Novel therapy fails for lowering blood pressure

March 29, 2014 by Kerry Sheridan
A medical student checking blood pressure using a sphygmomanometer and stethoscope. Image: Wikipedia.

An experimental therapy that was once hailed as a possible cure for people whose high blood pressure does not respond to medication, has been shown to be ineffective, a US study said Saturday.

Known as , the process involves inserting a catheter into a patient's arteries and delivering radiofrequency energy that inactivates kidney nerves.

It was believed to offer a pathway to lowering blood pressure by interrupting electrical signals to and from the kidney, an organ that is a key player in regulating blood pressure.

It has been approved for use in 80 countries, but is still considered experimental in the United States.

In a randomized trial of 535 people, in which some were treated with the procedure and others received a fake therapy, both groups saw decreases in blood pressure after six months, but the difference between them was not statistically significant.

In other words, the real thing did not lower their blood pressure any better than a placebo.

The findings were published in the New England Journal of Medicine, and were presented at the American College of Cardiology annual meeting.

"This is the first blinded trial or sham controlled trial in the field of renal denervation," said Deepak Bhatt, professor of medicine at Harvard Medical School, and co-principal investigator.

"We found safety of this approach but no actual added medical benefit," he told reporters.

Experts urge caution

The company that owns the technology, Medtronic, first announced in January that findings from Bhatt's study, called SYMPLICITY HTN-3, had shown the product to be ineffective and said it would halt enrollment in studies using it in Japan, India and the United States.

Medtronic bought the technology, known as the Symplicity Catheter System, in 2011 for $800 million dollars when it acquired the California-based company Ardian, Inc.

Franz H. Messerli, director of the hypertension program at Mount Sinai hospital in New York, said this finding could spell the end for renal denervation, even though it contradicts most previous research on the therapy.

"Previously, renal denervation has been widely touted as the next big therapy for millions of patients with resistant hypertension. It has even been called a possible new 'cure,'" said Messerli.

"However, the SYMPLICITY HTN-3 study results now may close the book on renal denervation and bring the renal-denervation train to a grinding halt."

High blood pressure raises the risk of heart attack and stroke for up to a billion adults across the globe.

About 10 percent of patients are diagnosed with resistant hypertension, which means their systolic is 140 mm Hg or higher even when they are taking maximum doses of at least three medications to lower it.

Anthony DeMaria, editor in chief of the Journal of the American College of Cardiology, said the study was "one of the most anticipated" of the meeting.

Early data on the procedure led to "an initial rush of enthusiasm," he told reporters, adding that some research has shown as many as 10,000 of these procedures have been done worldwide already, including in Europe.

"There is some really tantalizing data out there suggesting this could be a benefit," he said.

But more research needs to be done to figure out whether the procedure is actually accomplishing what it sets out to do, and for now experts are urging caution.

"It is clear that we only have a minimal understanding of what is going on," DeMaria said.

Explore further: Renal denervation achieves significant and sustained blood pressure reduction

Related Stories

Renal denervation achieves significant and sustained blood pressure reduction

August 27, 2012
Renal denervation leads to significant and sustained blood pressure reduction for up to 18 months in patients with treatment resistant hypertension, according to research presented at ESC Congress 2012. The new clinical data ...

Study tests new therapy for treatment-resistant hypertension

June 28, 2012
(Medical Xpress) -- Treatment-resistant hypertension affects nearly 6 million Americans and another 94 million people worldwide and is associated with increased cardiovascular risk, including stroke and heart attack, as well ...

Radio waves to kidneys lower persistent high blood pressure

December 17, 2012
Directing short bursts of radio waves at nerves surrounding the kidneys lowered blood pressure for at least six months and up to one year among patients with hypertension that persists regardless of taking multiple medications ...

Kidney procedure might help ease tough-to-treat high blood pressure

November 20, 2013
(HealthDay)—A new therapy may help lower tough-to-treat high blood pressure in people with chronic kidney disease, a new study finds.

NY-Presbyterian Hospital announces participation in trial for hard-to-treat hypertension

October 25, 2012
Patients with hypertension whose blood pressure cannot be brought down to safe levels despite taking three or more medications may have some relief coming their way. An innovative, first-of-its-kind clinical trial for a device ...

ESC recommends patients and centres for renal denervation

April 25, 2013
Up to 10 per cent of patients with high blood pressure are resistant to treatment, which puts them at increased risk of cardiovascular events, including heart attacks. Clinical trials show that catheter-based renal denervation ...

Recommended for you

How Gata4 helps mend a broken heart

August 15, 2017
During a heart attack, blood stops flowing into the heart; starved for oxygen, part of the heart muscle dies. The heart muscle does not regenerate; instead it replaces dead tissue with scars made of cells called fibroblasts ...

Injectable tissue patch could help repair damaged organs

August 14, 2017
A team of U of T Engineering researchers is mending broken hearts with an expanding tissue bandage a little smaller than a postage stamp.

Air pollution linked to cardiovascular disease; air purifiers may lessen impact

August 14, 2017
Exposure to high levels of air pollution increased stress hormone levels and negative metabolic changes in otherwise healthy, young adults in a recent study conducted in China. Air purifiers appeared to lessen the negative ...

Study hints at experimental therapy for heart fibrosis

August 14, 2017
Researchers report encouraging preclinical results as they pursue elusive therapeutic strategies to repair scarred and poorly functioning heart tissues after cardiac injury—describing an experimental molecular treatment ...

Scientists identify mutations in venous valve disease

August 14, 2017
A team of scientists has discovered that mutations in the genes FOXC2 and GJC2 are associated with defects in venous valves, flaps within veins that help maintain proper blood flow.

Mechanism behind sudden cardiac deaths in sports uncovered

August 10, 2017
Researchers have worked out the mechanism behind sudden cardiac deaths that follow a hard blow to the chest.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.