Patent Foramen Ovale and Migraine: A Quantitative Systematic Review

Microemboli may link spreading depression, migraine aura, and patent foramen ovale

OBJECTIVE

Patent foramen ovale and pulmonary arteriovenous shunts are associated with serious complications such as cerebral emboli, stroke, and migraine with aura. The pathophysiological mechanisms that link these conditions are unknown. We aimed to establish a mechanism linking microembolization to migraine aura in an experimental animal model.

METHODS

We introduced particulate or air microemboli into the carotid circulation in mice to determine whether transient microvascular occlusion, insufficient to cause infarcts, triggered cortical spreading depression (CSD), a propagating slow depolarization that underlies migraine aura.

RESULTS

Air microemboli reliably triggered CSD without causing infarction. Polystyrene microspheres (10 microm) or cholesterol crystals (<70 microm) triggered CSD in 16 of 28 mice, with 60% of the mice (40% of those with CSD) showing no infarcts or inflammation on detailed histological analysis of serial brain sections. No evidence of injury was detected on magnetic resonance imaging examination (9.4T; T2 weighted) in 14 of 15 selected animals. The occurrence of CSD appeared to be related to the magnitude and duration of flow reduction, with a triggering mechanism that depended on decreased brain perfusion but not sustained tissue damage.

INTERPRETATION

In a mouse model, microemboli triggered CSD, often without causing microinfarction. Paradoxical embolization then may link cardiac and extracardiac right-to-left shunts to migraine aura. If translatable to humans, a subset of migraine auras may belong to a spectrum of hypoperfusion disorders along with transient ischemic attacks and silent infarcts.

Spreading depression: from serendipity to targeted therapy in migraine prophylaxis

Despite the relatively well-characterized headache mechanisms in migraine, upstream events triggering individual attacks are poorly understood. This lack of mechanistic insight has hampered a rational approach to prophylactic drug discovery. Unlike targeted abortive and analgesic interventions, mainstream migraine prophylaxis has been largely based on serendipitous observations (e.g. propranolol) and presumed class effects (e.g. anticonvulsants). Recent studies suggest that spreading depression is the final common pathophysiological target for several established or investigational migraine prophylactic drugs. Building on these observations, spreading depression can now be explored for its predictive utility as a preclinical drug screening paradigm in migraine prophylaxis.

Patent foramen ovale in patients with tension headache: is it as common as in migraineurs? An age- and sex-matched comparative study

The association of patent foramen ovale (PFO) and atrial septal aneurysm (ASA) with migraine headache attack (MHA) has been clearly shown. The same findings have been recently demonstrated also in cluster headache. Although tension-type headaches (TTH) are the most common kind of headache, their association with these atrial septal abnormalities has never been studied before. The study was conducted to clarify whether there was a significant association between the presence of such atrial septal abnormalities and tension headache, when compared with migraineurs. One hundred consecutive patients with migraine and 100 age- and sex-matched subjects with TTH and 50 healthy volunteers with no headache were enrolled in the study and underwent a complete transesophageal echocardiographic study with contrast injections at rest and with the Valsalva maneuver. There was no significant difference between the age and the sex of the participants of the three groups. The overall prevalence of PFO was 23% in patients with TTH and that of large PFOs was only 11%. The 23% prevalence of PFO in patients with TTH was not statistically different from 16% found in our normal control group. Furthermore, we found a significantly higher prevalence of PFO in migraineurs (50%) when compared with patients with tension headache (p < 0.001). This was also true for the collective presence of large PFOs and ASAs (35%) (p < 0.001). Although atrial septal anomalies have an association with MHA, they do not have a significant association with TTH.

