Potential source of cerebral embolism in migraine with aura: a transcranial Doppler study

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.

Right-to-left shunt is common in chronic migraine

Our aim was to determine the prevalence of right-to-left shunt (RtLS) in patients with chronic migraine (CM), and to correlate the presence and grade of RtLS with aura and neurological symptoms, and duration and severity of disease. The prevalence of RtLS in migraine without aura is similar to that of the general population (between 20 and 35%). In migraine with aura, the prevalence is much higher (approximately 50%). The prevalence in CM, with or without aura, is unknown. Consecutive patients between the ages of 18 and 60 years with CM attending a tertiary care specialty headache clinic over an 8-week period were eligible. There were 131 patients in the study. A structured diagnostic interview was performed. Bubble transcranial Doppler with Valsalva manoeuvre determined RtLS presence and grade. Sixty-six percent (86/131) of patients had RtLS, a statistically significantly greater rate than those reported in the general population and in migraine with or without aura ( P < 0.001). There was no difference in RtLS rate or grade between those with and those without aura. Specific headache features and the presence of neurological symptoms were similar between those with and those without RtLS. Compared with both the general population and the episodic migraine population (with and without aura), patients with CM, with or without aura, are more likely to have RtLS. The clinical implications of our findings need to be determined.

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.

Embolic implications of combined risk factors in patients with patent foramen ovale (the CARPE criteria): consideration for primary prevention closure?

BACKGROUND

Large patent foramen ovale (PFO), spontaneous right-to-left shunt, large atrial septal aneurysm (ASA), coagulation abnormalities, and prominent eustachian valve (EV) have all been independently suggested as risk factors for recurrent stroke. We sought to retrospectively evaluate risk of stroke and impact of transcatheter PFO closure in patients with concurrent large PFO, spontaneous right-to-left shunt, large ASA, coagulation abnormalities, and prominent EV.

METHODS

Between March 2006 and October 2008, 36 (mean age 44 +/- 10.9 years, 28 females) out of 120 consecutive patients referred to our center for transcatheter PFO closure had concomitant diagnosis of (a) large PFO on transcranial Doppler (TCD) and transesophageal echocardiography (TEE), (b) spontaneous right-to-left shunt on TCD, (c) large ASA, (d) prominent EV, and (e) coagulation abnormalities. All patients fulfilled the standard current indications for transcatheter closure and underwent preoperative TEE and brain magnetic resonance imaging (MRI), with subsequent intracardiac echocardiographic-guided transcatheter PFO closure.

RESULTS

Compared to the remaining PFO population in the same period, patients with all five concomitant features had more ischemic brain lesions on MRI, previous history of recurrent stroke, more frequently a history of venous thromboembolism, and more severe migraine with aura. The concomitance of all the features confers the highest risk of recurrent stroke (OR 9.9, 3.0-18 [95% CI], P < 0.001).

CONCLUSIONS

Despite its small sample size and nonrandomized retrospective nature, this is the first study to suggest that patients with concurrence of all the investigated characteristics have potentially a higher risk of stroke compared to controls. We thus propose the CARP criteria as a basis for further larger, longitudinal studies to assess the potential benefits of transcatheter closure in this patient subset in the absence of clinical recurrent stroke.

Transcatheter interatrial shunt closure as a cure for migraine: can it be justified by paradoxical embolism-risk-driven criteria?

BACKGROUND

Some ongoing trials have suggested that closure of the patent foramen ovale (PFO) may reduce migraine symptoms. We sought to assess the safety and effectiveness of migraine treatment by means of PFO transcatheter closure using paradoxical embolism risk-driven criteria.

METHODS

We enrolled 75 patients (48 women and 27 men, mean age 40 +/- 3.7 years) who were referred to our center over a 12-month period for a prospective study to evaluate severe disabling migraine, despite antiheadache therapy and the PFO. Migraine Disability Assessment Score (MIDAS) was used to assess the incidence of migraine headache and severity. Criteria for intervention included all of the following: basal shunt, curtain shunt pattern on transcranial Doppler, presence of interatrial septal aneurysm, 3 to 4 class MIDAS score, symptomatic significant aura, coagulation abnormalities, migraine refractory to conventional drugs.

