title: Hypertension in patients with neurovascular compression is associated with increased central sympathetic outflow.
abstract: Recent data suggest a causal relationship between essential hypertension and neurovascular compression (NVC) at the rostral ventrolateral medulla. An increase of central sympathetic outflow might be an underlying pathomechanism. The sympathetic nerve activity to muscle was recorded in 21 patients with hypertension with NVC (NVC+ group) and in 12 patients with hypertension without NVC (NVC- group). Heart rate variability, respiratory activity, BP, and central venous pressure at rest and during unloading of cardiopulmonary baroreceptors with lower-body negative pressure and during a cold pressor test were also measured. Resting sympathetic nerve activity to muscle was twice as high in the NVC+ group compared with the NVC- group (34 +/- 22 versus 18 +/- 6 bursts/min; P < 0.05). Resting heart rate (P = 0.06) and low- to high-frequency power ratio values (P = NS) (as indicators of cardiac sympathovagal balance) tended to be augmented as well in the NVC+ group. The sympathetic nerve activity to muscle response to the cold pressor test was increased in the NVC+ group versus the NVC- group (+15 +/- 11 versus 6 +/- 12 bursts/min; P = 0.05), but hemodynamic and sympathetic nerve responses to lower-body negative pressure did not differ between the two groups. It is concluded that NVC of the rostral ventrolateral medulla in patients with essential hypertension is accompanied by increased central sympathetic outflow. Therefore, these data support the hypothesis described in the literature: in a subgroup of patients, essential hypertension might be causally related to NVC of the rostral ventrolateral medulla, at least in part, via an increase in central sympathetic outflow.
authors.affiliation: *Medical Clinic IV, Division of Nephrology and Hypertension, and Department of Neurosurgery, University of Erlangen-Nuremberg, Germany; and Medical Clinic, Division of Nephrology and Hypertension, University of Frankfurt, Germany.
authors.forename: Hans P
authors.initials: HP
authors.lastname: Schobel
authors.affiliation: *Medical Clinic IV, Division of Nephrology and Hypertension, and Department of Neurosurgery, University of Erlangen-Nuremberg, Germany; and Medical Clinic, Division of Nephrology and Hypertension, University of Frankfurt, Germany.
authors.forename: Helga
authors.initials: H
authors.lastname: Frank
authors.affiliation: *Medical Clinic IV, Division of Nephrology and Hypertension, and Department of Neurosurgery, University of Erlangen-Nuremberg, Germany; and Medical Clinic, Division of Nephrology and Hypertension, University of Frankfurt, Germany.
authors.forename: Ramin
authors.initials: R
authors.lastname: Naraghi
authors.affiliation: *Medical Clinic IV, Division of Nephrology and Hypertension, and Department of Neurosurgery, University of Erlangen-Nuremberg, Germany; and Medical Clinic, Division of Nephrology and Hypertension, University of Frankfurt, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Geiger
authors.affiliation: *Medical Clinic IV, Division of Nephrology and Hypertension, and Department of Neurosurgery, University of Erlangen-Nuremberg, Germany; and Medical Clinic, Division of Nephrology and Hypertension, University of Frankfurt, Germany.
authors.forename: Elmar
authors.initials: E
authors.lastname: Titz
authors.affiliation: *Medical Clinic IV, Division of Nephrology and Hypertension, and Department of Neurosurgery, University of Erlangen-Nuremberg, Germany; and Medical Clinic, Division of Nephrology and Hypertension, University of Frankfurt, Germany.
authors.forename: Karsten
authors.initials: K
authors.lastname: Heusser
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D006973:Hypertension / Q000209:etiology* / Q000503:physiopathology*; D018810:Magnetic Resonance Angiography; D008297:Male; D008526:Medulla Oblongata / Q000098:blood supply* / Q000473:pathology; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation*; D009408:Nerve Compression Syndromes / Q000150:complications* / Q000175:diagnosis; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D014652:Vascular Diseases / Q000150:complications* / Q000175:diagnosis