title: Acute effects of calcineurin inhibitors on kidney allograft microperfusion visualized by contrast-enhanced sonography.
abstract: BACKGROUND
  Calcineurin inhibitors induce detrimental vascular remodeling, which may be one cause of chronic allograft failure. Real-time contrast-enhanced sonography (CES) is a relatively new technique in providing quantitative information on microvascular tissue perfusion in kidney allografts in more detail. The purpose of the study was to explore whether acute changes of kidney allograft microperfusion due to the administration of cyclosporine A (CsA) and tacrolimus (Tac) can be evidenced using real-time CES.
  
  
  METHODS
  In an explorative single-center clinical trial, renal parenchymal tissue perfusion of 32 stable kidney allograft recipients was evaluated with CES before and 2 hr after the intake of CsA or Tac. In addition to laboratory and clinical parameters, Doppler indices and estimated glomerular filtration rate were measured.
  
  
  RESULTS
  Although systolic and diastolic blood pressure and color Doppler indices did not significantly differ, there was a significant decrease of renal blood flow 2 hr after the intake of CsA compared with baseline (4.78±2.31 dB/s, 49%, respectively). In contrast, kidney allograft microperfusion was neither significantly reduced in patients receiving CsA paralleled by calcium channel blockers nor significantly reduced in patients receiving Tac. Furthermore, there was a significant correlation between renal blood flow obtained before drug administration and kidney function.
  
  
  CONCLUSIONS
  CES revealed a 49% reduction of kidney allograft microperfusion 2 hr after the intake of CsA, which might be abrogated by calcium channel blockers. In comparison to CsA, Tac did not result in a significant decrease of kidney blood flow.
authors.affiliation: Department of Nephrology, University Hospital, Heidelberg, Germany. lars.kihm@med.uni-heidelberg.de
authors.forename: Lars P
authors.initials: LP
authors.lastname: Kihm
authors.forename: Carsten
authors.initials: C
authors.lastname: Blume
authors.forename: Jörg
authors.initials: J
authors.lastname: Seckinger
authors.forename: Vinzent
authors.initials: V
authors.lastname: Hankel
authors.forename: Dominik
authors.initials: D
authors.lastname: Stoffler
authors.forename: Christian
authors.initials: C
authors.lastname: Morath
authors.forename: Martin
authors.initials: M
authors.lastname: Zeier
authors.forename: Vedat
authors.initials: V
authors.lastname: Schwenger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D065095:Calcineurin Inhibitors; D003287:Contrast Media; D016572:Cyclosporine / Q000009:adverse effects*; D004791:Enzyme Inhibitors / Q000009:adverse effects*; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects*; D007668:Kidney / Q000098:blood supply / Q000000981:diagnostic imaging / Q000187:drug effects*; D016030:Kidney Transplantation / Q000000981:diagnostic imaging / Q000276:immunology; D008297:Male; D055806:Microvessels / Q000000981:diagnostic imaging / Q000187:drug effects; D008875:Middle Aged; D010743:Phospholipids; D013459:Sulfur Hexafluoride; D016559:Tacrolimus / Q000009:adverse effects*; D014184:Transplantation, Homologous / Q000276:immunology; D018615:Ultrasonography, Doppler, Color / Q000379:methods*; D055815:Young Adult
chemical_list: D065095:Calcineurin Inhibitors; D003287:Contrast Media; D004791:Enzyme Inhibitors; D007166:Immunosuppressive Agents; D010743:Phospholipids; C420843:contrast agent BR1; D016572:Cyclosporine; D016559:Tacrolimus; D013459:Sulfur Hexafluoride