title: Early assessment of renal resistance index after kidney transplant can help predict long-term renal function.
abstract: BACKGROUND
  Color Doppler ultrasonography of intrarenal arterial resistance index (RI), performed early after kidney transplant, has proven to reliably predict short-term allograft function. The aim of this study was to assess whether it could also predict long-term renal function.
  
  
  METHODS
  We retrospectively analysed 76 kidney transplant patients who underwent RI assessment within 1 month after the transplant, subdivided into two groups according to RI values, lower (group A) or higher (group B) than its median value (0.635).
  
  
  RESULTS
  Compared with group A subjects, the patients of group B were older at the time of transplant (42 +/- 9 vs 35 +/- 8 years; P = 0.001), the donor age was also older (41 +/- 16 vs 33 +/- 13 years; P = 0.02) and had a slightly higher proteinuria (0.54 +/- 0.5 vs 0.32 +/- 0.2 g/24 h; P = 0.02). Serum creatinine, ciclosporin or tacrolimus trough level, arterial blood pressure, number of human leukocyte antigen (HLA) mismatches, anti-hypertensive medications and incidence of delayed graft function were not significantly different between the two groups. By univariate analysis, RI turned out to directly correlate with the recipient age, donor age and daily proteinuria (P = 0.007, P = 0.0007 and P = 0.02, respectively). Multivariate analysis showed that only donor and recipient age maintained their independent predictive value on RI. Kaplan-Meier analysis, considering a serum creatinine increase >50% as the endpoint of the study, showed a statistically significant different graft survival in the two groups (log-rank test = 5.489; P = 0.01). The univariate relative risk of deterioration of graft function among patients with higher RI was 3.77. Proteinuria and recipient age increased the risk as well.
  
  
  CONCLUSIONS
  Our data seem to suggest that early determination of RI can help predict long-term graft function in kidney transplant recipients.
authors.affiliation: Centro Regionale Trapianti, Ospedale Madonna delle Grazie, Contrada cattedra ambulante, 75100 Matera, Italy. asaracino@inwind.it
authors.forename: Angelo
authors.initials: A
authors.lastname: Saracino
authors.forename: Giovanni
authors.initials: G
authors.lastname: Santarsia
authors.forename: Angela
authors.initials: A
authors.lastname: Latorraca
authors.forename: Vito
authors.initials: V
authors.lastname: Gaudiano
mesh_terms: D000328:Adult; D000367:Age Factors; D005260:Female; D006085:Graft Survival; D006801:Humans; D007668:Kidney / Q000098:blood supply / Q000503:physiopathology* / Q000601:surgery; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D011507:Proteinuria / Q000473:pathology / Q000503:physiopathology; D012189:Retrospective Studies; D014019:Tissue Donors; D018608:Ultrasonography, Doppler; D014655:Vascular Resistance