An Experimental Procedure Paid for by the General Public
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There are two aspects of renal nerve ablation that ought to be addressed. Renal nerve ablation is a fascinating method that was extremely successful in animal experiments as long as 30 years ago and may prove be beneficial to patients.
- Ablation could potentially be used for millions of patients in Germany alone. For such widespread use, a single controlled trial (Symplicity 2) involving 102 patients and lasting six months is no basis for general recommendations to German physicians. Symplicity 2 did not include a placebo group, and the endpoint, blood pressure, was not verified by independent researchers. This unreliable method may explain why ablation led to a decrease in systolic office blood pressure of 32mmHg but only 11mmHg in 24-hour blood pressure. The publication on baroreceptor stimulation which was also discussed by the authors shows unambiguously how striking the effects of even placebo treatment can be on blood pressure in patients with treatment-refractory hypertension. Because of these shortcomings of the Symplicity 2 trial, the US authorities, unlike their German counterparts, have to our knowledge not approved renal nerve ablation and have demanded a better-controlled trial.
- It is regrettable that in our health-care system an experimental procedure is being developed at the expense of the general public rather than manufacturers. This is quite unlike the situation for pharmaceutical products, which are only approved after much more intensive testing. A voluntary register of uncontrolled data is no solution for determining the clinical value of ablation. What is needed for this purpose are appropriate randomized clinical trials of sufficient duration: a couple of months is insufficient for the indication of hypertension. The extent to which uncontrolled data can overestimate the efficacy of interventions used to treat hypertension is exemplified by the history of dilation of atherosclerotic renal arterial stenosis.
Prof. Dr. med. Johannes Mann
Städt. Klinikum München-Schwabing, firstname.lastname@example.org
Prof. Dr. med. Karl Hilgers, Prof. Dr. med. Roland Veelken
Prof. Dr. med. Friedrich Luft, Universitätsklinik Charité, Berlin
Conflict of interest statement
Prof. Hilgers has received fees for consultancy on the Advisory Board of Daiichi Sankyo. He has also received reimbursement for participation fees, travel expenses, and accommodation costs and lecture fees from Novartis.
Prof. Veelken has received reimbursement of participation fees for conferences and travel and accommodation costs from Novartis. He has received lecture fees from Novartis and Roche.
Prof. Mann and Prof. Luft declare that no conflict of interest exists.
|1.||Mahfoud F, Himmel F, Ukena C, Schunkert H, Böhm M, Weil J: Treatment strategies for resistant arterial hypertension. Dtsch Arztebl Int 2011; 108(43): 725–31. VOLLTEXT|