Renal Denervation Therapy - A new Treatment for Resistant Hypertension

64 year old farmer from Nellore with a history of blood pressure and diabetes had a sudden episode of inability to use his left upper and lower limbs and was found to have very high blood pressure – 220/130mmHg. CT scan confirmed that he had a damage in a small region of the brain – an infarct. The neurologist had recommended that his blood pressure had to be controlled as failure to do that could increase the damaged area. Anti hypertensive medications were started orally as well as by intravenous route but to no avail. Despite the use of five different  types of drugs the blood pressure could not be controlled satisfactorily all the time. Investigations were done to find out if there were other treatable causes of high BP. In the face of such a problem a new treatment has been available for the past two years as an investigational method but has gradually attained widespread acceptance in Europe. 

One of the mechanism by which BP is maintained is by the regulation of the diameter of the blood vessels, particularly of the arteries to important organs such as brain, liver, intestines and most importantly the kidneys. The kidneys are able to regulate the formation of urine and the amount of sodium and potassium in the urine by the feedback mechanism provided by the nerves that populate the surface of the renal arteries. Finally the BP is maintained at a normal rate.

 Renal artery sympatheic innervations and Radiofrequency ablation (In pic)

In patients with high BP where despite numerous drugs the BP is difficult to control it was hypothesized that by removing the effects of these nerves the predominant effect of trying to maintain a high BP is effectively neutralized . This can result in fall of BP. We can utilize this response to control BP in our patients by destroying these nerves. This can be done by radiofrequency energy which by resistive heating will functionally neutralize the nerves.  This was done in our patient by using conventional radiofrequency energy using very low power at low temperatures and small duration. The remarkable advantage of this treatment is the absolute lack of side effects of the treating source the radiofrequency energy which is the same electromagnetic radiation that is used in communication between our mobiles and the tower. The procedure has to be done with great care taking to see that the correct amount of power is used at the correct locations and for the correct time. With such care complications that can  potentially occur with this procedure can be nullified and good longterm benefits obtained.

For the patient in question the BP dropped from 164/102 to 146/86 at the end of the procedure and has since been well controlled with the blood pressure being normal at 135/80 on 30^th June 2012.

Catheter being withdrawn from distal to proximal at different sites of ablation (In Pic)

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Dr. Joy Thomas

MD, MD, DM, FACC, FHRS, FCSI

Chief Consultant Cardiologist & Electrophysiologist,

Head and Director, Department of Cardiology,

Global Health City. Chennai