Device Significantly Reduces Blood Pressure, Improves Heart Function
Long-term data from Rheos clinical trial continues to show favorable results
Tuesday, August 25, 2009
A device that was first implanted in the United States at the University of Rochester Medical Center as part of a clinical trial is showing not only a significant reduction in blood pressure, but also an improvement in heart structure function for heart failure patients.
The Rheos System, developed by CVRx Inc. of Minnesota, activates the carotid baroreflex, the body’s system for regulating blood pressure, and may provide a future treatment option for the millions of people who cannot control their hypertension with medications and lifestyle modifications, said cardiologist John Bisognano, M.D., Ph.D., associate professor of Medicine and director of Cardiac Rehabilitation and Clinical Preventive Cardiology.
Two-year and three-year data from European and U.S. clinical studies evaluating the safety and clinical effectiveness of the Rheos System were presented by Bisognano and Marcos Rothstein, M.D., of the Washington University School of Medicine at the most recent scientific session of the American College of Cardiology. The findings show a significant reduction in blood pressure in patients with drug-resistant hypertension who have a systolic blood pressure of 160 mmHg or greater, despite being on at least three anti-hypertension medications, including a diuretic.
Results are based on cuff measurements after two and three years of active Rheos therapy for the first European and U.S. patients enrolled in these trials at 11 medical centers, Bisognano said. After three years of active Rheos treatment, systolic blood pressure was reduced by an average of 31 mmHg in 22 patients. The Rheos implants were well tolerated.
Additional clinical data demonstrate that continuous use of Rheos Therapy in 33 Stage II hypertension patients (systolic blood pressure > 160 mmHg) improves left atrial and ventricular chamber size and dimension and improves diastolic filling velocities. These benefits were incremental to those achieved with aggressive medical therapy.
Specifically, Rheos therapy decreased the size of the heart (left ventricular mass and left atrial dimension) and decreased diastolic blood flow velocities, suggesting an improvement in left ventricular filling pressure over a 12-month period. These changes reduce the amount of energy the heart uses to meet the needs of the body and decrease stress on the heart. A feasibility study is now under way to assess the potential benefit of Rheos therapy in advanced heart failure patients.
How the device works
The Rheos System activates the carotid baroreceptors, central components of the body’s natural cardiovascular regulation system. The baroreceptors prompt signals that are sent through neural pathways to the brain and interpreted as a rise in blood pressure. The brain works to counteract this perceived rise in blood pressure by sending signals to other parts of the body (heart, blood vessels and kidneys) that relax the blood vessels and inhibit the production of stress-related hormones. These changes enable the heart to increase blood output, while maintaining or reducing its workload, thereby reducing blood pressure when it is elevated and alleviating the symptoms of heart failure.
Karl A. Illig, M.D., chief of the Division of Vascular Surgery, is principal investigator for the Rochester trial site. Cardiologist John D. Bisognano, M.D., Ph.D., associate professor of Medicine, who has been involved in development of this technology, and serves as a primary co-investigator.