Radio frequency-based renal denervation: a story of simplicity?

ABSTRACT

Radio frequency-based renal denervation is a safe and effective way of lowering blood pressure, a common condition associated with high cardiovascular risk. Several catheters have been developed to administer energy to the renal arteries and their side branches, thereby modulating sympathetic renal activity. The Symplicity Flex™ and Symplicity Spyral™ are first- and second-generation devices, respectively, for radio frequency-based renal denervation. There is a continuous need to further improve and adjust interventional antihypertensive therapies. Several randomized controlled trials have been conducted to investigate the safety and efficacy of these catheters and most were able to show radio frequency-based renal denervation to be feasible, safe and effective in lowering blood pressure in hypertensive patients with and without concomitant antihypertensive medication. Herein, the authors discuss the pathophysiologic concepts of renal denervation and its procedural approaches, report catheter designs, summarize clinical trials outcomes and, finally, discuss real-world evidence.

High blood pressure causes illness and death worldwide. Treatment of high blood pressure is usually based on lifestyle modification and blood pressure-lowering drugs. Renal denervation represents a minimally invasive approach to lower blood pressure by interrupting the nerves surrounding the renal arteries. These nerves are involved in the body's fight-or-flight and rest-and-digest systems, the so-called autonomous nervous system. The Spyral™ catheter system uses radio frequency energy to modulate renal nerve activity. Trials have consistently shown that renal denervation is safe. The first-generation catheter was a monoelectrode catheter called Symplicity Flex™ and several points in the renal artery had to be treated. The second-generation device called the Symplicity Spyral™ catheter, on the other hand, has a multielectrode design and consequently fewer ablation points are sufficient for complete denervation. Caused by the positive effects on blood pressure and the consistent safety reports, renal denervation is considered by current guidelines as an alternative and additive treatment approach in patients with high blood pressure.