Salt sensitivity risk derived from nocturnal dipping and 24-h heart rate predicts long-term blood pressure reduction following renal denervation

Background: Renal denervation (RDN) has been consistently shown in recent sham-controlled clinical trials to reduce blood pressure (BP). Salt sensitivity is a critical factor in hypertension pathogenesis, but cumbersome to assess by gold-standard methodology. Twenty-four-hour average heart rate (HR) and mean arterial pressure (MAP) dipping, taken by ambulatory blood pressure monitoring (ABPM), stratifies patients into high, moderate, and low salt sensitivity index (SSI) risk categories. Objectives: We aimed to assess whether ABPM-derived SSI risk could predict the systolic blood pressure reduction at long-term follow-up in a real-world RDN patient cohort. Methods: Sixty participants had repeat ABPM as part of a renal denervation long-term follow-up. Average time since RDN was 8.9 +/- 1.2 years. Based on baseline ABPM, participants were stratified into low (HR < 70 bpm and MAP dipping > 10%), moderate (HR >= 70 bpm or MAP dipping <= 10%), and high (HR >= 70 bpm and MAP dipping <= 10%) SSI risk groups, respectively. Results: One-way ANOVA indicated a significant treatment effect (P = 0.03) between low (n = 15), moderate (n = 35), and high (n = 10) SSI risk with systolic BP reduction of 9.6 +/- 3.7 mmHg, 8.4 +/- 3.5 mmHg, and 28.2 +/- 9.6 mmHg, respectively. Baseline BP was not significantly different between SSI Risk groups (P = 0.18). High SSI risk independently correlated with systolic BP reduction (P = 0.02). Conclusions: Our investigation indicates that SSI risk may be a simple and accessible measure for predicting the BP response to RDN. However, the influence of pharmacological therapy on these participants is an important extraneous variable requiring testing in prospective or drug naive RDN cohorts.