RESULTS

On the basis of the inclusion criteria, we shortlisted 20 patients (12 women, mean age 35 +/- 6.7 years, mean MIDAS score 38.9 +/- 5.8) for transcatheter closure of PFO and excluded the rest who were referred to the neurologist for medical therapy. The procedure was successful in all of the patients with no perioperative or in-hospital complications. After a mean follow-up of 10 +/- 3.1 months (range 6-14), all patients' migraine symptoms improved (mean MIDAS score 3.0 +/- 2.1, P < 0.03) with PFO complete closure in all patients on transesophageal and transcranial Doppler ultrasound.

CONCLUSION

In this small pilot series, we adopted the criteria which in our opinion best reflected the risk of paradoxical embolism in these patients. By adopting the proposed criteria, primary transcatheter closure of the PFO resulted in a significant reduction in migraine.

Transcatheter closure of patent foramen ovale with radiofrequency: acute and intermediate term results in 144 patients

AIMS

Currently available devices for transcatheter closure of patent foramen ovale (PFO) which rely on a permanent implant have limitations, including late complications. The study objective was to evaluate the safety, feasibility, and effectiveness of the PFx Closure System, the first transcatheter technique for PFO closure without an implantable device.

METHODS AND RESULTS

A prospective study of 144 patients was conducted at nine clinical sites from October 2005 through August 2007. All patients had a history of cryptogenic stroke, transient ischemic attack, migraines, or decompression illness. The mean balloon stretched diameter of the PFO was 7.9 +/- 2.5 mm. Technical success (successful application of radiofrequency energy) was achieved in 130 patients. One patient required a transfusion as a result of blood loss during the procedure. There were no other major procedural complications. There were no recurrent strokes, deaths, conduction abnormalities, or perforations following the procedure. At a mean follow-up of 6 months, successful closure was achieved in 79 patients (55%). In PFOs with balloon sized or stretched diameters less than 8 mm, the closure rate was 72% (53/74).

CONCLUSION

This study demonstrates that transcatheter closure of a PFO without a permanent implant is technically feasible and safe. Further technique and device modifications are required to achieve higher closure rates.

Transcranial Doppler ultrasonography: a diagnostic tool of increasing utility

PURPOSE OF REVIEW

Since its introduction in 1982, transcranial Doppler ultrasonography has become an important diagnostic and monitoring tool in patients with surgical disease. It has applications in the perioperative period, as well as in the intensive care unit. It is therefore appropriate for the anesthesiologist to maintain an understanding of its current utility.

RECENT FINDINGS

Transcranial Doppler has an established role in diagnosing cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage and for guiding transfusion therapy in children with sickle cell disease. It has application in the preoperative evaluation of patients with cerebrovascular disease, as well as that of an intraoperative monitor in carotid endarterectomy and carotid stenting. It is useful for detecting right-to-left shunts in settings in which transesophageal echocardiography is not desirable. Its value in settings such as traumatic brain injury, hepatic failure, and migraine headache has yet to be fully clarified.

SUMMARY

Although there are several settings in which transcranial Doppler has well established usefulness, there are many more in which it is likely valuable, such as traumatic brain injury, ischemic stroke, and fulminant hepatic failure. Further research is needed in these fields to elucidate the exact role for transcranial Doppler.

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.

Transcranial Doppler for patent foramen ovale screening: is there a good correlation with transesophageal echocardiography?

Right-to-left shunt (RLS) can be identified by contrast-enhanced transcranial Doppler (cTCD) in patent foramen ovale (PFO) patients. AIM: To evaluate cTCD for PFO screening comparing it to cTEE. METHOD: 45 previous cTCD performed for PFO diagnosis and correlated its findings with cTEE. Patients were submitted to a cTCD standardized technique and were divided in two groups according to RLS: Group 1, patients with a positive RLS and Group 2 when RLS was negative. RESULTS: 29 (65%) patients were included in group 1 and 16 (35%) in group 2. PFO confirmation by cTEE was performed in 28 (62%) patients. cTCD had a 92.85% sensitivity, 82.35% specificity, 89.65% positive predictive value and 87.5% negative predictive value when compared to cTEE for PFO diagnosis. CONCLUSION: Standardized technique cTCD allows for RLS visualization in PFO patients with a good correlation with cTEE and can be used as a screening test before cTEE.

