During EuroPCR 2014, Felix Mahfoud, University Hospital in Homburg, Germany, and Konstantinos Tsioufis, University of Athens, Greece, reflected on the potential future role of modulation of the sympathetic nervous system in patients with difficult-to-control hypertension.
In the context of the SYMPLICITY-HTN-3 clinical trial results, questions were raised about the extent of the procedure's efficacy although the randomised, controlled trial confirmed the safety of renal denervation.
"In terms of efficacy, some studies have shown that renal denervation can achieve a clinically relevant reduction of office and ambulatory blood pressure in patients with difficult-to-control hypertension. There is a need for more research to identify the pathophysiology of the condition and to select the best patients who will benefit from treatment with the procedure," Tsioufis stated.
F. Mahfoud expanded on this, saying that the safety of renal denervation has never been contested as the primary safety endpoint of the study was met. F. Mahfoud said that, although renal denervation with radiofrequency did not show a significant difference with regard to the efficacy endpoint compared to the control group, it is unlikely that the procedure does not work in humans.
Other aspects to be considered are: SYMPLICITY HTN-3 may be underpowered; antihypertensive drugs may have been maximised, but not stabilised; the patient population may differ from Caucasians recruited in previous trials; the results may just be accidental; and the procedure may not have been performed effectively.
The underlying pathophysiology is much more complex than initially thought: "Maybe we are moving away from Symplicity to complexity, in terms of how we deliver energy and where the sweet spots for renal denervation are," F. Mahfoud commented. "On top of it there may be a learning curve for renal denervation; there is a lot more to learn and a lot more to understand," concluded F. Mahfoud.
"Renal denervation was developed as a promising therapy for the treatment of patients who suffer from resistant hypertension lacking treatment alternatives," stated William Wijns, EuroPCR Course Co-director. The physicians all agreed that this condition represents an unmet clinical need, adding that up until now, data from clinical trials and registries confirmed that renal denervation is a safe procedure. Further to this, they said that renal denervation is an option in patients with difficult-to-control hypertension, in whom other treatments have failed.