sample size, our study suggests that the prevalence of ASA in PFO with migraine patients is associated with ischemic stroke, larger PFO size, and migraine with aura.

Migraine with aura and persistent foramen ovale

The association between migraine with aura and persistent foramen ovale (PFO), as well as other right-to-left shunts, is described. A hypothesis that might explain this association is discussed. Observational studies suggested that when a PFO is closed patients who have migraine with aura are usually improved. The Migraine Intervention with STARFlex Technology (MIST) Trial was a randomised double-blind trial in patients with severe intractable migraine with aura and a moderate-large PFO that compared implantation of STARFlex devices with the intention of closing their PFO versus a sham procedure. It was hoped that the trial would demonstrate whether PFO closure would cure migraine. A series of problems in design and execution of the trial are discussed.

Patent Foramen Ovale and Migraine: Closing the Debate--A Review

BACKGROUND

A link between patent foramen ovale (PFO) and migraine as well as the utility of closure of PFO and its effect on migraine have been subjects of debate. The present review is an effort to gather the available evidence on this topic and formulate recommendations.

METHODS

A systematic search of electronic databases (Medline, Embase, Cochrane Library) was performed. A separate search in associated reference lists of identified studies was done. Observational studies and clinical trials published in English using the International Headache Society criteria for diagnosis of migraine were included in the analysis. The search was performed in 3 categories: prevalence of migraine in patients with PFO, prevalence of PFO in migraine patients, and effect of PFO closure and its effect on migraine. The quality of evidence and strength of recommendations during review of these studies was analyzed.

RESULTS

About 14 observational studies with 2602 subjects who had PFO were identified. Migraine prevalence ranged from 16% to 64%. Another 20 studies reported 2444 patients with migraine; the prevalence of PFO ranged from 15% to 90%. About 20 observational studies (1194 patients) that examined the effect of PFO closure on migraine were identified. Resolution of migraine was reported in 10% to 83% of patients, improvement in 14% to 83%, no change in 1% to 54%, and worsening in 4% to 8%. The overall quality of these observational studies was poor. Finally, 3 randomized clinical trials included a total of 238 patients who underwent PFO closure compared with 234 patients in the control groups. All 3 trials failed to meet their primary end points defined as migraine resolution and greater than 50% reduction in migraine days at 1 year. In 2 of the clinical trials, there was some benefit noted in a small subset of migraine patients with aura, but the numbers were too small to extrapolate the findings to the general migraine population.

CONCLUSIONS

There is no good quality evidence to support a link between migraine and PFO. Closure of PFO for migraine prevention does not significantly reduce the intensity and severity of migraine. We do not recommend the routine use of this procedure in current practice.

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.

Patent foramen ovale influences the presentation of decompression illness in SCUBA divers

BACKGROUND

Few have examined the influence of patent foramen ovale (PFO) on the phenotype of decompression illness (DCI) in affected divers.

METHODOLOGY

A retrospective review of our database was performed for 75 SCUBA divers over a 10-year period.

RESULTS

Overall 4,945 bubble studies were performed at our institution during the study period. Divers with DCI were more likely to have positive bubble studies than other indications (p<0.001). Major DCI was observed significantly more commonly in divers with PFO than those without (18/1,000 v.s. 3/1,000, p=0.02). Divers affected by DCI were also more likely to require a longer course of hyperbaric oxygen therapy (HBOT) if PFO was present (p=0.038). If the patient experienced one or more major DCI symptoms, the odds ratio of PFO being present on a transoesophageal echocardiogram was 3.2 (p=0.02) compared to those who reported no major DCI symptoms.

CONCLUSION

PFO is highly prevalent in selected SCUBA divers with DCI, and is associated with a more severe DCI phenotype and longer duration of HBOT. Patients with unexpected DCI with one or more major DCI symptoms should be offered PFO screening if they choose to continue diving, as it may have considerable prognostic and therapeutic implications.

