Renal sympathetic denervation

Renal Sympathetic Denervation (RSD) is a minimally invasive procedure used to treat resistant hypertension. Resistant hypertension is defined as high blood pressure that remains uncontrolled despite the use of three or more antihypertensive medications, including a diuretic. The procedure involves the use of radiofrequency ablation or ultrasound to disrupt the renal sympathetic nerves, which play a significant role in blood pressure regulation.

Overview

The kidneys have a pivotal role in blood pressure regulation, partly through the sympathetic nervous system. The sympathetic nervous system increases blood pressure by activating the renin-angiotensin-aldosterone system and increasing sodium retention. Renal sympathetic denervation aims to reduce the sympathetic efferent and afferent activity to the kidneys, thereby decreasing blood pressure.

Indications

Renal sympathetic denervation is primarily indicated for patients with resistant hypertension. It is considered when a patient's blood pressure remains high despite the use of multiple blood pressure-lowering medications. Other potential indications are being studied, including heart failure, chronic kidney disease, and metabolic syndrome.

Procedure

The procedure is performed under local anesthesia and sedation. It involves the insertion of a catheter through the femoral artery in the groin, which is then guided to the renal arteries. Once in place, radiofrequency energy or ultrasound is delivered through the cathenter to ablate the renal sympathetic nerves located in the walls of the renal arteries. The procedure typically takes about 40 minutes to an hour.

Efficacy

Clinical trials have shown mixed results regarding the efficacy of renal sympathetic denervation. Some studies report significant reductions in blood pressure in patients with resistant hypertension, while others have not found a significant benefit. Ongoing research aims to better define the patient population that may benefit most from this procedure.

Risks and Complications

As with any invasive procedure, renal sympathetic denervation carries potential risks and complications. These may include renal artery stenosis, pseudoaneurysm, hematoma at the puncture site, and, rarely, renal artery dissection. However, the procedure is generally considered safe, and serious complications are rare.

Future Directions

Research is ongoing to refine the technique, improve patient selection, and expand the indications for renal sympathetic denervation. New technologies and approaches are being developed to increase the safety and efficacy of the procedure.

See Also

• Hypertension
• Renin-angiotensin system
• Sympathetic nervous system
• Chronic kidney disease