WASHINGTON – Injection of dehydrated alcohol through the wall of the renal artery can be added to a growing list of renal denervation strategies that have been associated with sustained blood pressure reductions, according to data presented as a latebreaker at 2019 CRT meeting.
For the primary efficacy endpoint of change in systolic blood pressure at six months, the mean reduction six months after denervation was 11 mmHg as measured with 24-hour ambulatory blood pressure monitoring (ABPM), according to Horst Sievert, MD, PhD, Director of the CardioVascular Center, Frankfurt, Germany.
“Alcohol denervation was associated with efficient and safe lowering of systolic blood pressure,” reported Dr. Sievert, who said these data have prompted a new set of studies, including a phase 2 controlled trial that will evaluate the effect of renal denervation for control of blood pressure off-medication.
After consent was withdrawn from one patient, study results were available from 44 patients with treatment resistant hypertension who were enrolled in this initial study. Entry requirements included a mean systolic blood pressure greater than 150 mmHg while taking at least three antihypertensive medications from different classes.
In this study, the alcohol was delivered with a proprietary device called the Peregrine System™ infusion catheter (Ablation Solutions). This catheter is equipped with microneedles that remain retracted until the catheter is navigated into position. Once in the renal artery, the microneedles are deployed to inject alcohol into the perivascular space, which produces a neurolytic effect.
The technical success for delivery of the alcohol was achieved in 100% of the study group. There were no serious adverse events associated with treatment. Minor adverse events included those involving the access site, such as pain, as well as two dissections that resolved without treatment. One patient complained of abdominal pain on the day of the procedure, but that also resolved, according to Dr. Sievert.
Over the course of followup, patients remained on the therapies they were taking prior to the intervention. There was no change in antihypertensive therapy during the first month of followup in 84% of treated patients. Of those who did have a change in medication, all but one involved a reduction in medication prompted by improved blood pressure control. At six months, there was no change in medication for 73% of those evaluated.
Following alcohol denervation, there was a mean 7 mmHg reduction in diastolic pressure as measured with 24-hour ABBM.
Based on these data, a trials program is being launched. In addition to the phase 2 multinational off-medication trial, which is enrolling 300 patients who are being randomized to the alcohol denervation therapy or a sham control, an open-label crossover trial will be conducted to confirm the safety and tolerability of this approach.
Delivery of alcohol through the catheter device used in this study requires a renal artery diameter of at least 4 mm. This is a potential limitation for smaller individuals, but several other devices used for denervation share this requirement, according to Dr. Sievert.
The potential advantage of this approach is that “you can stay proximal,” according to Dr. Sievert, contrasting this technique with renal denervation by radiofrequency ablation. He explained that radiofrequency renal denervation requires a relatively distal approach to achieve an appropriate energy penetration for target nerve ablation. Further study is needed to determine whether more proximal delivery has any clinical advantage.
SOURCE: 2019 Cardiovascular Research Technologies (CRT) Meeting.