Monday, March 26, 2012


Well, the spring American College of cardiology annual scientific meeting is on at Chicago. Not surprisingly, One day one we saw a few papers on renal denervation for the treatment of resistant hypertension. Renal denervation is the procedure to ablate the sympathetic nerves around the renal artery in an attempt to lower BP in patients with resistant hypertension ( defined as inability to control the BP despite 4-5 medications ).
Dr Paul Sobotka presented a follow-up to Symplicity HTN 1 after 3 years, and Dr Murray Esler presented the 2 year follow-up of Symplicity HTN 2. These are both relative small studies, and also without a control sham operation.
Nonetheless, we have learn a few more things, 3 years later.
1. We learn that this procedure, even if successfully done, may not lower the BP immediately. It may take months to see an office BP response. This is upsetting, as you never know if you have done a good job or not.
2. There is an almost 10-20% of "non-responders" to this procedure. Some of these "non-responders", as shown by Dr Sobotka, do slowly respond over 6 months.
3. This procedure can be painful and does have some complications, including a case of renal artery dissection ( treated with stenting ), a case of severe hypotension, and a case of severe hypertension, following the procedure. These were all seen in Symplicity HTN 2.
4. For some reason yet unanswered, following successful renal denervation, the office BP gets lowered, but the 24 hr ambulatory BP shows almost no response.
5. That following successful denervation, the office BP comes down, but the number of tablets may not. This I find very difficult to understand. we are actually treating anumber.
6. All these now gives rise to two group of physicians, the believers and the non- believers.
7. This can only mean that we need more data. Symplicity HTN 3, a big multi-center study with a sham procedure control arm, and using ambulatory BP monitoring, is underway, to try and sort out all these issues.

So although many of us think that it is a wonderful idea to ablate renal sympathetic nerves to control BP, we find that the idea is too symplistic and the data is somewhat confusing. More studies are obviously needed.

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