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Editor's Choice – The Prognostic Value of the WIfI Classification in Patients with Chronic Limb Threatening Ischaemia: A Systematic Review and Meta-Analysis

Open ArchivePublished:June 20, 2019DOI:https://doi.org/10.1016/j.ejvs.2019.03.040

      Objectives

      The Society for Vascular Surgery has proposed the Wound, Ischaemia, and foot Infection (WIfI) classification system as a prognostic tool for the one year amputation risk and the added value of revascularisation in patients with chronic limb threatening ischaemia (CLTI). This systematic review summarises the current evidence on the prognostic value of the WIfI classification system in clinical practice.

      Design

      Systematic review and meta-analysis following the PRISMA guidelines.

      Materials

      The Embase, MEDLINE, and Cochrane databases were searched up to June 2018.

      Methods

      All studies using the WIfI classification for patients with CLTI were eligible. Outcomes of interest were major amputation, limb salvage, and amputation free survival in relation to WIfI clinical stage. The methodological quality of studies was appraised with the Quality in Prognosis Studies (QUIPS) tool. If possible, data were pooled and analysed using a random effects model. Study selection, quality assessment, and data extraction were carried out by two authors independently.

      Results

      The search yielded 12 studies comprising 2669 patients, most of whom underwent endovascular or open revascularisation. Overall study quality was moderate. All but one were retrospective studies, including a variety of subpopulations of patients with CLTI, such as only haemodialysis dependent, diabetic or non-diabetic patients. The WIfI classification was derived from chart data or prospectively maintained databases, both documented before the WIfI classification was published. Estimated one year major amputation rates from four studies comprising 569 patients were 0%, 8% (95% CI 3–21%), 11% (95% CI 6–18%) and 38% (95% CI 21–58%), for WIfI stages I–IV, respectively.

      Conclusions

      The likelihood of an amputation after one year in patients with CLTI increases with higher WIfI stages, which is important prognostic information. Prospective evaluations are needed to determine its role in clinical practice.

      Keywords

      The Society for Vascular Surgery Wound Ischaemia and foot Infection (WIfI) classification has been developed as a tool to help clinical decision making in patients with CLTI. This systematic review shows that the WIfI classification can, to some extent, predict major amputation after one year. However, the current evidence is not sufficient for the instrument to be helpful in clinical decision making for patients with CLTI.

      Introduction

      Since critical limb ischaemia was defined in 1982, the epidemiology of patients presenting with this diagnosis has changed.
      • Jamieson C.
      The definition of critical ischaemia of a limb.
      To reflect these changes the 2017 ESC/ESVS (European Society of Cardiology/European Society for Vascular Surgery) guideline on the diagnosis and treatment of peripheral arterial disease has replaced the term critical limb ischaemia with chronic limb threatening ischaemia (CLTI).
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
      Three arguments were given for this change; first, not all patients suffering from this disease are ‘critical’ at risk of losing their affected limb even in the absence of revascularisation. Second, due to the increase in diabetes and neuro-ischaemic ulcers it was pointed out that severe ischaemia is not the only underlying cause.
      • Armstrong D.G.
      • Cohen K.
      • Courric S.
      • Bharara M.
      • Marston W.
      Diabetic foot ulcers and vascular insufficiency: our population has changed, but our methods have not.
      The third reason was that the risk of amputation does not entirely depend on the extent of ischaemia but also on the presence of a wound and infection.
      Separate classification systems have been used for patients with ischaemia (i.e. Rutherford and Fontaine) or for patients with a diabetic foot (i.e. Wagner and Texas). In 2014, Mills et al.
      • Mills Sr., J.L.
      • Conte M.S.
      • Armstrong D.G.
      • Pomposelli F.B.
      • Schanzer A.
      • Sidawy A.N.
      • et al.
      The society for vascular Surgery lower extremity threatened limb classification system: risk stratification based on wound, ischemia, and foot infection (WIfI).
      stated that the existing classification systems neither took into account the natural history of CLTI nor assessed or graded the major risk factors that influence limb loss and clinical management. Hence, they presented a new classification system to be used to predict the one year amputation risk and the added value of a revascularisation. The determinants of these two outcomes were the presence and dimensions of wound or tissue loss, the presence and grade of infection, and the severity of ischaemia, each scored on a scale from 0 to 3. By means of a Delphi consensus these three determinants were combined into a clinical risk score, ranging from very low (1) to high (4). This is currently known as the Wound, Infection, and Ischaemia (WIfI) classification system for the risk of amputation after one year, and the benefit or requirement of revascularisation. The classification and the clinical scores are shown in Tables S2 and S3.
      Multiple studies have evaluated the prognostic value of the WIfI classification as summarised in the scoping review by Mills.
      • Mills J.L.
      • Sr
      The application of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification to stratify amputation risk.
      Some of these studies showed that the risk of amputation increased with a higher WIfI grade but predominantly included diabetic patients or those who underwent revascularisation.
      • Beropoulis E.
      • Stavroulakis K.
      • Schwindt A.
      • Stachmann A.
      • Torsello G.
      • Bisdas T.
      Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia.
      • Zhan L.X.
      • Branco B.C.
      • Armstrong D.G.
      • Mills J.L.
      • Sr
      The Society for Vascular Surgery lower extremity threatened limb classification system based on Wound, Ischemia, and foot Infection (WIfI) correlates with risk of major amputation and time to wound healing.
      In order to evaluate the prognostic value of this new classification system in all CLTI patients, the available evidence was reviewed regarding the value of the WIfI classification in patients presenting with CLTI to predict the one year major amputation risk and the benefit of revascularisation.

      Materials and Methods

      This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses statement.
      • Moher D.
      • Liberati A.
      • Tetzlaff J.
      • Altman D.G.
      • Group P.
      Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement.
      The protocol was registered as PROSPERO CRD42018086641.

      Literature search

      With the aid of a clinical librarian a systematic literature search was created to query the Embase, MEDLINE, and Cochrane databases from their inception to June 2018. The full search strategy is shown in Table S1. No language or other restrictions were applied.

      Eligibility criteria

      Studies were eligible if they included patients with diabetic foot ulcers and/or CLTI and evaluated the prognostic value of the WIfI classification system regardless of revascularisation or revascularisation method and duration of follow up. Articles published before 2014 were excluded since the original article on the WIfI classification was published in 2014. Titles and abstracts were screened independently by two reviewers (N.R., K.P.). Discrepancies were resolved by discussion or by a third arbitrator. Subsequently, full texts were retrieved and screened independently by two reviewers (N.R., K.P.). Again, discrepancies were resolved by discussion.

      Data extraction and outcomes

      Data were extracted independently by the same two authors (N.R., K.P.) and recorded on a predefined form. Study characteristics extracted were study design, inclusion and exclusion criteria, type of treatment, endpoints, follow up period, restaging of the WIfI classification, and baseline patient characteristics such as age, gender, diabetes, renal disease, or dialysis dependence. The outcomes of interest were major amputation (amputation level at which the foot is not sufficiently functional to allow walking without a prosthesis), limb salvage (no major amputation with healing of ulcers), and amputation free survival (AFS, composite of patient being alive without major amputation).
      • Rutherford R.B.
      • Baker J.D.
      • Ernst C.
      • Johnston K.W.
      • Porter J.M.
      • Ahn S.
      • et al.
      Recommended standards for reports dealing with lower extremity ischemia: revised version.
      Disparities were checked and resolved.

      Risk of bias assessment

      The methodological quality assessment of the individual studies was performed independently by two reviewers (N.R., K.P.) using the Quality in Prognosis Studies (QUIPS) tool.
      • Hayden J.A.
      • van der Windt D.A.
      • Cartwright J.L.
      • Cote P.
      • Bombardier C.
      Assessing bias in studies of prognostic factors.
      A GRADE table was created with GRADEPRO for the certainty of evidence on the three outcomes, namely major amputation, AFS, and limb salvage after one year.
      • GRADEpro G.D.T.
      GRADEpro guideline development tool [software].

