title: Symmetrical Ambulatory Arterial Stiffness Index: relationship with serum cystatin C levels.
abstract: OBJECTIVE
  Increased central arterial stiffening is the consequence of many disease states such as diabetes, atherosclerosis, and chronic renal disease. Symmetrical Ambulatory Arterial Stiffness Index (Sym-AASI) may provide a simple clinical approach to evaluate arterial stiffness. This study has tried to evaluate the relationship of Sym-AASI with cystatin C levels.
  
  
  METHODS
  The sample subjects were 53 males and 34 females (mean age = 59.3 ± 13.5 years). Kidney function was evaluated by measuring serum cystatin C and estimated glomerular filtration rate (eGFR). The ambulatory BP was measured noninvasively for 24 h.
  
  
  RESULTS
  Patients in the highest quartile showed an older age (p < 0.001) and worse eGFR (p < 0.001). Pulse pressure (PP) increased as cystatin C was higher. Mean Sym-AASI showed an increase from the first to the last cystatin C quartile. Correlation test showed a significant relationship of Sym-AASI with age (r = 0.573), serum creatinine (r = 0.237), eGFR (-0.323), cystatin C (r = 0.427), systolic blood pressure (r = 0.525), and PP (r = 0.647). Multivariate regression analysis showed that age, cystatin C, nocturnal systolic blood pressure reduction, and nocturnal diastolic blood pressure fall were independently related to Sym-AASI. There was not any independent association between eGFR and Sym-AASI or between cystatin C and PP.
  
  
  CONCLUSIONS
  Increased Sym-AASI seems to be independently associated with serum cystatin C levels. Sym-AASI seems to be better than PP to detect changes in the arterial wall. This could be a simple and easy method to evaluate arterial stiffness in hypertensive patients without needing more complex devices.
authors.affiliation: Department of Nephrology, Hypertension Unit, Hospital Infanta Cristina, Badajoz, Spain. nrroblesp@yahoo.es
authors.forename: Nicolas Roberto
authors.initials: NR
authors.lastname: Robles
authors.forename: Candido
authors.initials: C
authors.lastname: Mena
authors.forename: Josefa
authors.initials: J
authors.lastname: Martin de Prado
authors.forename: Francisco
authors.initials: F
authors.lastname: Garcia Gallego
authors.forename: Antonio
authors.initials: A
authors.lastname: Cidoncha
authors.forename: Julio
authors.initials: J
authors.lastname: Herrera
mesh_terms: D000328:Adult; D000368:Aged; D001158:Arteries / Q000503:physiopathology*; D015415:Biomarkers / Q000097:blood; D003404:Creatinine / Q000097:blood; D055316:Cystatin C / Q000097:blood*; D003935:Diagnostic Techniques, Cardiovascular; D004548:Elasticity; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000503:physiopathology*; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D003404:Creatinine