SIR to Host Balanced Look at Renal Denervation
By Jim Knaub
Using a catheter to deliver radio-frequency energy to nerves in the kidneys to help control blood pressure is intriguing. Renal denervation could provide an effective treatment for people with high blood pressure who don’t respond to medical therapy, and up to one-third of patients with hypertension may be resistant to medical therapy, according to a study by Michael Doumas, MD, published in the International Journal of Hypertension. The procedure is involved in trials in the United States and around the world to investigate the treatment.
Renal denervation utilizes a catheter introduced through the femoral artery and then maneuvered into the renal artery. Once the catheter tip is in place within the artery, low radio-frequency energy is applied to the nearby renal nerves and reduces the hyperactivation of the sympathetic nervous system, which is an established contributor to chronic hypertension. Each kidney is treated in the procedure.
Some think it eventually could provide a minimally invasive, cost-effective alternative to medical therapy—but that’s getting ahead of things.
Two-year results from a renal denervation trial called the Symplicity HTN-2 were presented at the American College of Cardiology meeting in March and showed a significant reduction in blood pressure among the study subjects. Medtronic, which developed the Symplicity system, also is conducting the procedure’s first randomized controlled clinical trial. The company expects enrollment for the Symplicity HTN-3 trial to be completed sometime this summer.
The study will randomize 530 patients in up to 90 US medical centers and will compare results from patients with treatment-resistant high blood pressure who receive renal denervation and medical therapy with patients who receive only medical therapy. The study’s primary end points are blood pressure changes from baseline to six months following randomization and the incidence of major adverse events one month following randomization.
Early studies in the United States and other countries have shown promise, but research defining when to use the procedure and how it performs compared with medical therapies in well-controlled studies is ongoing. The session at the Society of Interventional Radiology annual meeting in New Orleans should provide an interesting, balanced update on renal denervation technique and research.
— Jim Knaub is editor of Radiology Today. |
