A procedure to deactivate the nerves connecting the kidneys to the brain could provide an alternative to medication for high blood pressure.
Patients who suffer from hypertension, or high blood pressure, often rely on medication to relieve their symptoms. But researchers at the University of Bristol and the Bristol Heart Institute (BHI) in the UK have joined forces to find a way to treat the disorder without the use of drugs.
They’ve found an answer in renal denervation, which involves removing the nerves connecting the kidneys to the brain. The procedure has shown early success in reducing high blood pressure in both animal and human trials.
“We have used renal denervation in patients who have hard-to-treat blood pressure. Similar to the results from the basic science experiments, we have also seen reductions in blood pressure, which has been essential for reducing the risk of heart and renal disease and stroke in our patients,” said Dr. Angus Nightingale, who runs the Specialist Hypertension Clinic at the BHI, in a press release. “This is an exciting new treatment for these patients who have struggled with high blood pressure which tablets are not controlling.”
The University of Bristol and BHI collaborators, called the CardioNomics high blood pressure team, recently published their findings in the journal Hypertension.
To perform renal denervation, doctors use low-intensity radio frequency lesioning via a small catheter inserted into the renal artery. This process disrupts nerve signal transmission from the kidneys to the brain. The minimally invasive procedure takes one to two hours to perform and is done using a local anesthetic with some sedation.
Renal denervation trials have been successful for 19 patients at the BHI so far.
Dr. Julian Paton of the University of Bristol’s School of Physiology and Pharmacology, who led the study team, recommends the procedure for patients whose blood pressure, when measured at home or with an ambulatory 24-hour blood pressure cuff device, is more than 140/90 mmHG (millimeters of mercury), or who are on at least three high blood pressure medications, including a diuretic.
“It is becoming a popular technique for patients with both resistance and poor tolerability to high blood pressure medication,” said Dr. Andreas Baumbach of the BHI in a press release.
There are two likely reasons why deactivating the nerves connecting the kidneys to the brain lowers blood pressure, Paton told Healthline.
“First, the procedure reduces or removes signals emanating from the kidney that instruct the central nervous system to hoist blood pressure. Renal denervation removes these blood pressure elevating signals,” he said.
“Second, renal denervation also removes communication from the central nervous system to the kidney,” Paton added. “In hypertensive patients we believe this communication is abnormally busy, resulting in a number of effects that all cause blood pressure to rise, including narrowing of the arteries in the kidney, release of a blood pressure raising hormone from the kidney, and elevation of salt retention.”
This new technique will hopefully give patients with hypertension an effective alternative to medication with few if any side effects.
“The problem with high blood pressure is that patients develop resistance to their tablets or unpleasant side effects,” Paton said in a press release. “Our new interventional approaches are based on studies where we have found causative mechanisms generating high blood pressure, so we think that they will be most efficacious in patients. And, with luck, they will also mean less pill taking too.”
With a grant from Medtronic, a major developer of medical technology, CardioNomics hopes to expand its efforts even further.