WIfI classification: the Society for Vascular Surgery lower extremity threatened limb classification system, a literature review

Cerqueira, Lorena de Oliveira; Duarte Júnior, Eliud Garcia; Barros, André Luis de Souza; Cerqueira, José Roberto; Araújo, Walter Júnior Boim de

Lorena de Oliveira Cerqueira

Universidade Vila Velha – UVV, Cirurgia Vascular, Vila Velha, ES, Brasil.

https://orcid.org/0000-0003-2806-0577

Eliud Garcia Duarte Júnior

Universidade Vila Velha – UVV, Cirurgia Vascular, Vila Velha, ES, Brasil.

Centro de Atuação Precoce em Úlceras Vasculares e Complicações do Pé Diabético – PROPÉ, Departamento de Cirurgia Vascular, Vila Velha, ES, Brasil.

Hospital Estadual de Urgência e Emergência do Espírito Santo – HEUE, Departamento de Cirurgia Vascular, Vila Velha, ES, Brasil.

Hospital Santa Mônica de Vila Velha, Serviço de Cirurgia Vascular e Endovascular, Vila Velha, ES, Brasil.

https://orcid.org/0000-0003-1504-6303

André Luis de Souza Barros

Universidade Vila Velha – UVV, Cirurgia Vascular, Vila Velha, ES, Brasil.

Centro de Atuação Precoce em Úlceras Vasculares e Complicações do Pé Diabético – PROPÉ, Departamento de Cirurgia Vascular, Vila Velha, ES, Brasil.

https://orcid.org/0000-0002-2808-7326

José Roberto Cerqueira

Hospital Santa Mônica de Vila Velha, Serviço de Cirurgia Vascular e Endovascular, Vila Velha, ES, Brasil.

https://orcid.org/0000-0002-9074-020X

Walter Júnior Boim de Araújo

Universidade Federal do Paraná – UFPR, Hospital de Clínicas, Serviço de Angiorradiologia e Cirurgia Endovascular, Curitiba, PR, Brasil.

Hospital Angelina Caron, Departamento de Residência Médica em Cirurgia Vascular e Endovascular, Curitiba, PR, Brasil.

https://orcid.org/0000-0003-1537-0285

Conflicts of interest: No conflicts of interest declared concerning the publication of this article.

Correspondence Lorena de Oliveira Cerqueira Universidade Vila Velha – UVV, Cirurgia Vascular Rua Arthur Czartoryski, 132/204 - Jardim da Penha CEP 29060-370 - Vitória (ES), Brasil Tel.: +55 (33) 98861-5146 E-mail: lorena.o.cerqueira@outlook.com

Author information LOC - Physician graduated, Universidade Vila Velha (UVV); Intern, Serviço de Cirurgia Vascular e Endovascular, Hospital Santa Mônica and Centro de Atuação Precoce em Úlceras Vasculares e Complicações do Pé Diabético (PROPÉ). EGDJ - Vascular surgeon, Sociedade Brasileira de Angiologia e Cirurgia Vascular (SBACV); Coordinator, PROPÉ; Vascular surgeon, Hospital Estadual de Urgência e Emergência do Espírito Santo (HEUE); Vascular surgeon, Hospital Santa Mônica de Vila Velha; Preceptor, UVV. ALSB - Vascular surgeon, PROPÉ - Centro de Atuação Precoce em Úlceras Vasculares e complicações do Pé Diabético; Preceptor, Universidade de Vila Velha (UVV). JRC - Vascular surgeon, SBACV; Attending coordinator, Serviço de Cirurgia Vascular e Endovascular, Hospital Santa Mônica. WJBA - MSc and PhD on Surgery, UFPR; Board-certified in Vascular Surgery, Vascular Doppler Ultrasound, Angioradiology and Endovascular Surgery from (SBACV)/Colégio Brasileiro de Radiologia (CBR)/Associação Médica Brasileira (AMB); Board-certified in Interventional Radiology and Angioradiology from Sociedade Brasileira de Radiologia Intervencionista e Cirurgia Endovascular (Sobrice)/CBR/AMB; Full member, SBACV and Sobrice; Primary physician, Serviço de Angiorradiologia e Cirurgia Endovascular, Hospital de Clínicas, Universidade Federal do Paraná (UFPR); Preceptor of Residência Médica em Cirurgia Vascular e Endovascular, Hospital de Clínicas, UFPR and Hospital Angelina Caron; Coordinator, Serviço de Ecografia Vascular; Owner partner of Instituto da Circulação.