Current views of the risk of stroke for migraine with and migraine without aura

The association between migraine and stroke is complex and is a continued focus of attention. Several observational studies have identified migraine as an independent risk factor for ischemic stroke. However, a distinction should be made between migraine with and migraine without aura. The migraine-stroke association is mostly apparent for young women with migraine with aura. The association between migraine with aura and stroke is weaker in older age groups, which may be due to the fact that traditional cardiovascular risk factors are more prominent with increasing age. Most studies have not found an association between migraine without aura and ischemic stroke. Although there are several hypotheses about the biologic link between migraine with aura and ischemic stroke, the precise mechanisms remain unclear. However, because the absolute risk of stroke is low in patients with migraine with aura, and migraine without aura is likely not associated with ischemic stroke, most migraine patients will not experience a stroke event.

Management of patients with refractory migraine and PFO: Is MIST I relevant?

The results of the randomized clinical trial entitled: Migraine Intervention with Starflex Technology (MIST), produced surprising and disappointing results on the effect of PFO closure to decrease migraine headaches. There have been allegations of misrepresentation of the effectiveness of this device. These issues have significant implications in how randomized clinical trials are performed that will impact current and future planned trials of PFO closure to treat migraine headaches.

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.

Migraine-associated risks and comorbidity

This review reports important co-morbid conditions of migraine and resulting consequences for the choice of acute and preventive treatments of migraine. Comorbidity in this context means the occurrence of two diseases in an individual beyond chance. The basis of comorbidity can be genetic and/or based on common environmental factors. In some cases, the temporal relationship is unclear and one disease can cause another disease. In order to prove a real comorbidity, large-scale and well-performed epidemiological studies are required.

Patent foramen ovale and migraine: a cross-sectional study from the Northern Manhattan Study (NOMAS)

BACKGROUND

A causal relationship between patent foramen ovale (PFO) and migraine has been hypothesized, and improvement of migraine frequency and severity after percutaneous PFO closure has been reported. Population-based data on the relationship between PFO and migraine are sparse, however. The objective of this study was to examine the association between PFO and migraine among stroke-free individuals in an urban, population-based, multiethnic cohort.

METHODS AND RESULTS

As a part of the ongoing Northern Manhattan Study (NOMAS), 1101 stroke-free subjects were assessed for self-reported history of migraine. The presence of PFO was assessed by transthoracic echocardiography. The mean age of the group was 69+/-10 years; 58% were women. Forty-eight percent were Caribbean Hispanic, 24% were white, 26% were black, and 2% were another race/ethnicity. The prevalence of self-reported migraine was 16% (13% migraine with aura). The prevalence of PFO was 15%. Migraine was significantly more frequent among younger subjects, women, and Hispanics. The prevalence of PFO was not significantly different between subjects who had migraine (26/178, or 14.6%) and those who did not (138/923, or 15.0%; P=0.9). In an adjusted multivariate logistic regression model, the presence of PFO was not associated with increased prevalence of migraine (odds ratio 1.01, 95% confidence interval 0.63 to 1.61). Increasing age was associated with lower prevalence of migraine in both subjects with a PFO (odds ratio 0.94, 95% confidence interval 0.90 to 0.99 per year) and those without PFO (odds ratio 0.97, 95% confidence interval 0.95 to 0.99 per year). The observed lack of association between PFO and migraine (with or without aura) was not modified by diabetes mellitus, hypertension, cigarette smoking, or dyslipidemia.

CONCLUSIONS

In this multiethnic, elderly, population-based cohort, PFO detected with transthoracic echocardiography and agitated saline was not associated with self-reported migraine. The causal relationship between PFO and migraine remains uncertain, and the role of PFO closure among unselected patients with migraine remains questionable.

