ACC: Medtronic's renal denervation study returns, showing drops in stubbornly high blood pressure

Kidney
Medtronic said data from the off-medication trial and an ongoing on-medication study would be included in an eventual FDA application for the Symplicity Spyral system. (jlcampbell104/CC BY 2.0)

Medtronic is back with new data finally demonstrating the effectiveness of its catheter-based ablation procedure aimed at the kidneys to help lower high blood pressure where multiple medications have failed.

Known as renal denervation, the procedure burns out overactive nerves lining the arteries that feed the kidneys, lessening their links to the brain. They are believed to play a large role in drug-resistant hypertension, as the organs work to remove salt and excess water from the bloodstream.

The field saw setbacks in 2014 when an earlier version of the medtech giant’s Symplicity system missed its endpoints in a large, pivotal blinded trial—with results running counter to previously published clinical data and Medtronic’s past studies as well as the use of the procedure in other countries.

But now, a similarly sham-controlled study of the newer Spyral model—featuring four spaced-out electrodes for more even ablation—showed average drops of 6.5 mmHg in systolic blood pressure when taken in a doctor’s office after three months.

In addition, participants saw average reductions of 3.9 mmHg at home over a 24-hour period, measured by a wearable blood pressure monitor.

The study had previously delivered positive interim results in 2017 as a pilot before being expanded into a larger trial. The latest data were presented virtually at the annual meeting of the American College of Cardiology, held together with the World Congress of Cardiology. 

“These results show that [renal denervation] offers an effective alternative approach to traditional medications that require patient adherence for reducing blood pressure,” said study lead author Michael Böhm of the Saarland University Medical Center in Hamburg, Germany. 

The 24-hour wearable monitor also tracked lower blood pressure readings throughout the night and early mornings, when the effects of blood pressure medications are reduced and the risk is highest for adverse events, Böhm said.

The international study enrolled 331 total patients with high blood pressure, with half receiving the active device treatment. Participants were required to stop taking their blood pressure medications at least three weeks before the start of the trial. 

The drugs were still detected in blood tests of 36 patients, but Medtronic said there were still consistent results in the protocol’s analysis with their exclusion. A separate study evaluating patients on their medication is currently enrolling participants with results expected in 18 months.

The Symplicity Spyral device also showed no major adverse effects, with zero cases of vascular complications, stroke, bleeding, heart attack or death, as well as no instances of new renal disease or elevated kidney biomarkers. After three months, one person was hospitalized for emergency high blood pressure.

Currently, there are no such devices approved for use in the U.S., though renal denervation has been used clinically in Europe, Canada, South America and elsewhere. With about half of people with elevated blood pressure not seeing results from their medications, Medtronic has estimated that its procedure could deliver a multibillion-dollar market.

“This study establishes [renal denervation] as an additional option beyond exercise or lifestyle modification for patients with high blood pressure who are unwilling to take or cannot tolerate medication,” Böhm said, adding that both the off- and on-medication studies will be included in an eventual FDA application for the system.

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