Alcohol-Based Renal Denervation Throws Down the Gauntlet

WASHINGTON — Renal denervation using alcohol showed good 1-year results in a small observational study, making it another promising contender in the field of catheter-based hypertension treatment.

A year after the procedure in which a Peregrine system catheter infused alcohol 0.3-0.6 mL at a time into perivascular sites, patients with baseline ambulatory blood pressure (BP) averaging 151/89 mm Hg maintained reductions in both systolic (average -10 mm Hg, P=0.014) and diastolic BP (-7 mm Hg, P=0.007) on 24-hour monitoring.

Office measurements showed similar drops in systolic (-20 mm Hg, P<0.001) and diastolic BP (-11 mm Hg, P<0.001), Horst Sievert, MD, of Germany's CardioVascular Center Frankfurt, told the audience here at the Cardiovascular Research Technologies (CRT) meeting.

“Alcohol-mediated renal denervation allows efficient and safe nerve ablation and significant BP lowering,” he and his colleagues concluded. Sievert called it a “very straightforward” procedure that penetrates deeper than radiofrequency and is on par with ultrasound.

“Overall, these results demonstrate favorable safety and efficacy for a novel method of renal denervation,” according to David Kandzari, MD, of Atlanta’s Piedmont Heart Institute. “The reductions in BP are at least consistent with what we have observed with other successful technologies, and the safety with this novel method is also reassuring. Further late-term imaging of the renal arteries is expected also to confirm safety.”

All 45 patients in the study had complete procedures, but there was a 7% rate of peri-procedural serious adverse events (mainly access site complications). Importantly, there were no strokes, transient ischemic attacks, MIs, sudden deaths, or other major cardiac events; no vascular abnormalities or new stenosis; and no changes in renal function among study participants. Operators noted two minor dissections that resolved on their own without intervention.

The Peregrine System is CE Marked for use in Europe. Sievert’s team conducted their post-market study at nine sites there.

They included adults who, despite being on three or more anti-hypertensive medications, had hypertension with three office BP readings averaging at least 150/85 mm Hg and a 24-hour mean systolic ambulatory BP of 135 mm Hg or higher.

Patients had to have sufficiently large renal arteries in order to get alcohol-mediated renal denervation. They were age 55 years on average and 62% were men. A third of patients had diabetes; half had hyperlipidemia.

Study participants were told not to change medications through 6 months and the majority obliged.

Of the 45 patients who got the procedure, 29 completed a 12-month follow-up.

The investigators noted that they are moving ahead with randomized off- and on-med trials (TARGET BP OFF MED in Europe and TARGET BP in the U.S., both featuring sham controls) as well as the prospective TARGET BP Safety study.

The challenge of these ongoing studies will be medication adherence, Sievert said at a CRT press conference.

It’s clear that renal denervation is “effective” albeit with small effects, the investigator said. “The community of referring doctors and patients would probably hesitate when the BP reduction is ‘only’ 10 mm Hg. What we need are outcomes studies to prove that this BP reduction has effects on morbidity and mortality.”