title: Resistive index and chronic allograft nephropathy evaluated in protocol biopsies as predictors of graft outcome.
abstract: BACKGROUND
  The presence of chronic allograft nephropathy (CAN) in protocol biopsies is negatively associated with graft survival. Although recent studies have indicated that the resistive index (RI) is a predictor of graft failure, it does not correlate with CAN in stable grafts. We therefore studied the relationship between RI and CAN and examined the predictive value of both parameters on graft outcome.
  
  
  METHODS
  Included were patients transplanted between 1997 and 2002 and who had protocol biopsies and RI determinations. Renal lesions were blindly evaluated according to Banff 97 criteria. Mean glomerular volume, cortical interstitial volume fraction and intimal arterial volume fraction were estimated using a point counting technique. RI was determined before biopsy in at least two different renal locations. The outcome variable was defined as graft failure or a 30% serum creatinine increase between protocol biopsy and last follow-up.
  
  
  RESULTS
  Eighty-seven patients were included. RI correlated with recipient age (R = 0.52, P < 0.0001), diastolic blood pressure (R = -0.36, P = 0.0006), pulse pressure index (R = 0.27, P = 0.009) and g-score for histological glomerulitis (rho = 0.30, P = 0.0054), but there were no correlations between RI and chronic Banff scores or any morphometric parameter. The presence of CAN (relative risk, 3.5; 95% confidence interval 1.2-10.2; P = 0.02) but not RI was associated with the outcome variable.
  
  
  CONCLUSIONS
  RI was associated with surrogate measures of vascular compliance such as recipient age and pulse pressure index but not with chronic allograft damage, even when it was evaluated by histomorphometry. Our results indicate that histology may be superior to RI in predicting graft function deterioration, at least in patients with stable renal function.
authors.affiliation: Department of Nephrology, Hospital Universitari Bellvitge, C/Feixa Llarga s/n, L'Hospitalet, 08907 Barcelona, Spain.
authors.forename: Augusto
authors.initials: A
authors.lastname: Vallejos
authors.forename: Gabriela
authors.initials: G
authors.lastname: Alperovich
authors.forename: Francesc
authors.initials: F
authors.lastname: Moreso
authors.forename: Concepcion
authors.initials: C
authors.lastname: Cañas
authors.forename: M Eugenia
authors.initials: ME
authors.lastname: de Lama
authors.forename: Montserrat
authors.initials: M
authors.lastname: Gomà
authors.forename: Xavier
authors.initials: X
authors.lastname: Fulladosa
authors.forename: Marta
authors.initials: M
authors.lastname: Carrera
authors.forename: Miguel
authors.initials: M
authors.lastname: Hueso
authors.forename: Josep M
authors.initials: JM
authors.lastname: Grinyó
authors.forename: Daniel
authors.initials: D
authors.lastname: Serón
mesh_terms: D000328:Adult; D001707:Biopsy, Needle; D002908:Chronic Disease; D005260:Female; D005500:Follow-Up Studies; D005921:Glomerulonephritis / Q000209:etiology / Q000473:pathology*; D006084:Graft Rejection / Q000150:complications / Q000473:pathology*; D006085:Graft Survival; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy; D007678:Kidney Glomerulus / Q000473:pathology; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D014184:Transplantation, Homologous