      Data analysis

      If continuous data were presented as medians, with (interquartile) ranges, the means and standard deviations were estimated.
      • Luo D.
      • Wan X.
      • Liu J.
      • Tong T.
      Optimally estimating the sample mean from the sample size, median, mid-range, and/or mid-quartile range.
      The DerSimonian and Laird random effects model was chosen a priori to calculate the pooled risk and 95% confidence interval (CI) for major amputation after one year, limb salvage after one year, and one year AFS because of presumed clinical heterogeneity between studies. The amount of statistical heterogeneity between studies was assessed using the I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
      statistic. Statistical analyses were conducted using R-Studio (R-Studio Inc., Boston, MA, USA). Analysis of publication bias was not carried out because of the low number of studies eventually included in the systematic review.

      Results

      Study selection

      The search yielded a total of 1702 studies of which 12 were included for qualitative analysis (Fig. 1).
      • Beropoulis E.
      • Stavroulakis K.
      • Schwindt A.
      • Stachmann A.
      • Torsello G.
      • Bisdas T.
      Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia.
      • Zhan L.X.
      • Branco B.C.
      • Armstrong D.G.
      • Mills J.L.
      • Sr
      The Society for Vascular Surgery lower extremity threatened limb classification system based on Wound, Ischemia, and foot Infection (WIfI) correlates with risk of major amputation and time to wound healing.
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.
      • Mathioudakis N.
      The Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system predicts wound healing but not major amputation in patients with diabetic foot ulcers treated in a multidisciplinary setting.
      • Ramanan B.
      • Ahmed A.
      • Wu B.
      • Causey M.W.
      • Gasper W.J.
      • Vartanian S.M.
      • et al.
      Determinants of midterm functional outcomes and wound healing in a hospital-based limb preservation program.
      • Ricco J.B.
      • Gargiulo M.
      • Stella A.
      • Abualhin M.
      • Gallitto E.
      • Desvergnes M.
      • et al.
      Impact of angiosome- and nonangiosome-targeted peroneal bypass on limb salvage and healing in patients with chronic limb-threatening ischemia.
      • Robinson W.P.
      • Loretz L.
      • Hanesian C.
      • Flahive J.
      • Bostrom J.
      • Lunig N.
      • et al.
      Society for Vascular Surgery Wound, Ischemia, foot Infection (WIfI) score correlates with the intensity of multimodal limb treatment and patient-centered outcomes in patients with threatened limbs managed in a limb preservation center.
      • Ward R.
      • Dunn J.
      • Clavijo L.
      • Shavelle D.
      • Rowe V.
      • Woo K.
      Outcomes of critical limb ischemia in an urban, safety net hospital population with high WIfI amputation scores.
      • Leithead C.
      • Novak Z.
      • Spangler E.
      • Passman M.A.
      • Witcher A.
      • Patterson M.A.
      • et al.
      Importance of postprocedural Wound, Ischemia, and foot Infection (WIfI) restaging in predicting limb salvage.
      • van Haelst S.T.W.
      • Teraa M.
      • Moll F.L.
      • de Borst G.J.
      • Verhaar M.C.
      • Conte M.S.
      Prognostic value of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification in patients with no-option chronic limb-threatening ischemia.
      • Tokuda T.
      • Hirano K.
      • Sakamoto Y.
      • Mori S.
      • Kobayashi N.
      • Araki M.
      • et al.
      Use of the Wound, Ischemia, foot Infection classification system in hemodialysis patients after endovascular treatment for critical limb ischemia.
      One of the main reasons for exclusion of full text articles was overlapping patient samples. One of the included papers presented midterm results
      • Ramanan B.
      • Ahmed A.
      • Wu B.
      • Causey M.W.
      • Gasper W.J.
      • Vartanian S.M.
      • et al.
      Determinants of midterm functional outcomes and wound healing in a hospital-based limb preservation program.
      and the excluded paper reported on the short term results of virtually the same cohort.
      • Causey M.W.
      • Ahmed A.
      • Wu B.
      • Gasper W.J.
      • Reyzelman A.
      • Vartanian S.M.
      • et al.
      Society for Vascular Surgery limb stage and patient risk correlate with outcomes in an amputation prevention program.
      A second paper on a subgroup of patients who underwent infrapopliteal angioplasty
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Meng Y.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system following infrapopliteal endovascular interventions for critical limb ischemia.
      was excluded since this was a subgroup analysis of a series of patients with first time revascularisation.
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.
      The remaining reasons for exclusion are listed in Fig. 1. Eventually, eight studies were available for quantitative synthesis.
      Figure 1
      Figure 1PRISMA flow diagram. PRISMA = Preferred Reporting Items for Systematic reviews and Meta-Analyses; WIFI = wound, ischemia and foot infection.

      Study characteristics

      The 12 included studies reported on a total of 2669 patients (Table 1). One study was conducted in Japan,
      • Tokuda T.
      • Hirano K.
      • Sakamoto Y.
      • Mori S.
      • Kobayashi N.
      • Araki M.
      • et al.
      Use of the Wound, Ischemia, foot Infection classification system in hemodialysis patients after endovascular treatment for critical limb ischemia.
      three studies in Europe,
      • Beropoulis E.
      • Stavroulakis K.
      • Schwindt A.
      • Stachmann A.
      • Torsello G.
      • Bisdas T.
      Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia.
      • Ricco J.B.
      • Gargiulo M.
      • Stella A.
      • Abualhin M.
      • Gallitto E.
      • Desvergnes M.
      • et al.
      Impact of angiosome- and nonangiosome-targeted peroneal bypass on limb salvage and healing in patients with chronic limb-threatening ischemia.
      • van Haelst S.T.W.
      • Teraa M.
      • Moll F.L.
      • de Borst G.J.
      • Verhaar M.C.
      • Conte M.S.
      Prognostic value of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification in patients with no-option chronic limb-threatening ischemia.
      the other eight in the United States (Table 2). The studies included different populations of patients presenting with CLTI. For example, one study included only patients with diabetes,
      • Mathioudakis N.
      The Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system predicts wound healing but not major amputation in patients with diabetic foot ulcers treated in a multidisciplinary setting.
      whereas another excluded patients with diabetes.
      • Beropoulis E.
      • Stavroulakis K.
      • Schwindt A.
      • Stachmann A.
      • Torsello G.
      • Bisdas T.
      Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia.
      Treatments also varied among the studies: six studies included patients treated by revascularisation which was surgical in only one,
      • Ricco J.B.
      • Gargiulo M.
      • Stella A.
      • Abualhin M.
      • Gallitto E.
      • Desvergnes M.
      • et al.
      Impact of angiosome- and nonangiosome-targeted peroneal bypass on limb salvage and healing in patients with chronic limb-threatening ischemia.
      endovascular in only two others,
      • Beropoulis E.
      • Stavroulakis K.
      • Schwindt A.
      • Stachmann A.
      • Torsello G.
      • Bisdas T.
      Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia.
      • Tokuda T.
      • Hirano K.
      • Sakamoto Y.
      • Mori S.
      • Kobayashi N.
      • Araki M.
      • et al.
      Use of the Wound, Ischemia, foot Infection classification system in hemodialysis patients after endovascular treatment for critical limb ischemia.
      and both surgical and endovascular in yet another.
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.
      In two studies the nature of invasive treatment was not specified.
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.
      • Leithead C.
      • Novak Z.
      • Spangler E.
      • Passman M.A.
      • Witcher A.
      • Patterson M.A.
      • et al.
      Importance of postprocedural Wound, Ischemia, and foot Infection (WIfI) restaging in predicting limb salvage.
      The other six studies included also patients with conservative treatment (Table 3). The WIfI classification was determined either at presentation, admission, or pre-operatively, two studies did not specify this (Table 2).
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.
      • Ward R.
      • Dunn J.
      • Clavijo L.
      • Shavelle D.
      • Rowe V.
      • Woo K.
      Outcomes of critical limb ischemia in an urban, safety net hospital population with high WIfI amputation scores.
      In another two studies the WIfI classification was determined at baseline as well as during follow up or after intervention.
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.
      • Leithead C.
      • Novak Z.
      • Spangler E.
      • Passman M.A.
      • Witcher A.
      • Patterson M.A.
      • et al.
      Importance of postprocedural Wound, Ischemia, and foot Infection (WIfI) restaging in predicting limb salvage.
      Table 1Baseline characteristics of individual studies.
      StudyIncluded–excluded (n)
      Numbers are reported as patients, if noted per limbs.
      Age (years, mean)F:M (n)Diabetes (n)Renal disease (n)Treatment (n)
      Beropoulis
      • Beropoulis E.
      • Stavroulakis K.
      • Schwindt A.
      • Stachmann A.
      • Torsello G.
      • Bisdas T.
      Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia.
      126