Migraine and ischemic stroke: a debated question

Numerous epidemiologic observations reporting high prevalence of migraine among young individuals with stroke as well as dysfunction of cerebral arteries during migraine attacks prompt speculation on the existence of a comorbidity between the two disorders. The recent finding of silent infarct-like brain lesions in migraineurs reinforced this hypothesis and raised questions on whether migraine may be a progressive disorder rather than simply an episodic disorder. Stroke can occur during the course of migraine attacks with aura, supporting the assumption of a causal relation between the two diseases. Migraine may accentuate other existing risk factors for stroke, and both jointly increase the risk of cerebral ischemia outside of migraine attacks. In this regard, the role of migraine might be that of predisposing condition for cerebral ischemia. Migraine and ischemic stroke may be the end phenotype of common pathogenic mechanisms. Evidence of a migraine-stroke relation in cases of specific disorders, such as CADASIL (cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy) and MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes), strongly supports this concept. Finally, acute focal cerebral ischemia can trigger migraine attacks, and, thus, migraine may be the consequence of stroke. In this paper, we will review contemporary epidemiologic studies, discuss potential mechanisms of migraine-induced stroke and comorbid ischemic stroke, and pose new research questions.

Comorbid neuropathologies in migraine: an update on cerebrovascular and cardiovascular aspects

Several conditions are comorbid with migraine; our review is focused on the relation between migraine, and cerebrovascular and cardiovascular diseases. Despite many studies showed an association between migraine and patent foramen ovale, it is still not known whether its presence might be causal for the migraine pathogenesis and currently its closure cannot be recommended for migraine prevention. On the contrary, conflicting epidemiological data link migraine to arterial hypertension and the use of antihypertensive agents acting on the renin-angiotensin system sounds promising in migraine prevention. A complex bidirectional relation exists between migraine and stroke, and new evidences show a clear association between migraine and coronary heart disease. In both conditions, migraine represents a defined risk factor although the magnitude of the risk varies across the different studies. However, since the risk is low in the general population, it is not possible to identify which migraineurs will develop a cardiovascular or a cerebrovascular event making difficult to apply preventive measures.

New-onset and persistent migraine early after percutaneous atrial septal defect closure disappear at follow-up

AIMS

Recently we reported that percutaneous atrial septal defect (ASD) closure had no influence on the prevalence of migraine during a short followup period. 12 % of patients however developed a new-onset migraine after the ASD closure. As it has been suggested that the closing device might induce or maintain migraine temporarily, we were interested in the prevalence of migraine at longer follow-up.

METHODS

All 75 patients included in the previous study, received the same structured headache questionnaire. A neurologist, blinded to previous data, diagnosed migraine with or without aura (MA+ or MA-) according to the International Headache Criteria. McNemar paired X2 test was used to evaluate changes in the occurrence of migraine.

RESULTS

Seventy-one patients (94.7%) answer the questionnaire (55 women, mean age at closure 51 +/- 18 years). Mean follow-up time was 52 +/- 13 months. The overall migraine prevalence decreased from 30.7% before to 22.5% after closure (P=0.21). A significant reduction was noted in patients with new-onset migraine early after closure (n=7), where migraine disappeared in 6 patients (P=0.031). In the group with persistent migraine early after closure (n=13), another 6 patients became migraine-free (P=0.031).

CONCLUSION

Percutaneous ASD closure was not related to a significant decrease in overall migraine prevalence. However, new-onset and persistent migraine early after closure disappeared.

Nickel allergy in interatrial shunt device-based closure patients

BACKGROUND

The possibility of nickel toxicity has been raised with interatrial shunt closure devices constructed of nitinol. This study is aimed to assess the potential adverse symptoms in terms of incidence, duration, and significance, in patients with interatrial shunt and nickel allergy who underwent nitinol device-based closure.

