An exciting and promising new procedure, which can help lower blood pressure in patients with resistant hypertension (hypertension not controlled by medication), is currently under study in 90 medical centers, including ours, throughout the U.S. The procedure, called renal denervation, involves interrupting nerves of the sympathetic nervous system that connect the brain and the kidneys as they course through the renal arteries (the arteries to the kidneys). The procedure involves introducing a catheter through an artery in the groin (as is done for a heart catheterization), advancing it up the aorta to the renal arteries and interrupting the nerves using radiofrequency ablation. This can lower blood pressure through reduction of nerve signals to the kidneys and brain.
Resistant hypertension is defined in this study as a systolic blood pressure in the office above 160 despite treatment with at least three blood pressure drugs, one of which is a diuretic. The initial studies show blood pressure lowering by an impressive 25-30 millimeters. The current study (the procedure is not yet FDA approved and is not available outside the study), is intended to lead to FDA approval.
Is the procedure as good as the hype? Hopefully the ongoing study will answer questions about it. Here are some frequent questions about it:
Is it safe? It seems to be. The risk is pretty much the same as the risk of cardiac catheterization -- bleeding at the site in the groin and, very infrequently, injury to the kidney artery. The risk is not zero, but it is low.
Is it for everyone with hard-to-control hypertension? No. Blood pressure can be brought under control, and without side effects, in most patients, by adjusting medications, most of which have a long track record. Consultation with a hypertension specialist is recommended if your hypertension is not under control or if you are living with drug side effects (a list of hypertension specialists throughout the U.S. can be found at ash-us.org). At the moment, given the proven benefit of drug therapy when it brings blood pressure under control, it is preferable to a procedure whose effectiveness is still under study.
Can renal denervation get you off medication? The studies so far have demonstrated blood pressure lowering in 90 percent or more of cases but, in most, the amount of medication was not reduced.
If your blood pressure is normal but you are on many medications, could renal denervation enable you to reduce or eliminate lifelong medications? Possibly, but studies have not looked at patients whose blood pressure is under control. Is a procedure preferable to lifelong medication? We don't know.
A quick fix always sounds attractive, and for people whose hypertension cannot be controlled, this procedure could be a very attractive alternative. But caution dictates seeking the right combination of drugs before rushing to a new procedure.
How can you find out if you are eligible and appropriate for the procedure? You must be between 21 and 80, have an office blood pressure above 160 mm, and be on at least three drugs, including a diuretic. You can find out about additional criteria, and obtain further information, by contacting a participating medical center. A list of participating centers can be found at http://www.medtronicrdn.com.
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