Significant reduction in blood pressure with implantable device system

A device first implanted in the United States at the University of Rochester Medical Center as part of a clinical trial is showing a significant reduction in blood pressure in patients who suffer from severe hypertension and cannot control their condition with medications or lifestyle changes.

Early findings were shared this week by University of Rochester Medical Center cardiologist John Bisognano, M.D., Ph.D., and Minneapolis-based device-maker CVRx at the American Heart Association 2006 Scientific Sessions in Chicago.

The ongoing study is assessing the safety and clinical efficacy of the RheosTM Baroreflex Hypertension TherapyTM System, an implantable device for the treatment of hypertension in patients with drug-resistant hypertension, who have a systolic blood pressure of 160 mmHg or greater. The University of Rochester implanted the first device in the U.S. in March 2005, and performed a total of three of the initial 10 implantations.

Hypertension affects about 65 million people in the U.S. It is estimated to cause one in every eight deaths worldwide. Each increase of 20 mmHg in systolic blood pressure or 10 mmHg in diastolic blood pressure above normal level is associated with a two-fold increase in death rates from stroke, coronary heart disease and other vascular causes. Approximately 25 percent of people with hypertension cannot control their high blood pressure, despite the use of multiple medications.

"The Rheos System is a novel device that activates the carotid baroreflex, the body's own system for regulating blood pressure," Bisognano said. "We are pleased with the clinical results to date and look forward to expanding the clinical evaluation of the Rheos System. New approaches to the widespread, chronic and costly problem of hypertension are needed. The Rheos System has the potential to prevent the progression to more serious illnesses, including heart and kidney disease, stroke and death."

The system works by electrically activating the baroreflex system based in the carotid arteries in the neck. Low-level electrical stimulation to this area sends signals to the brain, "telling" it to take action to lower blood pressure through a variety of mechanisms, including blood vessel dilatation, heart rate reduction and promotion of fluid excretion by the kidneys. In this way, the system provides a physiologic approach to reducing high blood pressure by allowing the brain to direct the body's own control mechanisms. It consists of a battery-powered implantable generator, which is inserted under the skin near the collarbone, and two carotid sinus leads, which run from the generator to the left and right carotid sinus in the neck. While implantation is slightly more involved, the general principle is similar to the implantation of cardiac pacemakers.

The trial is designed to assess device safety and efficacy in patients with systolic blood pressure of 160 mmHg or greater, despite being on at least three anti-hypertension medications, including one diuretic. The presentation reported on the first 10 U.S. patients enrolled in the trial. After one month of surgical recovery, baseline blood pressure was assessed and the device was activated. Three months of active Rheos therapy reduced systolic blood pressure by an average of 22 mmHg (180 mmHg vs. 158 mmHg) and diastolic blood pressure by an average of 18 mmHg (105 mmHg vs. 87 mmHg), using office cuff measurements. The implants were well tolerated and there were no unanticipated serious adverse events related to the system or procedure.

In October, CVRx received a conditional investigational device exemption (IDE) approval from the U.S. Food and Drug Administration to begin a pivotal clinical trial that will evaluate the safety and effectiveness of the RheosTM Baroreflex Hypertension TherapyTM System in a much larger number of patients. The University of Rochester team recently implanted a fourth device as part of the study.

"These interim clinical results are favorable and promising for the many people with drug-resistant hypertension," said Nadim Yared, president and CEO of CVRx. "We are excited about launching our pivotal trial and look forward to working with our investigators."

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Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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