Hypertension represents a major health problem with an appalling annual toll. Despite the plethora of antihypertensive drugs, hypertension remains resistant in a considerable number of patients, thus creating the need for alternative strategies, including interventional approaches. Recently, catheter-based renal sympathetic denervation has been shown to be fairly safe and effective in patients with resistant hypertension. Pathophysiology of kidney function, interaction and crosstalk between the kidney and the brain, justifies the use of renal sympathetic denervation in the treatment of hypertension. Data from older studies have shown that sympathectomy has effectively lowered blood pressure and prolonged life expectancy of hypertensive patients, but at considerable cost. Renal sympathetic denervation is devoid of the adverse effects of surgical sympathectomy, due to its localized nature, is minimally invasive, and provides short procedural and recovery times. This paper outlines the pathophysiological background for renal sympathetic denervation, describes the past and the present of this interventional approach, and considers several future potential applications. 1. Introduction Resistant hypertension is defined as uncontrolled blood pressure despite the use of optimal doses of three antihypertensive agents, of which one is a diuretic [1–4]. Using this definition prevalence of resistant hypertension can be as high as 30% in some regions, but prevalence of true resistant hypertension is most likely around 5% in organized referral centers [2–4]. Although several factors contribute to “resistant hypertension” (poor patient adherence, physician inertia, inappropriate drug combinations or inadequate dosing, drug-interaction, and secondary causes), the fact is that a small percentage of hypertensive patients remain with unacceptably high blood pressure levels. It has been shown that a majority of patients with resistant hypertension and no identifiable secondary causes have activated sympathetic nervous system and increased sympathetic outflow (Figure 1). The high prevalence of hypertension in the general population renders this small percentage of patients significant, in terms of actual patient numbers. The above, combined with several limitations of drug therapy (cost, adverse effects, polypharmacy, etc.), create the need for other therapeutic options, such as devices and interventions. Figure 1: Demonstrates pathophysiology of resistant hypertension. Increased sympathetic outflow is a fundamental abnormality in most patients. Despite the availability of
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