Percutaneous renal denervation in patients with treatment-resistant hypertension: final 3-year report of the Symplicity HTN-1 study
Selected in The Lancet by R. Dworakowski
Henry Krum, Markus P Schlaich, Michael Böhm, Felix Mahfoud, Krishna Rocha-Singh, Richard Katholi, Murray D Esler
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What is known
The Symplicity HTN-1, a proof-of-concept and safety study showed that catheter based renal denervation (RDN) significantly reduced blood pressure (BP) in patients with drug-resistant hypertension at 1, 12 and 24 months. There were unanswered questions regarding long-term sustainability and possibility of reinnervation.
88 patients out of 153 pts from Simplicity HTN-1 study were followed up for 36 months.
The significant reduction in systolic (32 mmHg) and diastolic blood pressure (14mmHg) persisted. This suggests that a significant functional regrowth or reinnervation of the kidneys is unlikely.
Drops of 10 mm Hg or more in systolic blood pressure were seen in 69% of patients at 1 month, 81% at 6 months, 85% at 12 months, 83% at 24 months, and 93% at 36 months.
One new renal artery stenosis requiring stenting and three deaths unrelated to RDN occurred during follow-up.
This is a first study with long-term results for catheter-based RDN. The results confirmed that RDN is safe and hypotensive response is sustainable at 36 months. However these results are very promising they have to be taken cautiously. The main limitation of Simplicity HTN-1 is lack of control group, small number of patients and significant drop out rate.
The average of antihypertensive medications at baseline and at 36 months follow-up remained similar. There is a possibility of better patient compliance, more effective medical treatment at higher dosage or placebo effect for patients taking part in clinical study at follow up.
At the moment RDN should not be considered as a procedure allowing to stop/reduce a dosage of antihypertensive medications. It is an exciting new technique that could help to treat resistant hypertension but further studies are needed before expanding this technique into patient with milder forms of hypertension responding to medical therapy.