      Excl: 17
      7752:74042 CKD

      12 ESRD/Dialysis
      Endovascular revascularisation
      Cull
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.
      139

      151 Limbs

      Excl: 26
      7053:869119 ESRDRevascularisation, not specified
      Darling
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.
      903

      992 Limbs

      Excl: NR
      71368:535660155 DialysisRevascularisation (limbs):

      524 Open

      468 Endovascular
      Mathioudakis
      • Mathioudakis N.
      The Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system predicts wound healing but not major amputation in patients with diabetic foot ulcers treated in a multidisciplinary setting.
      217

      Excl: NR
      5891:12621739 CKD

      27 Dialysis
      60 Revascularisation:

      16 Open

      29 Endovascular

      6 Open after endovascular

      9 Hybrid

      157 Conservative
      Leithead
      • Leithead C.
      • Novak Z.
      • Spangler E.
      • Passman M.A.
      • Witcher A.
      • Patterson M.A.
      • et al.
      Importance of postprocedural Wound, Ischemia, and foot Infection (WIfI) restaging in predicting limb salvage.
      172

      Excl: NR
      6472:100898 DialysisRevascularisation, not specified
      Zhan
      • Zhan L.X.
      • Branco B.C.
      • Armstrong D.G.
      • Mills J.L.
      • Sr
      The Society for Vascular Surgery lower extremity threatened limb classification system based on Wound, Ischemia, and foot Infection (WIfI) correlates with risk of major amputation and time to wound healing.
      201

      Excl: NR
      5842:15918777 CKD

      41 Dialysis
      48 Revascularisation, not specified

      153 Conservative
      Ramanan
      • Ramanan B.
      • Ahmed A.
      • Wu B.
      • Causey M.W.
      • Gasper W.J.
      • Vartanian S.M.
      • et al.
      Determinants of midterm functional outcomes and wound healing in a hospital-based limb preservation program.
      128

      157 Limbs

      Excl: NR
      6661:96

      (limbs)
      11837 ESRD91 Revascularisation (Limbs):

      51 Open

      40 Endovascular

      46 Conservative
      Ricco
      • Ricco J.B.
      • Gargiulo M.
      • Stella A.
      • Abualhin M.
      • Gallitto E.
      • Desvergnes M.
      • et al.
      Impact of angiosome- and nonangiosome-targeted peroneal bypass on limb salvage and healing in patients with chronic limb-threatening ischemia.
      120

      Excl: NR
      7233:876931 CKDSurgical revascularisation
      Robinson
      • Robinson W.P.
      • Loretz L.
      • Hanesian C.
      • Flahive J.
      • Bostrom J.
      • Lunig N.
      • et al.
      Society for Vascular Surgery Wound, Ischemia, foot Infection (WIfI) score correlates with the intensity of multimodal limb treatment and patient-centered outcomes in patients with threatened limbs managed in a limb preservation center.
      257

      280 Limbs

      Excl: NR
      6573:1847 Diet

      27 N-insulin

      179 Insulin
      154 CKD

      30 ESRD
      106 Revascularisation (Limbs):

      60 Endovascular

      59 Open

      15 Hybrid

      174 Conservative
      Ward
      • Ward R.
      • Dunn J.
      • Clavijo L.
      • Shavelle D.
      • Rowe V.
      • Woo K.
      Outcomes of critical limb ischemia in an urban, safety net hospital population with high WIfI amputation scores.
      92

      98 Limbs

      Excl: 119
      6340:527117 CKD84 Revascularisation (Limbs):

      37 Open

      34 Endovascular

      13 Hybrid

      14 Conservative
      Tokuda
      • Tokuda T.
      • Hirano K.
      • Sakamoto Y.
      • Mori S.
      • Kobayashi N.
      • Araki M.
      • et al.
      Use of the Wound, Ischemia, foot Infection classification system in hemodialysis patients after endovascular treatment for critical limb ischemia.
      163

      Excl: 240 limbs
      7153:110112163 DialysisEndovascular revascularisation
      Van Haelst
      • van Haelst S.T.W.
      • Teraa M.
      • Moll F.L.
      • de Borst G.J.
      • Verhaar M.C.
      • Conte M.S.
      Prognostic value of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification in patients with no-option chronic limb-threatening ischemia.
      150

      Excl: 10
      6747:1035534 CKD81 Bone marrow – mononuclear cells

      79 Conservative
      CKD = chronic kidney disease; ESRD = end stage renal disease; NR = not reported; Excl = number of patients excluded; F = females; M = males.
      Numbers are reported as patients, if noted per limbs.
      Table 2Characteristics of individual studies.
      StudyInclusion criteriaExclusion criteriaStudy designEndpointsFU

      (mean, SD)
      Timing of stagingRestaging
      Beropoulis
      • Beropoulis E.
      • Stavroulakis K.
      • Schwindt A.
      • Stachmann A.
      • Torsello G.
      • Bisdas T.
      Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia.


      Germany

      2016
      CLI: ABI ≤ 0.40 and/or rest pain and/or with(out) tissue loss in presence of PAD, Rutherford 4–6, >2 weeks CLI. Only one leg per patient, first treatmentAcute ischaemia, trauma, isolated iliac interventions, non-atherosclerotic disease, hypercoagulable states, diabetes, no endovascular treatmentRetrospective

      Prospective data

      Jan ‘13 – Sep ‘14

      Single centre
      Primary: death and major amputation, Major amputation, death14 months

      (SD 8)
      Pre-operativelyNo
      Cull
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.


      US

      2016
      CLI

      Rutherford V-VI scheduled to undergo revascularisation
      Vasospastic, collagen vascular disease, vasculitis, Buerger's disease, acute limb ischaemia, athero-embolic disease, arterial traumaRetrospective

      Prospective data

      2007–2011

      Single centre
      Major amputation at one year, wound healing, amputation free survival27.5 months

      (SD 11)
      Wound and infection, pre-operative

      Ischaemia post-operative
      Secondary intervention

      <6 weeks after initial; restaging ischaemia positive

      >6 weeks after, with improvement restaging Ischaemia positive
      Darling
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.


      US

      2017
      First time revascularisation CLTINo symptoms CLTI, aborted endovascular procedures, missing data on WIFIRetrospective

      Chart review

      2005–2014

      Single centre
      Major amputation, RAS, death1.6 yearsNRNo
      Mathioudakis
      • Mathioudakis N.
      The Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system predicts wound healing but not major amputation in patients with diabetic foot ulcers treated in a multidisciplinary setting.


      US

      2017
      All patients presenting at Diabetic Foot Ulcer serviceNRRetrospective

      Prospective data

      2012–2015

      Single centre
      Major amputation, wound healingNRInitial presentationNo
      Leithead
      • Leithead C.
      • Novak Z.
      • Spangler E.
      • Passman M.A.
      • Witcher A.
      • Patterson M.A.
      • et al.
      Importance of postprocedural Wound, Ischemia, and foot Infection (WIfI) restaging in predicting limb salvage.


