Society for Vascular Surgery limb stage and patient risk correlate with outcomes in an amputation prevention program

A Review of WIfI Clinical Staging to Predict Outcomes in Patients With Threatened Limbs

The Society for Vascular Surgery Wound, Ischemia, and foot Infection's (WIfI's) threatened limb classification system serves to comprehensively assess the severity of disease in patients with chronic limb-threatening ischemia by identifying and grading the main factors that place the threatened limb at greatest risk: wound severity, ischemic burden, and presence of infection. Each of these 3 factors is graded and the limb placed into a clinical stage, with increasing stage associated with severity of limb threat and predicted risk of major limb amputation at 1 year. Globally, there is a growing body of evidence reported from multiple institutions that has assessed amputation rates and wound-healing outcomes following revascularization in patients with WIfI clinical staging. Risk of major amputation at 1 year is low in clinical stage 1, moderate in stages 2 and 3, and high in stage 4. Higher clinical stages are associated with prolonged time to wound healing, while 1-year wound healing rates consistently decrease with increasing clinical stage. Additional avenues of investigation utilizing WIfI as an objective clinical staging tool have yielded new insights into which patients benefit from revascularization, complexity of care, hospital length of stay, quality of life, ethnic and socioeconomic disparities, as well as spurred interest in other modalities of assessing limb perfusion and their possible clinical utility. Ongoing study and refinement of WIfI grading and clinical staging will continue to improve its prognostic utility.

Association between tissue loss type and amputation risk among Medicare patients with concomitant diabetes and peripheral arterial disease

OBJECTIVE

Prior studies have described risk factors associated with amputation in patients with concomitant diabetes and peripheral arterial disease (DM/PAD). However, the association between the severity and extent of tissue loss type and amputation risk remains less well-described. We aimed to quantify the role of different tissue loss types in amputation risk among patients with DM/PAD, in the context of demographic, preventive, and socioeconomic factors.

METHODS

Applying International Classification of Diseases (ICD)-9 and ICD-10 codes to Medicare claims data (2007-2019), we identified all patients with continuous fee-for-service Medicare coverage diagnosed with DM/PAD. Eight tissue loss categories were established using ICD-9 and ICD-10 diagnosis codes, ranging from lymphadenitis (least severe) to gangrene (most severe). We created a Cox proportional hazards model to quantify associations between tissue loss type and 1- and 5-year amputation risk, adjusting for age, race/ethnicity, sex, rurality, income, comorbidities, and preventive factors. Regional variation in DM/PAD rates and risk-adjusted amputation rates was examined at the hospital referral region level.

RESULTS

We identified 12,257,174 patients with DM/PAD (48% male, 76% White, 10% prior myocardial infarction, 30% chronic kidney disease). Although 2.2 million patients (18%) had some form of tissue loss, 10.0 million patients (82%) did not. The 1-year crude amputation rate (major and minor) was 6.4% in patients with tissue loss, and 0.4% in patients without tissue loss. Among patients with tissue loss, the 1-year any amputation rate varied from 0.89% for patients with lymphadenitis to 26% for patients with gangrene. The 1-year amputation risk varied from two-fold for patients with lymphadenitis (adjusted hazard ratio, 1.96; 95% confidence interval, 1.43-2.69) to 29-fold for patients with gangrene (adjusted hazard ratio, 28.7; 95% confidence interval, 28.1-29.3), compared with patients without tissue loss. No other demographic variable including age, sex, race, or region incurred a hazard ratio for 1- or 5-year amputation risk higher than the least severe tissue loss category. Results were similar across minor and major amputation, and 1- and 5-year amputation outcomes. At a regional level, higher DM/PAD rates were inversely correlated with risk-adjusted 5-year amputation rates (R2 = 0.43).

CONCLUSIONS

Among 12 million patients with DM/PAD, the most significant predictor of amputation was the presence and extent of tissue loss, with an association greater in effect size than any other factor studied. Tissue loss could be used in awareness campaigns as a simple marker of high-risk patients. Patients with any type of tissue loss require expedited wound care, revascularization as appropriate, and infection management to avoid amputation. Establishing systems of care to provide these interventions in regions with high amputation rates may prove beneficial for these populations.

Relevance of BEST-CLI trial endpoints in a tertiary care limb preservation program

OBJECTIVE

Major adverse limb event-free survival (MALE-FS) differed significantly by initial revascularization approach in the BEST-CLI randomized trial. The BEST-CLI trial represented a highly selected subgroup of patients seen in clinical practice; thus, we examined the endpoint of MALE-FS in an all-comers tertiary care practice setting.

METHODS

This is a single-center retrospective study of consecutive, unique patients who underwent technically successful infrainguinal revascularization for chronic limb-threatening ischemia (2011-2021). MALE was major amputation (transtibial or above) or major reintervention (new bypass, open bypass revision, thrombectomy, or thrombolysis).

RESULTS

Among 469 subjects, the mean age was 70 years, and 34% were female. Characteristics included diabetes (68%), end-stage renal disease (ESRD) (16%), Wound, Ischemia, and foot Infection (WIfI) stage 4 (44%), Global Limb Anatomic Staging System (GLASS) stage 3 (62%), and high pedal artery calcium score (pMAC) (22%). Index revascularization was autogenous vein bypass (AVB) (30%), non-autogenous bypass (NAB) (13%), or endovascular (ENDO) (57%). The composite endpoint of MALE or death occurred in 237 patients (51%) at a median time of 189 days from index revascularization. In an adjusted Cox model, factors independently associated with MALE or death included younger age, ESRD, WIfI stage 4, higher GLASS stage, and moderate-severe pMAC, whereas AVB was associated with improved MALE-FS. Freedom from MALE-FS, MALE, and major amputation at 30 days were 90%, 92%, and 95%; and at 1 year were 63%, 70%, and 83%, respectively. MALE occurred in 144 patients (31%) and was associated with ESRD, WIfI stage, GLASS stage, pMAC score, and index revascularization approach. AVB had superior durability, with adjusted 2-year freedom from MALE of 72%, compared with 66% for ENDO and 51% for NAB. Within the AVB group, spliced vein conduit had higher MALE compared with single-segment vein (hazard ratio, 1.8; 95% confidence interval, 0.9-3.7; P = .008 after inverse propensity weighting), but there was no statistically significant difference in major amputation. Of the 144 patients with any MALE, the first MALE was major reintervention in 47% and major amputation in 53%. Major amputation as first MALE was associated with non-AVB index approach. Indications for major reintervention were symptomatic stenosis/occlusion (54%), lack of clinical improvement (28%), asymptomatic graft stenosis (16%), and iatrogenic events (3%). Conversion to bypass occurred after 6% of ENDO cases, two-thirds of which involved distal bypass targets at the ankle or foot.

