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Renal Denervation for HTN: A 'Work in Progress'

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Using renal denervation to control resistant hypertension still has promise, despite the technique's failure to turn in results different from sham treatment in the SYMPLICITY HTN-3 trial, according to researchers.

In a 12-month follow-up of originally denervated patients from the trial, and 6-month follow-up of crossover patients, there was no significant difference between the groups in the rate of a composite safety endpoint: 6.8% in the original renal denervation group, 5.3% in the crossover group, and 7.2% in the noncrossover group, reported director of the American Society of Hypertension Comprehensive Hypertension Center at the University of Chicago, and colleagues.

Action Points

  • Note that 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.

The composite endpointed consisted of death, vascular complications, new-onset end-stage renal disease, embolic events resulting in end-organ damage, renal artery reintervention, and hypertensive emergency or crisis.

In addition, at 1 year, patients in all three groups had lower office and ambulatory blood pressures compared with baseline, although the reduction in the 24-hour ambulatory readings was not significant in the noncrossover patients.

"Renal denervation is a work in progress," Bakris stated at a press conference at the European Society of Cardiology meeting. "It definitely is not dead. I would say it is out of the ICU now and probably onto the floor."

The average reduction for office and 24-hour ambulatory blood pressure, respectively, at 1 year was:

  • Renal denervation: 18.9 mmHg systolic, 7.8 mmHg diastolic and 7.6 mmHg systolic, 4.7 mmHg diastolic
  • Crossover (baseline was the time of the procedure at 6 months): 17.7 mmHg systolic, 7.1 mmHg diastolic and 9.2 mmHg systolic, 4.9 mmHg diastolic
  • Noncrossover: 21.4 mmHg systolic, 8.2 mmHg diastolic and 6.1 mmHg systolic, 2.9 mmHg diastolic

Results in the noncrossover group were not significant for change from baseline, the group stated, but Bakris pointed out that 6-month decrease in systolic blood pressure among the crossover population from baseline was statistically significant (P<0.001).

Bakris' group stated that the 12-month data indicated that renal denervation was safe "with no difference in major adverse events between the treated and original sham procedure groups out to 12 months."

While there was a worsening of blood pressure after 6 months in the control patients who remained on medical therapy throughout 1 year, the authors attributed this to changes in therapeutic adherence.

They acknowledged that "possible confounding factors including the population studied, drug prescription changes, variable adherence to therapy, and procedural variability all remain unresolved at 12 months."

who was not involved in the study, called the short-term results "very encouraging." He pointed out that one advantage of denervation is that the results are permanent, and not dependent upon a patient's lifestyle choices.

"I think that renal denervation will be resurrected," said DiMario, professor of clinical cardiology at Royal Brompton & Harefield Hospital in London. "I don't think that patients could become resistant to their medication, and they don't necessarily become noncompliant with medication. But they could become noncompliant with their diet or with their exercise regimen. They may have begun using tobacco or alcohol. The advantage of denervation is that it is permanent."

Di Mario also told ֱ that the denervation devices are also improving, making the procedure easier to perform with better and more predictable results.

"I think it is a shame that there has been an overreaction to the initial results of SYMPLICITY as well as over-enthusiasm," he said. "There are nonresponders to renal denervation, but most people do well with it. We do not have good medication for resistant hypertension."

From the American Heart Association:

Disclosures

Di Mario disclosed a relevant relationship with Medtronic.

Bakris disclosed relevant relationships with Bayer AG, Boehringer-Ingelheim GmbH, Bristol-Myers Squibb Company, Daiichi Sankyo Company Limited, Janssen Pharmaceuticals, Medtronic, Inc., Relypsa, and Takeda.

Primary Source

European Society of Cardiology

Bakris G, et al, "SIMPLICITY HTN3 Trial: 12-month outcomes following un-blinding of subjects at 6 months" ESC 2014.