Endpoints for Clinical Effects of Renal Denervation: What Is the Best Surrogate?
Renal denervation (RDN) is an effective treatment for resistant hypertension (HTN) but does not always result in lower blood pressures. New techniques to assess the success of RDN and measure sympathetic nerve activity may allow for improved patient selection for RDN, documentation of procedural technical success, and evaluation of patients in whom there is a late loss of clinical benefit. A number of potential surrogates, including blood and urinary biomarkers, recordings of nerve activity, and continuous monitoring to assess oscillations in heart rate and blood pressure, have been identified and evaluated. Assessing the effectiveness of RDN requires careful differentiation of technical success (i.e., effective ablation of nerve signaling in the renal arteries) and clinical outcomes (including surrogate endpoints such as left ventricular hypertrophy and “hard” outcomes such as mortality). In this chapter, we review the relevant renal artery anatomy and procedural characteristics of RDN; appraise the existing literature studying the value of surrogate markers for both technical success and clinical outcomes for RDN across multiple organ systems including cardiovascular, renal, and endocrine; and explore the relevance of these biomarkers as they relate to the potential applications of RDN for resistant HTN as well as alternative disease processes including atherosclerosis, heart failure, arrhythmia, chronic kidney disease, and the metabolic syndrome.