CONCLUSIONS

In this consecutive, all-comers cohort, disease complexity was associated with procedural selection and MALE-FS. AVB independently provided the greatest MALE-FS and freedom from MALE and major amputation. Compared with the BEST-CLI randomized trial, MALE after ENDO in this series was more frequently major amputation, with relatively few conversions to open bypass.

The natural history of isolated common femoral endarterectomy for chronic limb-threatening ischemia

OBJECTIVE

Occlusive disease of the common femoral artery can generate profound lower extremity ischemia as the normal collateral pathways from the profunda to the superficial femoral artery cannot adequately develop. In patients with lifestyle-limiting claudication, isolated common femoral endarterectomy (CFE) is highly effective. Because CFE does not provide direct, in-line flow to the plantar arch, it has been felt to provide inadequate revascularization to patients with chronic limb-threatening ischemia (CLTI). The purpose of this retrospective clinical study was to report and assess the natural history of selected patients with CLTI treated with isolated CFE (without concomitant infrainguinal revascularization).

METHODS

Consecutive CFEs performed in a large, urban hospital for CLTI between 2014 and 2021 were reviewed. Patient characteristics, limb, and anatomical stages using the Wound, Ischemia, foot Infection (WIfI) and Global Limb Anatomic Staging System were tabulated. Limb-specific and survival-related end points were analyzed.

RESULTS

Fifty-eight patients presenting with CLTI underwent isolated CFE (mean age, 74 ± 10 years; 62% male, 90% current or prior smoker). Comorbidities included diabetes (52%), coronary artery disease (55%), congestive heart failure (22%), and end-stage renal failure on hemodialysis (5%). Patients presented with either rest pain (36%) or tissue loss (64%); the latter group exhibited advanced limb threat (68% in WIfI stage 3 or 4). The majority of patients had associated severe infrainguinal disease (50% Global Limb Anatomic Staging Systems 3). After a median follow-up of 17 months (range, 10-29 months), vascular reintervention was required in 7 patients (12%). One patient (2%) required major limb amputation after presentation in WIfI stage 4 (W3I3fI0). Indeed, WIfI stage 4 was a significant univariate predictor of the need for subsequent infrainguinal bypass (P = .034).

CONCLUSIONS

Isolated CFE as primary therapy in highly selected patients with CLTI was safe and effective. Index limb stage is predictive of the need for associated infrainguinal revascularization in this complex population.

Investigator attitudes on equipoise and practice patterns in the BEST-CLI trial

OBJECTIVES

There has been significant variability in practice patterns and equipoise regarding treatment approach for chronic limb-threatening ischemia (CLTI). We aimed to assess treatment preferences of Best Endovascular vs Best Surgical Therapy in Patients with CLTI (BEST-CLI) investigators prior to and following the trial.

METHODS

An electronic 60-question survey was sent to 1180 BEST-CLI investigators in 2022, after trial conclusion and before announcement of results. Investigators' preferences were assessed across clinical scenarios for both open (OPEN) and endovascular (ENDO) revascularization strategies. Vascular surgeon (VS) surgical and ENDO preferences were compared with a 2010 survey administered to prospective investigators before trial funding.

RESULTS

For the 2022 survey, the response rate was 20.2% and was comprised of VSs (76.3%), interventional cardiologists (11.4%) and interventional radiologists (11.6%). The majority (72.6%) were in academic practice and 39.1% were in practice for >20 years. During initial CLTI work-up, 65.8%, 42.6%, and 55.9% of respondents always or usually ordered an arterial duplex, computed tomography angiography, and vein mapping, respectively. The most common practice distribution between ENDO and OPEN procedures was 70/30. Postoperatively, a majority reported performing routine duplex surveillance of vein bypass (99%), prosthetic bypass (81.9%), and ENDO interventions (86%). A minority reported always or usually using the wound, ischemia, and foot infection (WIfI) criteria (25.8%), GLASS (8.3%), and a risk calculator (14.8%). More than one-half (52.9%) agreed that the statement "no bridges are burned with an ENDO-first approach" was false. Intervention choice was influenced by availability of the operating room or ENDO suite, personal schedule, and personal skill set in 30.1%, 18.0%, and 45.9% of respondents, respectively. Most respondents reported routinely using paclitaxel-coated balloons (88.1%) and stents (67.5%); however, 73.3% altered practice when safety concerns were raised. Among surgeons, 17.8%, 2.9%, and 10.3% reported performing >10 annual alternative autogenous vein bypasses, composite vein composite vein bypasses, and bypasses to pedal targets, respectively. Among all interventionalists, 8%, 24%, and 8% reported performing >10 annual radial access procedures, pedal or tibial access procedures, and pedal loop revascularizations. The majority (89.1%) of respondents felt that CLTI teams improved care; however, only 23.2% had a defined team. The effectiveness of the teamwork at institutions was characterized as highly effective in 42.5%. When comparing responses by VSs to the 2010 survey, there were no changes in preferred treatment based on Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC) II classification or conduit preference. In 2022, OPEN surgery was preferred more for a popliteal occlusion. For clinical scenarios, there were no differences except a decreased proportion of respondents who felt there was equipoise for major tissue loss for major tissue loss (43.8% vs 31.2%) and increased ENDO choice for minor tissue loss (17.6% vs 30.8%) (P < .05).

CONCLUSIONS

There is a wide range of practice patterns among vascular specialists treating CLTI. The majority of investigators in BEST-CLI had experience in both advanced OPEN and ENDO techniques and represent a real-world sample of technical expertise. Over the course of the decade of the BEST-CLI trial, there was overall similar equipoise among VSs.

The value of Wound, Ischemia and foot Infection classification in patients undergoing endovascular therapy

OBJECTIVE

This study aimed to evaluate the correlation between the Society for Vascular Surgery (SVS) Wound, Ischemia and foot infection (WIfI) classification system and clinical outcomes for 1-year limb amputation-free survival (AFS), freedom from reintervention, and wound healing rate in a cohort of patients affected by chronic limb-threatening ischemia treated exclusively by endovascular procedures.

METHODS

We analyzed a prospective, consecutive cohort of 203 patients (203 limbs) who underwent infrainguinal endovascular revascularization at a single center between March 2018 and January 2021. These patients were stratified into clinical stages 1 to 4 based on the SVS WIfI classification and categorized into two groups: WIfI 1 to 3 (n = 101 limbs) and WIfI 4 (n = 102 limbs). The SVS objective performance goals of 1-year limb AFS, freedom from reintervention, and wound healing were compared between the groups and assessed using the Kaplan-Meier method. Angiographic lesion characteristics and angioplasty details were compared.

