Over the past four years, the science of renal sympathetic denervation (RDN) for the treatment of resistant hypertension patients has quickly advanced. As RDN moves forward, Dr. Kintur Sanghvi saw the need for a comprehensive educational platform to increase awareness and knowledge. RDNworld.org was launched online in September 2013.
What is renal denervation?
The kidneys play a vital role in the regulation of intravascular volume and blood pressure. Kidneys influence blood pressure control mainly by following 3 pathways, each of which is directly affected by the sympathetic nervous system:
- Pressure natriuresis (auto-regulation of renal arterial flow);
- Renin Angiotensin Aldosterone System (RAAS); and
- Sympathetic tone modification.
Chronic over-activity of the sympathetic nervous system is demonstrated in hypertensive patients. There are efferent (taking nerve impulses from brain to kidney) and afferent (taking nerve impulses from kidney to brain) renal nerves that travel in outer layer of renal artery and physiologically connects the kidney with the brain.
The concept of reducing the crosstalk between the kidneys and the brain is not new. During the late 1930’s, the first report of non-selective thoracolumbar splanchnincectomy (from the 8th to the 12th dorsal root ganglion) from the United Stated was published to treat hypertension. Clinical trial data revealed a 5-year mortality rate of those treated surgically (n=1266) of 19%. In comparison, in those patients that did not undergo the surgery (n=467) the 5-year mortality rate was 54%. Some successfully operated upon patients had lower blood pressure extending out to 10 years.
Today, renal denervation (RDN) is a minimally invasive, catheter-based endovascular procedure to ablate the renal nerves and disrupt the cross talk (sympathetic signals) between the kidneys and the brain. Thus far, in a non-blinded, randomized, controlled trial with a crossover design, and in observational studies, this treatment has shown substantial reduction in blood pressure in patients suffering from severe resistant hypertension.
What is the reason for the buzz behind renal denervation?
In 2000, 972 million (26%) adults had hypertension worldwide. In 2025, about 1.5 billion people (29%) are projected to have hypertension. Hypertension costs $131 billion annually in health-care expenditures in the U.S. One in three adults in the U.S. has hypertension and less than half have it controlled per guidelines. Every 20/10 mmHg increase in blood pressure is associated with more than a twofold increase in the stroke and cardiovascular mortality. For example, a middle age (between age 40 and 69) patient with a blood pressure of 175/105 mmHg is 8 times more likely to die from a cardiovascular event in the next 10 years in comparison to a patient of the same age/ethnicity/sex with a blood pressure of 115/75 mmHg.
On the other hand, even small reductions in blood pressure translate into a cardiovascular mortality benefit. A meta-analysis of 61 prospective observational studies evaluating data of 1 million adults between the age of 40-89, from multiple different countries and ethnicities showed that just reducing the mean systolic blood pressure by 2 mm translates into a 7% relative risk reduction of cardiovascular mortality and an 11% relative risk reduction of stroke mortality.
Against the backdrop of a high rate of non-compliance to long-term medical treatment, unhealthy lifestyles, and the overall global burden of hypertension, renal denervation has shown promise. Data has shown a large drop in office blood pressure.
Can you tell us about your educational initiative at www.renaldenervationworld.org?
RDNworld, at renaldenervationworld.org, is a non-biased, non-branded, global, mobile-optimized, dynamic digital portal envisioned as the central location to educate and explore the evolution of RDN for both health care professionals and patients. Professional education spans from the basics of the sympathetic nervous system to how the procedure is done, to the applications of RDN beyond the treatment of hypertension, serving the needs of all levels of health care professionals, including RNs, NPs, PAs and physicians. The educational content is organized to bridge cardiologists, referring primary care physicians, interventionists, and nephrologists (hypertension specialists). Patient education covers the basics of hypertension/resistant hypertension, and explains renal denervation.
What is the goal of the www.renaldenervationworld.org?
Historically, all new inventions/technology and science take years before being adopted by the medical community. Many patients suffer because of this late adoption. One example is transradial intervention. I have been an advocate of the transradial catheterization since 2000. The first transradial percutaneous coronary intervention was performed in 1993. Even with its vast benefits, it took the United States 20 years to adapt the transradial technique. Last year, only 16% of catheterizations were performed via radial access. The most common reason for slow adaptation is inadequate education.
The goal of renaldenervationworld.org is the fast dissipation of RDN science, bringing awareness and education of the technique and its benefit or side effects to the community. In the next 10 years, there is going to be tremendous activity/discussion/debates related to renal denervation treatment. The debates will relate to:
- The safety and efficacy of RDN in resistant hypertension patients;
- The subset of patients that could benefit (resistant/moderate resistant hypertension/ uncontrolled hypertension/congestive heart failure/diabetes mellitus/obstructive sleep apnea);
- Which treatment technique of sympathetic nerve modulation is better for performing RDN (radiofrequency vs. ultrasound; endovascular/transurethral/external; nanoparticles/peri-vascular pharmacologic ablation/baroreceptor stimulation).
Our goal is to be a platform that simplifies and presents the information in a concise, un-biased manner. We hope to be able to educate all parties involved in taking care of hypertension patients worldwide.
Multiple educational websites for interventional cardiology exist. How do you envision RDNworld impacting education differently?
The Internet does offer a great deal of information; however, finding all the literature at one location on a single topic is most useful. The literature and data presented on the site are concise and extremely user-friendly, which can appeal to readers at different levels. The platform’s sole focus is renal denervation (sympathetic nerve modulation), with an effort to bridge the interests of all subspecialists intimately involved in taking care of hypertensive patients or those suffering the complications of hypertension.
What are the unique educational features www.renaldenervationworld.org offers?
The platform not only offers thorough, comprehensive, non-biased education to professionals, but has educational tools where clinicians can refer patients for further information about this investigational treatment option. Healthcare professionals can interact with the medical community by submitting a case, reviewing the clinical trial archives, and querying the internationally acclaimed RDN experts. In the research/science section of the site, all the international active clinical trials recruiting patients with different clinical conditions and major published research are available. In the future, patients will be able blog about their experience with RDN treatment. We also review new technologies in the pipeline for RDN and the role of RDN “beyond HTN”, including obstructive sleep apnea, diabetes, heart failure, and arrhythmia. The portal is a dynamic platform that will continue to update the participants with news, upcoming conferences, and important publications.