Electric Nerve Stimulation to Monitor the Efficacy of Renal Denervation

Abstract

See related article, pp 450–456 In 2009, Krum et al1 reported a substantial blood pressure decrease (−27/17 mm Hg at 12 months) after percutaneous radiofrequency catheter-based renal sympathetic denervation in a cohort of 45 patients with resistant hypertension. One year later, the results of this proof-of-concept study were confirmed in 106 resistant hypertensive patients randomized 1:1 to renal denervation plus previous drug treatment versus drug treatment alone, with a blood pressure decrease of −32/12 mm Hg at 6 months in the renal denervation group ( P <0.0001), contrasting with virtually unchanged blood pressure in the control group (SYMPLICITY HTN-2).2 However, the SYMPLICITY studies have important limitations, addressed in detail elsewhere.3 Accordingly, there is a growing consensus that renal denervation should remain the ultima ratio in resistant hypertension3 and should only be administered by multidisciplinary teams in tertiary referral centres, after careful patient selection. Unfortunately, besides higher baseline systolic blood pressure and use of central sympatholytic agents,4 SYMPLICITY studies failed to identify independent predictors of blood pressure response after renal denervation. Therefore, patient selection is almost entirely based on negative criteria, such as exclusion of patients with secondary and white coat hypertension or with narrow or too short renal arteries. In individual cases, whether lack of blood pressure decrease after renal denervation is due to poor contribution of the sympathetic system to the pathogenesis or the maintenance of hypertension, …