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A minimally invasive procedure that disables nerves leading to the kidneys maintained reduced blood pressure for 6 months with less prescribed medications.Investigators have announced the 6-month results of an international clinical trial on the safety and effectiveness of renal denervation by ultrasound as a treatment for mild to moderate high blood pressure.
The findings featured recently at the American College of Cardiology Conference in New Orleans and in a study paper in the journal Circulation. Surgeons carry out the procedure, which takes about 1 hour, under local anesthetic. It decreases activity in nerves that link the brain to the kidneys and carry signals that regulate blood pressure.
The 2-month results from the randomized, controlled trial had already shown that the procedure resulted in a more significant reduction in blood pressure, compared with a “sham operation.” None of the people in the trial took their blood pressure drugs during the first 2 months. They then resumed blood pressure medication in a managed way, as necessary.
Now, the more recent results reveal that the participants who underwent the ultrasound surgery maintained their reduced blood pressure for 6 months. Compared with those who had the sham operation, fewer participants who had the surgery needed to resume blood pressure medication, and those who did required fewer drugs at lower doses.
“These results,” says lead trial investigator in the United Kingdom Melvin D. Lobo, a professor at Queen Mary University in London and also of Barts Health NHS Trust, both in the U.K., “point towards an exciting future for this new technology.” Having high blood pressure increases the risk of heart disease, heart failure, and other conditions. Some people can keep their blood pressure under control by watching their weight, doing plenty of exercise, and maintaining a healthful diet. Others may need to supplement these measures with medication.
However, some people struggle to control high blood pressure even with lifestyle changes and medication. The kidneys have a rich system of nerves for sending and receiving messages. Scientists have discovered that overactivity in this system can raise blood pressure through its interaction with the body’s sympathetic nervous system. Renal denervation by ultrasound is a treatment that aims to relieve high blood pressure by disrupting the nerves leading to the kidneys.
The procedure involves inserting a device through a catheter in the groin to reach up into the artery of a kidney. The device emits ultrasound waves that then heat up and damage some of the nerve fibers that surround the artery. Those who underwent renal denervation also showed a greater reduction in blood pressure. After 6 months, the average reduction was 18.1 millimeters of mercury (mm Hg) in the treatment group and 15.6 mm Hg in the sham operation group.