Integrative Blood Pressure Response to Upright Tilt Post Renal Denervation.
BACKGROUND
Whether renal denervation (RDN) in patients with resistant hypertension normalizes blood pressure (BP) regulation in response to routine cardiovascular stimuli such as upright posture is unknown. We conducted an integrative study of BP regulation in patients with resistant hypertension who had received RDN to characterize autonomic circulatory control.


METHODS
Twelve patients (60 ± 9 [SD] years, n = 10 males) who participated in the Symplicity HTN-3 trial were studied and compared to 2 age-matched normotensive (Norm) and hypertensive (unmedicated, HTN) control groups. BP, heart rate (HR), cardiac output (Qc), muscle sympathetic nerve activity (MSNA), and neurohormonal variables were measured supine, and 30° (5 minutes) and 60° (20 minutes) head-up-tilt (HUT). Total peripheral resistance (TPR) was calculated from mean arterial pressure and Qc.


RESULTS
Despite treatment with RDN and 4.8 (range, 3-7) antihypertensive medications, the RDN had significantly higher supine systolic BP compared to Norm and HTN (149 ± 15 vs. 118 ± 6, 108 ± 8 mm Hg, P < 0.001). When supine, RDN had higher HR, TPR, MSNA, plasma norepinephrine, and effective arterial elastance compared to Norm. Plasma norepinephrine, Qc, and HR were also higher in the RDN vs. HTN. During HUT, BP remained higher in the RDN, due to increases in Qc, plasma norepinephrine, and aldosterone.


CONCLUSIONS
We provide evidence of a possible mechanism by which BP remains elevated post RDN, with the observation of increased Qc and arterial stiffness, as well as plasma norepinephrine and aldosterone levels at approximately 2 years post treatment. These findings may be the consequence of incomplete ablation of sympathetic renal nerves or be related to other factors.
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA.|University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Erin J
EJ
Howden
Baylor Soltero Cardiovascular Research Center, Baylor Scott and White Research Institute, Dallas, Texas, USA.
Cara
C
East
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA.|University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Justin S
JS
Lawley
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA.|University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Abigail S L
ASL
Stickford
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA.
Myrthe
M
Verhees
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA.|University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Qi
Q
Fu
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA.|University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Benjamin D
BD
Levine
D000368:Aged; D000450:Aldosterone / Q000097:blood; D000959:Antihypertensive Agents / Q000627:therapeutic use; D062186:Arterial Pressure / Q000187:drug effects; D015415:Biomarkers / Q000097:blood; D002302:Cardiac Output; D003430:Cross-Sectional Studies; D004351:Drug Resistance; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D007668:Kidney / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D056888:Patient Positioning; D011187:Posture; D012077:Renal Artery / Q000503:physiopathology / Q000601:surgery*; D013562:Sympathectomy; D018667:Tilt-Table Test; D013997:Time Factors; D016896:Treatment Outcome; D014655:Vascular Resistance; D059289:Vascular Stiffness
D000959:Antihypertensive Agents; D015415:Biomarkers; D000450:Aldosterone; D009638:Norepinephrine
ablation; autonomic nervous system; blood pressure; human; hypertension; physiology; sympathetic activity