RESULTS

The average age was 72.4 years (44.3% male, 85.2% had hypertension, 80.3% had diabetes, and 87.7% had tissue loss). There were statistical differences between the groups in 1-year limb AFS Kaplan-Meier rate between WIfI clinical stages 1 to 3 group and WIfI clinical stage 4 group (82% vs 66%, respectively; P < .001), but there was no statistical difference in freedom from reintervention and wound healing rates between the groups (70% vs 64% [P = .62] and 74% vs 79% [P = .90], respectively). Owing to angiographic lesion characteristics, femoropopliteal and infrapopliteal segment distributions were similar between the groups, but there was a statistical difference in target lesion location to tibial vessels (55.4% vs 71.6%, respectively; P = .025).

CONCLUSIONS

In this cohort of patients with chronic limb-threatening ischemia, SVS WIfI clinical stage 4 had worse results in the 1-year limb AFS rate, but there was no statistical difference in freedom from reintervention and wound healing rates between the groups.

A framework for perioperative care for lower extremity vascular bypasses: A Consensus Statement by the Enhanced Recovery after Surgery (ERAS®) Society and Society for Vascular Surgery

The Society for Vascular Surgery and the Enhanced Recovery After Surgery (ERAS) Society formally collaborated and elected an international, multi-disciplinary panel of experts to review the literature and provide evidence-based suggestions for coordinated perioperative care for patients undergoing infrainguinal bypass surgery for peripheral artery disease. Structured around the ERAS core elements, 26 suggestions were made and organized into preadmission, preoperative, intraoperative, and postoperative sections.

Treatment Outcomes between Bypass Surgery and Endovascular Therapy in Patients with Chronic Limb-Threatening Ischemia classified as Bypass-preferred category based on Global Vascular Guidelines

OBJECTIVE

To examine outcomes between bypass surgery and endovascular therapy (EVT) in patients with chronic limb-threatening ischemia (CLTI), classified as bypass-preferred according to the Global Vascular Guidelines (GVG).

METHODS

We retrospectively analyzed the multi-center data of patients who underwent infrainguinal revascularization for CLTI with Wound, Ischemia, and foot Infection (WIfI) Stage 3-4 and Global Limb Anatomical Staging System (GLASS) Stage III, which is classified as bypass-preferred category by the GVG between 2015 and 2020. The endpoints were limb salvage and wound healing.

RESULTS

We analyzed 301 patients and 339 limbs following 156 bypass surgery and 183 EVT. The 2-year limb salvage rates were 92.2% in the bypass surgery group and 76.3% in the EVT group, respectively (P < .01). The 1-year wound healing rates were 86.7% in the bypass surgery group and 67.8% in the EVT group (P < .01). Multivariate analysis shows decreased serum albumin level (P < .01), increased wound grade (P = .04), and EVT (P < .01) were risk factors for major amputation. Decreased serum albumin level (P < .01), increased wound grade (P < .01), GLASS infrapopliteal grade (P = .02), and inframalleolar (IM) P grade (P = .01), and EVT (P < .01) were risk factors for impaired wound healing. Subgroup analysis of limb salvage in patients after EVT, decreased serum albumin level (P < .01), increased wound grade (P = .03), increased IM P grade (P = .04), congestive heart failure (P < .01) were risk factors for major amputation. According to scoring by existence of these risk factors, 2-year limb salvage rates following EVT were 83.0% and 42.8% for the total score of 0-2 and of 3-4, respectively (P < .01).

CONCLUSIONS

Bypass surgery provides better limb salvage and wound healing in patients with WIfI Stage 3-4 and GLASS Stage III, which is classified as bypass-preferred category by the GVG. In patients after EVT, serum albumin level, wound grade, IM P grade, and congestive heart failure were related to major amputation. Although bypass surgery may be considered as initial revascularization procedure in patients classified as bypass-preferred category, in case that EVT has to be selected, relatively acceptable outcomes can be expected in patients with less these risk factors.

Presenting limb severity is associated with long-term outcomes after infrainguinal revascularization for chronic limb-threatening ischemia

OBJECTIVE

The SVS Wound, Ischemia, foot Infection (WIfI) limb staging system was established to estimate risk of major amputation in chronic limb-threatening ischemia (CLTI) and better stratify outcomes comparisons. There is little data on treatment outcomes beyond 1 year based on presenting WIfI stage.

METHODS

This is a single-institution retrospective study of 413 patients who underwent infrainguinal revascularization for CLTI (2011-2021) with data available for WIfI staging. Patient characteristics and outcomes were gathered from the electronic medical record. Data were analyzed based on presenting WIfI stage and initial treatment received at our center.

RESULTS

Presenting WIfI stages were 1 to 2 (23%), 3 (27%), and 4 (50%). Index revascularization approach was endoluminal (59%), autogenous vein bypass (29%), or non-autogenous bypass (13%). Operative mortality within 30 days was 2.9% and was not associated with WIfI stage or revascularization approach. Median limb follow-up time was 502 days (interquartile range [IQR], 112-1256 days), and median survival follow-up time was 932 days (IQR, 343-1770 days). Major amputation or death occurred in 19% and 46% of patients at median times of 119 days (IQR, 28-314 days) and 739 days (IQR, 204-1475 days), respectively. WIfI stage was independently associated with major amputation (P = .001), as was initial revascularization approach (P = .01). In a Cox proportional hazards model, factors independently associated with major amputation were male sex (hazard ratio [HR], 1.4; 95% confidence interval [CI], 1.04-2.0; P = .03), diabetes (HR, 1.8; 95% CI, 1.3-2.5; P = .001), WIfI stage 4 (HR, 2.3; 95% CI, 1.5-3.5; P < .001), and non-autogenous bypass (HR, 2.9; 95% CI, 2.1-4.2; P < .001). In a Cox proportional hazards model for mortality, independently associated factors were age (HR, 1.04; 95% CI, 1.02-1.05; P < .001), end-stage renal disease (HR, 2.8; 95% CI, 1.9-4.0; P < .001), congestive heart failure (HR, 1.9; 95% CI, 1.4-2.5; P < .001), chronic obstructive pulmonary disease (HR, 1.5; 95% CI, 1.1-2.1; P = .02), and WIfI stage 4 (HR, 1.6; 95% CI, 1.04-2.2; P = .03). Among those presenting with WIfI stage 4 limbs, Kaplan-Meier estimated rates of freedom from major amputation or death at 2 years were 71% ± 3.7% and 68% ± 3.5%, respectively. In an inverse propensity weighted Cox proportional hazards model, non-white race (HR, 1.5; 95% CI, 1.01-2.2; P = .047), diabetes (HR, 2.0; 95% CI, 1.2-3.3; P = .008), Global Anatomic Staging System infrapopliteal grade (HR, 1.2; 95% CI, 1.05-1.3; P = .005), non-autogenous bypass (HR, 3.2; 95% CI, 1.9-5.3; P < .001), and endoluminal revascularization (HR, 2.6; 95% CI, 1.6-4.3; P < .001) were independently associated with major amputation in the WIfI stage 4 subgroup.

