title: A randomized controlled study of CPAP effect on plasma aldosterone concentration in patients with resistant hypertension and obstructive sleep apnea.
abstract: OBJECTIVE
  The high prevalence of obstructive sleep apnea in patients with resistant hypertension could be mediated by an activation of the renin-angiotensin-aldosterone system. This study assessed the impact of continuous positive airway pressure (CPAP) treatment on plasma aldosterone concentration (PAC).
  
  
  METHODS
  One hundred and twenty-four patients with resistant hypertension were assessed, and those who fulfilled inclusion criteria (n = 116) underwent full night polysomnography, 24-h ambulatory blood pressure monitoring, and PAC measurement. Patients with an apnea-hypopnea index above 15 (n = 102) were randomized to CPAP (n = 50) or to conventional treatment (n = 52) for 3 months.
  
  
  RESULTS
  Seventy-eight patients completed the follow-up (36 CPAP, 42 conventional treatment); 58 had true resistant hypertension (74.3%), whereas 20 had white-coat resistant hypertension (25.6%). Most patients were men (70.7%), age 58.3 ± 9.4 years, and the mean apnea-hypopnea index was 50.1 ± 21.6. In patients with true resistant hypertension, CPAP achieved a significant decrease in most 24-h BP measurements and a nonsignificant decrease in PAC (25 ± 8.7 vs. 22.7 ± 9 ng/dl; P < 0.182). In patients with white-coat resistant hypertension, CPAP achieved a significant decrease in PAC (26.1 ± 11.2 vs. 18.9 ± 10.1 ng/dl; P < 0.041) and in night-time DBP. After adjustment, a weak but significant association was found between cumulative time spent with SaO2 below 90% (CT90%) and baseline PAC (P < 0.047, R 0.019), and between changes in PAC and changes in office DBP (P < 0.020, R 0.083) CONCLUSIONS:: Night-time hypoxemia and changes in DBP showed an association with baseline and changes in PAC, respectively. CPAP achieved a significant reduction in PAC only in patients with white-coat resistant hypertension, although the CPAP effect on BP was highest in patients with true resistant hypertension.
authors.affiliation: aServei de Pneumologia, Sleep Unit, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona bCIBER de Enfermedades Respiratorias (CIBERES), Instituto Nacional de Salud Carlos III, Madrid cServei de Nefrologia dServei de Neurofisiologia Clínica, Sleep Unit eServei d'Anàlisis Clíniques, Hospital Universitari Vall d'Hebron, Barcelona fServicio de Neumología, Hospital Universitari i Politècnic La Fe, Valencia, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Lloberes
authors.forename: Gabriel
authors.initials: G
authors.lastname: Sampol
authors.forename: Eugenia
authors.initials: E
authors.lastname: Espinel
authors.forename: Alfons
authors.initials: A
authors.lastname: Segarra
authors.forename: Maria-Antònia
authors.initials: MA
authors.lastname: Ramon
authors.forename: Odile
authors.initials: O
authors.lastname: Romero
authors.forename: Roser
authors.initials: R
authors.lastname: Ferrer
authors.forename: Miguel-Angel
authors.initials: MA
authors.lastname: Martínez-Garcia
authors.forename: José-Luis
authors.initials: JL
authors.lastname: Tovar
mesh_terms: D000368:Aged; D000450:Aldosterone / Q000097:blood*; D001794:Blood Pressure; D045422:Continuous Positive Airway Pressure; D004351:Drug Resistance; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D012083:Renin / Q000097:blood; D020181:Sleep Apnea, Obstructive / Q000097:blood*
chemical_list: D000450:Aldosterone; D012083:Renin