iPod-Sized Device High Blood Pressure

Some 15 million Americans have high blood pressure that can't be controlled with medication, leaving them at high risk for early death, stroke, heart disease or kidney failure.

Researchers at Washington University School of Medicine in St. Louis are evaluating whether an investigational device can help these patients keep their blood pressure in check. Similar to a pacemaker, the iPod-sized device is implanted under the skin near the collarbone, with wires that carry electrical signals to nerve receptors along the carotid arteries in the neck. The signals activate the body's own system for regulating blood pressure.

"The device is designed to fool the brain into thinking a person's blood pressure is much higher than it really is," says the lead investigator of a U.S. study evaluating the device, Marcos Rothstein, M.D., a professor of medicine at Washington University and medical director of dialysis services at Barnes-Jewish Hospital. "The brain, as the body's central command center, responds by slowing the heart rate, relaxing the blood vessels, and filtering more salt and water from the kidneys - all of which lower blood pressure."

At the recent annual meeting of the American College of Cardiology, Rothstein presented data from a small multi-center study of 38 patients with uncontrollable high blood pressure in whom the device was implanted. On average, their blood pressure was 183/105 despite taking antihypertensive medications. Two to three years after the device was implanted, they had reduced their systolic blood pressure (top number) by an average of 31 points and diastolic pressure by an average 21 points. "These are patients for whom no drugs have worked," Rothstein says. "They had no other options."

There were minimal side effects related to the device, the most common being temporary pain at the site where the device was implanted.