Heart Health
A nondrug approach to lower blood pressure
Called renal denervation, the technique targets nerves that supply the kidneys. Who's a candidate for this recently approved procedure?
- Reviewed by Christopher P. Cannon, MD, Editor in Chief, Harvard Heart Letter; Editorial Advisory Board Member, Harvard Health Publishing
In 2023, the FDA approved two renal denervation systems for treating high blood pressure (hypertension) that can't be controlled with lifestyle changes and medication — a serious problem in the United States.
Both systems work by disrupting some of the nerves surrounding the renal arteries, which supply blood to the kidneys. One system uses ultrasound energy to target the nerves, and the other uses radiofrequency energy. A third system, still under review at the FDA, uses alcohol.
|
The network of nerves throughout your body receives signals from your brain, heart, and kidneys to help regulate your blood pressure. Heightened activity in these nerves can raise blood pressure. A procedure that disrupts some of the nerves surrounding the arteries that supply the kidneys can lower blood pressure. |
Possible candidates
A typical blood pressure target is less than 130/80, but doctors may adjust that goal based on a person's other health conditions.
About one in seven people has what's known as resistant hypertension, defined as a blood pressure that's above their goal despite the use of three or more blood pressure drugs, including a diuretic. These people are the most obvious candidates for renal denervation, according to an American Heart Association scientific statement published Aug. 5, 2024, in Hypertension.
However, both systems are approved more broadly as add-on treatment for people whose blood pressure remains high despite lifestyle changes and medications, even if they don't precisely meet the definition of resistant hypertension. "The average person with hypertension needs two to three medications to reach their blood pressure target," says Dr. Randall Zusman, director of the Division of Hypertension at Harvard-affiliated Massachusetts General Hospital. But some people need four, five, or even six different drugs to reach their goal, he adds.
Some people who appear to have resistant hypertension simply aren't taking their drugs as prescribed. "They're reluctant to use medications because of earlier experiences with unpleasant side effects, or they're already taking so many other drugs they don't want to take additional ones," says Dr. Zusman. But potential candidates for renal denervation also include people currently taking just two drugs, or even just one, who cannot tolerate higher doses or additional medications.
How effective is the procedure?
Renal denervation lowers systolic blood pressure (the first number in a reading) by an average of 8 to 9 points — about the same as what people get with a single blood pressure drug. However, the response varies widely; some people experience more dramatic drops, while others have no response. So far, efforts to pinpoint why the procedure works better for certain people have been fruitless, and exactly how renal denervation works remains unclear. The latest evidence suggests the benefits persist for at least three years.
What happens during renal denervation?
For the procedure, a physician guides a thin, flexible catheter into a vessel at the top of the thigh and threads it through the blood vessels to the renal arteries (see illustration). A tiny device at the catheter's tip disables some of the nerves leading to each kidney. The procedure is done under conscious sedation (you're drowsy and relaxed but may feel some pain) and takes about 45 minutes. Afterward, people stay in the hospital or surgery center for at least six hours and sometimes overnight.
Most catheter-based treatments for heart problems are now done through an artery in the wrist, which leads to less bleeding and a faster recovery. "But the catheters in the currently available renal denervation devices aren't narrow or long enough to pass through the wrist down to the kidneys," says Dr. Joseph Garasic, medical director of the Cardiac Catheterization Laboratory at Massachusetts General Hospital. However, catheters that would enable a wrist approach are in development and should be available within a year or two, he says.
For now, renal denervation is being performed only at major medical centers and those that participated in clinical trials of one of the devices. "Right now, we're focusing on treating people with the greatest need — for example, someone with a systolic blood pressure of 180 despite taking five medications," says Dr. Garasic. But he anticipates broader use of the technique in the coming years, especially after the wrist catheters become available.
"In the future, I think doctors might use renal denervation in younger people newly diagnosed with high blood pressure as an alternative to drug therapy," says Dr. Zusman.
Image: © pixologicstudio/Getty Images
About the Author
Julie Corliss, Executive Editor, Harvard Heart Letter
About the Reviewer
Christopher P. Cannon, MD, Editor in Chief, Harvard Heart Letter; Editorial Advisory Board Member, Harvard Health Publishing
Disclaimer:
As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review or update on all articles.
No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.
