Only about half of patients have their hypertension under control. Most need multiple drugs to treat it. Some 10 percent, more than 7 million people like Ezzell, have the resistant hypertension that is the initial target of the nerve-zapping procedure _ people with high blood pressure despite three or more different kinds of medications.
Renal denervation, the procedure being promoted by Minneapolis-based Medtronic and other companies, has its roots in primitive nerve-severing operations performed in the 1950s, which often lowered blood pressure but at the expense of permanently injuring patients. Only in recent years have researchers revisited the technique, after companies developed easy-to-use catheters that can beam radiofrequency waves to burn away specific nerves without damaging the surrounding blood vessel.
It’s aimed at only the hardest-to-treat patients. In small Medtronic studies, those treated saw the key top number of a blood pressure reading drop an average of 33 points, although they still needed their medications. Medtronic reported in March that the improvements were lasting up to three years. The company’s Symplicity catheter is approved to treat hypertension in Europe and Australia, as are some competitors’ versions.
The U.S. Food and Drug Administration required a more rigorous study, now enrolling more than 500 people, that includes an unusual step to prove if it really works. Some patients receive the real procedure and some get a fake _ just the catheter, no zapping. Patel describes patients wearing a blindfold and earphones while lying sedated on the treatment table, to ensure they don’t know which they’re getting.
Although pilot studies show few side effects, potential risks include bleeding, an injured blood vessel, immediate blood pressure or heartbeat problems, or complications from medications used in the procedure.
Ezzell’s systolic pressure, that top number, hovers around 190 and sometimes jumps to a super-dangerous 230, despite his six daily drugs.
Ezzell was treated this month and is waiting to see if his blood pressure drops, which earlier research shows happens gradually over six months.
Cardiologists are excited by the early findings, said Dr. Gordon Tomaselli, the heart association’s president.
But “what we don’t know is the long-term effect” of nerve zapping, Tomaselli cautioned. “It’s going to take a little bit of time to make sure there are not adverse effects two years, three years, 10 years down the line.”
In the last three years, the FDA has approved similar catheters that beam radio waves to treat asthma and a type of irregular heartbeat, conditions traditionally treated with medications.
More than five dozen companies are pursuing devices for hypertension, from catheters similar to Medtronic’s to permanent implants left in arteries to regulate blood pressure.
In Europe, Medtronic’s hypertension procedure costs about $14,000, sticker shock compared with the generic prices of standard hypertension medications and another reason for careful study to prove its effects.
Gwen Dirks, 71, of Virginia, Ill., was grateful to get the procedure in an early study. Her blood pressure was 200 over 120 despite two drugs.
“I’ve been on medications since I was 40,” Dirks said. “Over the years I have tried many different things and got to the point where they no longer worked.”