August 28, 2012
Renal Denervation Shows Health Benefits In A Number Of Areas
Connie K. Ho for redOrbit.com — Your Universe Online
Dull headaches, Dizzy spells. Nosebleeds. These are just a few of the symptoms of high blood pressure. There are medications to treat high blood pressure, but not all patients can be treated with the drugs available on the market. After conducting various studies, researchers recently discovered that renal denervation could lead to the reduction of blood pressure at a significant and sustained rate over an 18-month period for patients who are treated for resistant hypertension.
Despite three different prescription blood pressure medications, treatment for resistant hypertension has been difficult. Resistant hypertension has affected about 120 million throughout the world, causing premature death due to kidney disease as well as cardiovascular events like heart attack, heart failure, and stroke. As such, the researchers wanted to complete this study to better understand anxiety and depression, quality of life, sleeping quality, stress tolerance and intensity of headaches before and after renal denervation. The research findings, part of the clinical data from Simplicity HTN-2 randomized clinical trial, were presented at the European Society of Cardiology (ESC) Congress 2012.
"Treatment resistant hypertension is one of the most challenging forms of hypertension to manage because it does not respond to blood pressure lowering drugs," commented Dr. Murray Esler, the associated director of the Baker IDI and Diabetes Institute of Melbourne in Australia, in a prepared statement.
According to the Mail Online, renal denervation is a “radical therapy that zaps the kidney with radio waves.” The procedure allows for the disruption of afferent and efferent nerves inside and outside of the kidney. The minimally invasive procedure utilizes radio frequency energy from a catheter device that is placed in the renal arteries from the groin. High blood pressure is sometimes the result of weak signals from the brain to the nerves in the kidney. The procedure is thought to be effective in treating patients who are resistant to drug therapy.
The Simplicity HTN-2 trial was a prospective, randomized, controlled study by various international centers to determine the safety and effectiveness of renal denervation. Participants who had treatment resistant hypertension were randomly grouped into either having renal denervation along with antihypertension medication in an experiment group or antihypertensive medication in a control group at one of 24 centers in 11 different countries. There were a total of 173 patients who had resistant hypertension. The participants also recorded their psychological status, stress tolerance, sleeping quality and intensity of headaches before and after renal denervation.
"In patients with resistant hypertension overactivity of the sympathetic nervous system causes hyperarousal, leading to higher anxiety and stress levels," remarked Dr. Denise Fischer from Saarland University Hospital in the statement. "Renal denervation reduces office blood pressure and resting heart rate and does not impair psychological processes."
Based on the results, the researchers determined that renal denervation was effective and safe in both treatment groups up to 18 months after the procedure.
"Up to one-third of hypertensive individuals undergoing therapy are considered resistant to treatment. We are encouraged to see that renal denervation shows substantial and sustained blood pressure reduction in treatment resistant patients,” noted Esler in the statement. "We know the renal nerves play a crucial role in blood pressure elevation and this study shows those nerves can be targeted with renal denervation without major side effects."
The scientists also found that renal sympathetic denervation could help lessen anxiety, stress and depression as well as improve quality of life in patients who had resistant hypertension.
"Renal denervation may have a positive effect on psychological processes, stress perception and processing as well as quality of life. It improves sleeping quality and may reduce the intensity of headache," continued Fischer in the statement.
Furthermore, the study showed that renal denervation could improve blood pressure and arterial pressure. Other benefits include short recovery times. The procedure would be beneficial to those who have arterial hypertension and suffer from anxiety and panic disorders.
"A significant reduction in blood pressure response was observed in at least half of the patients who underwent splanchnicectomy," commented Klass Fransen, a researchers from the University Hospital of Schleswig-Holstein, in the statement. "But the treatment led to severe adverse events such as orthostatic hypotension, anhidrosis and intestinal disturbances. After the discovery of effective antihypertensive drugs, splanchnicectomy became neglected and disregarded over time."
The team notes that the procedure can be applied to real world patient populations of individuals with resistant hypertension.
"The Simplicity Hypertension I and II studies have suggested that this procedure significantly lowers blood pressure in these patients with few remaining options in terms of treatment," explained Dr. Darren Mylotte, a Canadian researcher, in the statement. "However, patients included in clinical trials are often highly selected, and therefore may not reflect the patient encountered by physicians on a day-to-day basis. As such, the results of these trials may not be applicable to less-selected patient populations."
The study also showed that renal denervation resulted in better outcomes than standard drug treatment for patients who have advanced heart failure.
"The improvement of the contractile function of the left side of the heart by more than 10 percent in patients after renal denervation was a surprise," said Dr. MiloÅ¡ TÃ¡borskÃ½, a researcher from the University Hospital Olomouc, in the statement. "This parameter has practically not changed in patients treated by the classic drugs. The difference in response might be explained by a continuous decrease of the renal sympathetic activity in the complex pathophysiology of heart failure."
The investigators believe that more research needs to be done to identify whether there are other benefits of renal denervation.
"Further studies are needed to determine whether the benefits of RDN translate into a reduced risk of cardiovascular events," continued Fransen in the statement.
The procedure could be offered in the United Kingdom in coming months.
“When this [treatment] came out it was a question of whether it was going to last, because it sounded too good to be true. Eighteen months isn´t that long, but it seems as if it does last,” concluded Peter Weissberg, medical director of the British Heart Foundation, in an article by Nick Collins of The Telegraph. “Renal denervation will become part of the management of this group of difficult-to-treat patients in the future, it is just a question of how long that takes.”