Renal denervation’s comeback as a potential treatment for patients with drug-resistant hypertension rolls on.
Renal denervation with ultrasound energy produced a significant, median 4.5–mm Hg incremental drop in daytime, ambulatory, systolic blood pressure, compared with sham-treatment after 2 months follow-up in a randomized study of 136 patients with drug-resistant hypertension maintained on a standardized, single-pill, triple-drug regimen during the study.
Courtesy American College of Cardiology
Dr. Ajay J. Kirtane
The results “confirm that ultrasound renal denervation can lower blood pressure across a spectrum of hypertension,” concluded Ajay J. Kirtane, MD, at the annual scientific sessions of the American College of Cardiology. Renal denervation procedures involve percutaneously placing an endovascular catheter bilaterally inside a patient’s renal arteries and using brief pulses of energy to ablate neurons involved in blood pressure regulation.
A former ‘hot concept’
“Renal denervation was a hot concept a number of years ago, but had been tested only in studies without a sham control,” and initial testing using sham controls failed to show a significant benefit from the intervention, noted Deepak L. Bhatt, MD, an interventional cardiologist and professor of medicine at Harvard Medical School in Boston who was not involved with the study. The significant reductions in systolic blood pressure reported with renal denervation, compared with control patients in this study, “are believable” because of inclusion of a true control cohort, he added. “This really exciting finding puts renal denervation squarely back on the map,” commented Dr. Bhatt during a press briefing.
Dr. Deepak L. Bhatt
Dr. Bhatt added that, while the median 4.5–mm Hg incremental reduction in daytime, ambulatory, systolic blood pressure, compared with control patients – the study’s primary endpoint – may seem modest, “in the world of hypertension it’s a meaningful reduction” that, if sustained over the long term, would be expected to produce meaningful cuts in adverse cardiovascular events such as heart failure, stroke, and MI.
“The question is whether the effects are durable,” highlighted Dr. Bhatt, who helped lead the first sham-controlled trial of renal denervation, SYMPLICITY HTN-3, which failed to show a significant blood pressure reduction, compared with controls using radiofrequency energy to ablate renal nerves. A more recent study that used a different radiofrequency catheter and sham controls showed a significant effect on reducing systolic blood pressure in the SPYRAL HTN-OFF MED Pivotal trial, which by design did not maintain patients on any antihypertensive medications following their renal denervation procedure.
Dr. Kirtane noted that, although the median systolic blood pressure reduction, compared with controls treated by a sham procedure, was 4.5 mm Hg, the total median systolic pressure reduction after 2 months in the actively treated patients was 8.0 mm Hg when compared with their baseline blood pressure.
Concurrently with his report the results also appeared in an article posted online (Lancet. 2021 May 16;doi: 10.1016/S0140-6736(21)00788-1).
Denervation coupled with a single, daily three-drug pill
The RADIANCE-HTN TRIO study ran at 53 centers in the United States and Europe, and randomized 136 adults with an office-measured blood pressure of at least 140/90 mm Hg despite being on a stable regimen of at least three antihypertensive drugs including a diuretic. The enrolled cohort averaged 52 years of age and had an average office-measured pressure of about 162/104 mm Hg despite being on an average of four agents, although only about a third of enrolled patients were on treatment with a mineralocorticoid-receptor antagonist (MRA) such as spironolactone.
At the time of enrollment and 4 weeks before their denervation procedure, all patients switched to a uniform drug regimen of a single, daily, oral pill containing the calcium channel blocker amlodipine, the angiotensin receptor blocker valsartan or olmesartan, and the diuretic hydrochlorothiazide with no other drug treatment allowed except for unusual, prespecified clinical circumstances. All patients remained on this drug regimen for the initial 2-month follow-up period unless their blood pressure exceeded 180/110 mm Hg during in-office measurement.
The denervation treatment was well tolerated, although patients reported brief, transient, and “minor” pain associated with the procedure that did not affect treatment blinding or have any lingering consequences, said Dr. Kirtane, professor of medicine at Columbia University Vagelos College of Physicians and Surgeons in New York.
A reason to use energy delivery by ultrasound rather than by radiofrequency to ablate nerves in the renal arteries is that the ultrasound approach exerts a more uniform effect, allowing effective treatment delivery without need for catheter repositioning into more distal branches of the renal arteries, said Dr. Kirtane, who is also an interventional cardiologist at NewYork-Presbyterian/Columbia University Irving Medical Center.
But each method has its advantages, he added.
He also conceded that additional questions need to be addressed regarding which patients are most appropriate for renal denervation. “We need to figure out in which patients we can apply a device-based treatment,” Dr. Kirtane said during the press briefing. Patients with what appears to be drug-resistant hypertension often do not receive treatment with a MRA because of adverse effects, and many of these patients are not usually assessed for primary aldosteronism.
In SYMPLICITY HTN-3, “about half the patients who were seemingly eligible became ineligible” when they started treatment with a MRA, noted Dr. Bhatt. “A little spironolactone can go a long way” toward resolving treatment-resistant hypertension in many patients, he said.
RADIANCE-HTN TRIO was sponsored by ReCor Medical, the company developing the tested ultrasound catheter. Dr. Kirtane has received travel expenses and meals from ReCor Medical and several other companies, and Columbia has received research funding from ReCor Medical and several other companies related to research he has conducted. Dr. Bhatt has no relationship with ReCor Medical. He has been a consultant to and received honoraria from K2P, Level Ex, and MJH Life Sciences; he has been an advisor to Cardax, Cereno Scientific, Myokardia, Novo Nordisk, Phase Bio, and PLx Pharma; and he has received research funding from numerous companies.