Patent foramen ovale and scuba diving: a practical guide for physicians on when to refer for screening

Divers are taught some basic physiology during their training. There is therefore some underlying knowledge and understandable concern in the diving community about the presence of a patent foramen ovale (PFO) as a cause of decompression illness (DCI). There is an agreement that PFO screening should not be done routinely on all divers; however, when to screen selected divers is not clear. We present the basic physiology and current existing guidelines for doctors, advice on the management and identify which groups of divers should be referred for consideration of PFO screening. Venous bubbles after diving and right to left shunts are common, but DCI is rare. Why this is the case is not clear, but the divers look to doctors for guidance on PFO screening and closure; both of which are not without risks. Ideally, we should advise and apply guidelines that are consistent and based on best available evidence. We hope this guideline and flow chart helps address these issues with regard to PFOs and diving.

Relation between migraine and size of echocardiographic intrapulmonary right-to-left shunt

An increased prevalence of intrapulmonary right-to-left shunt (RLS) has been shown in patients with migraine. The aim of this study was to determine whether the size of intrapulmonary RLS was associated with migraine with aura (MA+) and migraine without aura (MA-) in subjects screened for hereditary hemorrhagic telangiectasia. A total of 462 consecutive subjects were screened for hereditary hemorrhagic telangiectasia and underwent transthoracic contrast echocardiography. A pulmonary shunt was established when contrast appeared in the left atrium after 4 cardiac cycles. Shunt size was assessed semiquantitatively as small (<30 microbubbles), moderate (30 to 100 microbubbles), or large (>100 microbubbles). A headache questionnaire was completed by 420 subjects (91%). Two independent neurologists diagnosed migraine according to the International Headache Society criteria. Of 420 screened subjects (mean age 43.4 ± 15.4 years, 61.4% women), 44 (10.5%) had MA+ and 45 (10.7%) had MA-. MA+ was an independent predictor for an intrapulmonary RLS (odds ratio [OR] 2.96, 95% confidence interval [CI] 1.36 to 6.47, p=0.006) in multivariate analysis. MA- was not correlated with RLS (OR 1.21, 95% CI 0.56 to 2.64, p=0.60). When comparing patients with MA+ to those without migraine in a multivariate analysis, the presence of an intrapulmonary shunt predicted MA+ (OR 2.5, 95% CI 1.2 to 5.2, p=0.01), as did female gender (OR 3.15, 95% CI 1.29 to 7.65, p<0.01). The correlation of MA+ and RLS could be entirely attributed to large intrapulmonary shunts (OR 7.61, 95% CI 3.11 to 18.61, p<0.001), as small (OR 0.6, 95% CI 0.13 to 2.78, p=0.52) and moderate (OR 1.33, 95% CI 0.35 to 5.02, p=0.68) shunts did not appear to be risk factors for MA+. In conclusion, patients with large intrapulmonary RLS have an increased risk for MA+.

Migraine aura pathophysiology: the role of blood vessels and microembolisation

Migraine attacks with auras are sometimes associated with underlying hereditary or acquired cerebrovascular disorders. A unifying pathophysiological explanation linking migraine to these conditions has been difficult to identify. On the basis of genetic and epidemiological evidence, we suggest that changes in blood vessels, hypoperfusion disorders, and microembolisation can cause neurovascular dysfunction and evoke cortical spreading depression, an event that is widely thought to underlie aura symptoms. In fact, recent experimental data have indicated that focal, mild, and transient ischaemia can trigger cortical spreading depression without an enduring tissue signature. Although migraine with aura has many causes (eg, neuronal network excitability), it seems that migraine and stroke might both be triggered by hypoperfusion and could therefore exist on a continuum of vascular complications in a subset of patients who have these hereditary or acquired comorbid vascular conditions.