METHODS

We prospectively enrolled 46 consecutive patients (mean age 35 +/- 28.8 years, 30 female) over a 12-month period referred to our center for catheter-based closure of interatrial shunts. Patients were investigated for previous hypersensivity to nickel and were required to test potential nickel allergy with cutaneous patch test (TRUE test) before device implantation. Routinely, clinical visit with laboratory examinations, and TTE were scheduled at 1, 6, and 12 months.

RESULTS

Nine patients (19.5%, mean age 31.3 +/- 13.2 years) had proved symptomatic and instrumental nickel allergy as showed by cutaneous patch skin test but preferred to be implanted. All patients underwent successful transcatheter closure with an immediate occlusion rate of 100% without intraoperative complications. Between the 2nd and 3rd postoperative day, 8 out of 9 patients developed a sort of 'device syndrome' that included concurrent chest discomfort, exertional dyspnea and asthenia, and mild leukocytosis. The syndrome was treated with Prednison and Clopidogrel and in all was resolved after 1-week therapy. Interestingly, none of the patients without nickel allergy developed postclosure symptoms (P < .001).

CONCLUSIONS

In conclusion, nickel allergy is still a problematic issue in patients scheduled for transcatheter closure of intracardiac shunts; however, our brief study suggests that nickel allergy is not per se a contraindication to nitinol device closure.

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.

Patent foramen ovale closure: past, present and future

Patent foramen ovale (PFO) is a common congenital abnormality that has been implicated in a number of disease processes, including cryptogenic stroke and migraine headaches. Medical treatment for these processes is often considered inadequate and mechanical closure of the PFO is an attractive, albeit controversial, alternative. PFO closure has become common practice in many centers, although recent guidelines limit its indication to certain subsets of patients. This review first focuses on the anatomy, physiology and pathophysiology of PFO, and then reviews the currently available and experimental devices for PFO closure, as well as the present clinical data pertaining to them. Finally, we present our perspective of the PFO closure, with regard to its current use and future directions.

Asymptomatic significant patent foramen ovale: giving patent foramen ovale management back to the cardiologist

Percutaneous closure of patent foramen ovale (PFO) is still a much debated issue. Although many questions remain open, patients are finding out about PFO management and are beginning to ask for the most rapid and complete solution to their potential problems in spite of the warnings from the medical profession about off-label indications for transcatheter closure. As a result, asymptomatic patients with PFO are coming into medical offices to be assured about stroke risk or treated for any degree of migraine. The cardiologist should be the preferred interlocutor in asymptomatic significant PFO: he is competent in assessing the associated anatomical and functional risk factors, and he is the only specialist who can evaluate on the basis of the anatomo-functional picture the potential risk of paradoxical embolism and discuss with patients eventual off-label indications to closure.

White Matter Lesions in Migraine and Right-to-Left Shunt: A Conventional and Diffusion MRI Study

Subjects with migraine with aura (MA) have a high prevalence of white matter lesions (WMLs) on magnetic resonance imaging (MRI). Moreover, right-to-left shunt (RILES), mainly due to patent foramen ovale, is frequently associated with MA. The aim of this study was to clarify the relationship between RILES and WML in MA. We enrolled 87 consecutive subjects affected by MA. Patients were screened for migraine characteristics and cerebrovascular risk factors. Transcranial Doppler was used to diagnose RILES and MRI with T2-weighted and diffusion-weighted imaging (DWI) to evaluate presence, number and volume of WMLs. RILES was present in 45% of patients. We did not detect any DWI hyperintense lesion; WMLs were present in 61% of patients on T2-weighted images. Presence of WMLs did not correlate with any migraine clinical feature, whereas the presence, number and volume of WMLs increased with subjects' age. There was no significant difference in the total volume and number of WMLs in the group with and without RILES. In conclusion, RILES does not increase the likelihood of finding WMLs in migraineurs.

Migraine Intervention With STARFlex Technology (MIST) Trial

Background— Patent foramen ovale (PFO) is prevalent in patients with migraine with aura. Observational studies show that PFO closure resulted in migraine cessation or improvement in ≈80% of such patients. We investigated the effects of PFO closure for migraine in a randomized, double-blind, sham-controlled trial.

