title: Systolic pressure response to voluntary apnea predicts sympathetic tone in obstructive sleep apnea as a clinically useful index.
abstract: The present investigation tested the hypotheses that systolic arterial pressure (SAP) responses to voluntary apnea (a) serve as a surrogate of sympathetic nerve activity (SNA), (b) can distinguish Obstructive Sleep Apnea (OSA) patients from control subjects and (c) can document autonomic effects of treatment. 9 OSA and 10 control subjects were recruited in a laboratory study; 44 OSA subjects and 78 control subjects were recruited in a clinical study; and 21 untreated OSA subjects and 14 well-treated OSA subjects were recruited into a treatment study. Each subject performed hypoxic and room air voluntary apneas in triplicate. Muscle SNA (MSNA) and continuous AP were measured during each apnea in the laboratory study, while systolic arterial pressure (SAP) responses were measured continuously and by standard auscultation in the clinical and treatment studies. OSA subjects exhibited increased mean arterial pressure (MAP), SAP and MSNA responses to hypoxic apnea (all P<0.01) and the SAP response highly correlated with the MSNA response (R(2)=0.72, P<0.001). Clinical assessment confirmed that OSA subjects exhibited markedly elevated SAP responses (P<0.01), while treated OSA subjects had a decreased SAP response to apnea (P<0.04) compared to poorly treated subjects. These data indicate that (a) OSA subjects exhibit increased pressor and MSNA responses to apnea, and that (b) voluntary apnea may be a clinically useful assessment tool of autonomic dysregulation and treatment efficacy in OSA.
authors.affiliation: Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, United States.
authors.forename: Noah P
authors.initials: NP
authors.lastname: Jouett
authors.affiliation: Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, United States.
authors.forename: Janelle M
authors.initials: JM
authors.lastname: Hardisty
authors.affiliation: Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, United States.
authors.forename: J Ryan
authors.initials: JR
authors.lastname: Mason
authors.affiliation: Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, United States.
authors.forename: Dorene
authors.initials: D
authors.lastname: Niv
authors.affiliation: Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, United States.
authors.forename: James J
authors.initials: JJ
authors.lastname: Romano
authors.affiliation: Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, United States; Sleep Consultants of Texas, 1521 Cooper St., Fort Worth, TX 76104, United States.
authors.forename: Donald E
authors.initials: DE
authors.lastname: Watenpaugh
authors.affiliation: Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, United States; Sleep Consultants of Texas, 1521 Cooper St., Fort Worth, TX 76104, United States.
authors.forename: John R
authors.initials: JR
authors.lastname: Burk
authors.affiliation: Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, United States. Electronic address: michael.smith@unthsc.edu.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Smith
mesh_terms: D000368:Aged; D001049:Apnea / Q000503:physiopathology*; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D002245:Carbon Dioxide / Q000494:pharmacology; D016022:Case-Control Studies; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006973:Hypertension / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000494:pharmacology; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000503:physiopathology*
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen
keywords: Arterial pressure response; Obstructive sleep apnea; Sympathetic