Feb 28, 2024

One weekend turned a non-believer into a renal denervation champion

Dr. Stefan Tunev was originally very skeptical about medical device technology to treat high blood pressure. He’s not anymore. 

When Medtronic was considering the purchase of a company developing medical device technology to treat high blood pressure, our Dr. Stefan Tunev was skeptical, to say the least.

Dr. Stefan Tunev and team
Dr. Stefan Tunev and team

“When we were first looking at acquiring the technology, I said ‘this will never work,’” he recalls. “But it didn’t take long for me to completely change my mind.”

It took, in fact, one long weekend in 2009.

A veterinary pathologist  by training and a comparative medicine expert at Medtronic, Dr. Tunev was asked to review the pre-clinical safety and efficacy data of a startup called Ardian. The technology involved a catheter-based treatment that disrupted nerves going to the kidneys to lower blood pressure, commonly known in the medical community today as renal denervation. Initially skeptical about the idea, Dr. Tunev packed up a microscope and spent three intense days combing through Ardian’s data.

“I must have looked at thousands of slides that weekend,” he remembered. “Their data was impressive. I completely changed my mind in those three days.”

Dr. Tunev was among a team of several scientists and engineers whose recommendations our leaders considered when they decided to acquire Ardian’s technology.

But his biggest contribution to our renal denervation project came five years later in 2014.

Critical Crossroads

A major clinical study (Symplicity HTN-3) suggested the therapy didn’t work, and the future of renal denervation reached a crossroads. Most of our competitors halted their research and we considered doing the same. Dr. Tunev’s team again dug into the data and concluded Medtronic should continue our renal denervation programs, but with a new recommendation of how to apply the device.

Sean Salmon, EVP and President of our cardiovascular portfolio, remembers the moment.

“Stefan’s work at that point was critical,” Sean said. “His wasn’t the only voice of course. But I don’t think we would have decided to go on if it wasn’t for Stefan’s contribution.”

“We were absolutely convinced the therapy was effective if applied the right way in the right location,” Dr Tunev remembers. “It’s very gratifying to have been one of the voices contributing to the decision to keep going.”

Renal denervation ambassador

Today, Dr. Tunev is a senior distinguished scientist at Medtronic. He leverages his knowledge and experience in developing the science behind our technologies, translates that information into clinical context and presents it all to physicians and healthcare leaders around the world. Although he works on multiple therapies and devices, renal denervation remains one of his favorites.

Part scientist, part ambassador, part advocate, he’s rarely in the same place for long. He’s constantly traveling, working to convince health professionals that our recently approved Symplicity Spyral renal denervation system should be a big part of the future in treating high blood pressure.

“I have big dreams. It’s incredibly exciting to think that we now have an additional tool to fight one of the largest inadequately addressed medical issues of our time (high blood pressure),” he said.

Dr. Tunev finds that many healthcare professionals are skeptical, and he understands. He was once skeptical too.

“I believe this therapy, this device, is going to help a lot of people,” he said. “Physicians constantly share stories with me about cases in which drugs alone don’t fully control their patient’s high blood pressure. But renal denervation often helps them. Thanks to this procedure, those physicians are able to make a difference to humankind when maybe they couldn’t before. That’s very rewarding, for them – and for all of us.”

Important Safety Information

The Symplicity™ blood pressure procedure (BPP) is a minimally invasive procedure approved to help lower high blood pressure. The procedure is approved as a complement to treatments you may already be trying, such as lifestyle modifications and high blood pressure medications that might not be adequately controlling your blood pressure.

Receiving the Symplicity BPP should be a based on a joint decision between you and your doctor consider the benefits and risks of the device and procedure. Please talk to your doctor to decide whether or not the Symplicity BPP is right for you.

If you have a pacemaker or an ICD your doctor will follow-up with steps to take ahead of the procedure if you decide it is right for you.

At the time of your procedure, your doctor may detect certain anatomical conditions (e.g., your blood vessels are too big or too small) that do not allow the blood pressure procedure to continue.

You should not receive the procedure if you cannot tolerate medications that are required for the procedure, like atropine, nitroglycerin, systemic blood thinners, or certain pain medications. These medications are to help you in case your heart rate drops too low, you experience pain, or your blood vessels tighten during the procedure. You should not receive the procedure if you are pregnant.

The Symplicity BPP has not been studied in patients:

  • Who are breastfeeding
  • Who are under 18 years old
  • Who have isolated systolic hypertension (only the “top number” of your blood pressure is high)
  • Who have secondary causes of high blood pressure
  • Who have had a renal stent placed less than 3 months prior to the procedure
  • Who had a prior minimally invasive treatment in their renal arteries (stenting, angioplasty or prior renal denervation)

Potential Risks of the Symplicity BPP: (Note that you may experience other problems that have not been previously observed with this procedure)

  • Allergic reaction to the imaging solution
  • Damage to your arteries
  • Future narrowing of your arteries
  • Arterio-enteric fistula (an abnormal connection between your aorta and your gastrointestinal tract)
  • AV fistula (an irregular connection between an artery and a vein)
  • Bleeding or blood clots
  • Bruising where the device enters your body (mild or severe)
  • Cardiac arrest or Heart attack
  • Death
  • Deep vein thrombosis
  • Swelling
  • Slow heart rate
  • Infection
  • Low or high blood pressure
  • Damage to your kidneys that may cause one or both to stop working
  • Nausea or vomiting
  • Peripheral ischemia (lack of blood supply to your limbs)
  • Pulmonary embolism (a sudden block in your arteries that send blood to your lungs)
  • Pseudoaneurysm (blood collecting on the outside of a vessel wall causing a balloon-like widening)
  • Pain or discomfort
  • Skin burns from the failure of the equipment during the procedure
  • Exposure to radiation
  • Stroke

For further information, please call and/or consult Medtronic at 707-525-0111 or Medtronic’s website at medtronic.com


Related content