The findings will be presented at the Society of Interventional Radiology's 36th Annual Scientific Meeting in Chicago.
During the procedure, called therapeutic renal denervation, a catheter-based probe that uses radiofrequency energy silences certain nerve fibers near the kidney. These are the small nerves that carry signals back and forth from the brain and kidney, and help regulate blood pressure levels.
Six months after silencing these fibers, study participants with difficult-to-treat high blood pressure had significant improvement of their blood pressure readings.
Findings from the study were first published in The Lancet in 2010.
With the experimental procedure, “we can lower the number of drugs a person needs to take and have better control of blood pressure and prevent major cardiovascular events such as stroke, heart attack, and renal failure,” says study researcher Marc R. Sapoval, MD, PhD, a professor of clinical radiology and chair of the cardiovascular radiology department at Hopital Europeen Georges-Pompidou in Paris. “In the US, there are 45 million people with high blood pressure, and half of them are not well-controlled, so this procedure has huge potential.”
Reduction in Blood Pressure
Of 106 people whose blood pressure was not controlled with at least three drugs, 39% of the participants who received the new treatment achieved the recommended blood pressure level and 50% showed a measurable benefit after six months.
Specifically, systolic pressure (the upper number in a blood pressure reading) fell by an average of 32 points and diastolic pressure (the lower number in a blood pressure reading) fell by an average of 12 points, the study shows.
There were no procedure-related complications reported in this trial, but some studies have shown an increased risk of renal artery damage, Sapoval says.
Now researchers plan to study the experimental procedure in larger numbers of people for longer periods of time.
“The first message is to take your blood pressure pills appropriately, and if your blood pressure is not controlled by taking three drugs, the new procedure may be an option in the future,” he says.
But Matthew R. Weir, MD, a professor and director of the division of nephrology at the University of Maryland School of Medicine in Baltimore, has concerns.
“My belief is that this device therapy is not ready for prime time,” Weir says in an email. Weir is a board member of the American Society of Hypertension.
“It is expensive, and not without risks [and] more important is ... to teach physicians how to treat resistant hypertension. Most patients are treatable,” he says. “These patients should be referred to hypertension specialists.”