The endpoint on measuring the clinical effects of renal denervation: What are the best surrogates

Abstract

In the past several years, renal denervation has proven to be an effective treatment for resistant hypertension (HTN). Unfortunately the procedure does not always lower blood pressure and many patients continue to need drugs for HTN. While there are several potential explanations for this persistent elevation of blood pressure after renal denervation, one is that the renal nerves were not completely ablated. Another is that the HTN was not caused by increased sympathetic nerve activity (SNA) in the individual patient, and that other stimuli for HTN persists after renal denervation. In addition, accumulating evidence suggests that renal denervation also benefits other conditions including heart failure (HF), atrial fibrillation and insulin resistance. Thus in the near future this procedure might be frequently employed for several common medical problems. A major problem is that it will not be sufficient to simply measure blood pressure to ascertain successful renal denervation. Given these considerations, it is apparent that we need surrogate measures of increased sympathetic activity and procedural success. In this chapter we will discuss direct and indirect methods for assessing SNA in humans, how these can be used to screen patients for renal denervation, how they could be used to gauge technical success and how these various methods might be used in specific diseases.