Renal sympathetic denervation: early impact on ambulatory resistant hypertension

Galectin-3 and prediction of therapeutic response to renal sympathetic denervation

The profibrotic mediator Galectin-3 (Gal-3) has been associated with aldosterone-mediated vascular inflammation, fibrosis, and stiffness. We evaluated whether the Gal-3 levels and change in Gal-3 as associated with renal denervation can serve as prediction of therapeutic response to renal denervation. A total of 42 patients with resistant hypertension undergoing renal sympathetic denervation (RDN) were included. Blood pressure was evaluated by 24-h ambulatory measurement before RDN and 1, 3 and 6 months after RDN. Treatment response was defined as a drop in systolic ambulatory blood pressure of >5 mm Hg after 6 months. Blood samples were assessed for Gal-3 levels. For the entire group, a significant drop in mean systolic ambulatory blood pressure of 5.2 ± 18.6 mm Hg was observed (p = 0.032). The responder rate was 50% (n = 21). At baseline, Gal-3 levels were significantly higher in responders (14.5 ± 6.0 vs. 10.95 ± 4.6 ng/ml, p = 0.017). There were no significant changes of Gal-3 levels during the follow-up period. The profibrotic biomarker may help to identify patients suitable for RDN.

Renal denervation for the management of resistant hypertension

Renal sympathetic denervation (RSD) as a therapy for patients with resistant hypertension has attracted great interest. The majority of studies in this field have demonstrated impressive reductions in blood pressure (BP). However, these trials were not randomized or sham-controlled and hence, the findings may have been overinflated due to trial biases. SYMPLICITY HTN-3 was the first randomized controlled trial to use a blinded sham-control and ambulatory BP monitoring. A surprise to many was that this study was neutral. Possible reasons for this neutrality include the fact that RSD may not be effective at lowering BP in man, RSD was not performed adequately due to limited operator experience, patients’ adherence with their anti-hypertensive drugs may have changed during the trial period, and perhaps the intervention only works in certain subgroups that are yet to be identified. Future studies seeking to demonstrate efficacy of RSD should be designed as randomized blinded sham-controlled trials. The efficacy of RSD is in doubt, but many feel that its safety has been established through the thousands of patients in whom the procedure has been performed. Over 90% of these data, however, are for the Symplicity™ system and rarely extend beyond 12 months of follow-up. Long-term safety cannot be assumed with RSD and nor should it be assumed that if one catheter system is safe then all are. We hope that in the near future, with the benefit of well-designed clinical trials, the role of renal denervation in the management of hypertension will be established.