Implantable Device Lowers Blood Pressure
For individuals who have hypertension that does not respond well to drugs, there may soon be an implantable device that can lower their blood pressure. Scientists at the University of Rochester Medical Center are in the advanced stages of testing an experimental device that reduces blood pressure, and it may be cost effective as well.
High blood pressure for adults is defined as a systolic pressure of 140 mmHg or higher, or a diastolic pressure of 90 mmHg or higher. Normal blood pressure is lower than 120 mmHg/80 mmHg, and anything in between these two ends of the spectrum is defined as prehypertension. The American Heart Association notes that about 73.6 million people in the United States age 20 and older have high blood pressure, which is about one in three adults.
The new blood pressure device is called the Rheos High Blood Pressure or Hypertension Therapy System and consists of a battery-powered implantable generator which is placed under the skin near the collarbone. The device has two leads that go to the left and right carotid sinus in the neck. When blood pressure rises, the brain receives signals, which it then responds to by sending signals to the body to relax the blood vessels and inhibit production of stress-related hormones.
To determine whether the implantable device would be cost effective, investigators with the University of Rochester study evaluated data from two large population-based studies and compared the incidence of stroke and heart attack for people with and without the benefit of using the device. They then projected the health care costs associated with stroke and heart attack over a patient’s lifetime. They concluded that if the implantable device maintains its current level of performance, then it is a cost effective way to control high blood pressure.
In order to be considered a cost effective approach to high blood pressure, the study determined that Rheos needed to reduce blood pressure by 24 mmHg. In the current trials the device has lowered blood pressure by 30 to 35 mmHg.
Although most people who have high blood pressure can control it effectively through proper nutrition, exercise, and use of medication, a significant percentage do not response adequately to this approach and often need multiple medications. It is estimated that 20 to 30 percent of people who have high blood pressure are resistant to drug treatment. Two of the strongest risk factors for drug-resistant hypertension are age and obesity.
Rheos is currently in Phase III clinical trials at various locations throughout the United States, including Rochester, as a way to treat drug-resistant hypertension. Finding a way to control this type of high blood pressure is important because these individuals are at greatly increased risk for stroke, heart attack, heart failure, kidney disease, and death. Availability of an implantable device could greatly improve the lives of millions of people who have drug-resistant high blood pressure.
American Heart Association
Gonzaga CC, Calhoun DA. Current Hypertension Reports 2008 Dec; 10(6): 496-503
Young KC et al. Journal of Clinical Hypertension (Greenwich CT) 2009 Oct; 11(10): 555-63