title: Prediction of the severity and outcome of acute tubular necrosis based on continuity of Doppler spectrum in the early period after kidney transplantation.
abstract: BACKGROUND
  Doppler flow spectrum, quantified in the segmental arteries of the graft early after kidney transplantation (KTx), reflects the exacerbation of interstitial oedema. In some patients, the spectrum is characterized by the absence of blood flow during part or during the whole diastole of the cardiac cycle. We have previously observed that such discontinuous flow is associated with a more severe clinical course of acute tubular necrosis (ATN). In order to further verify this hypothesis, we have quantified prospectively the timing of blood flow in Doppler spectrum within the cardiac cycle.
  
  
  METHODS
  Doppler sonography was performed in 173 recipients between 2 and 4 days after KTx. A total of 18 patients with a diagnosed episode of acute rejection or primary graft non-function were excluded from the analysis. Fifty-three out of 155 patients (34%) developed ATN, defined as a requirement for more than one haemodialysis session after KTx. In patients with a discontinuous spectrum of flow, we have quantified the ratio of time during the whole cardiac cycle in which the flow is present [flow time index (FTI) expressed as %].
  
  
  RESULTS
  The discontinuous spectrum of flow was present in 35 out of 53 (66.0%) patients with ATN but only in 6 out of 102 (5.9%) patients with immediate or slow graft function. The relative risk of ATN occurrence for patients with discontinuous spectrum of flow was 5.98 (3.83-9.34) and the duration of ATN in these patients was twice as long-12 (10-14) versus 6 (5-8) days. In patients with ATN a significant correlation was found between FTI and duration of ATN (r = -0.357, P = 0.035).
  
  
  CONCLUSIONS
  The discontinuous spectrum of flow in the segmental arteries of the kidney graft in the early period after KTx is typical for ATN and predicts its duration.
authors.affiliation: Department of Nephrology, Endocrinology and Metabolic Diseases, Medical University of Silesia, Katowice, Poland.
authors.forename: Aureliusz
authors.initials: A
authors.lastname: Kolonko
authors.forename: Jerzy
authors.initials: J
authors.lastname: Chudek
authors.forename: Andrzej
authors.initials: A
authors.lastname: Wiecek
authors.forename: Andrzej
authors.initials: A
authors.lastname: Wicek
mesh_terms: D000328:Adult; D005260:Female; D006084:Graft Rejection / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D016030:Kidney Transplantation; D007684:Kidney Tubules / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000473:pathology*; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012039:Regional Blood Flow / Q000502:physiology; D012077:Renal Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D014463:Ultrasonography