title: An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.
abstract: OBJECTIVE
  The Society for Vascular Surgery (SVS) recently established the Lower Extremity Threatened Limb Classification System, a staging system using Wound characteristic, Ischemia, and foot Infection (WIfI) to stratify the risk for limb amputation at 1 year. Although intuitive in nature, this new system has not been validated. The purpose of the following study was to determine whether the WIfI system is predictive of limb amputation and wound healing.
  
  
  METHODS
  Between 2007 and 2010, we prospectively obtained data related to wound characteristics, extent of infection, and degree of postrevascularization ischemia in 139 patients with foot wounds who presented for lower extremity revascularization (158 revascularization procedures). After adapting those data to the WIfI classifications, we analyzed the influence of wound characteristics, extent of infection, and degree of ischemia on time to wound healing; empirical Kaplan-Meier survival curves were compared with theoretical outcomes predicted by WIfI expert consensus opinion.
  
  
  RESULTS
  Of the 158 foot wounds, 125 (79%) healed. The median time to wound healing was 2.7 months (range, 1-18 months). Factors associated with wound healing included presence of diabetes mellitus (P = .013), wound location (P = .049), wound size (P = .007), wound depth (P = .004), and degree of ischemia (P < .001). The WIfI clinical stage was predictive of 1-year limb amputation (stage 1, 3%; stage 2, 10%; stage 3, 23%; stage 4, 40%) and wound nonhealing (stage 1, 8%; stage 2, 10%; stage 3, 23%; stage 4, 40%) and correlated with the theoretical outcome estimated by the SVS expert panel.
  
  
  CONCLUSIONS
  The theoretical framework for risk stratification among patients with critical limb ischemia provided by the SVS expert panel appears valid. Further validation of the WIfI classification system with multicenter data is justified.
authors.affiliation: Department of Surgery, University of South Carolina School of Medicine-Greenville, Greenville Health System/University Medical Center, Greenville, SC. Electronic address: dcull@ghs.org.
authors.forename: David L
authors.initials: DL
authors.lastname: Cull
authors.affiliation: Department of Surgery, University of South Carolina School of Medicine-Greenville, Greenville Health System/University Medical Center, Greenville, SC.
authors.forename: Ginger
authors.initials: G
authors.lastname: Manos
authors.affiliation: Department of Surgery, University of South Carolina School of Medicine-Greenville, Greenville Health System/University Medical Center, Greenville, SC.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Hartley
authors.affiliation: Department of Surgery, University of South Carolina School of Medicine-Greenville, Greenville Health System/University Medical Center, Greenville, SC.
authors.forename: Spence M
authors.initials: SM
authors.lastname: Taylor
authors.affiliation: Department of Surgery, University of South Carolina School of Medicine-Greenville, Greenville Health System/University Medical Center, Greenville, SC.
authors.forename: Eugene M
authors.initials: EM
authors.lastname: Langan
authors.affiliation: Department of Surgery, University of South Carolina School of Medicine-Greenville, Greenville Health System/University Medical Center, Greenville, SC.
authors.forename: John F
authors.initials: JF
authors.lastname: Eidt
authors.affiliation: Department of Surgery, University of South Carolina School of Medicine-Greenville, Greenville Health System/University Medical Center, Greenville, SC.
authors.forename: Brent L
authors.initials: BL
authors.lastname: Johnson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000671:Amputation, Surgical; D016638:Critical Illness; D003661:Decision Support Techniques; D017719:Diabetic Foot / Q000145:classification / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D007511:Ischemia / Q000145:classification / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery*; D023821:Limb Salvage; D035002:Lower Extremity / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D058729:Peripheral Arterial Disease / Q000145:classification / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D012955:Societies, Medical; D013997:Time Factors; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures; D014945:Wound Healing