New approach examined for hard-to-treat hypertension
By Lauran Neergaard and Matthew Perrone, AP
May 30, 2012, 12:17 am TWN
WASHINGTON--Despite an arsenal of drugs, millions of people can't get their blood pressure down to safe levels. Now, in a high-stakes experiment at dozens of U.S. hospitals, scientists are testing a dramatically different approach for the toughest-to-treat patients, by burning away some overactive nerves deep in the body that can fuel rising blood pressure.
To attempt an invasive treatment — a catheter is threaded through blood vessels in the groin up to the kidneys — reflects doctors' frustration with a disease that too often is underrated because people with it don't look or feel sick until a lot of damage has been done.
Pharmaceutical therapies have been the cornerstone of medicine for nearly a century, offering convenient, noninvasive treatment for countless diseases. But when it comes to some of the most stubborn chronic conditions, including diabetes, obesity and hypertension, medications too often aren't enough.
Researchers increasingly are trying medical devices and minimally invasive surgeries to help, such as stomach-shrinking techniques that improve obesity-caused diabetes and the new hypertension experiment.
"I think we have to hit on all cylinders if we're going to take on these very important diseases," said Dr. Steven Nissen, chair of the Cleveland Clinic's department of cardiology. "There are many examples where this convergence is taking place, where you push the drugs as far as you can, but when they can't go any further, you step in with more invasive approaches."
Cardiologists' interest in the nerve-zapping procedure also reflects how severe the burden of hypertension is poised to become, with many middle-aged baby boomers already affected.
"People are living longer with hypertension, and the disease tends to get worse as you get older," said Dr. Suzanne Oparil, a hypertension specialist at the University of Alabama, Birmingham. "The complications pile on later."
If deadening kidney nerves sounds like a strange way to attack hypertension, consider that nerves in the body's "fight or flight" system play a role in signaling kidney functions, which in turn help regulate blood pressure, such as by relaxing or tightening key arteries.
"If there was a snake in the room, all of our blood pressures would go up, appropriately so," explained interventional cardiologist Dr. Manesh Patel of Duke University, one of more than 60 medical centers around the country studying Medtronic Inc.'s nerve-zapping procedure.
But sometimes those nerves stay switched on when they shouldn't be, something today's medications can't address. The hope is that destroying a small number of the nerves could calm an overactive system, relaxing arteries and lowering blood pressure.
"Interrupting that signal makes physiologic sense," Patel said.
Some 78 million people in America, about 1 in 3 adults, have high blood pressure, meaning readings of 140 over 90 or higher. An additional 27 million people will have it by 2030, says a grim forecast from the American Heart Association. That's because the population is getting fatter and older. In fact, about half of Americans in their 50s have high blood pressure but by age 75, three-fourths do.