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PARIS -- Out in everyday practice, renal denervation with the Symplicity device safely lowers blood pressure in patients with hypertension, preliminary results from the Global SYMPLICITY registry showed.
Of the first 617 patients included in the registry, only two had vascular complications related to access during the procedure, and none had serious events stemming from delivery of the radiofrequency energy to the renal artery; the rate of vasospasm was 9%, according to Felix Mahfoud, MD, of Saarland University Medical Center in Homburg/Saar, Germany.
Action Points
- This study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
- Note that this registry study of patients who have received renal denervation demonstrated a low complication rate and a moderate, but impressive, sustained reduction in blood pressure at 3 and 6 months.
Through 6 months of follow-up, there were two hospitalizations for hypertensive crisis, two myocardial infarctions, one new case of end-stage renal disease from nephrotoxic overdose, and one death that was not considered to be related to the procedure, he reported at the EuroPCR meeting here.
The procedure was not only safe, but also effective at lowering blood pressure, with reductions in office-based readings ranging from 13/6 mm Hg among patients with a baseline systolic blood pressure of 140 mm Hg or higher to 28/18 mm Hg among those with a baseline systolic pressure of 180 mm Hg or higher at 3 months. The findings were similar at 6 months.
"The take-home message will be hopefully ... that renal denervation is a safe procedure providing blood pressure lowering in patients with high blood pressure at baseline and that that procedure might have an impact on clinical outcomes," Mahfoud said in an interview.
The Global SYMPLICITY registry is part of the clinical program evaluating the Symplicity device. It has been approved for use in Europe and elsewhere but remains restricted to investigational use in the U.S. Medtronic, which makes the Symplicity device, announced on Thursday that it has completed enrollment in Symplicity HTN-3, the pivotal U.S. trial.
The registry has a targeted enrollment of about 5,000 patients from about 200 centers worldwide; 149 sites spread throughout Canada, Mexico, South America, Europe, Africa, the Middle East, Asia, and Australia have already started collecting data.
Any patient who receives renal denervation can be included in the registry, and thus the study will include patients with hypertension and other conditions associated with increased sympathetic activity, including heart failure, insulin resistance, atrial fibrillation, sleep apnea, and chronic kidney disease.
Most of the first 617 patients included the registry (60%) were treated in accordance with the European Society of Cardiology's recently published consensus paper on renal denervation, which recommended treatment in patients with a systolic blood pressure of 160 mm Hg or higher (or at least 150 mm Hg for type 2 diabetics) who were taking at least three antihypertensive medications, including a diuretic.
About one-fifth of the patients (22%) started with a systolic blood pressure of at least 180 mm Hg, which was the average baseline blood pressure in the Symplicity HTN-1 and HTN-2 trials.
The average starting blood pressure overall was 164/89 mm Hg, and patients were taking an average of 4.35 medications. Common comorbidities included diabetes (38.2%), renal disease (30.1%), sleep apnea (16.3%), a history of cardiac disease (49%), heart failure (9.3%), and atrial fibrillation (11.9%).
The registry data showed significant drops in blood pressure measured both in the office and with 24-hour ambulatory monitoring, although the reductions were smaller than those seen in the clinical trials.
That's not surprising, according to Mahfoud, because out in everyday practice blood pressure is not recorded as appropriately as in a clinical trial setting and poor compliance to medication becomes more of an issue. In fact, he said, a recent study showed that 47% of patients with resistant hypertension were not adherent to their medication regimens.
Also contributing to the smaller reductions in the real-world population is the fact that the average starting blood pressure was lower than in the clinical trials, Mahfoud said, adding that it is known that renal denervation induces greater reductions in blood pressure among those with the highest readings initially.
Disclosures
Mahfoud reported receiving institutional grant/research support from Medtronic, St. Jude, Recor, and serving as a consultant for St. Jude, Medtronic, Boston Scientific, and Cordis. Medtronic makes the Symplicity renal denervation device.
Primary Source
European Association of Percutaneous Cardiovascular Interventions
Source Reference: Mahfoud F, et al "Early results following renal denervation for treatment of hypertension in a real-world population: the Global SYMPLICITY registry" EuroPCR 2013.