(NBC) - A nationwide clinical trial is testing a minimally invasive procedure, called renal denervation. It zaps the nerves involved in this multi-organ system.

"You're interrupting the fight or flight nervous system from sending signals to the kidneys which help lower blood pressure," said Crystal Simpson M.D., a nephrology fellow.

Doctors thread a catheter to the kidney artery and apply radio frequency waves to certain nerves.

The idea is to calm the signals between the brain and kidneys, causing the blood vessels to relax.

Renal denervation is not approved in the US, but studies in Europe suggest it works.

"It showed a significant reduction in their blood pressure, 20 to 30 millimeters, now out 3 years or more," said Manesh Patel, M.D., of Duke University Medical Center.

Patients in the trial won't know if they're getting the real procedure or a fake.

So far, doctors have seen minimal side effects linked to the procedure, but admit they don't know much about the long-term effects.

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