Aims: No intraprocedural assessment is currently available to evaluate the extent of nerve ablation by renal denervation (RDN). We prospectively evaluated the association of intraprocedural reduction of renal veno-arterial norepinephrine gradient with blood pressure (BP) response after RDN.
Methods and results: In 46 consecutive RDN patients, the periprocedural norepinephrine veno-arterial difference was defined as veno-arterial norepinephrine gradient. We observed a reduction of the office systolic BP from 176±19 mmHg to 165±24 mmHg (p=0.02) at three months and 163±22 mmHg (p=0.02) at six months. The mean and maximum systolic ABP decreased by 5 mmHg (p=0.03) and 9 mmHg (p=0.02), respectively. There was a decrease of the norepinephrine RV-RA difference from pre- to post-procedural levels (median 186 pg/ml [54;466] vs. 81 pg/ml [0;182], p=0.02). OBP responders (office systolic BP reduction ≥10 mmHg) showed a greater reduction of the norepinephrine gradient compared to non-responders (-290±450 pg/ml vs. -4±106 pg/ml, p=0.01). Patients with a reduction of norepinephrine gradient in both kidneys showed the most pronounced decrease of the systolic OBP (-24±14 mmHg) compared to patients with a reduction of norepinephrine gradient in only one kidney (-7±15 mmHg) or patients without a norepinephrine reduction (-3±19 mmHg, p=0.03 vs. bilateral reduction).
Conclusions: Measuring renal norepinephrine gradient during RDN may be a method to gauge the extent of renal nerve ablation.
Trial registration: ClinicalTrials.gov NCT01875809.