CONCLUSIONS

Presenting WIfI stage is strongly associated with long-term risks of major amputation and death following infrainguinal revascularization for CLTI and should be used to stratify outcomes comparisons. Effective revascularization is critical in WIfI stage 4 disease, and autogenous vein bypass provides durable long-term limb preservation.

Outcomes of Partial Calcanectomy in an Academic Limb Salvage Center: A Multicenter Review

Chronic nonhealing heel ulcerations have been established as an independent risk factor for major amputation, with poor rates of limb salvage success. Partial calcanectomy is a controversial limb salvage procedure reserved for patients with these heel ulcerations. We conducted a retrospective cohort study reviewing 39 limbs that underwent a partial calcanectomy from 2012 to 2018 to evaluate the proportion of patients healed, time to healing, ulcer recurrence, and postoperative functional level compared to the preoperative state. In addition, age, gender, body mass index, smoking status, coronary artery disease, diabetes mellitus, renal insufficiency, dialysis, peripheral arterial disease, method of closure, and percent of calcaneus resected were evaluated. Mean follow-up for our cohort was 2.3 years. We had a 1 year mortality rate of 11%, and a major amputation rate of 18%. Our results demonstrated a 77% healing rate with a median time to healing of 162 days. We found that patients who were closed primarily had a faster time to healing compared to patients who underwent closure by secondary intention. Our data showed that ulcer recurrence developed in 57% of healed limbs. We found that 76% of our patients were ambulatory postoperatively. These results suggest that partial calcanectomy is a viable limb salvage procedure with a predictable level of ambulation and function in a high-risk patient population.

A Prospective Analysis of the SVS WIfI Classification System to Stratify Immediate and 1-Year Patient Outcomes

The purpose of this study was to prospectively enroll patients that presented to the emergency department with a lower extremity infection, stratify risk and record outcomes. Risk stratification was performed based on the Society of Vascular Surgery Wound, foot Infection, and Ischemia (WIfI) classification system. This study aimed to establish the efficacy and validity of this classification in predicting patient outcomes during immediate hospitalization and throughout a 1 year follow up. A total of 152 patients were enrolled in the study and of these, 116 met the inclusion criteria and had at least 1 year of follow up for analysis. Each patient was assigned a WIfI score based on wound, ischemia, and foot infection severity according to the classification guidelines. Patient demographics as well as all podiatric and vascular procedures were recorded. The major end points of the study were rates of proximal amputation, time to wound healing, surgical procedures, surgical dehiscence, readmission rates, and mortality. A difference in rates of healing (p = .04), surgical dehiscence (p < .01), and 1 year mortality (p = .01) with increasing WIfI stage as well as across the individual component scores was noted. This analysis further supports the application of the WIfI classification system early during patient care to stratify risk and identify the need for early intervention and a multispecialty team approach to potentially improve outcomes in the severe multicomorbid patient.

Microbiology of Diabetic Foot Infections in a Tertiary Care Hospital in São Paulo, Brazil

Diabetic foot infections (DFIs) are one of the causes of hospitalization in diabetic patients and, when this occurs, empirical antibiotic therapy is necessary. We have conducted a retrospective study of patients with DFI that required hospitalization to evaluate microbiologic profile and the susceptibility pattern of these infections. We evaluated 320 patients, of which 223 (69.7%) were male with a media age of 71 years with 276 isolates. Gram-positive bacteria were responsible for 188 (68.1%) of the isolates, while Gram-negative bacilli were responsible for 88 (31.9%). E. faecalis was the most prevalent pathogen, followed by S. aureus and coagulase negative Staphylococci. Among Gram-negative pathogens, P. aeruginosa was the most prevalent agent. Regarding the susceptibility profile, we found ampicillin-sensitive enterococci in 89% of the cases, oxacillin-sensitive S. aureus in 47%, but in coagulase-negative staphylococci, oxacillin was sensible only in 20%. The susceptibility profile of Gram-negatives was very good with 76% susceptibility of P. aeruginosa to ceftazidime and meropenem. The other prevalent Enterobacterales had great susceptibility to ceftazidime, piperacillin-tazobactam and 100% susceptibility to meropenem, with the exception of K. pneumoniae, which had 75% susceptibility to meropenem. Knowledge of microbiological profile and susceptibility patterns of patients with DFIs is useful to guide empirical therapy.

Pedal arterial calcification score is associated with hemodynamic change and major amputation after infrainguinal revascularization for chronic limb-threatening ischemia

OBJECTIVE

Pedal medial arterial calcification (pMAC) is associated with major amputation in patients with CLTI. We hypothesize this association is related to unresolved distal ischemia. We investigated relationships across pMAC score, hemodynamic change, and major amputation following infrainguinal revascularization for CLTI.

METHODS

This is a single-institution retrospective study of 306 patients who underwent technically successful infrainguinal revascularization for CLTI (2011-2020) and had foot x-rays for blinded pMAC scoring (0-5). 136 (44%) had toe pressure measurements performed within 90 days before and 60 days after revascularization. Ischemia grade (0-3) was assigned using the SVS WIfI system.

RESULTS

Revascularization approach was open bypass in 118 (38%) and endovascular in 188 (62%) patients. pMAC scores were trichotomized [0-1 (125; 41%), 2-4 (116; 38%), 5 (65; 21%)]. Post-revascularization WIfI ischemia grade was improved in 78/136 (57%) and unchanged/worsened in 58/136 (43%). Lower pMAC score was associated with hemodynamic improvement (p=0.004). Failure to improve the ischemia grade was associated with major amputation (p=0.0002) In the endovascular subgroup, WIfI ischemia grade was improved in 43/90 (48%) with available measurements, and 37/188 (20%) underwent major amputation. In a multivariate logistic model, pMAC 5 was the only factor independently associated with unimproved ischemia grade after endovascular treatment [OR 4.0 (1.1-16.6), p=0.04]. In a Cox proportional hazards model, factors independently associated with major amputation after endoluminal revascularization were WIfI stage 4 [HR 2.7 (1.3-5.7), p=0.007] and pMAC score [pMAC 2-4: HR 10.6 (1.4-80.7), p=0.02; pMAC 5: HR 15.5 (2.0-119), p=0.008]. In the bypass subgroup, WIfI ischemia grade was improved in 35/46 (76%) with available measurements but was not associated with pMAC score (p=0.88) or any other baseline patient or limb characteristics. 19/118 (16%) underwent major amputation. In a Cox proportional hazards model including bypass conduit, WIfI stage, and pMAC score; the only factor independently associated with major amputation after bypass was use of non-autologous conduit [HR 5.6 (1.8-17.6), p=0.003].

CONCLUSION

The pMAC score is independently associated with persistent distal ischemia and major amputation after technically successful revascularization for CLTI. These data suggest that pMAC may be a marker for hemodynamic response to revascularization and risk of limb loss, and it may have a stronger influence on the outcome of endoluminal interventions.

