Blood pressure response to renal
denervation is highly variable, and the proportion of responders is disappointing. This may be partly because of accessory renal arteries too small for
denervation, causing incomplete ablation. Renal nerve stimulation before and after renal
denervation is a promising approach to assess completeness of renal
denervation and may predict blood pressure response to renal
denervation. The objective of the current study was to assess renal nerve stimulation-induced blood pressure increase before and after renal
sympathetic denervation in main and accessory renal arteries of anaesthetized patients with drug-resistant
hypertension. The study included 21 patients. Nine patients had at least 1 accessory renal artery in which renal
denervation was not feasible. Renal nerve stimulation was performed in the main arteries of all patients and in accessory renal arteries of 6 of 9 patients with accessory arteries, both before and after renal
sympathetic denervation. Renal nerve stimulation before renal
denervation elicited a substantial increase in systolic blood pressure, both in main (25.6±2.9 mm Hg; P<0.001) and accessory (24.3±7.4 mm Hg; P=0.047) renal arteries. After renal
denervation, renal nerve stimulation-induced systolic blood pressure increase was blunted in the main renal arteries (Δ systolic blood pressure, 8.6±3.7 mm Hg; P=0.020), but not in the nondenervated renal accessory renal arteries (Δ systolic blood pressure, 27.1±7.6 mm Hg; P=0.917). This residual source of renal sympathetic tone may result in persistent
hypertension after ablation and partly account for the large response variability.