title: Significance of ankle brachial index and collaterals for prediction of critical limb ischemia in infrainguinal peripheral arterial occlusive disease.
abstract: OBJECTIVE
  Chronic limb ischemia (CLI) is a clinical diagnosis, but should be approved by technical tests like the ankle-brachial index (ABI). Although the ABI is well established, less is known about the influence of collateralization on clinical stage.
  
  
  METHODS
  Magnetic resonance angiographies (MRA) of 129 lower extremities were searched for morphological changes and for the number of collateral vessels according to Sorlie. Ankle pressures were recorded as higher (APmax) and lower (APmin) systolic blood pressures of the two ankle arteries with consecutive calculation of ABImax and ABImin.
  
  
  RESULTS
  In comparisons of ROC curves, APmax (AUC=0.749) did significantly better as a prognostic marker than APmin (AUC=0.642) (p=0.005) and ABImax (AUC=0.744) did significantly better than ABImin (AUC=0.650) (p=0.019). APmax showed a positive likelihood ratio (+LR) of 5.79 and a negative likelihood ratio (-LR) of 0.47 (cutoff ≤55 mmHg). For the number of collateral vessels a +LR 2.27 and a -LR of 0.09 and in patients with an APmax ≤55 mmHg a +LR of 5.50 and a -LR of 0.00 were calculated (cutoff ≤1 collateral vessel).
  
  
  CONCLUSIONS
  Whereas APmax is more eligible for verification of CLI, collateral count is better in exclusion of CLI. Both seem to be independent factors for validating the clinical diagnosis of CLI.
authors.affiliation: Clinic of Vascular Surgery, Klinikum rechts der Isar, Technische Universitaet Muenchen, Munich, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Zimmermann
authors.forename: C
authors.initials: C
authors.lastname: Roenneberg
authors.forename: C
authors.initials: C
authors.lastname: Reeps
authors.forename: H
authors.initials: H
authors.lastname: Wendorff
authors.forename: M
authors.initials: M
authors.lastname: Wildgruber
authors.forename: H H
authors.initials: HH
authors.lastname: Eckstein
mesh_terms: D000368:Aged; D000842:Ankle; D055109:Ankle Brachial Index; D001794:Blood Pressure; D005260:Female; D006801:Humans; D007511:Ischemia / Q000175:diagnosis* / Q000473:pathology; D007866:Leg / Q000473:pathology; D018810:Magnetic Resonance Angiography / Q000379:methods; D008297:Male; D008875:Middle Aged; D058729:Peripheral Arterial Disease / Q000175:diagnosis* / Q000503:physiopathology*; D011379:Prognosis; D012372:ROC Curve; D012189:Retrospective Studies