title: Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system following infrapopliteal endovascular interventions for critical limb ischemia.
abstract: OBJECTIVE
  The Society for Vascular Surgery (SVS) Lower Extremity Guidelines Committee has composed a new threatened lower extremity classification system that reflects the three major factors that impact amputation risk and clinical management: Wound, Ischemia, and foot Infection (WIfI). Our goal was to evaluate the predictive ability of this scale following any infrapopliteal endovascular intervention for critical limb ischemia (CLI).
  
  
  METHODS
  From 2004 to 2014, a single institution, retrospective chart review was performed at the Beth Israel Deaconess Medical Center for all patients undergoing an infrapopliteal angioplasty for CLI. Throughout these years, 673 limbs underwent an infrapopliteal endovascular intervention for tissue loss (77%), rest pain (13%), stenosis of a previously treated vessel (5%), acute limb ischemia (3%), or claudication (2%). Limbs missing a grade in any WIfI component were excluded. Limbs were stratified into clinical stages 1 to 4 based on the SVS WIfI classification for 1-year amputation risk, as well as a novel WIfI composite score from 0 to 9. Outcomes included patient functional capacity, living status, wound healing, major amputation, major adverse limb events, reintervention, major amputation, or stenosis (RAS) events (> ×3.5 step-up by duplex), amputation-free survival, and mortality. Predictors were identified using Kaplan-Meier survival estimates and Cox regression models.
  
  
  RESULTS
  Of the 596 limbs with CLI, 551 were classified in all three WIfI domains on a scale of 0 (least severe) to 3 (most severe). Of these 551, 84% were treated for tissue loss and 16% for rest pain. A Cox regression model illustrated that an increase in clinical stage increases the rate of major amputation (hazard ratio [HR], 1.6; 95% confidence interval [CI], 1.1-2.3). Separate regression models showed that a one-unit increase in the WIfI composite score is associated with a decrease in wound healing (HR, 1.2; 95% CI, 1.1-1.4) and an increase in the rate of RAS events (HR, 1.2; 95% CI, 1.1-1.4) and major amputations (HR, 1.4; 95% CI, 1.2-1.8).
  
  
  CONCLUSIONS
  This study supports the ability of the SVS WIfI classification system to predict 1-year amputation, RAS events, and wound healing in patients with CLI undergoing endovascular infrapopliteal revascularization procedures.
authors.affiliation: Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass.
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Darling
authors.affiliation: Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass.
authors.forename: John C
authors.initials: JC
authors.lastname: McCallum
authors.affiliation: Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Soden
authors.affiliation: University of Rochester School of Medicine and Dentistry, Rochester, NY.
authors.forename: Yifan
authors.initials: Y
authors.lastname: Meng
authors.affiliation: Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Wyers
authors.affiliation: Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass.
authors.forename: Allen D
authors.initials: AD
authors.lastname: Hamdan
authors.affiliation: Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Hence J
authors.initials: HJ
authors.lastname: Verhagen
authors.affiliation: Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass. Electronic address: mscherme@bidmc.harvard.edu.
authors.forename: Marc L
authors.initials: ML
authors.lastname: Schermerhorn
mesh_terms: D000671:Amputation, Surgical; D017130:Angioplasty / Q000009:adverse effects / Q000401:mortality; D001900:Boston; D016009:Chi-Square Distribution; D016638:Critical Illness; D003661:Decision Support Techniques; D018572:Disease-Free Survival; D006801:Humans; D007383:Intermittent Claudication / Q000145:classification / Q000000981:diagnostic imaging / Q000401:mortality / Q000628:therapy*; D007511:Ischemia / Q000145:classification / Q000000981:diagnostic imaging / Q000401:mortality / Q000628:therapy*; D053208:Kaplan-Meier Estimate; D023821:Limb Salvage; D035002:Lower Extremity / Q000098:blood supply*; D058729:Peripheral Arterial Disease / Q000145:classification / Q000000981:diagnostic imaging / Q000401:mortality / Q000628:therapy*; D011150:Popliteal Artery / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014945:Wound Healing; D014946:Wound Infection / Q000145:classification / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*