Renal denervation: a glimpse of hope?

Excerpt

The development of the treatment modality using renal denervation with radiofrequency energy endured many ups and downs [1]. After encouraging results in the initial studies, a pronounced variability in blood pressure responses of individual patients was noted in clinical practice. Trying to unravel this observed variability, several technical shortcomings, in addition to the issue of selecting the appropriate patient population, were distinguished. For example, the induced lesions had a restricted distribution and limited penetration depth, leaving a large part of the nerves in the perivascular areas distant from the vascular lumen unaffected [2]. This may be due to the increased intima and media thickness in these hypertensive patients. Furthermore, the initial advice to perform ablations primarily in the main renal artery, leaving the distal segments and side branches untreated, may not have been good advice, in hindsight. Increased interest in the anatomy of sympathetic renal innervation has led to several novel insights [3]. For example, there is a high interpatient variability in the anatomy of these nerves. However, in general, the density of renal sympathetic nerves is higher and the location of these nerves more superficial in the distal segments. Also, in renal arteries with larger diameters and thicker vessel parenchyma, the innervation is found further from the lumen and the nerves increase in thickness. These findings suggest that the ablation lesions might have been insufficient with respect to location, depth and, most likely, also in number, in many cases in the initially performed procedures. …