Usefulness of transcatheter patent foramen ovale closure in migraineurs with moderate to large right-to-left shunt and instrumental evidence of cerebrovascular damage

Transcatheter patent foramen ovale (PFO) closure might be effective in improving migraines. To assess the efficacy of PFO closure in migraineurs with a moderate to large right-to-left shunt and instrumental evidence of embolic cerebral damage, 76 highly symptomatic migraineurs were prospectively investigated. The presenting clinical syndrome was stroke in 16 patients, repeated transient ischemic attack in 32 patients, and lone migraine associated with cerebral ischemic lesions on magnetic resonance imaging in 28 patients. Migraine severity was assessed before PFO closure and monthly for 6 months after discontinuation of antiplatelet therapy. At the end of 12 months of follow-up, the averaged postprocedural total score was compared with the baseline score. Transcatheter PFO closure was successful in all patients, and the 12-month PFO closure rate was 97%. The baseline total migraine score was similar in patients with stroke, transient ischemic attack, and lone migraine (6.8 +/- 1.6, 6.7 +/- 1.4, and 6.9 +/- 1.7 respectively, p = NS). After a mean follow-up of 13.7 +/- 2.4 months, no recurrent cerebrovascular episodes had occurred. At the end of the follow-up period, a significant reduction in the total migraine score was observed in all groups, regardless of the initial clinical presentation. Migraine was completely abolished in 35 patients (46%), improved in 27 (36%), and unchanged in 14 (18%). The proportion of patients with migraine suppression and improvement was similar in the 3 groups. In conclusion, in highly symptomatic migraineurs with previous ischemic cerebral events and instrumental evidence of cerebral embolism, transcatheter PFO closure can result in improvement of migraine severity in a high percentage of patients.

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.

The epidemiology, burden, and comorbidities of migraine

We describe the epidemiology and comorbidities of migraine, which affects 12% of adults in occidental countries. Prevalence is three times higher in women, but 6% of men are affected, making it the most prevalent neurologic disorder in men. Although migraine is a remarkably common cause of temporary disability, many migraineurs have never consulted a physician for the problem. Many disorders are comorbid with migraine. For some such as depression, the association has been well described, but for others, the relationship has been recently suggested, such as in the case of clinical and subclinical vascular brain lesions and coronary heart disease.

Advances in the basic and clinical science of migraine

Migraine continues to be an elephant in the room of medicine: massively common and a heavy burden on patients and their healthcare providers, yet the recipient of relatively little attention for research, education, and clinical resources. Its visibility is gradually increasing, however, as advances in genetics, imaging, epidemiology, and pharmacology produce a more definitive understanding of the condition, and identify more specific and effective treatments. Rapid evolution of concepts regarding its prevalence, pathophysiology, and clinical management is leading to growing recognition of migraine as a fundamentally important disorder of the nervous system.

Cerebral ischemic events associated with 'bubble study' for identification of right to left shunts

BACKGROUND AND PURPOSE

Detection of an intracardiac shunt is frequently sought during the evaluation of patients with cryptogenic ischemic stroke and agitated saline intravenous injection, or "bubble study" (BS), is performed in most cases. We present the first attempt to identify the clinical features in patients who had cerebral ischemic events with BS.

METHODS

Using a list serve established by the American Academy of Neurology, a member posted a question regarding the safety of BS in patients with patent foramen ovale. A standardized questionnaire was used to gather data about patients with cerebral ischemic events, details of each case were reviewed, and the findings pooled.

RESULTS

Five patients with ischemic complications of BS (all female, aged 42 to 90 years) were identified from 4 institutions, 3 ischemic strokes and 2 transient ischemic attacks. Events occurred either during or within 5 minutes of BS. Early brain MRIs confirmed acute infarction in 3, including one who had transient symptoms. MRI infarct volumes were small, and deficits were mild in those who developed stroke. Diagnostic evaluation revealed a patent foramen ovale alone in one case, a pulmonary arteriovenous malformation in one case, and a patent foramen ovale and/or pulmonary shunt in 3 cases.

