Catheter-Based Renal Denervation Reduces Blood Pressure And Thus Offers A New Treatment Option For Patients With Resistant Hypertension

Main Category: Hypertension
Also Included In: Urology / Nephrology
Article Date: 03 Apr 2009 - 1:00 PDT

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Deactivation of nerves in the kidneys (renal denervation) using a catheter-based technique reduces blood pressure, and thus could be a treatment option for the many patients with hypertension (high blood pressure) who do not respond to conventional drugs. The findings appear in an Article published Online First and in an upcoming edition of The Lancet. Publication of the Article coincides with the announcement of the findings at the American College of Cardiology (ACC) meeting in Florida, USA.

Some 30-40% of the world's adult population suffer from hypertension, and, of these, 5-10% suffer truly resistant hypertension. Hyperactivity of the sympathetic nervous system serving the kidneys is associated with hypertension and its progression, as well as with chronic kidney disease, and heart failure. In this proof-of-principle study, Professor Henry Krum (Centre of Cardiovascular Research and Education in Therapeutics, Monash University, Melbourne, Australia) and colleagues trialled renal sympathetic denervation in patients with resistant hypertension - defined as systolic blood pressure ≥160 mm Hg on three or more antihypertensive medications, including a diuretic - to assess safety and blood-pressure reduction.

The study recruited 50 patients from five Australian and European centres. Five patients were excluded for anatomical reasons, and the remaining 45 received percutaneous radiofrequency catheter-based treatment between June 2007 and November 2008, with subsequent follow-up to one year. Treatment involved placing a catheter in the femoral artery, guiding it to the renal artery, and advancing it to where the nerves are located. Following this, 4-6 applications of radiofrequency energy were given so that maximum nerve disruption occurs. 'Office' blood pressure measurements and safety data were taken before treatment and at 1, 3, 6, 9, and 12 months after procedure.

The researchers found that in the treated patients, who were taking an average of 4.7 antihypertensive medications each, the mean blood pressure before denervation was 177/101 mm Hg. Office blood pressures were reduced by -14/-10, -21/-10, -22/-11, -24/-11, and -27/-17 mm Hg at 1, 3, 6, 9, and 12 months respectively. In the five non-treated patients, the mean rise in office blood pressure was +3/-2, +2/+3, +14/+9, and +26/+17 mm Hg at 1, 3, 6, and 9 months respectively.

The authors say: "We showed an excellent safety profile of this brief, catheter-based therapy. No long-term adverse events resulted from the procedure...Therapeutic renal denervation led to a large and persistent decrease in blood pressure, which was achieved in patients resistant to multiple existing hypertensive drug types. Moreover, reduction of blood pressure was evident as early as 1 month, was further reduced at 3 months, and persisted through subsequent assessments."

They conclude: "If randomised controlled trials confirm these initial findings, catheter-based renal sympathetic denervation might be helpful in the management of this public health issue."

In an accompanying Comment, Dr Michael Doumas, George Washington University, Washington, DC, USA, and Dr Stella Douma, Hippokration Hospital, Aristotle University of Thessaloniki, Greece, say that this new approach must be reserved for patients with truly resistant hypertension, only after drug therapy has failed or is not tolerated.

They conclude: "We strongly believe that Krum and colleagues provide hope for the management of a difficult clinical condition."

DOI:10.1016/S0140-6736(09)60566-3
The Lancet

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Tony Kirby
Press Officer
The Lancet
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