Limb-based patency as a measure of effective revascularization for chronic limb-threatening ischemia

OBJECTIVE

In 2019, the Global Vascular Guidelines on chronic limb-threatening ischemia (CLTI) introduced the concept of limb-based patency (LBP) defined as maintained patency of a target artery pathway (TAP) following intervention. The purpose of this study was to investigate the relationship between LBP and major adverse limb events following infrainguinal revascularization for CLTI.

METHODS

Consecutive patients undergoing revascularization for CLTI between 2016 and 2019 at a single tertiary institution with a dedicated limb preservation team were included. Subjects with aorto-iliac disease, prior infrainguinal stents or existing bypass grafts were excluded. Demographics, Global Limb Anatomic Staging System (GLASS) scores, Wound, Ischemia, foot Infection (WIfI) stages, revascularization details, and limb-specific outcomes were reviewed. LBP was defined by the absence of re-intervention, occlusion, critical stenosis (>70%), or hemodynamic compromise with ongoing symptoms of CLTI. Major adverse limb events (MALE) included thrombectomy or thrombolysis, new bypass, open surgical graft revision and/or major amputation.

RESULTS

184 unique limbs in 163 patients were analyzed. This cohort was composed of 66.9% male patients with a mean age of 72. Baseline characteristics included diabetes (66%), tissue loss (91%) and advanced WIfI stages (30% stage 3, 51% stage 4). GLASS stage 3 anatomic patterns were common (n=119; 65%). 60 limbs were treated with open bypass (65% involving tibial targets) while 124 underwent endovascular intervention (70% including infrapopliteal targets). 12-month freedom from MALE and loss of LBP were 74.0%±3.7% and 48.6%±4.2%, respectively. Diabetes (HR=2.56 [1.13-5.83]; p=.025) and loss of LBP (4.12 [1.96-8.64]; p<.001) were independent predictors of MALE in a Cox proportional hazard model. Loss of LBP was the sole independent predictor of major limb amputation after revascularization (HR=4.97 [1.89-13.09]; p=.001). Loss of LBP impacted both intermediate-risk limbs (HR=2.85 [1.02-7.97]; p=.047 in WIfI stages 1-3) and high-risk limbs (HR=3.99 [1.32-12.11]; p=.014 in WIfI stage 4). However, loss of LBP had the greatest impact on patients presenting with WIfI stage 4 disease (31% vs. 8% major limb amputation at 12-months in limbs without vs. with maintained LBP).

CONCLUSIONS

Anatomic durability of revascularization, as measured by LBP, is a key determinant of treatment outcomes in CLTI regardless of the initial mode of intervention undertaken. Loss of LBP is most detrimental in patients presenting with advanced limb threat (WIfI stage 4).

How to build a limb salvage program

Patients with chronic limb-threatening ischemia (CLTI) are medically complex and continue to experience high rates of amputation, despite improved diagnosis and treatment. Limb salvage programs and multidisciplinary teams provide comprehensive patient care and have been associated with reduced amputation rates. Recent societal guidelines suggest the adoption of limb salvage programs to improve care of patients with CLTI. In this article, we describe the critical components of a limb salvage program and outline the following steps to aid in their construction: community and institution assessment, formation of a multidisciplinary team, provision of patient care, and monitoring outcomes and processes refinement.

Closing the Gaps in Racial Disparities in Critical Limb Ischemia Outcome and Amputation Rates: Proceedings from a Society of Interventional Radiology Foundation Research Consensus Panel

Minority patients such as Blacks, Hispanics, and Native Americans are disproportionately impacted by critical limb ischemia and amputation due to multiple factors such as socioeconomic status, type or lack of insurance, lack of access to health care, capacity and expertise of local hospitals, prevalence of diabetes, and unconscious bias. The Society of Interventional Radiology Foundation recognizes that it is imperative to close the disparity gaps and funded a Research Consensus Panel to prioritize a research agenda. The following research priorities were ultimately prioritized: (a) randomized controlled trial with peripheral arterial disease screening of at-risk patients with oversampling of high-risk racial groups, (b) prospective trial with the introduction of an intervention to alter a social determinant of health, and (c) a prospective trial with the implementation of an algorithm that requires criteria be met prior to an amputation. This article presents the proceedings and recommendations from the panel.

Applicability of the Vascular Quality Initiative (VQI) mortality prediction model for infrainguinal revascularization in a tertiary limb preservation center population

OBJECTIVE

Patients undergoing revascularization for chronic limb-threatening ischemia (CLTI) are at elevated risk for both mortality and limb loss. To facilitate therapeutic decision-making, a mortality prediction model derived from the Vascular Quality Initiative (VQI) database has stratified patients into low, medium, and high risk, defined by 30-day mortality estimated of ≤3%, 3-5%, or >5% and 2-year mortality estimates of ≤30%, 30-50%, or ≥50%, respectively. The purpose of this study was to compare expected mortality risk derived from this model with observed outcomes in a tertiary center.

METHODS

Consecutive patients treated at a single center between 2016 and 2019 were analyzed. Baseline demographics, approach, and mortality events were reviewed. Observed mortality was obtained using life-table methods and compared using a log-rank test with the expected mortality risk which was calculated using the VQI model.

RESULTS

This study cohort consisted of 195 revascularization procedures in 169 unique patients stratified into 128 (66%) low, 50 (26%) medium, and 17 (8%) high-risk cases based on the VQI model. 90% of revascularizations were performed for tissue loss. Compared with the VQI population, comorbidities were prevalent and included unstable angina or myocardial infarction within 6 months (6% vs. 2.4% in VQI; p<0.001), congestive heart failure (30% vs. 23%; p<0.001), and dialysis dependence (14% vs. 0.9%; p<0.001). Patients were also older (31% vs. 21% ≥80 years old; p<0.001) and more likely to be frail (45% vs. 64% independent; p<0.001). High-risk patients were more prevalent in the endovascular group (11% of 132 endovascular interventions vs. 3% of 63 bypasses; p=0.056). 30-day observed mortality exceeded expected VQI prediction model mortality in all groups, although was not statistically significant. The VQI model adequately stratified the studied population into risk groups (p<0.001). Low risk CLTI patients (65% of the overall cohort) experienced 2- year mortality of 18.9%. However, observed mortality for medium and high-risk VQI strata were similar. After a median follow-up of 28 months, medium-risk patients incurred a significantly higher mortality than predicted (53.5%±2.1% vs. 36.8%±1.1%; p=0.016).

CONCLUSIONS

The VQI mortality prediction model discriminates mortality risk after limb revascularization in CLTI, accurately identifying a majority subgroup of patients who are suitable for either open or endovascular intervention. However, it may underestimate mortality in a tertiary referral population with high comorbidity burden and was not well calibrated for the medium-risk group. It may be more appropriate to dichotomize CLTI patients who are candidates for limb salvage into an average risk and high-risk group.