Author contributions: Conception and design: LOC, EGDJ Analysis and interpretation: LOC, EGDJ Data collection: LOC Writing the article: LOC Critical revision of the article: LOC, EGDJ, ALSB, JRC, WJBA Final approval of the article*: LOC, EGDJ, ALSB, JRC, WJBA Statistical analysis: N/A. Overall responsibility: LOC, EGDJ *All authors have read and approved of the final version of the article submitted to J Vasc Bras.

Tables (7)

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Table 1
Fontaine et al.¹⁰10 Fontaine R, Kim M, Kieny R. Surgical treatment of peripheral circulation disorders. Helv Chir Acta. 1954;21(5-6):499-533. PMid:14366554. and Rutherford et al.⁹9 Rutherford RB, Baker JD, Ernst C, et al. Recommended standards for reports dealing with lower extremity ischemia: Revised version. J Vasc Surg. 1997;26(3):517-38. http://dx.doi.org/10.1016/S0741-5214(97)70045-4. PMid:9308598.
http://dx.doi.org/10.1016/S0741-5214(97)... peripheral arterial disease classifications.

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Table 2
Wagner et al.¹¹11 Wagner FW Jr. The dysvascular foot: a system for diagnosis and treatment. Foot Ankle. 1981;2(2):64-122. http://dx.doi.org/10.1177/107110078100200202. PMid:7319435.
http://dx.doi.org/10.1177/10711007810020... classification of the diabetic foot.

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Table 3
The WIfI classification for threatened lower limbs: assessment of risk of amputation.¹1 Mills JL Sr, Conte MS, Armstrong DG, et al. The society for vascular surgery lower extremity threatened limb classification system: risk stratification based on Wound, Ischemia, and foot Infection (WIfI). J Vasc Surg. 2014;59(1):220-34.e2. http://dx.doi.org/10.1016/j.jvs.2013.08.003. PMid:24126108.
http://dx.doi.org/10.1016/j.jvs.2013.08....

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Table 4
Estimation of risk of amputation at 1 year, according to WIfI classification clinical stages, as proposed by expert panel.¹1 Mills JL Sr, Conte MS, Armstrong DG, et al. The society for vascular surgery lower extremity threatened limb classification system: risk stratification based on Wound, Ischemia, and foot Infection (WIfI). J Vasc Surg. 2014;59(1):220-34.e2. http://dx.doi.org/10.1016/j.jvs.2013.08.003. PMid:24126108.
http://dx.doi.org/10.1016/j.jvs.2013.08....

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Table 5
Estimate of need for/benefit of revascularization, according to the WIfI classification clinical stages, as proposed by expert panel. Infection must be controlled.¹1 Mills JL Sr, Conte MS, Armstrong DG, et al. The society for vascular surgery lower extremity threatened limb classification system: risk stratification based on Wound, Ischemia, and foot Infection (WIfI). J Vasc Surg. 2014;59(1):220-34.e2. http://dx.doi.org/10.1016/j.jvs.2013.08.003. PMid:24126108.
http://dx.doi.org/10.1016/j.jvs.2013.08....

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Table 6
Principal studies on which this article is based, published to test and validate the SVS WIfI classification, and their Conclusions.

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Table 7
Number of threatened limbs at each stage of the Wound, Ischemia, and foot Infection (WIfI) classification, with medians, weighted means, and 1-year amputation rates in parentheses.

Fontaine et al. ^¹⁰10 Fontaine R, Kim M, Kieny R. Surgical treatment of peripheral circulation disorders. Helv Chir Acta. 1954;21(5-6):499-533. PMid:14366554.		Rutherford et al. ^⁹9 Rutherford RB, Baker JD, Ernst C, et al. Recommended standards for reports dealing with lower extremity ischemia: Revised version. J Vasc Surg. 1997;26(3):517-38. http://dx.doi.org/10.1016/S0741-5214(97)70045-4. PMid:9308598. http://dx.doi.org/10.1016/S0741-5214(97)...
Stage	Clinical presentation	Grade	Category	Clinical presentation
I	Asymptomatic	0	0	Asymptomatic
IIa	Mild claudication	I	1	Mild claudication
IIb	Moderate to severe claudication	I	2	Moderate claudication
III	Ischemic pain at rest	I	3	Severe claudication
IV	Gangrene or ulceration	II	4	Ischemic pain at rest
		III	5	Minor tissue lesion
		III	6	Major tissue lesion