CONCLUSIONS

Ischemic cerebrovascular complications can occur in patients who undergo BS and are associated with the presence of cardiac or pulmonary shunts. The true incidence and degree of disability remains unknown, and further study is indicated to assess the impact of technical differences in BS methodology. Novel methods to promote physician communication such as the use of electronic list serves may reduce barriers to reporting of drug, technique, or device complications and should be explored to identify rare complications that otherwise will likely go unappreciated.

Stroke prevention in atrial fibrillation and other major cardiac sources of embolism

The frequency of cardioembolic stroke is expected to rise as the general population ages. Much of the increase may be attributed to atrial fibrillation, the most common cause of cardioembolic stroke and one that plays a substantial role in aging adults. Other sources of cardioembolic stroke may include ventricular thrombus from myocardial infarction, heart failure, structural heart defects such as patent foramen ovale (PFO), atrial septal aneurysm, proximal aortic atheroma, valvular heart disease, and endocarditis. Diagnostic studies, such as neuroimaging, ECG, and echocardiography, are helpful in uncovering cardioembolic sources of stroke. Medical therapy is predicated on the underlying mechanism. For example, warfarin may be indicated in certain patients who have atrial fibrillation, atrial, or ventricular thrombi, and PFO with atrial septal aneurysm and cryptogenic stroke in select young patients to prevent stroke. Newer diagnostic technologies, including multidetector CT and cardiac MRI, may be useful to diagnose cardiac causes of stroke when transesophageal echocardiography is indeterminate or cryptogenic stroke is present.

Migraine and patent foramen ovale: connecting flight or one-way ticket?

CONTEXT

The genesis of migraine in patients with patent foramen ovale (PFO) and its relationship with paradoxical stroke is still debated. Some authors agree that migraine with aura and PFO have higher coincidences than would be expected by chance and that it is possible that both conditions are inherited together.

OBJECTIVE

The present review aims to make a comprehensive attempt at clarifying the PFO-migraine connection in light of recent evidence from literature.

EVIDENCE ACQUISITION

A Medline search using both OVID and PubMed was performed by searching for literature in English regarding randomized trials, prospective cohort studies, meta-analyses, reviews and editorials about PFO and migraine between 1998 and 2008. Search key words were 'migraine' and 'patent foramen ovale' matched with 'prevalence', 'echocardiography', 'transcranial Doppler ultrasound', 'magnetic resonance imaging', 'coagulation abnormalities' and 'transcatheter closure treatment'. Additional reference material was obtained from the proceedings of relevant conferences on PFO and migraine, and the author's personal experience.

EVIDENCE SYNTHESIS

Echocardiographic, transcranial Doppler and MRI studies suggest that migraine patients are at higher risk of stroke compared with the normal population and often have white matter brain lesions on MRI. A large proportion of PFO patients have migraine, in particular migraine with aura, and migraine with aura patients plus PFO have larger shunts compared with migraine-free patients. It has been suggested that patients with migraine and large PFO have an increased risk of paradoxical embolism. Most patients with PFO and migraine respond well to transcatheter closure and this fact is unlikely to be caused just by a placebo effect.

CONCLUSIONS

Although many gray areas are still present, migraine with aura and large PFO seem to be strictly related to both anatomic and functional states at least in a proportion of patients.

From migraine to stroke

An association between migraine and ischemic stroke has been observed for many years but the exact mechanisms by which migraine can lead to stroke are currently still under investigation. Migraine seems to affect neurovascular factors and substances that increase the risk of stroke during and in between migraine attacks. Ischemic stroke can occur as a complication of an attack of migraine with aura. Epidemiological studies suggest that vascular risk factors are increased in migraineurs, thus increasing the incidence of stroke. Another important issue is a patent foramen ovale (PFO), which is a well-known risk factor for stroke and which, on the other hand, seems to be more frequent in migraineurs than in people without. The purpose of this review is to summarize the current literature linking the two neurological diseases: migraine and stroke.