A single center's 15-year experience with palliative limb care for chronic limb threatening ischemia in frail patients

OBJECTIVE

Our institution's multidisciplinary Prevention of Amputation in Veterans Everywhere (PAVE) program allocates veterans with critical limb threatening ischemia (CLTI) to immediate revascularization, conservative, primary amputation or palliative limb care based on previously published criteria. These four groups align with the approaches outlined by the Global Guidelines for management of CLTI. The current study delineates the natural history of the palliative limb care group of patients and quantifies procedural risks and outcomes.

METHODS

Veterans prospectively enrolled into the palliative limb cohort of our PAVE program between January 2005 and January 2020 were analyzed. The primary outcome was mortality. Secondary outcomes included overall and limb-related readmissions, limb loss and wound healing. Clinical Frailty Score (CFS) was calculated and 5-year expected mortalities were estimated using the Veterans Administration Quality Enhancement Research Initiative (VA QUERI) tool. Regression analysis was performed to establish associations among the following variables: mortality, WIfI score, Clinical Frailty Score, overall admissions and limb-related admissions.

RESULTS

The PAVE program enrolled 1158 limbs over 15 years. 157 (13.5%) limbs in 145 patients were allocated to the palliative limb care group. The overall mortality of the group was 88.2% (median 3.5 months; range 0-91 months). Of the patients that expired, 50% (n=64) died within 3 months of enrollment. The predicted 5-year mortality for the group was 66%. The average frailty score of the group was 6.2, denoting someone who is moderately to severely frail. Based on CFS, 106 patients were considered frail while 39 were considered not frail. There was no difference in mortality between frail and non- frail patients, however there was a statistically significant difference in early mortality (<3 months), 56.2% vs 37.5% (p = 0.032), respectively. The 30-day limb-related readmission rate was 4.7%. Eventual major amputation was necessary in 18 (11.5%) limbs. Wound healing occurred in 30 patients (20.6%). Regression analysis demonstrated no association between frailty score and mortality (r = 0.55, p = 0.159) or between WIfI score and mortality (r = 0.0165, p = 0.98). There was a significant association between WIfI score and limb-related admissions (r = 0.97, p <0.001).

CONCLUSION

Frail, chronic limb threatening ischemia patients have a high early mortality and a low risk of limb-related complications. They also have a low incidence of deferred primary amputation or limb-related readmissions. In our cohort, the vast majority of patients died within a few months of enrollment without needing an amputation. A comprehensive approach to the management of CLTI patients should include a palliative limb care option as a significant proportion of these patients have limited survival and can potentially avoid unnecessary surgery or major amputation.

Evaluation of revascularization benefit quartiles using the Wound, Ischemia, and foot Infection classification system for diabetic patients with chronic limb-threatening ischemia

OBJECTIVE

The Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system was developed to stratify the risk of 1-year major amputation. Recently, the WIfI scores were used to define the estimated revascularization benefit quartiles ranging from high benefit (Q1) to questionable benefit (Q4). The aim of our study was to evaluate the revascularization benefit quartiles in a cohort of diabetic patients presenting with chronic limb-threatening ischemia (CLTI).

METHODS

All diabetic patients presenting to our multidisciplinary diabetic foot and wound clinic (June 2012 to May 2020) who underwent lower extremity revascularization for CLTI were included. The affected limbs were graded using the WIfI system and assigned to an estimated benefit of revascularization quartile as previously published. One-year major amputation, complete foot healing, secondary patency, and amputation-free survival were calculated among the quartiles using Kaplan-Meier curve analyses and compared using Cox proportional hazards models.

RESULTS

Overall, 136 diabetic patients underwent revascularization of 187 limbs (mean age, 64.9 ± 11.2 years; 63.2% male; 58.8% black). The limbs were revascularized using an endovascular approach for 66.8% and open surgery for 33.2%. Of the 187 limbs, 27.3% had a high estimated benefit of revascularization (Q1), 31.6% had a moderate estimate benefit of revascularization (Q2), 20.3% had a low estimated benefit of revascularization (Q3), and 20.9% had a questionable benefit of revascularization (Q4). The estimated 1-year major amputation rates were 7.2% ± 4.1% for Q1, 3.8% ± 2.6% for Q2, 7.0% ± 4.8% for Q3, and 25.7% ± 7.5% for Q4 (P = .006). The estimated 1-year foot healing rates were 87.3% ± 5.7% for Q1, 84.8% ± 5.6% for Q2, 83.8% ± 7.4% for Q3, and 68.2% ± 9.1% for Q4 (P = .06). The overall secondary patency (P = .23) and amputation-free survival (P = .33) did not significantly differ among the groups. Using Cox proportional hazard modeling, the Q4 group had a significantly greater risk of major amputation compared with Q1 (hazard ratio, 4.26; 95% confidence interval, 1.15-15.70). Of the 14 limbs requiring major amputation, 9 (56.3%) had a patent revascularization at the time of amputation, including one of three limbs in Q1, two of two limbs in Q2, no limb in Q3, and six of nine limbs in Q4.

CONCLUSIONS

The questionable estimated revascularization benefit quartile using the WIfI classification system is significantly associated with 1-year major amputation in diabetic patients presenting with CLTI. Limbs with a questionable benefit of revascularization (Q4) will frequently require major amputation despite a patent revascularization, suggesting that the wound size and infection burden are the driving factors behind the elevated risk of major amputation in this group. Our findings support the previously described use of the WIfI classification system to predict revascularization benefit among diabetic patients with CLTI.

The utility of geriatric nutritional risk index to predict outcomes in chronic limb-threatening ischemia

OBJECTIVES

To assess geriatric nutritional risk index (GNRI) in patients with chronic limb-threatening ischemia (CLTI).

BACKGROUND

The prevalence of CLTI continues to rise, with major amputation and mortality remaining prominent. Frailty is a vital risk factor for adverse outcomes in cardiovascular care. The GNRI is a nutrition-based surrogate for frailty that has been utilized in Southeast Asia to predict adverse events in CLTI. It has not yet been evaluated in a primarily Western population, nor in the context of wound healing.

METHODS

Between 8August 2017 and April 2019, we identified patients undergoing endovascular interventions for CLTI at our institution, categorized into low GNRI (≤ 94, frail) versus normal GNRI (> 94, reference). We analyzed the risks of major adverse limb events (MALE), its individual components [mortality, major amputation, and target vessel revascularization (TVR)], amputation free survival (AFS), and wound healing using Kaplan-Meier and multivariate cox-proportional hazard regression analyses.