      US

      2017
      Threatened limb, patients who underwent revascularisation, also patients without tissue loss but with rest painMissing WIfI component, acute limb ischaemia, arteritis, non-healing incisions, emergency major amputationRetrospective

      EMR review

      Jan ‘14 – Jun ‘15

      Single centre
      Major amputation, AFSNRInitial presentation, immediately post-operatively, one and six months after interventionYes
      Zhan
      • Zhan L.X.
      • Branco B.C.
      • Armstrong D.G.
      • Mills J.L.
      • Sr
      The Society for Vascular Surgery lower extremity threatened limb classification system based on Wound, Ischemia, and foot Infection (WIfI) correlates with risk of major amputation and time to wound healing.


      US

      2015
      Consecutive threatened limbs due to varying degrees tissue loss, with or without ischaemia or infection with complete follow upPatients presenting and managed entirely on outpatient clinicRetrospective

      Chart review

      Jan ’10 – Dec ‘11

      Single centre
      Major amputation, AFS, Wound healing timeNot reported, methods state at least two yearsInitial presentation, before intervention.No
      Ramanan
      • Ramanan B.
      • Ahmed A.
      • Wu B.
      • Causey M.W.
      • Gasper W.J.
      • Vartanian S.M.
      • et al.
      Determinants of midterm functional outcomes and wound healing in a hospital-based limb preservation program.


      US

      2017
      All consecutive admissions to a limb preservation serviceNon-atherosclerotic disease, acute limb ischaemia, traumaRetrospective

      Prospective grading of WIfI

      Jul ’13 – Oct ‘14

      Single centre
      Major amputation, mortality, wound healing391 days

      (SD 107)
      On admissionNo
      Ricco
      • Ricco J.B.
      • Gargiulo M.
      • Stella A.
      • Abualhin M.
      • Gallitto E.
      • Desvergnes M.
      • et al.
      Impact of angiosome- and nonangiosome-targeted peroneal bypass on limb salvage and healing in patients with chronic limb-threatening ischemia.


      France/Italy

      2017
      All patients with CLTI, Rutherford 5–6, only a patent peroneal artery to the ankle, lower limb bypassIf also contralateral peroneal bypass, contralateral limb not includedRetrospective

      Prospective data

      Jan ’04 – Oct ‘15

      Multicentre
      Limb salvage, amputation free survival, wound healing79 months

      (SD 6)
      Pre-operativelyNo
      Robinson
      • Robinson W.P.
      • Loretz L.
      • Hanesian C.
      • Flahive J.
      • Bostrom J.
      • Lunig N.
      • et al.
      Society for Vascular Surgery Wound, Ischemia, foot Infection (WIfI) score correlates with the intensity of multimodal limb treatment and patient-centered outcomes in patients with threatened limbs managed in a limb preservation center.


      US

      2017
      CLI or diabetic foot ulcerationNRRetrospective

      Prospective data

      Oct ’13 – May ‘15

      Single centre
      Wound healing, limb salvage, AFS and mortality214 days

      (SD 183)
      At presentationNo
      Ward
      • Ward R.
      • Dunn J.
      • Clavijo L.
      • Shavelle D.
      • Rowe V.
      • Woo K.
      Outcomes of critical limb ischemia in an urban, safety net hospital population with high WIfI amputation scores.


      US

      2017
      Patients treated for CLI, who survived 12 months and had FU for limb status at 12 monthsNRRetrospective

      Prospective data

      Feb ‘10 – Jun ‘14

      Single centre
      Major amputationNot reported, methods state 12 monthsRetrospectively, not clearly defined.No
      Tokuda
      • Tokuda T.
      • Hirano K.
      • Sakamoto Y.
      • Mori S.
      • Kobayashi N.
      • Araki M.
      • et al.
      Use of the Wound, Ischemia, foot Infection classification system in hemodialysis patients after endovascular treatment for critical limb ischemia.


      Japan

      2018
      Haemodialysis patients undergoing a successful infrapopliteal EVT for CLIUnsuccessful EVT, bypass surgery, absence of HD, contralateral limb of same patientRetrospective

      Retrospective data

      Apr ’07 – Dec ‘15

      Single centre
      Amputation free survival, Wound healing784 days

      (SD 650)
      Pre-operativelyNo
      Van Haelst
      • van Haelst S.T.W.
      • Teraa M.
      • Moll F.L.
      • de Borst G.J.
      • Verhaar M.C.
      • Conte M.S.
      Prognostic value of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification in patients with no-option chronic limb-threatening ischemia.


      Netherlands

      2018
      Age >18 years, Rutherford IV or higher, ineligible for surgical or radiological revascularisationHistory of malignancy in past 10 years, life expectancy less than one year, HIV, Hepatitis B/C, Follow up impossible, inability to determine WIfIRetrospective

      Prospective data

      Sep ’06 – Jun ‘12

      Single centre
      Mortality, Major Amputation2 years

      (SD 1.7)
      Pre-treatmentNo
      CLI = critical limb ischaemia; EVT = endovascular therapy; NR = not reported; RAS = revascularisation, amputation, stenosis; SD = standard deviation; EMR = electronic medical record; HD = haemodialysis dependent; WIfI = wound, ischemia and foot infection; CLTI = chronic limb-threatening ischemia; PAD = peripheral arterial disease; US = United States; AFS = amputation-free survival; FU = follow up; ABI = ankle brachial index.
      Table 3Methodological assessment of individual studies (Quality in Prognosis Studies).
      Table thumbnail fx1

