Deep Brain Stimulation for Stubborn Hypertension
Case Study Suggests Stimulating Brain With Electrical Impulses May Treat High Blood Pressure
Blood Pressure Control continued...
At first, the neurostimulator seemed to help the pain, and when doctor’s measured their patient’s blood pressure, they were surprised to find that it had dropped significantly -- to as low as 80/53.
They took the patient off all his hypertension medications, and his blood pressure normalized to an average of110/65 in the first eight weeks after surgery. Within 12 weeks, his blood pressure had inched back up only slightly to 124/76.
After four months, the pain relief from the electrical stimulation wore off, but his blood pressure stayed down.
After more than two years, with blood pressure still near normal, his doctors tested his response by switching the neurostimulator on and off.
When the device was off, his blood pressure increased by about 18/5 points. When it was turned back on, his blood pressure dropped by 33/13 points.
Drug-Resistant High Blood Pressure
According to the National Center for Health Statistics, about one in three Americans has high blood pressure. Studies suggest that about one in eight people being treated for hypertension can’t get their blood pressure under control, even on three or more medications.
Uncontrolled high blood pressure can lead to myriad health problems including heart and kidney failure, eye damage and blindness, strokes and heart attacks, dementia, and erectile dysfunction.
When medication fails, newer surgical interventions -- including renal nerve ablation, where nerves in the major arteries of the kidneys are zapped and deactivated with radiofrequency energy, and carotid baroreceptor stimulation, where electrodes stimulate nerves near major arteries that supply blood to the brain -- may be options that can help reduce the risks of major complications from very high blood pressure.
“These treatments are not a panacea,” Patel says. “One-third of the people who get these interventions are still not helped.”
With further testing, experts think deep brain stimulation could become a third interventional option for patients.
“It’s a procedure with tiny, but important risks” says Pereira.
Those risks include bleeding in the brain, infection, and reactions to the surgical anesthesia.
Additionally, the electrodes may be placed too closely to other brain areas and affect things like speech and movement, and the wires may break or malfunction.
“But if we can follow a group of patients over three years or more and show that the blood pressure reductions are sustained, this could become an important third option.
Deep Brain Stimulation and Blood Pressure
The region of the brain being stimulated in these procedures, which is called the periaqueductal gray (PAG)/periventricular gray (PVG) region, acts like a switchboard for pain signals throughout the body. It also controls the body’s response to stress, the fight-or-flight response.
In response to a perceived threat, the body prepares for action by increasing the heart rate and blood pressure.
Some researchers think that stimulating the PAG/PVG region can help shut down an overactive stress response, letting blood pressure and heart rate return to normal levels.
In deep brain stimulation, electrodes are implanted into areas of the brain. Wires attach the electrodes to small, metal electrical impulse generators that are implanted under the skin on the chest.
Deep brain stimulation is FDA approved to treat movement disorders, including Parkinson’s disease and essential tremor. It is also has an FDA humanitarian device exemption for treatment of dystonia and severe cases of obsessive-compulsive disorder.