The sympathetic nervous system and new nonpharmacologic approaches to treating hypertension: a focus on renal denervation

The sympathetic nervous system is activated in a variety of cardiovascular and metabolic diseases. This is particularly the case for essential hypertension, in which various indices of adrenergic activity, such as plasma norepinephrine, norepinephrine spillover, and sympathetic nerve firing rate, are all well above the reference range of values, thereby documenting sympathetic overdrive. Evidence is available that sympathetic neural factors participate in disease progression, as well as in the development of cardiac and renal organ damage. These findings represent the rationale for therapeutic interventions that counteract the adrenergic overdrive in the hypertensive state. This paper, after reviewing the key findings of the neuroadrenergic abnormalities occurring in hypertension, examines the rationale and the technical details, as well as the results achieved so far, with the use of a new technique that allows the elimination of afferent and efferent innervation of the kidney in resistant hypertension, ie, the ablation of renal nerves. Strengths and potential limitations of the renal denervation approach are briefly addressed.