      Methodological quality assessment

      The methodological quality assessment of the studies is presented in Table 3. Statistical analysis and reporting was good in all studies. Five of the 12 studies did not report attrition of patients during the study period,
      • Zhan L.X.
      • Branco B.C.
      • Armstrong D.G.
      • Mills J.L.
      • Sr
      The Society for Vascular Surgery lower extremity threatened limb classification system based on Wound, Ischemia, and foot Infection (WIfI) correlates with risk of major amputation and time to wound healing.
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.
      • Mathioudakis N.
      The Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system predicts wound healing but not major amputation in patients with diabetic foot ulcers treated in a multidisciplinary setting.
      • Ramanan B.
      • Ahmed A.
      • Wu B.
      • Causey M.W.
      • Gasper W.J.
      • Vartanian S.M.
      • et al.
      Determinants of midterm functional outcomes and wound healing in a hospital-based limb preservation program.
      • Tokuda T.
      • Hirano K.
      • Sakamoto Y.
      • Mori S.
      • Kobayashi N.
      • Araki M.
      • et al.
      Use of the Wound, Ischemia, foot Infection classification system in hemodialysis patients after endovascular treatment for critical limb ischemia.
      while in four studies the reasons for loss to follow up were unknown.
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.
      • Ricco J.B.
      • Gargiulo M.
      • Stella A.
      • Abualhin M.
      • Gallitto E.
      • Desvergnes M.
      • et al.
      Impact of angiosome- and nonangiosome-targeted peroneal bypass on limb salvage and healing in patients with chronic limb-threatening ischemia.
      • Robinson W.P.
      • Loretz L.
      • Hanesian C.
      • Flahive J.
      • Bostrom J.
      • Lunig N.
      • et al.
      Society for Vascular Surgery Wound, Ischemia, foot Infection (WIfI) score correlates with the intensity of multimodal limb treatment and patient-centered outcomes in patients with threatened limbs managed in a limb preservation center.
      • Leithead C.
      • Novak Z.
      • Spangler E.
      • Passman M.A.
      • Witcher A.
      • Patterson M.A.
      • et al.
      Importance of postprocedural Wound, Ischemia, and foot Infection (WIfI) restaging in predicting limb salvage.
      The prognostic value of the WIfI classification was determined retrospectively in all but one study,
      • Ramanan B.
      • Ahmed A.
      • Wu B.
      • Causey M.W.
      • Gasper W.J.
      • Vartanian S.M.
      • et al.
      Determinants of midterm functional outcomes and wound healing in a hospital-based limb preservation program.
      which implies a certain risk of information bias. Seven studies conducted retrospective analyses of prospectively maintained databases,
      • Beropoulis E.
      • Stavroulakis K.
      • Schwindt A.
      • Stachmann A.
      • Torsello G.
      • Bisdas T.
      Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia.
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.
      • Mathioudakis N.
      The Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system predicts wound healing but not major amputation in patients with diabetic foot ulcers treated in a multidisciplinary setting.
      • Ramanan B.
      • Ahmed A.
      • Wu B.
      • Causey M.W.
      • Gasper W.J.
      • Vartanian S.M.
      • et al.
      Determinants of midterm functional outcomes and wound healing in a hospital-based limb preservation program.
      • Ricco J.B.
      • Gargiulo M.
      • Stella A.
      • Abualhin M.
      • Gallitto E.
      • Desvergnes M.
      • et al.
      Impact of angiosome- and nonangiosome-targeted peroneal bypass on limb salvage and healing in patients with chronic limb-threatening ischemia.
      • Robinson W.P.
      • Loretz L.
      • Hanesian C.
      • Flahive J.
      • Bostrom J.
      • Lunig N.
      • et al.
      Society for Vascular Surgery Wound, Ischemia, foot Infection (WIfI) score correlates with the intensity of multimodal limb treatment and patient-centered outcomes in patients with threatened limbs managed in a limb preservation center.
      • Ward R.
      • Dunn J.
      • Clavijo L.
      • Shavelle D.
      • Rowe V.
      • Woo K.
      Outcomes of critical limb ischemia in an urban, safety net hospital population with high WIfI amputation scores.
      • van Haelst S.T.W.
      • Teraa M.
      • Moll F.L.
      • de Borst G.J.
      • Verhaar M.C.
      • Conte M.S.
      Prognostic value of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification in patients with no-option chronic limb-threatening ischemia.
      four studies were retrospective analyses of (electronic) medical charts.
      • Zhan L.X.
      • Branco B.C.
      • Armstrong D.G.
      • Mills J.L.
      • Sr
      The Society for Vascular Surgery lower extremity threatened limb classification system based on Wound, Ischemia, and foot Infection (WIfI) correlates with risk of major amputation and time to wound healing.
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.
      • Leithead C.
      • Novak Z.
      • Spangler E.
      • Passman M.A.
      • Witcher A.
      • Patterson M.A.
      • et al.
      Importance of postprocedural Wound, Ischemia, and foot Infection (WIfI) restaging in predicting limb salvage.
      • Tokuda T.
      • Hirano K.
      • Sakamoto Y.
      • Mori S.
      • Kobayashi N.
      • Araki M.
      • et al.
      Use of the Wound, Ischemia, foot Infection classification system in hemodialysis patients after endovascular treatment for critical limb ischemia.
      Lastly, one study used another classification and converted these scores into the WIfI score retrospectively.
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.
      The certainty of evidence was low to very low for all three outcomes according to the GRADE approach. Full details are presented in Table S4.

      Outcomes

      An overview of the outcomes extracted from the studies is shown in Table 4, Table 5. The outcomes were either reported per patient or if noted, per limb. Three studies were excluded from meta-analysis, because they did not report their outcomes after one year of follow up.
      • Ricco J.B.
      • Gargiulo M.
      • Stella A.
      • Abualhin M.
      • Gallitto E.
      • Desvergnes M.
      • et al.
      Impact of angiosome- and nonangiosome-targeted peroneal bypass on limb salvage and healing in patients with chronic limb-threatening ischemia.
      • Robinson W.P.
      • Loretz L.
      • Hanesian C.
      • Flahive J.
      • Bostrom J.
      • Lunig N.
      • et al.
      Society for Vascular Surgery Wound, Ischemia, foot Infection (WIfI) score correlates with the intensity of multimodal limb treatment and patient-centered outcomes in patients with threatened limbs managed in a limb preservation center.
      • Leithead C.
      • Novak Z.
      • Spangler E.
      • Passman M.A.
      • Witcher A.
      • Patterson M.A.
      • et al.
      Importance of postprocedural Wound, Ischemia, and foot Infection (WIfI) restaging in predicting limb salvage.
      In addition, the study by Mathioudakis et al.
      • Mathioudakis N.
      The Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system predicts wound healing but not major amputation in patients with diabetic foot ulcers treated in a multidisciplinary setting.
      was excluded from the meta-analysis on clinical grounds because they only included diabetic foot ulcer patients with and without peripheral arterial disease. Five studies performed a multivariable analysis for the WIfI classification on major amputation, as shown in Table 4.
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.
      • Robinson W.P.
      • Loretz L.
      • Hanesian C.
      • Flahive J.
      • Bostrom J.
      • Lunig N.
      • et al.
      Society for Vascular Surgery Wound, Ischemia, foot Infection (WIfI) score correlates with the intensity of multimodal limb treatment and patient-centered outcomes in patients with threatened limbs managed in a limb preservation center.
      • Ward R.
      • Dunn J.
      • Clavijo L.
      • Shavelle D.
      • Rowe V.
      • Woo K.
      Outcomes of critical limb ischemia in an urban, safety net hospital population with high WIfI amputation scores.
      • van Haelst S.T.W.
      • Teraa M.
      • Moll F.L.
      • de Borst G.J.
      • Verhaar M.C.
      • Conte M.S.
      Prognostic value of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification in patients with no-option chronic limb-threatening ischemia.
      Table 4Outcome in WIfI stages
      StudyWIfI I (n=patients)
      Numbers are reported as patients, if noted per limbs.
      WIfI II

      (n=patients)
      Numbers are reported as patients, if noted per limbs.
      WIfI III

      (n=patients)
      Numbers are reported as patients, if noted per limbs.
      WIfI IV (n=patients)
      Numbers are reported as patients, if noted per limbs.
      Multivariable analysis

      WIfI for Major amputation
      Beropoulis
      • Beropoulis E.
      • Stavroulakis K.
      • Schwindt A.
      • Stachmann A.
      • Torsello G.
      • Bisdas T.
      Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia.


      FU: 1 year
      29

      AFS 87%

      Amp 0%
      42

      AFS 81%

      Amp 2%
      29

      AFS 81%

      Amp 3%
      26

      AFS 62%

      Amp 12%
      Cull
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.


      FU: 1 year
      36 (37 Limbs)

      Limb Sal 97%

      AFS 86%
      58 (63 Limbs)

      Limb Sal 89%

      AFS 83%
      37 (43 Limbs)

      Limb Sal 77%

      AFS 70%
      8 (8 limbs)

      Limb Sal 63%

      AFS 38%
      WIfI stage I OR 1 - reference

      II OR 4.8 (95% CI 0.6-40.5)

      III OR 10.8 (95% CI 1.3-88.8)

      IV OR 23.4 (95% CI 2.2-270.2)
      Darling
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.


      FU: 1 year
      12 Limbs

      Limb sal 100%
      293 Limbs

      Limb sal 96%
      249 Limbs

      Limb sal 96%
      438 Limbs

      Limb sal 79%
      HR 2.4 ( 95% CI 1.7-3.2)

      Clinical stage or reference not reported
      Mathioudakis
      • Mathioudakis N.
      The Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system predicts wound healing but not major amputation in patients with diabetic foot ulcers treated in a multidisciplinary setting.


