Renal Denervation Reduced BP in Majority of Patients

SAN FRANCISCO, CALIF.—Renal denervation was effective in lowering BP in almost three-fourths of patients after 6 months, according to data from a small registry study presented at TCT 2011.

Martin W. Bergmann, MD, PhD, of the Asklepios Clinic St. Georg, Hamburg, Germany, reported results of the Alster Hypertension Registry, which examined data on 36 patients who underwent renal denervation with the Symplicity Catheter System (Ardian) between May 2010 and March 2011. All of the patients had a systolic respiratory rate greater than 160 mm Hg, and were on three or more medications (including renin inhibitors and direct vasodilators) for their hypertension. Half of the patients had diabetes.

Bergmann noted that most patients had a minimum of four to five ablations applied to each side. Three patients had monolateral ablation.

For the majority of patients (74%), Bergmann noted more than a 10 mm Hg reduction in systolic blood pressure, which would continue in some patients over a 12-month period (see Figure). However, 9 patients were characterized by the researchers as “nonresponders,” meaning that there was less than a 10 mm Hg BP drop following the procedure. “What is interesting,” Bergmann told the audience, is that “we had an increase of responders at a later phase – about 3 to 6 months after ablation.” Bergmann also noted that 10 patients had to reduce their drug intake due to the denervation effect associated with the procedure.

Bergmann and colleagues split their research cohorts into two groups – one that initiated medication for their high BP more than 10 years ago and those that initiated less than 10 years ago. The researchers noted earlier responses in those patients who had received BP medications for shorter periods of time.

The researchers also noted a trend for better responses in those patients who had received more than 8 ablations. Taken together, Bergmann said his group’s data indicate the “duration of drug-treated hypertension and number of ablations may be related to effectiveness.” 

He cited a “disturbing” trend in the data, in that there was no detectable change in mean systolic BP in ambulatory 24 hour records. The researchers also did not note any changes in HbA1c levels associated with diabetes.

Similar to trials in other registries, the researchers did not note any drops in glomerular filtration rates; rather, some patients actually had increases in GFR over time.