{Soft hyphen}{Soft hyphen}{Soft hyphen}Neurogenic Hyperadrenergic Orthostatic Hypotension {-} A Newly-recognized Variant of Orthostatic Hypotension in Older Adults with Elevated Norepinephrine

We report a subset of patients who clinically have typical neurogenic OH but who paradoxically have elevated upright levels of plasma norepinephrine.

We retrospectively studied 83 OH patients evaluated at the Vanderbilt Autonomic Dysfunction Center between August 2007 and May 2013. Based upon standing norepinephrine, patients were dichotomized into a hyperadrenergic orthostatic hypotension group (hyperOH: upright NE ≥3.55 nmol/L [600 pg/mL], n=19) or a non-hyperadrenergic orthostatic hypotension group (nOH: upright NE < 3.55 nmol/L [600 pg/mL], n=64). Medical history and data from autonomic testing, including the Valsalva maneuver (VM), were analyzed. HyperOH patients had profound orthostatic falls in blood pressure, but less severe than in nOH (change in SBP: -53±31 mmHg vs. -68±33 mmHg, P=0.050; change in DBP: -18±23 mmHg vs. -30±17 mmHg, P=0.01). The expected compensatory increase in standing heart rate was similarly blunted in both hyperOH and nOH groups (84±15 bpm vs. 82±14 bpm; P=0.6). HyperOH patients had less severe sympathetic failure as evidenced by smaller falls in DBP during phase 2 of VM, and a shorter VM phase 4 blood pressure recovery time (16.5±8.9 sec vs. 31.6±16.6 sec; P<0.001) than nOH patients.

Neurogenic hyperOH patients have severe neurogenic orthostatic hypotension, but have less severe adrenergic dysfunction than nOH patients. Further work is required to understand if hyperOH patien...

Source: Clinical Science - February 23, 2015 Category: Biomedical Science Authors: P L Mar, C A Shibao, E M Garland, B K Black, I Biaggioni, A Diedrich, S Y Paranjape, D Robertson, S R Raj Source Type: research