      FU: 1 year
      61 Limbs

      Amp 4%
      24 Limbs

      Amp 3%
      72 Limbs

      Amp 5%
      60 Limbs

      Amp 6%
      Zhan
      • Zhan L.X.
      • Branco B.C.
      • Armstrong D.G.
      • Mills J.L.
      • Sr
      The Society for Vascular Surgery lower extremity threatened limb classification system based on Wound, Ischemia, and foot Infection (WIfI) correlates with risk of major amputation and time to wound healing.


      FU: 1 year
      39

      Amp 0%

      AFS 100%

      Limb Sal 100%
      50

      Amp 0%

      AFS 100%

      Limb Sal 100%
      53

      Amp 8%

      AFS 92%

      Limb Sal 92%
      59

      Amp 64%

      AFS 63%

      Limb Sal 36%
      Ramanan
      • Ramanan B.
      • Ahmed A.
      • Wu B.
      • Causey M.W.
      • Gasper W.J.
      • Vartanian S.M.
      • et al.
      Determinants of midterm functional outcomes and wound healing in a hospital-based limb preservation program.


      FU: 391 days
      20 Limbs

      AFS 75%

      Limb Sal 92%
      48 Limbs

      AFS 62%

      Limb Sal 81%
      41 Limbs

      AFS 69%)

      Limb Sal 93%
      48 Limbs

      AFS 57%

      Limb Sal 63%
      Ricco
      • Ricco J.B.
      • Gargiulo M.
      • Stella A.
      • Abualhin M.
      • Gallitto E.
      • Desvergnes M.
      • et al.
      Impact of angiosome- and nonangiosome-targeted peroneal bypass on limb salvage and healing in patients with chronic limb-threatening ischemia.


      FU: 3 years

      WIfI I-II and III-IV combined
      1311

      AFS WIfI I/II 87.4% +/- 8.3%
      4947

      AFS WIfI III/IV 48.4% +/- 5.3 %
      Robinson
      • Robinson W.P.
      • Loretz L.
      • Hanesian C.
      • Flahive J.
      • Bostrom J.
      • Lunig N.
      • et al.
      Society for Vascular Surgery Wound, Ischemia, foot Infection (WIfI) score correlates with the intensity of multimodal limb treatment and patient-centered outcomes in patients with threatened limbs managed in a limb preservation center.


      FU: 214 days
      48

      Amp 2%

      AFS 84%
      67

      Amp 5%

      AFS 75%
      64

      Amp 8%

      AFS 80%
      83

      Amp 17%

      AFS 69%
      WIfI stage IV HR 12

      (95% CI 1.6-94)

      Reference not reported
      Ward
      • Ward R.
      • Dunn J.
      • Clavijo L.
      • Shavelle D.
      • Rowe V.
      • Woo K.
      Outcomes of critical limb ischemia in an urban, safety net hospital population with high WIfI amputation scores.


      FU: 1 year
      5 Limbs

      Amp 0%
      21 Limbs

      Amp 14%
      14 Limbs

      Amp 21%
      58 Limbs

      Amp 34%
      OR 1.84 (95% CI 1.0-3.39)

      Clinical stage or reference not reported
      Tokuda
      • Tokuda T.
      • Hirano K.
      • Sakamoto Y.
      • Mori S.
      • Kobayashi N.
      • Araki M.
      • et al.
      Use of the Wound, Ischemia, foot Infection classification system in hemodialysis patients after endovascular treatment for critical limb ischemia.


      FU: 1 year
      16

      AFS 76%
      30

      AFS 58%
      56

      AFS 61%
      61

      AFS 46%
      Van Haelst
      • van Haelst S.T.W.
      • Teraa M.
      • Moll F.L.
      • de Borst G.J.
      • Verhaar M.C.
      • Conte M.S.
      Prognostic value of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification in patients with no-option chronic limb-threatening ischemia.


      FU: 1 year
      15

      Amp 0%
      50

      Amp 16%
      32

      Amp 13%
      53

      Amp 42%
      WIfI stage IV HR 2.39

      (95% CI 0.93 – 6.20)

      Reference not reported
      Amp = major amputation; AFS = amputation free survival; Limb sal = limb salvage; FU = follow up; WIfI = Wound, Ischaemia, and foot Infection; OR = odds ratio; CI = confidence interval.
      Numbers are reported as patients, if noted per limbs.
      Table 5Divergent reporting of WIfI classification.
      Study
      Amounts are reported as patients, if noted per limbs.
      Leithead
      • Leithead C.
      • Novak Z.
      • Spangler E.
      • Passman M.A.
      • Witcher A.
      • Patterson M.A.
      • et al.
      Importance of postprocedural Wound, Ischemia, and foot Infection (WIfI) restaging in predicting limb salvage.


      FU: NR

      Individual determinants WIfI post-operatively reported
      Wound

      1 month post-op

      Total: 148, Amp = 16

      01 4,9%

      23 34,5%

      6 months post-op

      Total: 115, Amp = 5

      01 2,7%

      23 22,2%
      Ischaemia

      1 month post-op

      01 11%

      23 9,5%



      6 months post-op

      01 2,2%

      23 11,5%
      Infection

      1 month post-op

      0 5,3%

      > 0 50%



      6 months post-op

      0 3,5%

      > 0 20%
      Darling
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.


      FU: one year
      WIfI Composite 13

      336 Limbs

      Limb sal 96%

      WIfI Mean Score I

      12 Limbs

      Limb sal 100%
      WIfI Composite 46

      557 Limbs

      Limb sal 89%

      WIfI Mean Score II

      542 Limbs

      Limb sal 96%
      WIfI Composite 79

      100 Limbs

      Limb sal 67%

      WIfI Mean Score III

      438 Limbs

      Limb sal 79%
      Amp = major amputation; FU = follow up; Limb sal = limb salvage; NR = not reported; WIfI = Wound, Ischaemia, and foot Infection.
      WIfI Composite: individual determinants of classification added together and score divided in presented scores.
      WIfI Mean Score: individual determinants added together and divided by number of known individual determinants.
      Amounts are reported as patients, if noted per limbs.
      Two studies applied the WIfI classification differently (Table 5). Leithead et al.
      • Leithead C.
      • Novak Z.
      • Spangler E.
      • Passman M.A.
      • Witcher A.
      • Patterson M.A.
      • et al.
      Importance of postprocedural Wound, Ischemia, and foot Infection (WIfI) restaging in predicting limb salvage.
      used it as a tool for post-revascularisation staging and expressed the outcomes per determinant (i.e. wound, ischaemia, foot infection) and not per clinical stage. Darling et al.
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.
      reported a WIfI composite score (i.e. a cumulative score of the individual determinants) and a WIfI mean score (i.e. the cumulative score of the individual determinants divided by the number of known determinants). This was done in order to weigh the individual determinants equally. The mean score allowed use of the classification in case not all determinants were known.

