Nothing doctors could do to control Michael Garrity’s dangerously high blood pressure — until they blocked some nerves in his kidneys. If it sounds strange, the kidneys help regulate blood pressure in part through signals from certain nerves. A new treatment disrupts overactive kidney nerves.
“My blood pressure was going up, I was short of breath and feeling tired, and it never happened again,” said Garrity, 62, of Needham, Massachusetts. He is still on medication, but at lower doses, and his blood pressure is back to normal for the first time in years. “I’m thrilled.” About half of US adults have high blood pressure, which is a major risk factor for heart attacks, strokes, kidney failure, and even dementia. Many people don’t even know they have high blood pressure until it causes serious damage.
“Know your blood pressure, know the numbers,” emphasized Dr. Randy Zusman of Massachusetts General Hospital, who specializes in the most difficult-to-treat cases and advises people who think they’re fine to at least get checked annually.
And only a small proportion of patients have well-controlled hypertension, meaning that new strategies are needed. The Food and Drug Administration approved this “renal denervation” option about a year ago based on studies showing modest benefits for patients whose blood pressure remains high despite multiple medications.
Now, after the American Heart Association recently deemed it promising, some hospitals, including Massachusetts General Brigham, are cautious about offering it while they figure out who is a good candidate — and whether their insurance will cover the thousands of dollars’ worth of minimally invasive procedure.
What is high blood pressure?
Two numbers describe the blood pressure. The top, “systolic” pressure is the force that blood exerts on the walls of the arteries as it is pumped out of the heart. The lower “diastolic” number measures the same pressure, but between heartbeats.
Normal is less than 120 over 80. Blood pressure naturally fluctuates throughout the day and rises when you are physically active or under stress. But when it stays high — invariably 130 over 80 or higher, according to the latest guidelines — it stiffens the arteries and makes the heart work harder.
How to measure pressure
This does not require a visit to the doctor. Pharmacies and sometimes even libraries offer screening, and people can use monitors at home. To avoid falsely high readings, the American Medical Association advises: sit quietly with your feet flat on the floor, legs uncrossed. Put the cuff on your bare arm, not on your clothes. Do not shake your hand – put it on the table.
Medicines are not the only way to treat high blood pressure
Changing your lifestyle is the first step, especially for healthy people. The recommendations call for losing weight, exercising, eating more fruit and vegetables, limiting salt and alcohol and taking steps to manage stress. Medications are mandatory when hypertension reaches 140 over 90. The average patient needs two to three medications, sometimes more, as well as a healthier lifestyle, Zusman said.
But the hypertension Garrity has battled since his late 20s is resistant to treatment. Despite taking four to six drugs plus a strict diet and exercise, his blood pressure regularly reached 150 over 100 or worse.
What is renal denervation?
Doctors pass a small catheter or tube through the blood vessels to reach the kidneys and then transmit ultrasound or radio frequency energy. Those impulses travel through the renal arteries to selectively affect surrounding nerves, said Dr. Joseph Horasich, the interventional cardiologist at Mass General who performed Garrity’s procedure. It takes about an hour.
While a pivotal US kidney denervation trial was already being used in other countries, it 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 is not a cure – and some patients do not benefit. But Harosic said multiple studies show an average drop in blood pressure of 8 to 10 points, which is a modest but important improvement. Some, like Garrity, see a larger drop, enough to gradually reduce their medication.
The FDA has deemed the procedure safe for carefully selected patients — it hasn’t been tested on, for example, those with kidney disease or narrowed arteries. And the studies only lasted a few years, not long enough to tell if nerves can eventually regenerate. The American Heart Association guidelines urge prospective patients and experienced physicians to have “thoughtful and informed discussions” to decide who is a good candidate.