Methods and Results— Patients who suffered from migraine with aura, experienced frequent migraine attacks, had previously failed ≥2 classes of prophylactic treatments, and had moderate or large right-to-left shunts consistent with the presence of a PFO were randomized to transcatheter PFO closure with the STARFlex implant or to a sham procedure. Patients were followed up for 6 months. The primary efficacy end point was cessation of migraine headache 91 to 180 days after the procedure. In total, 163 of 432 patients (38%) had right-to-left shunts consistent with a moderate or large PFO. One hundred forty-seven patients were randomized. No significant difference was observed in the primary end point of migraine headache cessation between implant and sham groups (3 of 74 versus 3 of 73, respectively; P =0.51). Secondary end points also were not achieved. On exploratory analysis, excluding 2 outliers, the implant group demonstrated a greater reduction in total migraine headache days ( P =0.027). As expected, the implant arm experienced more procedural serious adverse events. All events were transient.

Conclusions— This trial confirmed the high prevalence of right-to-left shunts in patients with migraine with aura. Although no significant effect was found for primary or secondary end points, the exploratory analysis supports further investigation. The robust design of this study has served as the model for larger trials that are currently underway in the United States and Europe.

Is migraine associated with right-to-left shunt a separate disease? Results of the SAM study

Migraine with aura (MA) is associated with the persistence of patent foramen ovale (PFO) in about 50% of cases, and migraineurs tend to have larger shunts than controls, suggesting that right-to-left shunt (RILES) determined by PFO could play a role in triggering migraine attacks. Moreover, some preliminary reports have suggested that PFO closure may give relief to both migraine and aura attacks. The aim of this study was to clarify if shunt-associated migraine (SAM) has clinical features that allow a distinction from shunt-unrelated migraine (SUM), in a prospective, multicentre, observational study (SAM study). We enrolled consecutive MA patients, who underwent a structured, standardized questionnaire for family and personal history and for detailed migraine features. All were systematically screened for RILES with transcranial Doppler, and for coagulation disorders. Overall, 460 patients were included; the SUM and SAM classes comprised 58% and 42% of patients, respectively. SAM patients were significantly younger (34.1 +/- 10 vs. 37.1 +/- 11 years), had a more frequent family history of migraine (76% vs. 66%) and a higher frequency of sensory symptoms of aura (51% vs. 41%); by contrast, there was a lesser association of SAM with other cardiac abnormalities and with coagulation disorders. The SAM study suggests that the effect of RILES on migraine features is not relevant. The higher family history of migraine in SAM suggests a possible genetic linkage between migraine and RILES.

Prevalence of migraine headaches in patients with congenital heart disease

The prevalence of migraine headaches (MH) is 12% in the general population and increases to 40% in patients with patent foramen ovale. This study evaluated the prevalence of MH in patients with congenital heart disease (CHD). Of 466 patients contacted from the UCLA Adult Congenital Heart Disease Center, 395 (85%) completed a questionnaire to determine the prevalence of MH. Patients were stratified by diagnosis of right-to-left, left-to-right, or no shunt. A group of 252 sex-matched patients with acquired cardiovascular disease served as controls. The prevalence of MH was 45% in adults with CHD compared to 11% in the controls (p<0.001). Of the 179 patients with MH, 143 (80%) had migraines with aura and 36 (20%) had migraines without aura versus 36% and 64% observed in the controls (p<0.001). The frequency of MH was 52% in the right-to-left shunt group, 44% in the left-to-right, and 38% in the no shunt group (p=NS). In patients with a right-to-left shunt who underwent surgical repair, 47% had complete resolution of MH, whereas 76% experienced >50% reduction in headache days per month. In conclusion, the prevalence of MH in all groups of adults with CHD is 3 to 4 times more than a sex-matched control population, with increasing prevalence of MH in patients with no shunt, left-to-right, and right-to-left shunt. The higher than expected frequency of MH in patients with CHD without an intracardiac shunt, suggests additional mechanisms to explain the significant association with MH.