The migraine association with cardiac anomalies, cardiovascular disease, and stroke

Migraine is positively associated with cardio- and cerebrovascular disorders and with structural heart anomalies. Migraine is more prevalent among people with right-to-left shunt by means of patent foramen ovale, atrial septal defects, and pulmonary arteriovenous malformations and among those with altered cardiac anatomy, such as mitral valve prolapse, atrial septal aneurysm, and congenital heart disease. Meanwhile, migraine increases the risk for cardiovascular disease and stroke. Although several hypotheses exist, explanation for these associations is lacking. This article reviews data supporting the association of migraine with right-to-left shunt, structural heart anomalies, cardiovascular disease, and ischemic stroke.

Patent Foramen Ovale and Migraine: A Quantitative Systematic Review

Initial studies indicate an increased prevalence of patent foramen ovale (PFO) in migraineurs with aura, and an increased prevalence of migraine and migraine with aura in persons with PFO. Retrospective analyses of PFO closure suggest clinically significant improvements in migraine patterns. The aim of this study was to examine the prevalence of migraine in patients with PFO, the prevalence of PFO in migraineurs, and the effect of PFO closure on migraine. We conducted a quantitative systematic review of articles on migraine and PFO that met inclusion criteria, then reviewed, appraised, and subjected them to data extraction. Of 134 articles identified, 18 met a priori selection criteria. The estimated strength of association between PFO and migraine, reflected by summary odds ratios (ORs), was 5.13 [95% confidence interval (CI) 4.67, 5.59], and between PFO and migraine with aura the OR was 3.21 (95% CI 2.38, 4.17). The grade of evidence was low. The association between migraine and PFO was OR 2.54 (95% CI 2.01, 3.08). The grade of evidence was low to moderate. Six studies of PFO closure suggested improvement in migraine, but had a very low grade of evidence. The low-to-moderate grade of evidence from observational studies supports an apparent association between PFO and migraine. Although PFO closure seemed to affect migraine patterns favourably, the very low grade of available evidence to support this association precludes definitive conclusions.

Emerging therapies for migraine

Migraine is a common disabling brain disorder that--considering its clinical and economic impact--is understudied and in need of additional management options. Currently, treatments are classified as preventive or acute-attack therapies, although it is expected that this distinction will become blurred over time. The gap-junction blocker tonabersat, an inducible nitric oxide synthase (NOS) inhibitor and botulinum toxin A are all being investigated in clinical trials as preventive therapies. Device-based approaches using neurostimulation of the occipital nerve have provided promising results, whereas the first study of patent foramen ovale closure for migraine prevention produced disappointing results. Calcitonin gene-related peptide receptor antagonists, vanilloid TRPV1 receptor antagonists and NOS inhibitors are all being investigated in clinical trials for acute migraine. There is much cause for optimism in this area of neurology and considerable benefit awaits our patients.

Foramen ovale perméable et migraine

Recent epidemiological data suggest a bidirectional link between patent foramen ovale (PFO) and migraine with aura (MA) with a relative risk of 2 for PFO in subjects with MA and for MA in subjects with PFO. There is no evidence for a link between PFO and migraine without aura. This link is not systematic and applies only to subsets of PFO, mostly large ones, and to subsets of patients with MA. Although comorbidity cannot be ruled out, it may be that this link is partly causal and that some large PFOs may favor MA attacks in genetically predisposed subjects, by allowing vasoactive substances, platelet emboli or paradoxical emboli to bypass the lung filter and trigger the cortical spreading depression of the aura. The first double blind randomised trial of PFO closure in refractory MA, "MIST", has failed to show a benefit on the primary efficacy end point: cessation of attacks during the analysis period included between 3 and 6 months after the procedure. There is thus at present no scientific reason to look for PFO or to close PFO in migraine patients.

