title: Rapid adaptation of the intrarenal resistance index after living donor kidney transplantation.
abstract: BACKGROUND
  Limited data exist concerning changes of renal perfusion directly after kidney transplantation. Colour-coded duplex sonography is the accepted method to assess kidney perfusion after transplantation. A widely used, although unspecific, Doppler parameter is the intrarenal resistance index (RI). The aim of this study was to clarify the influence of different patient- and procedure-related factors on RI before and immediately after living kidney transplantation.
  
  
  METHODS
  In a prospective study, 80 living kidney transplantation donor-recipient pairs were included. RI was measured in the donor 1 to 3 days before nephrectomy and in the recipient during the first hour after transplantation to examine the influence of age, heart rate, duration of cold and warm ischaemia time and immunosuppressive medications.
  
  
  RESULTS
  Mean RI did not differ between donors and recipients. RI correlated with age, both in donors (r = 0.58, P < 0.001) and recipients (r = 0.39, P < 0.001). In recipients, 10 or more years younger than their donors (n = 24), an average decrease of 0.05 in RI compared to the donors' value was observed (P = 0.01). Heart rate, cold and warm ischaemia time and immunosuppressive medications had no influence on the recipient RI. In patients with delayed graft function, a significant increase in RI within 14 days was observed. However, the initial RI was not predictive of graft function.
  
  
  CONCLUSIONS
  The transplanted kidney seems to be able to adjust its RI within a short time despite several potential harmful factors that can occur during the transplantation.
authors.affiliation: Department of Angiology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland.
authors.forename: Markus
authors.initials: M
authors.lastname: Aschwanden
authors.forename: Michael
authors.initials: M
authors.lastname: Mayr
authors.forename: Stephan
authors.initials: S
authors.lastname: Imfeld
authors.forename: Jürg
authors.initials: J
authors.lastname: Steiger
authors.forename: Kurt A
authors.initials: KA
authors.lastname: Jaeger
authors.forename: Christoph
authors.initials: C
authors.lastname: Thalhammer
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007668:Kidney / Q000098:blood supply* / Q000000981:diagnostic imaging; D007676:Kidney Failure, Chronic / Q000601:surgery*; D016030:Kidney Transplantation / Q000000981:diagnostic imaging / Q000502:physiology*; D019520:Living Donors; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018615:Ultrasonography, Doppler, Color; D014655:Vascular Resistance / Q000502:physiology*