Using an experimental procedure, doctors at the Emory Heart & Vascular Center are seeking to permanently lower high blood pressure without medication.
The Symplicity HTN-3 study aims to silence overactive nerves in the arteries of the kidneys that often fuel rising blood pressure. It focuses on the millions of Americans with treatment-resistant hypertension, which occurs when a person's blood pressure remains high even after treatment with at least three different medications to lower it.
During the minimally invasive procedure, a catheter is inserted through a small puncture in the groin and threaded into the kidney's arteries. Once there, the catheter delivers low-power radiofrequency energy that generates a tiny electric current. This current deactivates the nerves to the kidneys. Known as ablation, the technique is similar to one commonly used to stabilize irregular heartbeats.
"These nerves normally should relax and constrict the arteries to maintain normal blood pressure. But in many patients with high blood pressure, the nerves stay permanently switched on, which makes treatment of hypertension difficult," says Chandan Devireddy, who leads the clinical trial at Emory, which is one of 90 institutions nationally and the first in Georgia to study the nerve-zapping procedure. The researchers' goal is to interrupt the revved-up signaling, ultimately relaxing the overactive system and lowering blood pressure, Devireddy says.
Medical experts have been aware of the connection between blood pressure and kidney nerve fibers for decades. In the past, surgeons who attempted to remove these nerves had excellent results in lowering blood pressure, but the risks associated with open surgery were deemed too great. The minimally invasive approach takes advantage of 21st-century technical advances to lower that risk.
"Even though we are focused on treating uncontrolled high blood pressure," Devireddy says, "what we learn could eventually help us develop breakthroughs in the treatment of all forms of elevated blood pressure."