New research presented this morning suggests that two-thirds of all chronic migraine sufferers have a hole in their heart or a right-to-left shunt. This leads to abnormal blood flow that bypasses the filtration process within the lungs and may be a significant contributor to chronic headache pain.
Dr. Stephen Silberstein, director of the Jefferson Headache Center at Thomas Jefferson University Hospital and former president of the American Headache Society, presented these research findings this morning at the Transcatheter Cardiovascular Therapeutics scientific symposium in Washington, D.C. TCT is the largest annual gathering in the United States of interventional cardiologists, and Dr. Silberstein's research was sponsored (in part) via a grant from Coherex Medical.
Dr. Silberstein's presentation was titled "First Report of Clinical Trial Results: The Prevalence of PFO in Patients with Chronic Migraine." In the study, 66 percent (86 of 131) of adult chronic migraine sufferers in the statistically valid research effort were found to have an abnormal right-to-left shunt of blood that travels to the left side of the heart without being properly filtered by the lungs. According to Dr. Silberstein, the most common form of RLS heart defects are patent foramen ovales (PFOs), a condition that previous research shows is typically found in 25 percent of all people.
According to Dr. Silberstein, not all PFOs cause clinical problems in patients; however, this new data may indicate that patients who suffer from chronic migraine have a higher prevalence on PFO versus the general population.
"Although the possible connection between PFO heart defects and migraines has been known for awhile, we believe this is the first time such a clear connection can be drawn between those suffering chronic migraines and RLS defects," Dr. Silberstein said. "Since the vast majority of all RLS defects are PFOs and PFOs are found in roughly 25 percent of the population, we would expect roughly 25 percent of the participants in our study to have an RLS or a PFO - in other words, approximately 33 patients.
"Instead, we found a correlation more than 2.6 times the expected results (86 patients). This is a very significant difference. In other words, it's highly likely there's a strong connection between PFO/RLS heart defects and chronic migraines. If our results are borne out in future research, such studies will suggest a fairly simple way to eliminate or reduce chronic migraine pain - close PFO defects."
Migraine Research Study Highlights
In the study directed by Dr. Silberstein and led by Dr. Stephanie Nahas, a team of Thomas Jefferson University Hospital researchers selected 277 consecutive chronic migraine patients at the hospital's headache center as possible study participants. Of these- 182 patients agreed to participate in the study,
- 140 entered the study, and
- 131 completed the study.
Finally, each participant was screened for the possibility of an RLS heart defect via a bubble Transcranial Doppler (TCD) sonographic procedure. In this test, a saline solution was pre-agitated so both the solution and microscopic air bubbles could be injected into each patient. Medical professionals then used the TCD to monitor the flow of blood to the head to see how many (if any) air bubbles streamed into the brain.
According to Silberstein, the study results were quite remarkable. Sixty-six percent of the study participants (86 out of 131) were found to have an abnormal right-to-left blow flow shunt, most likely a PFO heart defect. Additionally, 55 patients were classified as having a moderate to large amount of bubbles streaming into the brain (11-300 bubbles or more than 300 bubbles, respectively).
"We applaud Drs. Silberstein and Nahas and their team for the quality and significance of their research," said Richard J. Linder, president and CEO of Coherex Medical. "To show such a correlation between chronic migraine headaches and a right-to-left shunt, likely through a PFO heart defect, is of high scientific value and significant news for the more than 100 million chronic migraine sufferers around the world.
"Interestingly enough, Dr. Silberstein's research also found that migraine with aura was not a predictor of having a right-to-left shunt or PFO in chronic migraine populations. This finding may indeed impact future randomized controlled trials in treating chronic migraine in patients with PFO."
About Patent Foramen Ovale (PFO) Heart Defects
A foramen ovale is a tunnel-like opening between the upper chambers of the heart that allows blood to bypass the lungs and is present in all fetuses. Normally, the foramen ovale closes soon after an infant is born. However, if this opening fails to close naturally after birth the opening is said to remain patent and the condition is called a patent foramen ovale (PFO).PFO is a common heart defect that occurs in approximately 25 percent of the population. Under certain conditions, a PFO may allow blood to bypass the lungs and shunt directly from the right side of the heart to the left. Since the lungs normally filter all blood flowing through the body, this shunt may allow unfiltered blood clots and other components to travel directly to the brain.
There are at least two medical conditions that may benefit from PFO closure: migraine and stroke. Migraine disease affects approximately 12 percent of adults. Multiple retrospective studies have demonstrated a marked reduction in migraine symptoms following PFO closure. As such, the worldwide market potential for PFO closure to treat migraine patients has been estimated to be more than $15 billion per year. According to the Stroke Council of the American Heart Association, approximately 500,000 strokes each year worldwide may be attributable to the presence of a PFO, which represents a potential annual market size of close to $2 billion.