Relation of atrial shunts to migraine in patients with ischemic stroke and peripheral emboli

This study investigated whether the increased incidence of stroke in young subjects with migraine is because they have an increased prevalence of atrial right-to-left shunts. The investigators report the prevalence of clinically relevant atrial shunts in those with stroke and migraine compared with those with stroke but without migraine and also in historic control groups of subjects who had migraine with aura but no stroke and in population controls. Of 60 consecutive stroke patients, 42 (70%) had large- or medium-sized atrial shunts. Transcatheter shunt closure was performed in 39 patients, of whom 35 had patent foramen ovales (mean diameter 9.8 +/- 4.1 mm) and 4 had atrial septal defects. If atrial shunts were unrelated to stroke in patients with migraines, shunt prevalence in those with migraine and stroke would be the same as in those with migraine but without stroke. However, a much greater shunt prevalence was found in those with stroke and migraine with aura (84%) than in those with migraine with aura but no stroke (38.1%, p <0.001), population controls (12.2%, p <0.001), and those with stroke but no migraine (55.6%, p <0.05). Shunt prevalence was also significantly greater in patients who had stroke and migraine without aura (75%) than in population controls (p <0.001) and in those with migraine with aura but no stroke (p <0.05). In conclusion, the increased incidence of stroke in subjects with migraine compared with the general population is because they have a higher prevalence of large atrial shunts and hence an increased risk for paradoxic embolism.

Patent foramen ovale and migraine--bringing closure to the subject

There is increasing interest in the relationship between migraine and patent foramen ovale (PFO). PFO is more common in migraineurs with aura, and migraine with aura is more prevalent in patients with PFO. Retrospective analyses of PFO closure for stroke prevention and decompression illness in divers have suggested that migraineurs with and without aura may derive significant benefit from PFO closure, but to date no prospective, randomized, sham-controlled study to confirm this has been completed. Herein we review published data regarding the relationship between migraine and PFO and discuss the rationale, justification, and important factors to consider in the conduct of prospective, controlled, clinical trials designed to evaluate the efficacy and safety of percutaneous device closure of PFO for migraine prevention.

Migraine: emerging treatment options for preventive and acute attack therapy

This review discusses emerging treatments of migraine in the context of what is now available. At present, patients are treated with a range of acute attack medicines or preventive treatments, with many having significant drawbacks. Important unmet needs are acute attack treatments that act by exclusively neural mechanisms with no vascular effects, and effective, well tolerated preventive medicines. Calcitonin gene-related peptide receptor antagonist, vanilloid receptor antagonists and nitric oxide synthase inhibitors are all in clinical trials for acute migraine. Tonaberset (a gap-junction blocker), an inducible nitric oxide synthase inhibitor and botulinum toxin A are in clinical trials for preventive therapy. Device-based approaches using neurostimulation of the occipital nerve are being studied, although the first study of patent foramen ovale closure for migraine prevention failed.

The Role of Cardiac and Pulmonary Pathology in Migraine: A Hypothesis

From observation of recent data linking migraine with right-to-left shunts and by analogy with the etiologies of decompression illness, we postulate that cardiac and pulmonary pathology can have an important effect on the cranial final common pathway that generates attacks of migraine. One possible mechanism is associated with a significant right-to-left shunt, which is usually through a persistent foramen ovale, but is sometime through a pulmonary shunt. This allows a venous agent, possibly 5-hydroxytryptamine, to bypass the lung filter. Migraine can occur when there is no shunt if similar agents are liberated in the left heart beyond the lung filter, possibly by platelet activation. Migraine could also occur if the venous agents are produced in such large amounts that they overwhelm the pulmonary filter or are unaffected by passage through the lungs. In some individuals migraine may be unrelated to blood-borne triggers.

The persistent foramen ovale and migraine

There is association between migraine, particularly migraine with aura, and large persistent foramen ovale (PFO) and other right-to-left shunts. Migraine is often improved by closure of a PFO in patients who have a large shunt. Inheritance of migraine is linked to the inheritance of large atrial shunts in some families. The data indicate that in some patients PFOs play a causal role in migraine with aura. These observations may also improve understanding of the etiology of migraine in patients who do not have a shunt.