title: Low plasma renin activity and high aldosterone/renin ratio are associated with untreated isolated systolic hypertension.
abstract: OBJECTIVE
  Isolated systolic hypertension (ISH) is generally encountered in elderly patients and there are scarce data regarding the renin-angiotensin-aldosterone system (RAAS) activity in patients with ISH. We aimed to determine the plasma renin activity (PRA), plasma aldosterone levels (PAL) and aldosterone/PRA ratio (PAL/PRA) in patients (age >50 years) with ISH and to compare these values with patients with essential hypertension (EH) as well as subjects with normal blood pressure values (control) who have similar age and cardiovascular risk profile.
  
  
  METHODS
  Consecutively, 42 untreated ISH patients, 30 patients with EH and 29 normal subjects were included in the study. Parameters were presented as median (interquartile range).
  
  
  RESULTS
  There were no significant differences regarding age, gender and other cardiovascular risk factors among groups. As expected, systolic, diastolic blood pressure and pulse pressure values were significantly different among groups. Besides, PRA values were found to be significantly lower in patients with ISH (0.4 [0.2-1.1] ng/ml/h) compared with the EH (0.95 [0.5-2.6] ng/ml/h, p =0.024) and control (1.3 [0.7-2.1] ng/ml/h, p =0.001) groups. Although, PAL were similar among groups, PAL/PRA ratio was significantly higher in ISH group (134.1 [73-224]) compared with those with EH (42.2 [35-84], p <0.001) and the control group (53.3 [30-106], p =0.001). No significant difference was present with respect to PAL/PRA ratio between EH and control groups.
  
  
  CONCLUSIONS
  Our findings suggested that in patients with ISH, despite lower PRA levels, PAL/PRA ratio is significantly higher compared with the patients with EH and subjects with normal blood pressure. Since higher PAL/PRA levels is an indicator of relative aldosterone excess, medications blocking RAAS activity including aldosterone antagonists may have useful cardiovascular consequences in addition to their antihypertensive effects in ISH.
authors.affiliation: Toros Hospital, Department of Cardiology, Mersin, Turkey.
authors.forename: Mine
authors.initials: M
authors.lastname: Durukan
authors.forename: Umit
authors.initials: U
authors.lastname: Guray
authors.forename: Tolga
authors.initials: T
authors.lastname: Aksu
authors.forename: Yesim
authors.initials: Y
authors.lastname: Guray
authors.forename: Burcu
authors.initials: B
authors.lastname: Demirkan
authors.forename: Sule
authors.initials: S
authors.lastname: Korkmaz
mesh_terms: D000368:Aged; D000450:Aldosterone / Q000097:blood*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012083:Renin / Q000097:blood*; D012084:Renin-Angiotensin System / Q000502:physiology; D012307:Risk Factors; D013599:Systole / Q000502:physiology
chemical_list: D000450:Aldosterone; D012083:Renin