Grade	Characteristics
0	Foot at risk, without evident ulcer, with thick calluses, prominent metatarsian heads, clawed toes, or other bone deformities
1	Uninfected superficial ulcer
2	Deep ulcer, bone not involved
3	Deep ulcer with formation of abscess or bone involvement
4	Localized gangrene in part of the foot
5	Extensive gangrene of the complete foot

Component	Grade	Description
Wound (W)	0	No ulcer or gangrene (ischemic pain at rest)
	1	Small or superficial ulcer on leg or foot, without gangrene (SDA or SC)
	2	Deep ulcer with exposed bone, joint, or tendon ± gangrene limited to digits (MAD or standard TMA ± SC)
	3	Deep, extensive ulcer involving forefoot and/or midfoot ± calcaneal involvement ± extensive gangrene (CR of the foot or nontraditional TMA)
Ischemia (I)	0	ABI	SBP of the ankle	TP, TcPO₂
	1	≥ 0.80	> 100 mmHg	≥ 60 mmHg
	2	0.6-0.79	70-100 mmHg	40-59 mmHg
	3	0.4-0.59 ≤ 0.39	50-70 mmHg < 50 mmHg	30-39 mmHg < 30 mmHg
foot Infection (fI)	0	Uninfected
	1	Mild local infection, involving only the skin and subcutaneous tissue, erythema > 0.5 to ≤ 2 cm
	2	Moderate local infection, with erythema > 2 cm or involving deeper structures
	3	Severe local infection with signs of SIRS

	Ischemia 0				Ischemia 1				Ischemia 2				Ischemia 3
Wound 0	VL	VL	L	M	VL	L	M	H	L	L	M	H	L	M	M	H
Wound 1	VL	VL	L	M	VL	L	M	H	L	M	H	H	M	M	H	H
Wound 2	L	L	M	H	M	M	H	H	M	H	H	H	H	H	H	H
Wound 3	M	M	H	H	H	H	H	H	H	H	H	H	H	H	H	H
	fI 0	fI 1	fI 2	fI 3	fI 0	fI 1	fI 2	fI 3	fI 0	fI 1	fI 2	fI 3	fI 0	fI 1	fI 2	fI 3

	Ischemia 0				Ischemia 1				Ischemia 2				Ischemia 3
Wound 0	VL	VL	VL	VL	VL	L	L	M	L	L	M	M	M	H	H	H
Wound 1	VL	VL	VL	VL	L	M	M	M	M	H	H	H	H	H	H	H
Wound 2	VL	VL	VL	VL	M	M	H	H	H	H	H	H	H	H	H	H
Wound 3	VL	VL	VL	VL	M	M	M	H	H	H	H	H	H	H	H	H
	fI 0	fI 1	fI 2	fI 3	fI 0	fI 1	fI 2	fI 3	fI 0	fI 1	fI 2	fI 3	fI 0	fI 1	fI 2	fI 3

