Renal sympathetic denervation

Renal sympathetic denervation (RSDN), is a minimally invasive, endovascular catheter based procedure using radiofrequency ablation or ultrasound ablation aimed at treating resistant hypertension (high blood pressure not controlled by medication). Nerves in the wall of the renal artery are ablated by applying radiofrequency pulses or ultrasound to the renal arteries. This causes reduction of sympathetic afferent and efferent activity to the kidney and blood pressure can be decreased. Early data from international clinical trials without sham controls was promising - demonstrating large blood pressure reductions in patients with treatment-resistant hypertension. However, in 2014 a prospective, single-blind, randomized, sham-controlled clinical trial failed to confirm a beneficial effect on blood pressure. A 2014 consensus statement from The Joint UK Societies did not recommend the use of renal denervation for treatment of resistant hypertension on current evidence. Renal sympathetic denervation (RSDN), is a minimally invasive, endovascular catheter based procedure using radiofrequency ablation or ultrasound ablation aimed at treating resistant hypertension (high blood pressure not controlled by medication). Nerves in the wall of the renal artery are ablated by applying radiofrequency pulses or ultrasound to the renal arteries. This causes reduction of sympathetic afferent and efferent activity to the kidney and blood pressure can be decreased. Early data from international clinical trials without sham controls was promising - demonstrating large blood pressure reductions in patients with treatment-resistant hypertension. However, in 2014 a prospective, single-blind, randomized, sham-controlled clinical trial failed to confirm a beneficial effect on blood pressure. A 2014 consensus statement from The Joint UK Societies did not recommend the use of renal denervation for treatment of resistant hypertension on current evidence. Prior to pharmacological management of hypertension, surgical sympathectomy was a recognized treatment for hypertension. This was often successful in reducing blood pressure but due to its non-selective nature the side effects of the procedure were poorly tolerated. Side effects included orthostatic hypotension, palpitations, anhydrosis, intestinal disturbances, loss of ejaculation, thoracic duct injuries and atelactasis.Modern antihypertensive pharmacological interventions have improved the control of hypertension, but only 34-66% of people with hypertension in England, USA and Canada have blood pressure at or below target levels. Resistant hypertension is defined as blood pressure above target (140/90mm Hg) despite concomitant use of 3 or more anti-hypertensives – one of which should be a diuretic. It has been estimated that 8-10% of people with hypertension fall into this category. Several commercial devices exist. These include Medtronic's Symplicity Renal Denervation System, St. Jude Medical’s EnligHTN™ System, Boston Scientific's Vessix V2™ Renal Denervation System, Covidien’s OneShot™ System, Recor’s Paradise™ System, Terumo's Iberis™ System and Cordis Corporation's RENLANE™ Renal Denervation System. Currently, no renal denervation device has FDA approval. The procedure involves endovascular access via the femoral artery with advancement of a catheter-mounted device into the renal artery. The device uses radiofrequency or ultrasound to ablate the renal nerves. Typically, numerous ablations are applied at a different longitudinal and rotational positions to ensure maximal denervation. The procedure does not involve a permanent implant.