Researchers trick the brain to lower blood pressure
Researchers test out a catheter-based probe that emits high-frequency energy directly into the renal artery to deactivate nerves that regulate blood pressure.
Elizabeth Armstrong Moore
Elizabeth Armstrong Moore is based in Portland, Oregon, and has written for Wired, The Christian Science Monitor, and public radio. Her semi-obscure hobbies include climbing, billiards, board games that take up a lot of space, and piano.
Researchers have unveiled encouraging results of the first human randomized control trial of a procedure called therapeutic renal denervation to reduce and control hypertension in patients where medications aren't working. The announcement came at this week's Society of Interventional Radiology's 36th Annual Scientific Meeting in Chicago.
While the study involved only 106 adults and was funded by the manufacturer of the catheter and generator, the procedure--which uses a catheter-based probe to emit high-frequency energy directly into the renal artery to deactivate nerves linked to high blood pressure--does appear to be effective. That's particularly notable because these patients are reported to have "resistant" hypertension that has not responded to drugs.
"Renal denervation, a minimally invasive, effective treatment, appears to be safe in the short term with a low incidence of local complications," says Marc Sapoval, professor of clinical radiology and chair of the cardiovascular radiology department at Hopital Europeen Georges-Pompidou in Paris. "After six months, 39 percent of patients receiving the endovascular denervation treatment had reached the recommended blood pressure level and, overall, 50 percent of patients showed a measurable benefit of the intervention."
Sapoval explains that the renal sympathetic system, which comprises the nerves that carry signals between the kidney and the brain, plays a key role in regulating blood pressure levels. If blood pressure goes up, the heart has to work harder, so the patient's risk of heart disease, kidney disease, and stroke also rises.
In 2009, the first human trial (subscription required)--a small proof-of-concept study of 45 patients with resistant hypertension--also showed that renal denervation caused "substantial and sustained" reduction in blood pressure without serious adverse effects.
For now, Sapoval's initial study group has been expanded to a multicenter, randomized controlled trial at 24 international sites. The U.S. Food and Drug Administration will also be conducting a large trial involving more than 100 U.S.-based interventional radiology teams.