CHICAGO (Reuters) - A device that destroys nerves leading to the kidney safely lowered blood pressure in people with treatment-resistant hypertension, potentially offering a new option for millions of people who struggle to keep their disease in check, researchers said on Wednesday.

The device, made by privately held Ardian Inc of Mountain View, California, lowered the top blood pressure reading by an average of 32 points after six months, compared with no change in patients who took the best available medicines.

“There are a lot of questions, but it is very exciting,” said Dr. Suzanne Oparil of the University of Alabama at Birmingham, who reviewed the findings presented at the American Heart Association meeting in Chicago.

The one-time treatment works by silencing nerves leading into and out of the kidney, which play a central role in the sympathetic nervous system, the body’s “fight or flight” response that can increase heart rate and blood pressure.

Procedures that surgically disrupt these nerves had been shown to lower high blood pressure decades ago, but were abandoned with the advent of drugs that target the renin-angiotensin system, which regulates blood pressure and fluid retention.

“Those drugs are good but not perfect,” said Dr Murray Esler of the Baker IDI Heart and Diabetes Institute in Melbourne, Australia, whose findings were released online by the Lancet.

“We can see that because of their failure in the patients on this trial. They are all on drugs of this type.”

BLOOD PRESSURE READING FELL BY 32 POINTS

High blood pressure, or too much force exerted by blood as it moves against vessel walls, is the leading risk factor for premature death worldwide.

Nearly half of Europeans have hypertension, and in the United States, about 75 million Americans do -- and only two-thirds of those people are treated. Among those who are, half do not get their blood pressure under control.

Normal blood pressure is considered to be 120 over 80 or lower. A top reading of over 140 is considered high blood pressure.

The treatment uses a thin tube or catheter that is inserted through a puncture in the groin and fished through blood vessels into the artery leading to the kidney.

Once in place, the device applies short bursts of low-power radiofrequency energy to destroy nerves lining the vessel. The device rotates to ensure no area receives too much energy.

In the study, about half of 106 patients were randomly picked to have the procedure in addition to their drugs. The other half only took medication.

“They were sick hypertensives on an average of five medications in both groups,” Esler said.

After six months, blood pressure among those who got the treatment fell by 32 points on the top reading and 12 points on the bottom reading, pushing some into the near-normal range. There was no change in the control group.

“It was a big effect,” Esler said. “The main pressure in the group after denervation was 145, and in 39 percent of them, it was 140 systolic.”

“It’s a much bigger effect than you would anticipate in a drug trial, particularly in these people, who are resistant to drugs anyway,” Esler said.

And it appears safe. “The side effects of the trial were almost zero,” Esler said. But it is not a cure, he said.

“Most of this group are still on medications. They are not cured. If you tried this out on milder hypertensives, maybe you could cure it. That is a dream, but we are thinking about it.”

The treatment is already approved for use in Europe, and Ardian Chief Executive Andrew Cleeland said the company is in talks with the Food and Drug Administration to structure a late-stage U.S. trial, which could start next year.

Cleeland said the procedure costs 10,000 euros, or about $13,500.

Cardiologist and past president of the American Heart Association Robert Bonow, who was not involved in the study, said, “There is some expense involved, but the expense may be less than patients taking four or five pills every day for 40 years.”