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PFO closure for migraine

Mark Reisman, MD, Director of Cardiovascular Research and Education

 

Migraine is a primary headache dis­order that causes significant suffering in approximately 13 percent of the popula­tion of the United States. It accounts for an estimated $23 billion in annual cost to the economy through health-care expenses and lost productivity.

Two major features of migraine are migraine aura (MA) and headache. MA occurs in nearly one-third of migraine pa­tients and consists of one or more focal neurological symptoms that develop gradually over 5-20 minutes and persist for less than 60 minutes. MA typically precedes development of migraine headache.

Several years ago single-center retrospective analyses first reported an apparent association between partial or complete relief of migraine symptoms and transcatheter clo­sure of patent foramen ovale (PFO) for secondary stroke prevention (Reisman M, et al., 2005). The fora­men ovale normally serves as a one-way valve in the interatrial septum for physiologic right-to-left shunt in utero. Complete fusion of interatrial septae normally occurs by two years of age. When septae fail to fuse, how­ever, the PFO is a potential tunnel that can be opened by reversal of the interatrial pressure gradient. PFO is the most common form of right-to-left circulatory shunt (RLS).

Studies have shown that as many as 50 percent of individuals with MA will have a PFO, whereas PFO is present in about 25 percent of the general population and in migraineurs without aura (MO). In analy­ses performed by Swedish researchers, MA patients had a larger RLS than patients with MO, despite similar interatrial anat­omy (Jesurum JT, et al., 2007), and were about 4.5 times more likely to have greater than 50 percent reduction in migraine fre­quency following PFO closure (Jesurum JT, et al., 2008). These observations indicated a potential pathophysiological relationship between migraine and PFO.

The mechanism for this potential re­lationship is not understood, but investi­gators have focused on possible interatrial transit of vasoactive chemicals that bypass the pulmonary capillary bed, or on micro­emboli from the venous circulation which might trigger cortical spreading depres­sion and transient regional hypoperfu­sion. Migraineurs may have higher plate­let reactivity (Jesurum JT et al., 2010) or pro-coagulant state (e.g., protein C or S deficiency) than non-migraineurs, possibly resulting in greater load of microemboli in the arterial circula­tion. The brains of migraineurs may be more sensitive to circulatory changes than are the brains of those without migraine. The combination of potential triggers and susceptible neuronal substrate may result in an enhanced risk of MA among pa­tients with PFO.

The Migraine Intervention with STARFlex Technology (MIST) trial was a randomized trial of PFO clo­sure in migraine (Dowson A et al.). The failure of the trial to meet its primary endpoint (cessation of headache) and secondary endpoint (>50-percent re­duction in headache frequency and days) was surprising. Eligibility criteria for the trial may have excluded those patients who were most likely to benefit from PFO clo­sure. For instance, patients were excluded from MIST if they had a history of stroke or hypercoagulability, and subjects had to fit within a narrow range of headache fre­quency. If patients with a greater migraine burden or hypercoagulability were more likely to achieve meaningful reductions in headache frequency and severity, these exclusion cri­teria could have altered the study outcome.

Other trials are in progress or in the pipeline that may better elu­cidate the effect of PFO closure on migraine. The migraine-PFO asso­ciation offers opportunities for col­laboration between scientists and clinicians in both neurology and cardiology. The long-term goals of collaborative trials are improved quality of life and reduced cerebro­vascular sequelae for individuals who suffer from migraine.

 

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Options widening for wide-necked aneurysms

 

Yince Loh, MD, Interventional Neuroradiology, Neurosurgery, Swedish Neuroscience Institute 

 

Intracranial aneurysms are present in up to 4 percent of the population. These potentially dangerous vascular lesions are being detected with increasing frequency in asymptomatic patients by advances in noninvasive imaging techniques, such as magnetic resonance angiography (MRA). Appearing like blisters on the wall of the brain’s blood vessels, aneurysms develop when the blood vessel’s native repair ability is exceeded by the mild, but constant, injury created by flowing blood under high pressure. The five most common risk factors for developing an aneurysm are: smoking, female gender, high blood pressure, middle age and family history.

Intracranial aneurysms are complex lesions that require a highly specialized, multidisciplinary approach that is individualized for each patient. Key members of the care team for these patients include endovascular neuroradiologists, neurosurgeons with special expertise in aneurysm surgery and neuroanesthesiologists. Availability of dedicated neurocritical care units is an essential care component. A consensus recommendation by these specialists may include close observation, obliteration of the aneurysm with a surgical clip, or filling the vascular outpouching with filamentous coils that are introduced by endovascular microcatheters via an artery in the leg. This latter process is called “coiling.”

Those aneurysms that have a balloon-like opening, or neck, from the parent vessel are typically good candidates for coiling. Not infrequently, however, the aneurysm’s shape does not permit safe coiling. When the aneurysm’s neck is wide, it appears more like a molehill than a balloon. A molehill configuration is often referred to as a “wide-necked aneurysm.” The wide neck allows an unwanted protrusion of coils back into the artery. This can lead to a number of problems, including failure to obliterate the aneurysm and stroke. Thus, in situations where an aneurysm is not surgically accessible or the patient cannot undergo surgery, no therapeutic options can be offered.

Until recently, wide-neck aneurysms could not be treated by coiling. The U.S. Food and Drug Administration, however, has approved a tubular device called an intracranial stent to be used for such situations.

