Multielectrode Renal-Denervation Device Appears Safe

Reed Miller

November 06, 2012

LOS ANGELES — Six month follow-up results of the EnligHTN I first-in-human multicenter trial of St Jude Medical's multielectrode renal-denervation catheter confirm the earlier promising results of the trial.

As reported by heartwire , St Jude's EnligHTN catheter is a four-electrode ablation catheter designed to create a predictable pattern of transmural lesions inside the renal artery that disrupt the renal sympathetic efferent and afferent nerves that contribute to systemic hypertension.

EnligHTN enrolled 47 patients with drug-resistant hypertension. Previously reported 30-day follow-up results showed that treatment with the device resulted in average office blood-pressure decreases of 28 mm Hg systolic and 10 mm Hg diastolic (p<0.0001 from baseline), with 78% of patients showing a drop in systolic pressure of at least 10 mm Hg.

Here at the American Heart Association 2012 Scientific Sessions, Dr Vasilios Papademetriou (Hippokration General Hospital of Athens, Greece) presented six-month results from the trial showing that renal denervation is safe. There were no serious periprocedural events, including no renal-artery dissections, aneurysms, new stenosis, flow-limiting renal-artery vasospasms, or any other major vascular-access complications. One patient showed worsening of a preexisting proteinuria, one patient showed symptomatic hypotension, and one patient showed worsening preexisting renal-artery stenosis. Also, no patients showed any clinically significant change in renal function measured by estimated glomerular filtration rate and serum creatinine.

The renal-denervation procedure with the EnligHTN system was effective at lowering blood pressure in the roughly three-quarters of patients who responded to the treatment. The average office BP in the 47 patients in the trial was 176 mm Hg systolic and 96 mm Hg diastolic. In the 45 patients who made it to the last follow-up, average office BP was 150/86 six months after their renal-denervation procedure (p<0.001). The average declines in 24-hour ambulatory blood pressure at six months were 10 mm Hg for systolic and 6 mm Hg for diastolic (p<0.001). About two-thirds of the patients showed enough reduction in their BP to be reclassified at a lower stage of hypertension and related treatment, and one-third of the patients treated EnligHTN were not hypertensive at all six months after their treatment.

Commenting on the study at the AHA conference, Dr Robert Carey (University of Virginia, Charlottesville, VA) pointed out that the results with the EnligHTN system weren't far off from the results seen with Medtronic's Symplicity system in the 106-patient SYMPLICITY HTN 2 trial. Six-month results of SYMPLICTY HTN-2 showed average declines in office-based BP drops of 32/12 mm Hg, and 84% of patients had a >10-mm-Hg drop in systolic blood pressure from baseline.

He cautioned that the results of the available clinical trials cannot be generalized to patients with less severe hypertension without new blinded controlled trials. Carey suggested that a sham-controlled trial be conducted to eliminate the possibility of a placebo effect with this therapy, and a clinical-outcomes trial must be conducted to prove that renal denervation reduces cardiac events over the long term in patients with hypertension at risk for these events.

The EnligHTN system has a European CE Mark but is not yet FDA approved.