SYMPLICITY HTN-3: Crossover Patients Strengthen the Case for Renal Denervation

Post hoc analysis of SYMPLICITY HTN-3 that includes data on patients who crossed over to renal denervation at 6 months reaffirms a positive correlation between the total number of ablations and the circumferential pattern of ablations on systolic BP reduction, according to a presentation at TCT 2014.

sat.bhatt.headStudy investigator Deepak L. Bhatt, MD, MPH, of Brigham and Women’s Hospital, Boston, Mass., commented: “With a larger sample size, we see further evidence of this correlation.”

A Focus on Crossover Patients

SYMPLICITY HTN-3 randomized 535 patients with severe resistant hypertension to renal denervation with the Symplicity Catheter System (n=364; Medtronic) or a sham procedure (n=171). Six-month results from the trial dealt a blow to the new therapy, showing no difference in the change in office BP between the 2 groups, while 12-month data confirmed both that similarity and the safety of the procedure.

According to the design of the trial, treatment assignment was unblinded at 6 months. Patients receiving sham control could crossover to renal denervation, provided they continued to satisfy study inclusion and exclusion criteria. Among 171 patients randomized to the sham procedure, 101 transitioned at 6 months to receive renal denervation.

In the analysis presented Saturday by Bhatt, patients who crossed over to renal denervation at 6 months had similar office BP reductions between 6 and 12 months at -17.7 mm Hg systolic/-7.1 mm Hg diastolic compared with those who were initially randomized to the therapy. Change in mean 24-hour ambulatory BP was –9.2 mm Hg systolic/–4.9 mm Hg diastolic for crossover patients.

sat.bhatt.figureMore evidence for link between technique and BP reduction 

In addition, Bhatt reiterated a possible correlation between procedural factors and outcomes with renal denervation.

As has been shown previously, “[t]here is a correlation with [a] greater number of ablations and greater change in office systolic BP between 0 and 6 months,” Bhatt said. “What we have now added is the crossover patients … and with this larger sample size, that same correlation or trend seemed to continue and, if anything, become more apparent.”

In particular, he explained, office systolic BP appears to decrease at higher numbers of ablations (see Figure), as does ambulatory systolic BP. Adding the crossover patients to the renal denervation group also magnified the apparent relationship between the number of four-quadrant ablations and the degree of BP reduction.

“Nevertheless, these are all post hoc observations which suggest hypotheses concerning optimization [of] denervation procedures that might inform the design of future renal denervation trials,” Bhatt said.

  

  

 Disclosures: 

  • SYMPLICITY HTN-3 was funded by Medtronic.
  • Bhatt reports conflicts of interest with multiple device and pharmaceutical companies.

 

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