RESULTS

A total of 255 patients were included in the analysis, with follow up of 14 ± 9.1 months. Lower GNRI was associated with higher cumulative event rates for MALE (71.0% vs. 43.3%, p <  0.001), mortality (34.3% vs. 15.2%, p < 0.001), major amputation (31.2% vs. 15.8%, p = 0.002), and freedom from AFS (56.0% vs. 28.2%, p < 0.001). There was a trend toward lower TVR and higher wound healing with higher GNRI score.

CONCLUSIONS

Our single-center, retrospective evaluation of GNRI (as a surrogate for frailty) correlated with increased risks of MALE, mortality, and major amputation. Future directions should focus not only on the recognition of these patients, but risk-factor modification to optimize long-term outcomes.

Pedal arterial calcification score is associated with the risk of major amputation in chronic limb-threatening ischemia

OBJECTIVE

The medial arterial calcification (MAC) score is a simple metric that describes the burden of inframalleolar calcification using a plain foot radiograph. We hypothesized that a higher MAC score would be independently associated with the risk of major amputation in patients with chronic limb-threatening ischemia (CLTI).

METHODS

We performed a single-institution, retrospective study of 250 patients who had undergone infrainguinal revascularization for CLTI from January 2011 to July 2019 and had foot radiographs available for MAC score calculation. A single blinded reviewer assigned MAC scores of 0 to 5 using two-view minimum plain foot radiographs, with 1 point each for calcification of >2 cm in the dorsalis pedis, plantar, and metatarsal arteries and >1 cm in the hallux and non-hallux digital arteries.

RESULTS

The MAC score was 0 in 36%, 1 in 5.2%, 2 in 8.4%, 3 in 14%, 4 in 14%, and 5 in 21%. The MAC score was trichotomized to facilitate analysis and clinical utility (mild, MAC score 0-1; moderate, MAC score 2-4; and severe, MAC score 5). The variables independently associated with a higher MAC score were male sex, diabetes, end-stage renal disease, and the global limb anatomic staging system pedal score. The MAC score was not associated with the Society for Vascular Surgery WIfI (wound, ischemia, foot infection) grade or overall WIfI stage (P = .58). The median follow-up was 759 days (interquartile range, 264-1541 days). A higher MAC score was significantly associated with the risk of major amputation (P < .0001). In a Cox proportional hazards multiple regression model for major amputation that included the trichotomized MAC score, diabetes, end-stage renal disease, and WIfI stage (1-3 vs 4). The MAC score (MAC score 5: hazard ratio [HR], 4.9; 95% confidence interval [CI], 1.9-13.1; P = .001; MAC score 2-4: HR, 3.4; 95% CI, 1.3-8.8; P = .01) and WIfI stage (WIfI stage 4: HR, 2.1; 95% CI, 1.1-3.9; P = .03) were significantly associated with the risk of major amputation. In the subsets of patients with the most advanced WIfI stage of 3 to 4 (191 of 250; 76%) and patients with diabetes (185 of 250; 74%), the MAC score further stratified the risk of major amputation on univariate and multivariate analyses.

CONCLUSIONS

The MAC score is a simple, practical tool and a strong independent predictor of major amputation in patients with CLTI. It provides novel clinical data that are currently unmeasured using any validated CLTI staging system. The MAC score is a promising standardized measure of inframalleolar disease burden that can be used in conjunction with the WIfI staging system to help improve outcomes stratification and determine the optimal treatment strategies for patients with CLTI.

Factors Associated With Key Outcomes in Diabetes Related Foot Disease: A Prospective Observational Study

OBJECTIVE

Diabetic foot disease is a serious and common complication of diabetes mellitus. The aim of this study was to assess limb and patient factors associated with key clinical outcomes in diabetic patients with foot ulcers.

METHODS

This was a prospective observational study of diabetic patients with foot wounds admitted to a major tertiary teaching hospital in South Australia or seen at associated multidisciplinary foot clinics between February 2017 and December 2018. Patient demographic and clinical data were collected, including limb status severity assessed by the WIfI system and grip strength. Participants were followed up for 12 months. The primary outcomes were major amputation, death, amputation free survival, and completion of healing of the index wound within one year.

RESULTS

A total of 153 participants were recruited and outcome data were obtained for 152. Forty-two participants underwent revascularisation during the research period. Eighteen participants (11.8%) suffered major amputation of the index limb and 16 (10.5%) died during follow up. Complete wound healing was achieved in 106 (70%) participants. There was a statistically significant association between WIfI stage and major amputation (subdistribution hazard ratio [SHR] 2.75), mortality (hazard ratio [HR] 2.60), amputation free survival (odds ratio [OR] 0.32), and wound healing (SHR 0.69). There was also a statistically significant association between time to healing and grip strength (SHR 0.50), and previous amputations (major or minor) (SHR 0.57).

CONCLUSION

This prospective study supports the ability of the WIfI classification system to predict one year key clinical outcomes in a diabetic population with foot ulcers. It also demonstrated that grip strength may be a useful predictor of wound healing.

Early evaluation of the infrainguinal revascularization strategy selection tool of the Global Vascular Guidelines for chronic limb-threatening ischemia patients

OBJECTIVE

The Global Vascular Guidelines (GVG) propose a novel Global Anatomic Staging System (GLASS) with the Wound, Ischemia, and foot Infection (WIfI) classification system as a clinical decision-making tool for interventions in chronic limb-threatening ischemia (CLTI). We assessed the validity of clinical staging and the relationship between the treatments recommended by the GVG and the outcomes of the actual procedures.

METHODS

This retrospective, single-center, observational study included 117 patients with CLTI undergoing infrainguinal revascularization in our hospital between 2015 and 2019. Of those patients, 55 underwent open bypass (OB) and 62 underwent endovascular revascularization (EVR). Femoropopliteal, infrapopliteal, and inframalleolar GLASS grades were assigned based on angiographic images. These grades were combined to determine the revascularization strategy recommended by the GVG: "endovascular," "indeterminate," and "open bypass." The indeterminate category includes three subcategories: GLASS stage III, WIfI stage 2; GLASS stage II, WIfI stage 3; and GLASS stage II, WIfI stage 4. For the purposes of this study, we labeled these subcategories A, B, and C, respectively. The primary outcome was the correlation between the revascularization strategies recommended by the GVG and the actual procedures performed. The relationships between the actual procedures and overall survival, limb salvage, and patency were also examined.

RESULTS

The femoropopliteal and infrapopliteal GLASS grades were higher in the OB group. EVR was performed more often for GLASS stages I and II and was more often classified as indeterminate B and C, whereas OB was performed more often in GLASS stage III and was more often classified as indeterminate A. There were no statistically significant differences in the inframalleolar/pedal disease descriptor or in the 30-day postoperative complication rates between the two groups. In higher GLASS stages, the technical success rate of EVR was lower, and lesion complexity was more severe. Patients for whom the recommended strategy according to the GVG would have been OB but who underwent EVR were associated with low limb salvage and patency rates.

