Renal Denervation Shows Worth in Resistant Hypertension

Ultrasound renal denervation reduced blood pressure (BP) among people confirmed to have resistant hypertension in the RADIANCE-HTN TRIO trial.

Denervation with the Paradise System led these patients to greater daytime ambulatory systolic BP reductions at 2 months than peers receiving a sham procedure (-8.0 mm Hg vs -3.0 mm Hg, P=0.022), according to Ajay Kirtane, MD, of Columbia University Medical Center/New York-Presbyterian Hospital and the Cardiovascular Research Foundation in New York City.

Changes in other systolic BP parameters also favoured renal denervation, including 24-hour ambulatory BP and office BP, Kirtane reported at the American College of Cardiology virtual meeting. Results from RADIANCE-HTN TRIO were published simultaneously in The Lancet.

The 136 people randomized to renal denervation or sham procedure in the study had been given a triple combination pill to make sure they were resistant to calcium channel blocker, angiotensin receptor blocker, and thiazide diuretic therapy.

“Overall, the RADIANCE-HTN TRIO trial enrolled largely different patient populations from previous studies, and yet yielded consistent results, suggesting that catheter-based renal denervation, using ultrasound or radiofrequency, lowers BP across a spectrum of hypertension severity, from mild hypertension among patients off antihypertensive medications to more severe hypertension among patients resistant to multiple antihypertensive medications,” Kirtane and colleagues wrote.

With an ever stronger body of evidence favoring renal denervation as a way to lower BP, FDA approval of this technology may be anticipated in the future, according to Randall Zusman, MD, of Massachusetts General Hospital and Harvard Medical School in Boston.

If approval happens, “renal denervation will offer an alternative strategy for the reduction of the BP of hypertensive patients and will, I believe, be an attractive option for many of my patients,” Zusman, who was a RADIANCE-HTN TRIO site investigator, told MedPage Today.

Yet the magnitude of systolic BP reduction that can be achieved with renal denervation has been consistently modest at best.

“The sham-controlled reduction in both ambulatory systolic BP and office systolic BP was arguably lower than what the European Expert Group considers a clinically meaningful reduction, i.e., 10 mmHg reduction in office systolic BP that corresponds to 6-7 mmHg reduction in ambulatory SBP,” commented Sanjay Kaul, MD, of Cedars-Sinai Medical Center in Los Angeles, in an email.

“This trial informs the feasibility of a comparative effectiveness trial of renal denervation and BP meds that are known to reduce office systolic BP by 7-10 mmHg (such as spironolactone). If the best-case scenario with renal denervation is a 5-8 mmHg reduction in systolic BP, what is the likelihood of a win against optimal medical therapy?” Kaul asked.

RADIANCE-HTN TRIO was conducted at centers in the U.S. and Europe.

Investigators had enrolled 989 adults with office BP at least 140/90 mm Hg. Of these, only the 136 with daytime ambulatory BP at least 135/85 mm Hg after 4 weeks on triple combination therapy were randomized to ultrasound renal denervation or sham.

The randomized cohort averaged age 52. One in five were women. Black patients constituted another one in five.

Denervation and control groups shared similar baseline characteristics. Patients had a mean office BP of 163/104 mm Hg despite being on four antihypertensive drugs on average at baseline.

Adherence to triple combination therapy at 2 months was a high 82% in both groups among those with urine samples.

Between baseline and 2 months, 93% of the renal denervation group and 85% of the sham group had no change in their baseline antihypertensive treatment. There was more frequent use of add-on new antihypertensive drugs, including spironolactone, in the sham group.

There were no differences in safety outcomes between the two study arms. Only one major adverse event — an access site pseudoaneurysm that was treated successfully — was adjudicated as being denervation-related.

The small sample size and short follow-up were major limitations of RADIANCE-HTN TRIO.

“We have no idea about the durability of BP reduction in this cohort; 2-month follow up is clearly not long enough, as acknowledged by the investigators. Neither do we have an idea of whether patients can get off or reduce the number of BP meds (to minimize side effects),” according to Kaul.

Follow-up of the trial cohort is being planned out to 5 years, Kirtane said.

His group noted that the degree of renal nerve ablation may not be uniform among people undergoing ultrasound denervation. A reliable perioperative marker of successful renal denervation is currently lacking.

Finally, it is not certain that renal denervation’s BP benefits will translate into cardiovascular benefit, according to Kaul, who cited clonidine, aliskiren (Tekturna), and beta blockers as examples of interventions that also reduce sympathetic drive but have not been shown to affect clinical outcomes in hypertension.