title: Relationship between renal hemodynamic status and aging in patients without diabetes evaluated by renal Doppler ultrasonography.
abstract: BACKGROUND
  Aging is well known as one of the major causes of a reduced glomerular filtration rate (GFR). The resistive index (RI) measured by renal Doppler ultrasonography (RDU) is thought to be a good indicator of renal vascular resistance induced by arteriosclerosis. In this study, we investigated whether RI could be used to evaluate the pathogenesis of renal damage or the mechanisms of reduction of renal function by aging.
  
  
  METHODS
  We investigated the correlation between RI and multiple clinical parameters and the influence of aging on the renal hemodynamic status of 194 in-patients (mean age 66.2 years) who underwent RDU at our hospital between February 2009 and July 2010.
  
  
  RESULTS
  RI was significantly correlated with the age, estimated GFR (eGFR), diastolic blood pressure, pulse pressure, and degree of albuminuria. Subjects aged ≥75 years showed a significantly higher correlation coefficient between eGFR and RI. RI showed a stronger correlation with age in subjects aged ≥75 years compared to eGFR.
  
  
  CONCLUSIONS
  The present study showed that renal vascular resistance and intra-renal arteriosclerosis had a greater impact on renal function in older than younger subjects, reflecting the possible mechanisms of renal function reduction due to aging.
authors.affiliation: Department of Geriatric Medicine and Nephrology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka (B6), Suita, Osaka 565-0871, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kawai
authors.forename: Kei
authors.initials: K
authors.lastname: Kamide
authors.forename: Miyuki
authors.initials: M
authors.lastname: Onishi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hongyo
authors.forename: Hiroko
authors.initials: H
authors.lastname: Yamamoto-Hanasaki
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Oguro
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Maekawa
authors.forename: Koichi
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Takeya
authors.forename: Ken
authors.initials: K
authors.lastname: Sugimoto
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Ohishi
authors.forename: Hiromi
authors.initials: H
authors.lastname: Rakugi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001161:Arteriosclerosis / Q000209:etiology; D005260:Female; D005919:Glomerular Filtration Rate; D006439:Hemodynamics; D006801:Humans; D007668:Kidney / Q000098:blood supply* / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D012079:Renal Circulation; D018608:Ultrasonography, Doppler; D014655:Vascular Resistance