Study	Nº of threatened limbs	Conclusions and important topics
Cull et al.¹⁵15 Cull DL, Manos G, Hartley MC, et al. An early validation of the Society for Vascular Surgery Lower Extremity Threatened Limb Classification System. J Vasc Surg. 2014;60(6):1535-41. http://dx.doi.org/10.1016/j.jvs.2014.08.107. PMid:25282695. http://dx.doi.org/10.1016/j.jvs.2014.08....	151	- The higher the WIfI clinical stage, the greater the risk of amputation at 1 year and the worse the healing of wounds.
	151	- Diabetes was independently associated with a higher risk of amputation at 1 year.
Zhan et al.¹²12 Zhan LX, Branco BC, Armstrong DG, Mills JL 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. J Vasc Surg. 2015;61(4):939-44. http://dx.doi.org/10.1016/j.jvs.2014.11.045. PMid:25656592. http://dx.doi.org/10.1016/j.jvs.2014.11....	201	- As WIfI clinical stage increases, the risk of major amputation increases, 1-year AFS reduces, and time taken for healing is prolonged.
	201	- Revascularization reduced the time taken for wounds to heal in patients at stage 3.
Darling et al.¹⁶16 Darling JD, McCallum JC, Soden PA, 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. J Vasc Surg. 2016;64(3):616-22. http://dx.doi.org/10.1016/j.jvs.2016.03.417. PMid:27380993. http://dx.doi.org/10.1016/j.jvs.2016.03....	551	- The WIfI classification was able to predict risk of amputation at 1 year and rate of wound healing in patients with CLI who had already undergone below-the-knee endovascular treatment.
Causey et al.¹⁷17 Causey MW, Ahmed A, Wu B, et al. Society for Vascular Surgery limb stage and patient risk correlate with outcomes in an amputation prevention program. J Vasc Surg. 2016;63(6):1563-73.e2. http://dx.doi.org/10.1016/j.jvs.2016.01.011. PMid:27036309. http://dx.doi.org/10.1016/j.jvs.2016.01....	160	- This study recommends use of the WIfI classification and the Project of Ex-Vivo vein graft Engineering via Transfection III (PIII) as supplementary tools for management of CLTI.
	160	- The WIfI classification had a good correlation with length of hospital stay and with severe adverse limb events, such as amputation, over the medium term. - Rates of revascularization increase with WIfI stage. It was suggested that the classification is capable of predicting patient benefit from revascularization.
Beropoulis et al.¹⁸18 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. J Vasc Surg. 2016;64(1):95-103. http://dx.doi.org/10.1016/j.jvs.2016.01.040. PMid:26994958. http://dx.doi.org/10.1016/j.jvs.2016.01....	126	- Confirmed the prognostic value of the WIfI classification in relation to risk of amputation and death in non-diabetic patients treated with endovascular techniques.
Ward et al.¹⁹19 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. Ann Vasc Surg. 2017;38:84-9. http://dx.doi.org/10.1016/j.avsg.2016.08.005. PMid:27546850. http://dx.doi.org/10.1016/j.avsg.2016.08...	98	- Amputation rates increased as WIfI stage increased.
	98	- Revascularization significantly reduced the risk of amputation among patients at high risk of amputation at 1 year, classified by the WIfI.
Darling et al.¹⁴14 Darling JD, McCallum JC, Soden PA, et al. Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations. J Vasc Surg. 2017;65(3):695-704. http://dx.doi.org/10.1016/j.jvs.2016.09.055. PMid:28073665. http://dx.doi.org/10.1016/j.jvs.2016.09....	992	- The study proposed two new scores to be used to complement or substitute the WIfI classification, the composite WIfI score and the mean WIfI score, because they were better predictors of the outcomes studied (mortality, risk of amputation, and RAS events), easier to administrate, and better for comparing results between patients.
		- The WIfI classification was a good predictor of major amputations and RAS events, but not of mortality. Only the new scores were consistent predictors of mortality in this study.
		- Patients revascularized for CLTI for the first time were at greater risk of a major amputation in the future, the higher their classification on any of the three scores used in the study.
Robinson et al.²⁰20 Robinson WP, Loretz L, Hanesian C, 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. J Vasc Surg. 2017;66(2):488-98.e2. http://dx.doi.org/10.1016/j.jvs.2017.01.063. PMid:28410924. http://dx.doi.org/10.1016/j.jvs.2017.01....	262	- Increases in WIfI stage were correlated with reductions in- AFS, but not with 1-year mortality.
Mathioudakis et al.²¹21 Mathioudakis N, Hicks CW, Canner JK, et al. 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. J Vasc Surg. 2017;65(6):1698-705.e. http://dx.doi.org/10.1016/j.jvs.2016.12.123. PMid:28274750. http://dx.doi.org/10.1016/j.jvs.2016.12....	279	-According to the study, “Among patients with DFU, the WIfI classification system correlated well with wound healing but was not associated with risk of major amputation at 1 year”.
	279	- Argues that a multidisciplinary approach to DFUs could help to reduction risk of amputation in patients at stage4.
Hicks et al.²²22 Hicks CW, Canner JK, Mathioudakis N, et al. The Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification independently predicts wound healing in diabetic foot ulcers. J Vasc Surg. 2018;68(4):1096-103. http://dx.doi.org/10.1016/j.jvs.2017.12.079. PMid:29622357. http://dx.doi.org/10.1016/j.jvs.2017.12....		-The WIfI classification was capable of predicting healing of wounds at 1 year in patients with DFU. Mean healing time increased as WIfI stage increased.
Van Haelst et al.²³23 Van Haelst ST, Teraa M, Moll FL, Borst GJ, Verhaar MC, Conte MS. Prognostic value of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification in patients with no-option chronic limb-threatening ischemia. J Vasc Surg. 2018;68(4):1104-13.e1. http://dx.doi.org/10.1016/j.jvs.2018.02.028. PMid:29802042. http://dx.doi.org/10.1016/j.jvs.2018.02....	150	-In a subpopulation with CLTI, without revascularization options, the SVS WIfI classification correlated well with mortality, minor and major amputation, AFS, and wound healing.
	150	- The study suggested that stage 2 patients (WIfI 030) should be reallocated to stage 3 to better reflect the risk of amputation when revascularization is not an option.

