University of Minnesota Team Tests New Approach to Treating High Blood Pressure

An interdisciplinary Medical School team is studying whether renal denervation can offer a new option for patients whose high blood pressure remains uncontrolled on medication.

For patients whose blood pressure stays high despite medication, University of Minnesota Medical School researchers are studying an option: a procedure that targets nerves connected to the kidneys.

The clinical trial focuses on renal denervation, which aims to lower blood pressure by interrupting nerve signals that may contribute to hypertension. The team includes Dr. John Osborn, a cardiovascular physiologist and professor in the Department of Surgery; Dr. Sabine Karam, an associate professor in the Department of Medicine’s Division of Nephrology and Hypertension; and Dr. Michael Borofsky, an associate professor of urology and head of the University’s endourology fellowship.

The study brings together three areas of expertise: blood pressure, kidney disease and procedures inside the urinary tract. According to Dr. Karam, “The kidney plays a central role in the etiology of hypertension.” 

Dr. Borofsky says his role comes from his work as an endourologist. “I do endoscopic surgery, with a telescope and a camera inside the urinary tract.”

The procedure involves the sympathetic nervous system, also known as the body’s fight-or-flight system. “When the sympathetic nervous system is too active, it can cause a lot of things like increasing your heart rate, constricting blood vessels, and elevating your blood pressure,” explains Dr. Osborn.

The idea comes from a long-running question in hypertension care.

“There’s an idea that maybe the nerves going to the kidneys are the problem and causing high blood pressure,” Dr. Osborn says.

Renal denervation is meant to interrupt those signals by denervating, or disabling, nerves connected to the kidneys. Current renal denervation procedures usually reach those nerves through an artery, but this trial takes a different route through the urinary tract.

That route is familiar to Dr. Borofsky, who often works inside the kidney while treating kidney stones. The new device uses that access point in a different way.

“All this time, there’s these nerves that sit under the surface of where we’re working,” Dr. Borofsky says. “The goal is to use the access, use the familiarity of working inside the kidney, to ablate those nerves.”

Because the route is already familiar to endourologists, the procedure may be easier for specialists to adopt. “Essentially, for an endourologist like me, it’s very technically familiar and very technically similar to what we do day in and day out,” Dr. Borofsky says.

Dr. Osborn adds one appeal of renal denervation. “The patients don't have to remember to do anything or take anything. It's just a one-time procedure.”

The work also connects to the University of Minnesota’s history. “The entire field of endourology really began at the University of Minnesota,” Dr. Borofsky explains. “It was literally where the field developed.” Dr. Karam adds, “We are the first site doing this procedure endourologically.”

The trial is enrolling patients whose blood pressure remains uncontrolled while taking two medications. So far, six patients have undergone the procedure at the University of Minnesota. Across sites, the goal is to enroll 60 patients.

Two out of three participants receive the actual procedure, and one receives a fake procedure. Dr. Borofsky says this design helps the team know whether the treatment itself is making the difference. “You really want to make sure that it’s the intervention, not just the act of undergoing anesthesia.”

The stakes are high. “Hypertension is the leading cause of cardiovascular disease,” Dr. Karam says. It can lead to strokes, heart attacks and kidney disease. “It is what we call a silent killer, by essence.”

The team hopes the trial can help open another path for patients. In an early pilot study using this technique, Dr. Karam says it, “not only dramatically lowered the blood pressure, but there was actually a small improvement in the glomerular filtration rate,” meaning kidney function also improved.

If those results can be repeated, she says, “I think it will be a life-changing procedure in many different ways.”