Study Finds Impaired Cardiac Baroreflex Sensitivity Predicts Response to Renal Denervation

August 21, 2013—Impaired cardiac baroreflex sensitivity (BRS) identifies patients with resistant hypertension who respond to renal denervation (RDN), according to conclusions from a study published by Christine S. Zuern, MD, et al online ahead of print in the Journal of the American College of Cardiology.

The investigators noted that the background of the study is that catheter-based RDN, as a novel treatment option for patients with resistant arterial hypertension, is assumed to reduce efferent renal and central sympathetic activity. This study was conducted to evaluate cardiac BRS as a predictor of response to RDN.

As summarized in the Journal of the American College of Cardiology, the study was composed of 50 patients who underwent RDN. Patient characteristics included a mean age of 60.3 ± 13.8 years and a mean systolic blood pressure (BP) on ambulatory BP monitoring of 157 ± 22 mm Hg, despite medication with antihypertensive drugs (mean, 5.4 ± 1.4).

Before administration of RDN, a 30-minute recording of continuous arterial BP and high-resolution electrocardiography (1.6 kHz in orthogonal XYZ leads) was performed in all patients under standardized conditions.

Cardiac BRS was assessed by phase-rectified signal averaging according to previously published technology assessments. Response to RDN was defined as a reduction in mean systolic BP on ambulatory BP monitoring by 10 mm Hg or more at 6 months after RDN.

The investigators found that at 6 months after RDN, the mean systolic BP on ambulatory BP monitoring was significantly reduced from 157 ± 22 mm Hg to 149 ± 20 mm Hg (P = .003). Of the 50 patients, 26 (52%) were classified as responders. BRS phase-rectified signal averaging was significantly lower in responders than nonresponders (0.16 ± 0.75 ms/mm Hg vs 1.54 ± 1.73 ms/mm Hg; P < .001). A receiver-operator characteristics analysis revealed an area under the curve for predicting the response to RDN by BRS phase-rectified signal averaging of 81.2% (95% confidence interval, 70%–90.1%; P < .001).

On multivariable logistic regression analysis, reduced BRS phase-rectified signal averaging was the strongest predictor of response to RDN that was independent from all other variables tested, reported the investigators in the Journal of the American College of Cardiology.