Using Ultrasound to Control Blood Pressure
A device that uses ultrasound to calm overactive nerves in the kidneys may help some people get their blood pressure under control, found researchers at VP&S with colleagues at the Université de Paris. “Renal ultrasound could be offered to middle-aged patients who are unable to get their blood pressure under control after trying lifestyle changes and drug therapy,” says Ajay Kirtane, MD, an interventional cardiologist and professor of medicine who co-led a study published in JAMA Cardiology.
Hypertension in middle age is thought to be caused, in part, by overactive nerves in the kidneys, which trigger water and sodium retention and release hormones that can raise blood pressure.
Antihypertensive drugs can lower blood pressure by dilating blood vessels, removing excess fluid, or blocking the hormones, but these medications do not target the renal nerves directly.
To calm overactive nerves in the renal artery, ultrasound is delivered to the nerves via a thin catheter inserted into a vein in the leg or wrist and threaded to the kidney. The device is still investigational and has not yet been approved by the FDA for use outside of clinical trials.
The research pooled data from three randomized trials of more than 500 patients with varying degrees of hypertension and medication use. Researchers found that the device consistently reduced daytime ambulatory blood pressure by an average of 8.5 points. Twice as many patients who received the ultrasound therapy reached their target daytime blood pressure (less than 135/85 mmHg) compared with those who did not receive the treatment. Improvements in blood pressure were seen as soon as one month after the procedure.
“Many patients in our clinical practice are just like the patients in our study, with uncontrolled blood pressure in the 150s despite some efforts,” says Dr. Kirtane, who directs the cardiac catheterization laboratories at NewYork-Presbyterian/Columbia. “Our study definitively shows that the device can lower blood pressure in a broad range of patients.
“Once the device is available after it’s been evaluated by the FDA, we envision recommending it to patients who have tried other therapies,” Dr. Kirtane says. “The hope is that by controlling blood pressure, we might be able to prevent kidney damage and other effects of uncontrolled blood pressure.”