      Meta-analyses

      Major amputation after one year

      Data for each WIfI stage from four studies (569 patients, 575 limbs) reporting on major amputation were pooled.
      • Beropoulis E.
      • Stavroulakis K.
      • Schwindt A.
      • Stachmann A.
      • Torsello G.
      • Bisdas T.
      Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia.
      • Zhan L.X.
      • Branco B.C.
      • Armstrong D.G.
      • Mills J.L.
      • Sr
      The Society for Vascular Surgery lower extremity threatened limb classification system based on Wound, Ischemia, and foot Infection (WIfI) correlates with risk of major amputation and time to wound healing.
      • Ward R.
      • Dunn J.
      • Clavijo L.
      • Shavelle D.
      • Rowe V.
      • Woo K.
      Outcomes of critical limb ischemia in an urban, safety net hospital population with high WIfI amputation scores.
      • van Haelst S.T.W.
      • Teraa M.
      • Moll F.L.
      • de Borst G.J.
      • Verhaar M.C.
      • Conte M.S.
      Prognostic value of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification in patients with no-option chronic limb-threatening ischemia.
      The estimated risk of a major amputation after one year was 0% for WIfI stage I patients, 8% (95% CI 3–21%, I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 58%) for stage II, 11% (95% CI 6–19%, I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 18%) for stage III, and 38% (95% CI 21–58%, I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 85%) for stage IV. The level of evidence for this outcome ranged from low to very low (Table 6, Table S4).
      Table 6Meta-analyses.
      Major amputation after one yearWIfI IWIfI IIWIfI IIIWIfI IV
      Beropoulis
      • Beropoulis E.
      • Stavroulakis K.
      • Schwindt A.
      • Stachmann A.
      • Torsello G.
      • Bisdas T.
      Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia.
      29

      0%
      42

      2%
      29

      3%
      26

      12%
      Zhan
      • Zhan L.X.
      • Branco B.C.
      • Armstrong D.G.
      • Mills J.L.
      • Sr
      The Society for Vascular Surgery lower extremity threatened limb classification system based on Wound, Ischemia, and foot Infection (WIfI) correlates with risk of major amputation and time to wound healing.
      39

      0%
      50

      0%
      53

      8%
      59

      64%
      Ward
      • Ward R.
      • Dunn J.
      • Clavijo L.
      • Shavelle D.
      • Rowe V.
      • Woo K.
      Outcomes of critical limb ischemia in an urban, safety net hospital population with high WIfI amputation scores.
      5

      0%
      21

      14%
      14

      21%
      58

      34%
      Van Haelst
      • van Haelst S.T.W.
      • Teraa M.
      • Moll F.L.
      • de Borst G.J.
      • Verhaar M.C.
      • Conte M.S.
      Prognostic value of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification in patients with no-option chronic limb-threatening ischemia.
      15

      0%
      50

      16%
      32

      13%
      53

      42%
      Pooled data, random effects model (95% CI)88

      0% N.E.
      163

      8% (3–21%)

      I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 58%
      128

      11% (6–19%)

      I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 18%
      196

      38% (21–58%) I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 85%
      GRADE certainty of evidenceLOWVERY LOWLOWVERY LOW
      Amputation free survival after one year
      Beropoulis
      • Beropoulis E.
      • Stavroulakis K.
      • Schwindt A.
      • Stachmann A.
      • Torsello G.
      • Bisdas T.
      Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia.
      29

      87%
      42

      81%
      29

      81%
      26

      62%
      Cull
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.
      36

      86%
      58

      83%
      37

      70%
      8

      38%
      Zhan
      • Zhan L.X.
      • Branco B.C.
      • Armstrong D.G.
      • Mills J.L.
      • Sr
      The Society for Vascular Surgery lower extremity threatened limb classification system based on Wound, Ischemia, and foot Infection (WIfI) correlates with risk of major amputation and time to wound healing.
      39

      100%
      50

      100%
      53

      92%
      59

      63%
      Ramanan
      • Ramanan B.
      • Ahmed A.
      • Wu B.
      • Causey M.W.
      • Gasper W.J.
      • Vartanian S.M.
      • et al.
      Determinants of midterm functional outcomes and wound healing in a hospital-based limb preservation program.
      20

      75%
      48

      62%
      41

      69%
      48

      57%
      Tokuda
      • Tokuda T.
      • Hirano K.
      • Sakamoto Y.
      • Mori S.
      • Kobayashi N.
      • Araki M.
      • et al.
      Use of the Wound, Ischemia, foot Infection classification system in hemodialysis patients after endovascular treatment for critical limb ischemia.
      16

      76%
      30

      58%
      56

      61%
      61

      46%
      Pooled data, random effects model (95% CI)140

      83% (73–91%)

      I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 32%
      228

      76% (60–87%)

      I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 76%
      216

      75% (62–84%)

      I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 70%
      202

      55% (47–63%)

      I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 18%
      GRADE certainty of evidenceLOWVERY LOWVERY LOWLOW
      Limb salvage after one year
      Cull
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.
      37

      97%
      63

      89%
      43

      77%
      8

      63%
      Darling
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.
      12

      100%
      293

      96%
      249

      96%
      438

      79%
      Zhan
      • Zhan L.X.
      • Branco B.C.
      • Armstrong D.G.
      • Mills J.L.
      • Sr
      The Society for Vascular Surgery lower extremity threatened limb classification system based on Wound, Ischemia, and foot Infection (WIfI) correlates with risk of major amputation and time to wound healing.
      39

      100%
      50

      100%
      53

      92%
      59

      36%
      Ramanan
      • Ramanan B.
      • Ahmed A.
      • Wu B.
      • Causey M.W.
      • Gasper W.J.
      • Vartanian S.M.
      • et al.
      Determinants of midterm functional outcomes and wound healing in a hospital-based limb preservation program.
      20

      92%
      48

      81%
      41

      93%
      48

      63%
      Pooled data, random effects model (95% CI)108

      95% (88–98%

      I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 0%
      454

      92% (81–97%)

      I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 81%
      386

      91% (79–97%)

      I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 82%
      553

      61% (36–82%)

      I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 93%
      GRADE certainty of evidenceLOWVERY LOWVERY LOWVERY LOW
      CI = confidence interval; WIfI = Wound, Ischaemia, and foot Infection; N.E. = Not estimable.

      Amputation free survival after one year

      Five studies comprising 757 patients and 786 limbs reported on AFS.
      • Beropoulis E.
      • Stavroulakis K.
      • Schwindt A.
      • Stachmann A.
      • Torsello G.
      • Bisdas T.
      Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia.
      • Zhan L.X.
      • Branco B.C.
      • Armstrong D.G.
      • Mills J.L.
      • Sr
      The Society for Vascular Surgery lower extremity threatened limb classification system based on Wound, Ischemia, and foot Infection (WIfI) correlates with risk of major amputation and time to wound healing.
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.
      • Ramanan B.
      • Ahmed A.
      • Wu B.
      • Causey M.W.
      • Gasper W.J.
      • Vartanian S.M.
      • et al.
      Determinants of midterm functional outcomes and wound healing in a hospital-based limb preservation program.
      • Tokuda T.
      • Hirano K.
      • Sakamoto Y.
      • Mori S.
      • Kobayashi N.
      • Araki M.
      • et al.
      Use of the Wound, Ischemia, foot Infection classification system in hemodialysis patients after endovascular treatment for critical limb ischemia.
      The estimated one year AFS was 83% (95% CI 73–91%, I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 32%) for patients classified as WIFI stage I, 76% (95% CI 60–87%, I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 76%) for stage II, 75% (95% CI 62–84%, I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 70%) for stage III, and IV 55% (95% CI 47–63%, I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 18%) for stage IV. The certainty of evidence on AFS after one year was low to very low (Table 6, Table S4).

      Limb salvage after one year

      Four studies,
      • Zhan L.X.
      • Branco B.C.
      • Armstrong D.G.
      • Mills J.L.
      • Sr
      The Society for Vascular Surgery lower extremity threatened limb classification system based on Wound, Ischemia, and foot Infection (WIfI) correlates with risk of major amputation and time to wound healing.
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.
      • Ramanan B.
      • Ahmed A.
      • Wu B.
      • Causey M.W.
      • Gasper W.J.
      • Vartanian S.M.
      • et al.
      Determinants of midterm functional outcomes and wound healing in a hospital-based limb preservation program.
      totalling 1369 patients and 1501 limbs, reported on limb salvage after one year, which was 95% (95% CI 88–98%, I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 0%) for patients having WIfI stage I, 92% (95% CI 81–97%, I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 81%) for stage II, 91% (95% CI 79–97%, I2 = 82%) for stage III, and 61% (95% CI 36–82%, I
      • Aboyans V.
      • Ricco J.B.
      • Bartelink M.E.L.
      • Bjorck M.
      • Brodmann M.
      • Cohnert T.
      • et al.
      Editor's choice - 2017 ESC guidelines on the diagnosis and treatment of peripheral arterial diseases, in collaboration with the european society for vascular Surgery (ESVS).
       = 93%) for stage IV). The GRADE certainty of evidence on limb salvage ranged from low to very low (Table 6, Table S4).