Study: nº of threatened limbs	Stage 1	Stage 2	Stage 3	Stage 4
Cull et al.:¹⁵15 Cull DL, Manos G, Hartley MC, et al. An early validation of the Society for Vascular Surgery Lower Extremity Threatened Limb Classification System. J Vasc Surg. 2014;60(6):1535-41. http://dx.doi.org/10.1016/j.jvs.2014.08.107. PMid:25282695. http://dx.doi.org/10.1016/j.jvs.2014.08.... 151	37 (3%)	63 (10%)	43 (23%)	8 (40%)
Zhan et al.:¹²12 Zhan LX, Branco BC, Armstrong DG, Mills JL 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. J Vasc Surg. 2015;61(4):939-44. http://dx.doi.org/10.1016/j.jvs.2014.11.045. PMid:25656592. http://dx.doi.org/10.1016/j.jvs.2014.11.... 201	39 (0%)	50 (0%)	53 (8%)	59 (64%)
Darling et al.:¹⁶16 Darling JD, McCallum JC, Soden PA, 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. J Vasc Surg. 2016;64(3):616-22. http://dx.doi.org/10.1016/j.jvs.2016.03.417. PMid:27380993. http://dx.doi.org/10.1016/j.jvs.2016.03.... 551	5 (0%)	111 (10%)	222 (11%)	213 (24%)
Causey et al.:¹⁷17 Causey MW, Ahmed A, Wu B, et al. Society for Vascular Surgery limb stage and patient risk correlate with outcomes in an amputation prevention program. J Vasc Surg. 2016;63(6):1563-73.e2. http://dx.doi.org/10.1016/j.jvs.2016.01.011. PMid:27036309. http://dx.doi.org/10.1016/j.jvs.2016.01.... 160	21 (0%)	48 (8%)	42 (5%)	49 (20%)
Beropoulis et al.:¹⁸18 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. J Vasc Surg. 2016;64(1):95-103. http://dx.doi.org/10.1016/j.jvs.2016.01.040. PMid:26994958. http://dx.doi.org/10.1016/j.jvs.2016.01.... 126	29 (0%)	42 (2%)	29 (3%)	26 (12%)
Ward et al.:¹⁹19 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. Ann Vasc Surg. 2017;38:84-9. http://dx.doi.org/10.1016/j.avsg.2016.08.005. PMid:27546850. http://dx.doi.org/10.1016/j.avsg.2016.08... 98	5 (0%)	21 (14%)	14 (21%)	58 (34%)
Darling et al.:¹⁴14 Darling JD, McCallum JC, Soden PA, et al. Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations. J Vasc Surg. 2017;65(3):695-704. http://dx.doi.org/10.1016/j.jvs.2016.09.055. PMid:28073665. http://dx.doi.org/10.1016/j.jvs.2016.09.... 992	12 (0%)	293 (4%)	249 (4%)	438 (21%)
Robinson et al.:²⁰20 Robinson WP, Loretz L, Hanesian C, 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. J Vasc Surg. 2017;66(2):488-98.e2. http://dx.doi.org/10.1016/j.jvs.2017.01.063. PMid:28410924. http://dx.doi.org/10.1016/j.jvs.2017.01.... 262	48 (4%)	67 (16%)	64 (10%)	83 (22%)
Mathioudakis et al.:²¹21 Mathioudakis N, Hicks CW, Canner JK, et al. 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. J Vasc Surg. 2017;65(6):1698-705.e. http://dx.doi.org/10.1016/j.jvs.2016.12.123. PMid:28274750. http://dx.doi.org/10.1016/j.jvs.2016.12.... 279	95 (6.5%)	33 (6%)	87 (8%)	64(6%)
Van Haelst et al.:²³23 Van Haelst ST, Teraa M, Moll FL, Borst GJ, Verhaar MC, Conte MS. Prognostic value of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification in patients with no-option chronic limb-threatening ischemia. J Vasc Surg. 2018;68(4):1104-13.e1. http://dx.doi.org/10.1016/j.jvs.2018.02.028. PMid:29802042. http://dx.doi.org/10.1016/j.jvs.2018.02.... 150	15 (0%)	50 (16%)	32 (13%)	53 (42%)
N = 2,970 (weighted mean)	306 (3%)	778 (7.32%)	835 (8.61%)	1,051 (25%)
Median (1-year amputation rate, %)	0%	9%	9%	23%

[1] Conflicts of interest: No conflicts of interest declared concerning the publication of this article.

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WIfI classification: the Society for Vascular Surgery lower extremity threatened limb classification system, a literature review

Abstract