For about a third of people with high blood pressure, medications fail to control their condition, increasing their risk for heart attack, stroke and other cardiac problems. But an ongoing clinical trial is using an existing medical technique to help those resistant to current treatments.
In a procedure called renal denervation, researchers zapped overactive nerve fibers close to the kidney with brief pulses of ultrasound in patients with high blood pressure resistant to drugs. The small blasts of sound waves were delivered via a catheter inserted in an artery in patients’ legs.
After two months, daytime blood pressure dropped by an average of 8 points in patients who received the ultrasound therapy compared to a 3-point drop in patients who received a placebo procedure — a “clinically meaningful drop,” the researchers from Columbia University Vagelos College of Physicians and Surgeons and NewYork-Presbyterian said in a statement.
Nighttime blood pressure also dropped by an average of 8.3 points in the treatment group compared to 1.8 points in the placebo group.
The team said the treatment, if eventually approved by federal health officials once clinical trials come to an end, can relieve people from having to take several hypertension medications — which can cause side effects — and help those who aren’t great at remembering to take pills every day.
The findings were published Sunday in The Lancet and presented at an American College of Cardiology conference.
“For patients with drug-resistant hypertension, a drop in blood pressure of 8 points — if maintained over longer-term follow-up — is almost certainly going to help reduce the risk of heart attack, stroke, and other adverse cardiac events,” co-principal investigator of the trial Dr. Ajay Kirtane, a professor of medicine at the university and an interventional cardiologist, said in the statement. “These results suggest that renal denervation has potential to become an important add-on to medication therapy — including for those who have difficulty managing several medications to control their hypertension.”
The clinical trial included 989 adults in Europe and the U.S. between 18 and 75 years old with moderate to severe high blood pressure. All participants were placed on the same medication plan for four weeks, which was a single pill that combined three commonly used hypertension drugs.
Of the 989 adults, 136 did not benefit from reduced blood pressure after taking the pill. In this group, 69 were treated with the ultrasound procedure and 67 with a placebo procedure.
The researchers say the kidney controls how much water enters the bloodstream, “acting as a central signaling center for other systems that regulate blood pressure.” In other words, the more water in the bloodstream, the higher the pressure.
The treatment works by delivering two to three zaps of ultrasound to overactive nerves that travel close to the renal arteries responsible for carrying blood from the heart to the kidney, simultaneously disrupting their signals and lowering blood pressure.
Existing hypertension treatments already target these nerves to reduce blood pressure, but the researchers say those medications “are only effective when you take them. Renal denervation is a therapy that’s always ‘on,’” Kirtane said.
“Additional studies will be needed to determine if this therapy may be effective for other groups, including older patients with hypertension and those with chronic kidney disease,” Kirtane added.
Trial participants will be monitored for five years to determine if the drop in blood pressure is maintained over time, the researchers said.