      Discussion

      The Society for Vascular Surgery introduced the WIfI classification to provide information regarding the risk of major amputation within one year and the benefit of revascularisation in patients with CLTI. This review shows that the likelihood of a major amputation after one year in patients with CLTI does increase with higher clinical WIfI stages, especially in stage IV. Similarly, the higher the WIfI stage, the lower AFS and limb salvage rates after one year.
      Sufficient evidence was not found to support the use of the WIfI classification to predict the benefit of revascularisation. The study by Robinson et al.
      • Robinson W.P.
      • Loretz L.
      • Hanesian C.
      • Flahive J.
      • Bostrom J.
      • Lunig N.
      • et al.
      Society for Vascular Surgery Wound, Ischemia, foot Infection (WIfI) score correlates with the intensity of multimodal limb treatment and patient-centered outcomes in patients with threatened limbs managed in a limb preservation center.
      presented these results only for the ischaemia determinant but not the complete WIfI classification. In addition, Leithead et al.
      • Leithead C.
      • Novak Z.
      • Spangler E.
      • Passman M.A.
      • Witcher A.
      • Patterson M.A.
      • et al.
      Importance of postprocedural Wound, Ischemia, and foot Infection (WIfI) restaging in predicting limb salvage.
      presented the benefit of restaging the classification after revascularisation but only presented the outcomes of the individual determinants (i.e. wound, ischaemia, foot infection) and not the clinical stage. Furthermore, they only presented post-operative results of staging WIfI, which makes the interpretation of their results on the benefit of restaging, and therefore benefit of revascularisation difficult. This review has some limitations. The included studies comprised a diverging range of patients: hospitalised vs. outpatient treatment, patients requiring haemodialysis, invasively or conservatively treated patients, and diabetic or non-diabetic patients. For this reason, individual studies showed different results. For example, major amputation rates after one year in the study of Beropoulis et al.,
      • Beropoulis E.
      • Stavroulakis K.
      • Schwindt A.
      • Stachmann A.
      • Torsello G.
      • Bisdas T.
      Validation of the Wound, Ischemia, foot Infection (WIfI) classification system in nondiabetic patients treated by endovascular means for critical limb ischemia.
      who included non-diabetic patients treated by endovascular revascularisation, were not considerably different for clinical WIfI stages I and IV (0% and 12%, respectively). In contrast, in the study by Zhan et al.,
      • Zhan L.X.
      • Branco B.C.
      • Armstrong D.G.
      • Mills J.L.
      • Sr
      The Society for Vascular Surgery lower extremity threatened limb classification system based on Wound, Ischemia, and foot Infection (WIfI) correlates with risk of major amputation and time to wound healing.
      in which only hospitalised, mostly diabetic patients were included and a large proportion of patients were treated conservatively, one year amputation rates were 0% and 64%, respectively. This could partly explain the statistical heterogeneity in the meta-analyses for WIfI stage IV on Major amputation and stage II–IV on Limb salvage (Table 6).
      Second, after the WIfI classification was published in 2014, it has been evaluated in only one prospective study.
      • Ramanan B.
      • Ahmed A.
      • Wu B.
      • Causey M.W.
      • Gasper W.J.
      • Vartanian S.M.
      • et al.
      Determinants of midterm functional outcomes and wound healing in a hospital-based limb preservation program.
      The other studies were retrospective analyses of data from charts or electronic medical records, or from prospectively maintained databases in which the data were collected before the introduction of the WIfI classification. Hence, only patients with sufficient data to determine the WIfI classification were suitable to be included in these studies. However, we do not think this has skewed the findings.
      Furthermore, it is possible that, due to the inclusion criteria of the individual studies, only patients with either a good or a poor prognosis were included. This would yield results of outliers and not the average patient with CLTI. Also, it is conceivable that converting information from medical charts on wounds and infection to grade WIfI stages is imprecise, because the exact information islikely to be missing. This could result in information bias.
      Finally, although the concept of the classification is promising, it only takes into account the status of the affected limb and not the patients’ comorbidities or overall condition. These determinants are well known to influence the course and management of the affected limb.
      • Schanzer A.
      • Mega J.
      • Meadows J.
      • Samson R.H.
      • Bandyk D.F.
      • Conte M.S.
      Risk stratification in critical limb ischemia: derivation and validation of a model to predict amputation-free survival using multicenter surgical outcomes data.
      • Schanzer A.
      • Goodney P.P.
      • Li Y.
      • Eslami M.
      • Cronenwett J.
      • Messina L.
      • et al.
      Validation of the PIII CLI risk score for the prediction of amputation-free survival in patients undergoing infrainguinal autogenous vein bypass for critical limb ischemia.
      Also, the vascular anatomy can restrict possible revascularisation options.
      The WIfI classification is only part of the puzzle in the prognosis and decision on the treatment of patients with CLTI.
      • Mills J.L.
      • Sr
      The application of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification to stratify amputation risk.
      In daily practice, vascular surgeons determine the optimum treatment not solely on the clinical status of the leg but on a more comprehensive view of the patient. Unfortunately, the multivariable analyses by Darling et al.
      • Darling J.D.
      • McCallum J.C.
      • Soden P.A.
      • Guzman R.J.
      • Wyers M.C.
      • Hamdan A.D.
      • et al.
      Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations.
      and Cull et al.
      • Cull D.L.
      • Manos G.
      • Hartley M.C.
      • Taylor S.M.
      • Langan E.M.
      • Eidt J.F.
      • et al.
      An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.
      did not include determinants other than WIfI, which ignores the association of other predictive factors for AFS, mortality, and amputation. In the study by Robinson et al.
      • Robinson W.P.
      • Loretz L.
      • Hanesian C.
      • Flahive J.
      • Bostrom J.
      • Lunig N.
      • et al.
      Society for Vascular Surgery Wound, Ischemia, foot Infection (WIfI) score correlates with the intensity of multimodal limb treatment and patient-centered outcomes in patients with threatened limbs managed in a limb preservation center.
      revascularisation lowered the risk of amputation, whereas this risk increased with a higher WIfI stage. However, in four studies reporting on the WIfI classification in multivariable analyses on major amputation, the reference group was not presented (Table 4).
      At present the classification gives a global indication of the prognosis, the logical next step is to determine its value as an instrument to guide clinical decision making. Ideally, this is done in future multicentre studies registering the WIfI classification prospectively in all patients presenting with CLTI.

      Conclusion

      The likelihood of an amputation after one year in patients with CLTI increases with higher WIfI stages, which is important prognostic information. Prospective evaluations are needed to determine its role in clinical practice.

      Conflict of Interest

      None.

      Funding

      This work was supported by the Netherlands Organisation for Health Research and Development (ZonMw) grant no. 843004106 . ZonMw did not play any role in the conduct and writing of this research.

      Acknowledgements

      We would like to thank Faridi S. van Etten-Jamaludin, clinical librarian and medical information specialist, for her advice on the search strategies for this review.

      Appendix A. Supplementary data

      The following is the Supplementary data to this article:

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      Linked Article

      • WIfI: Highlighting Hotspots of Limb Loss?
        European Journal of Vascular and Endovascular SurgeryVol. 58Issue 3
        • Preview
          The past three decades have established that limb loss is a multifactorial process. Alongside this growing appreciation, tools have been developed to aid clinicians in stratifying patients into high and low risk groups. The Society for Vascular Surgery Wound, Ischaemia and foot Infection (WIfI) classification was born out of the recognition that existing classification systems had deficiencies in the description of at least one domain.1 For example the Rutherford classification provides a granular description of the effects of tissue ischaemia, but fails to account for the role of foot infection in limb loss.
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