Once a stent is deployed across the neck of the aneurysm, coils are placed into the aneurysm through the stent wall. The stent struts prevent the coils from falling back into the artery by essentially creating a “chain link fence” across the neck of the aneurysm.

Stenting, however, produces another set of problems. A stent is a foreign body that can promote the formation of a blood clot inside the vessel, which is why patients are placed on two antiplatelet medications to thin the blood, usually aspirin and clopidogrel (Plavix®), after placement of a stent. The length of time required to thin the blood after stent placement is unclear, although stents may become incorporated into the vessel wall and covered with endothelium within weeks.

Emerging concepts in vascular neurology: TIA clinics help prevent strokes and unnecessary hospital admissions

Michael Fruin, ARNP, Swedish Neuroscience Institute

Tom Jaspee placed an anxious call to Dr. Lewis’s office at 9 a.m. sharp. He didn’t give many details, other than to say his wife was worried about problems he was having with his speech the previous night. Later that morning in Dr. Lewis’s office, Tom said he had trouble getting his thoughts out for a few minutes. He said he felt fine im­mediately afterwards and didn’t want to raise a ruckus. Tom’s wife added that his right face drooped and the episode took al­most 30 minutes to clear up. She was wor­ried that Tom had suffered a stroke.

Dr. Lewis was well aware of Tom’s high risk of stroke following his transient isch­emic attack (TIA). Realizing that he could not manage this urgent issue in his office, Dr. Lewis sent the patient to the emergency room and after a six-hour stay, Tom was admitted as an inpatient for a 24-hour ob­servation and evaluation.

This mock case study highlights the role a TIA clinic might have played in avoiding an emergency room visit and hos­pitalization, while still providing the TIA patient the necessary urgent care.

While hospital admission is appropri­ate for the subset of patients at high risk for having a stroke after TIA, significant num­bers of emergency room visits and admis­sions could be avoided by a recent advance in evaluating patients in a TIA clinic. TIA clinics are being pioneered in the United Kingdom, where patients with TIA can be seen by a stroke specialist in an urgent-care clinic setting in which a standardized pro­tocol of neurologic evaluation and diagnos­tic testing is administered.

The effectiveness of the TIA clinic is supported by findings from the EXPRESS Trial (Luengo-Fernandez R, et al.). In this trial, there was an 80 percent reduction of 90-day stroke risk when TIA and minor stroke patients received urgent evaluation and treatment in a standardized urgent-care clinic setting. Patients at high risk of stroke, such as those with high-grade ste­nosis of the internal carotid artery or with atrial fibrillation, are admitted to the neurology service as indicted. Patients at low risk of stroke receive patient education and a stroke prevention plan is implemented.

Reference

Luengo-Fernandez R, Gray AM, Rothwell PM. “Effect of urgent treatment for transient ischaemic attack and minor stroke on disability and hospital costs (EXPRESS study): a prospective population-based sequential comparison.” Lancet Neurology 8:235-243. 2009.

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Multimodal Treatment of Spinal Tumors symposium

Join us next week!
Multimodal Treatment of Spinal Tumors symposium
Friday, February 25, 2011
 
 
 
 Course Chair: Rod J. Oskouian, Jr., M.D, Neurosurgery, Spine Surgery, Swedish Neuroscience Institute.
 
 
 
 

 Today, health-care providers who treat patients with spinal tumors are able to offer a myriad of treatment options that were essentially non-existent in the recent past.  Internationally renowned speaker, inventor, entrepreneur and neurosurgeon, John R. Alder, M.D., will present the keynote presentation at this year’s symposium and initiate our discussion of  the technical and therapeutic options available for spinal tumor patients.

For full course information and to register: http//www.swedish.org/spinaltumors2011

 
 

Pediatric Neuroscience Center receives “Tuberous Sclerosis Complex (TSC) Clinic” Designation

February 3, 2011. The Tuberous Sclerosis Alliance announced today that it has designated the Swedish Pediatric Neuroscience Center (SPNC) at SNI as a TSC Clinic. Marcio Sotero, MD, medical director of SPNC, is the director of the new center. This designation is an important step forward in the regional delivery of care to patients with tuberous sclerosis, as the TSC Clinics closest to Seattle are located at the Barrow Neurological Institute in Phoenix and Children’s Hospital in Oakland, CA.

TSC is a genetic disorder that causes tumors to form in many different organs, primarily in the brain, eyes, heart, kidney, skin and lungs. Seizures are a very common manifestation, and some people with TSC experience developmental delay, mental retardation and autism.

SNI Grand Round Series 2011 – Epilepsy Genetics

Thursday, February 3, 2011
7:30am – 8:30am
Swedish Education Conference Center, Room B

 

Marcio Sotero de Menezes, MD, Pediatric Epilepsy, Pediatric Neurology, Swedish Neuroscience Institute

 

 

 

Objectives:

At the conclusion of this session, attendees will have an increased ability to:

  • Identify genetic epilepsy syndromes 
  • Explain treatment of genetic epilepsy syndromes

SNI Grand Round Series is every 1st and 3rd Thursday of each month. 

Winter Issue of BrainWaves Now Available

The Winter 2010 edition of BrainWaves is now available online.  

BrainWaves is the newsletter of the Swedish Neuroscience Institute. Published quarterly, BrainWaves provides information about neurological conditions treated at the Institute, and also profiles the programs, services, and new initiatives of the institute and its staff.

 

Also check out our past editions of the BrainWaves newsletter.