Sustained sympathetic and blood pressure reduction 1 year after renal denervation in patients with resistant hypertension

Abstract

Renal denervation (RDN) reduces muscle sympathetic nerve activity (MSNA) and blood pressure (BP) in resistant hypertension. Although a persistent BP-lowering effect has been demonstrated, the long-term effect on MSNA remains elusive. We investigated whether RDN influences MSNA over time. Office BP and MSNA were obtained at baseline, 3, 6, and 12 months after RDN in 35 patients with resistant hypertension. Office BP averaged 166±22/88±19 mm Hg, despite the use of an average of 4.8±2.1 antihypertensive drugs. Baseline MSNA was 51±11 bursts/min ≈2- to 3-fold higher than the level observed in healthy controls. Mean office systolic and diastolic BP significantly decreased by -12.6±18.3/-6.5±9.2, -16.1±25.6/-8.6±12.9, and -21.2±29.1/-11.1±12.9 mm Hg (P<0.001 for both systolic BP and diastolic BP) with RDN at 3-, 6-, and 12-month follow-up, respectively. MSNA was reduced by -8±12, -6±12, and -6±11 bursts/min (P<0.01) at 3-, 6-, and 12-month follow-up. The reduction in MSNA was maintained, despite a progressive fall in BP over time. No such changes were observed in 7 control subjects at 6-month follow-up. These findings confirm previous reports on the favorable effects of RDN on elevated BP and demonstrate sustained reduction of central sympathetic outflow ≤1-year follow-up in patients with resistant hypertension and high baseline MSNA. These observations are compatible with the hypothesis of a substantial contribution of afferent renal nerve signaling to increased BP in resistant hypertension and argue against a relevant reinnervation at 1 year after procedure.

Keywords: hypertension resistant to conventional therapy; sympathetic nervous system.