WEDNESDAY, July 27 (HealthDay News) -- For people with high
blood pressure that medication can't control, a new implantable
device shows promise, researchers report.
The device, surgically placed just below the collarbone, sends a
four- to six-volt electrical jolt to the carotid arteries. This is
said to lower blood pressure through a process known as baroreflex
The device might help tackle a growing problem, said the lead
author of the study, which was funded by CVRx Inc., the device's
"We are seeing more patients with resistant hypertension these days," noted Dr. John D. Bisognano, who is a consultant for CVRx Inc. and a professor of medicine in the division of cardiology at the University of Rochester. "There are a lot of heavier people. There are a lot of diabetic people. We are also realizing that the available drug treatment can't solve the problem for everybody."
As he explained it, the pulses generated by the implant trick
the body into thinking that blood pressure has spiked. In response,
the body sends out regulators that cause blood pressure to
The results of a new trial were presented in April at a meeting
of the American College of Cardiology in New Orleans and are now
being published in the July 27 issue of the
Journal of the American College of Cardiology.
The phase 3 trial included 265 patients whose systolic blood
pressure (the top number in a reading) was high -- an average of
179 mmHg, according to Bisognano. He said the patients were
hypertensive despite taking up to three blood pressure
Blood pressure readings higher than 140/90 mmHg increase the
risk of heart and kidney disease, stroke and death, experts
In one group of patients the device was activated one month
after implantation, while in another group activation of the device
was delayed for six months.
The researchers looked at several factors over the course of the
study. These included a reduction in systolic blood pressure at six
and 12 months, the safety of the operation needed to implant the
device, the safety of baroreflex activation therapy and the safety
of the device itself.
At monthly visits, if a patient's target was not met, the
voltage was upped to further lower blood pressure.
The device did work well in many patients, the researchers
reported. During the first six months, 42 percent of those whose
device was turned on got their systolic blood pressure down to 140
mmHg, compared with 24 percent of those whose device was not yet
In addition, there was a 40 percent reduction in the rate of
problems caused by high blood pressure in the group whose device
was turned on.
At one year, with the device now active in both groups, 52
percent of the patients reached the blood pressure goal of 140
mmHg, Bisognano said. He added that while using the device patients
continued to take their blood pressure medications as usual.
However, there was no further reduction in systolic blood
pressure among patients who received baroreflex activation therapy
for a year, compared with those who received it for six months,
Bisognano's group noted.
There were some safety issues as well. Some patients had
problems stemming from the placement of the electrodes in the neck,
including permanent nerve damage and complications from the surgery
itself. And although most patients (74.8 percent) had no problems,
that rate was still below the 82 percent the researchers had been
hoping for, Bisognano said.
Approval of the device by the U.S. Food and Drug Administration
is still years away, if ever. While a price tag for the device plus
implantation is yet uncertain, Bisognano said he believes the
treatment will be cost-effective given the cost of taking care of
patients who suffer heart attacks or strokes from hypertension. And
he noted that the device is currently being redesigned to use
smaller implantable leads that should reduce surgical
"This is a very promising device," Bisognano said. "It's something we are likely to see in the future."
Commenting on the study, Dr. Gregg C. Fonarow, a professor of
cardiology at the University of California, Los Angeles, said that
"of the 72 million adults with hypertension in the United States,
between 20 to 30 percent may have hypertension which is resistant
to conventional medical treatment."
There have been active investigations of a number of
experimental therapies designed to modulate the nervous system to
improve blood pressure control for these patients, he said.
"Although this trial demonstrated a sustained lowering of blood pressure and evidence that once the device was implanted therapy appeared reasonably safe, the trial did not demonstrate a significant reduction in early blood pressure control and there were greater than expected complications placing the device (approximately 1 in 4 patients experiencing a procedure-related complication)," Fonarow said.
Still, "some patients did experience impressive reductions in
blood pressure with the baroreflex activation therapy," he said.
"Further prospective studies will be required to evaluate the
safety and efficacy of this experimental therapy for resistant
For more information on high blood pressure, visit the
American Heart Association.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
Copyright © EBSCO Publishing. All rights reserved.