WASHINGTON (AP) — Nothing the doctors prescribed controlled Michael Garrity’s high blood pressure until they applied a treatment to remove some nerves in his kidneys. That may sound a little strange, but the reality is that the kidneys help regulate blood pressure in part through signals from certain nerves, and that new treatment interrupts the hyperactive renal nerves.
“My blood pressure would spike, I would become short of breath and feel exhausted, and that no longer happens,” said Garrity, 62, of Needham, Massachusetts. He still takes medications but at lower doses, and his blood pressure is normal for the first time in years. “I’m thrilled.”
About half of adults in the United States have high blood pressure, increasing the risk of heart attacks, strokes, kidney failure and even dementia. Many people don’t even realize they have hypertension until it has caused serious damage.
“People need to know their blood pressure, they need to know their numbers,” emphasized Dr. Randy Zusman of Massachusetts General Hospital, who specializes in the most challenging cases and urges people to at least have an annual checkup.
And only a fraction of patients have their hypertension well controlled, which means there is a need for novel strategies. The Food and Drug Administration approved the option of renal denervation about a year ago, based on studies that showed modest benefits in patients whose blood pressure remains high despite multiple medications.
Now, after the American Heart Association recently deemed it promising, some hospitals, including Mass General Brigham, are offering it with caution as they determine who makes good candidates, and whether insurance will cover a minimally invasive procedure that costs thousands of dollars.
What is high blood pressure?
Two numbers describe blood pressure. The top number, the systolic pressure, is the force that blood exerts on the walls of the arteries as it’s pumped out of the heart. The bottom number, the diastolic pressure, measures that same pressure but between beats of the heart.
Normal is less than 120 over 80. Blood pressure naturally fluctuates throughout the day, higher when you’re physically active or stressed. But when it stays high, consistently 130 over 80 or more, according to the latest guidelines, it hardens the arteries and makes the heart work harder.
How to measure blood pressure
You don’t need a doctor’s visit. Pharmacies and sometimes even libraries offer screenings, and people can use home monitors.
To avoid falsely high readings, the American Medical Association has these tips: Sit quietly with your feet flat on the floor, legs uncrossed. Place the cuff on a bare arm, not over clothing. Do not let the arm hang; support it on a table.
Medications aren’t the only way to treat high blood pressure
Lifestyle changes are the first step, especially for otherwise healthy individuals. Guidelines urge weight loss, regular exercise, a diet rich in fruits and vegetables, limiting salt and alcohol, and adopting strategies to manage stress.
Medication becomes essential once hypertension reaches 140 over 90. The average patient requires two or three medications, sometimes more, alongside a healthier lifestyle, said Zusman.
But the hypertension Garrity has battled since his twenties is resistant to treatment. Despite taking four to six medications plus a strict diet and exercise, his blood pressure regularly reached 150 over 100 or worse.
What is renal denervation?
Doctors insert a small catheter, or tube, through the blood vessels until reaching the kidneys, and then emit ultrasound or radiofrequency energy. Those pulses pass through the renal arteries to selectively target the surrounding nerves, explained Dr. Joseph Garasic, an interventional cardiologist at Mass General who performed Garrity’s procedure. It takes about an hour.
Although already used in other countries, a pivotal US trial of renal denervation failed about a decade ago, prompting changes before researchers tried again. In November 2023, the FDA approved two catheter systems, from ReCor Medical and Medtronic.
It isn’t a cure, and some patients don’t benefit. But Garasic said that multiple studies show, on average, a reduction of 8 to 10 points in blood pressure, a modest but meaningful improvement. Some, like Garrity, see greater reductions, enough to gradually reduce medications.
The FDA deemed the procedure safe for carefully selected patients; for instance, it wasn’t tested in people with kidney disease or narrowed arteries. And the studies have lasted only a few years, not long enough to know whether nerves might eventually regenerate.
Guidance from the American College of Cardiology urges potential patients and experienced physicians to have “informed and thoughtful” discussions to decide who makes a good candidate.