CONCLUSIONS

The GVG provide good guidance for the selection of the revascularization strategy. When the GVG indicate OB, it should be the treatment of choice, rather than EVR, for patients who are fit to undergo the procedure.

The Degree of Blood Supply and Infection Control Needed to Treat Diabetic Chronic Limb-Threatening Ischemia with Forefoot Osteomyelitis

BACKGROUND

Diabetic foot ulcers combined with ischemia and infection can be difficult to treat. Few studies have quantified the level of blood supply and infection control required to treat such complex diabetic foot ulcers. We aimed to propose an index for ischemia and infection control in diabetic chronic limb-threatening ischemia (CLTI) with forefoot osteomyelitis.

METHODS

We retrospectively evaluated 30 patients with diabetic CLTI combined with forefoot osteomyelitis who were treated surgically from January 2009 to December 2016. After 44 surgeries, we compared patient background (age, sex, hemodialysis), infection status (preoperative and 1- and 2-week postoperative C-reactive protein [CRP] levels), surgical bone margin (with or without osteomyelitis), vascular supply (skin perfusion pressure), ulcer size (wound grade 0-3 using the Society for Vascular Surgery Wound, Ischemia, and foot Infection classification), and time to wound healing between patients with healing ulcers and those with nonhealing ulcers.

RESULTS

Preoperative CRP levels and the ratio of ulcers classified as wound grade 3 were significantly lower and skin perfusion pressure was significantly higher in the healing group than in the nonhealing group (P < .05). No other significant differences were found between groups.

CONCLUSIONS

This study demonstrates that debridement should be performed first to control infection if the preoperative CRP level is greater than 40 mg/L. Skin perfusion pressure of 55 mm Hg is strongly associated with successful treatment. We believe that this research could improve the likelihood of salvaging limbs in patients with diabetes with CLTI.

Revascularization of multiple tibial arteries is not associated with improved limb salvage

OBJECTIVE

We sought to determine the benefit of performing multiple tibial artery revascularization compared with single vessel revascularization for patients with chronic limb-threatening ischemia (CLTI).

METHODS

We performed a single-center, retrospective cohort study of all patients with CLTI treated with below-the-knee endovascular intervention from 2012 to 2019. Group 1 included patients who had undergone single tibial artery revascularization. Group 2 included patients who had undergone multiple (two or more) tibial artery revascularization. More proximal disease, if present, was treated, in addition to the tibial disease. The primary endpoint was freedom from amputation. The secondary endpoints included the reintervention rates and all-cause mortality.

RESULTS

A total of 527 limbs in 470 patients with CLTI (nonhealing ulcers, 62%; gangrene, 33%; and ischemic rest pain, 5%) were included in the present study. Of the 527 limbs, 245 (46%) had undergone single vessel revascularization and 282 (54%) had undergone multiple vessel revascularization. The mean follow-up was 19 ± 18 months. No difference was found in freedom from amputation between the two groups (68% vs 63%; P = .109). On multivariable analysis, the factors associated with amputation included dialysis (odds ratio [OR], 1.68; 95% confidence interval [CI], 1.16-2.45), dyslipidemia (OR, 1.37; 95% CI, 0.96-1.94), and gangrene (OR, 2.08; 95% CI, 1.50-2.98). No differences were found in the reintervention rates between the two groups (21.2% vs 16.7%; P = .13). The overall survival rate was 73% in both study groups.

CONCLUSIONS

The results from the present large, single-center study have demonstrated that multiple below-the-knee vessel revascularization is not associated with improved limb salvage compared with single vessel revascularization.

Comparison of WIFi, University of Texas and Wagner Classification Systems as Major Amputation Predictors for Admitted Diabetic Foot Patients: A Prospective Cohort Study

Introduction:

Classifications systems are powerful tools that could reduce the length of hospital stay and economic burden. The Would, Ischemia, and Foot Infection (WIFi) classification system was created as a comprehensive system for predicting major amputation but is yet to be compared with other systems. Thus, the objective of this study is to compare the predictive abilities for major lower limb amputation of WIFi, Wagner and the University of Texas Classification Systems among diabetic foot patients admitted in a tertiary hospital through a prospective cohort design.

Materials and Methods:

Sixty-three diabetic foot patients admitted from June 15, 2019 to February 15, 2020. Methods included one-on-one interview for clinico-demographic data, physical examination to determine the classification. Patients were followed-up and outcomes were determined. Pearson Chi-square or Fisher’s Exact determined association between clinico-demographic data, the classifications, and outcomes. The receiver operating characteristic (ROC) curve determined predictive abilities of classification systems and paired analysis compared the curves. Area Under the Receiver Operating Characteristic Curve (AUC) values used to compare the prediction accuracy. Analysis was set at 95% CI.

Results:

Results showed hypertension, duration of diabetes, and ambulation status were significantly associated with major amputation. WIFi showed the highest AUC of 0.899 (p = 0.000). However, paired analysis showed AUC differences between WIFi, Wagner, and University of Texas classifications by grade were not significantly different from each other.

Conclusion:

The WIFi, Wagner, and University of Texas classification systems are good predictors of major amputation with WIFi as the most predictive.

Impact of the coronavirus disease 2019 pandemic on an academic vascular practice and a multidisciplinary limb preservation program

With the aggressive resource conservation necessary to face the coronavirus disease 2019 pandemic, vascular surgeons have faced unique challenges in managing the health of their high-risk patients. An early analysis of patient outcomes after pandemic-related practice changes suggested that patients with chronic limb threatening ischemia have been presenting with more severe foot infections and are more likely to require major limb amputation compared with 6 months previously. As our society and health care system adapt to the new changes required in the post–coronavirus disease 2019 era, it is critical that we pay special attention to the most vulnerable subsets of patients with vascular disease, particularly those with chronic limb threatening ischemia and limited access to care.

A Comparison Between Diabetic Foot Classifications WIfI, Saint Elian, and Texas: Description of Wounds and Clinical Outcomes

Several wound classification systems are used to assess diabetic foot wounds. The recommendations for their use depend on the authors and foot associations. In this study, we compared Saint Elian score system, WIfI classification and Texas in 101 patients with foot wounds, and we followed them for a median of 149 days, finding differences both in the assigned risk and in the association with major amputation and wound healing. Saint Elian and WIfI scores match when Saint Elian is low or high risk but not when it is moderate. WIfI stages correlate with major amputation and wound healing. Saint Elian III correlates with major amputation. Prevalence of major amputations was 41% for WIfI 4 and 83% for Saint Elian III. WIfI 1 and 2 and Saint Elian I had a rate of wound healing of 80% to 85%. Stages 1 and 2 of WIfI score behave similar with regard to wound healing, 82% and 80% (P = .71), and major amputation, 0% and 10% (P = .68). Stages I and II of Saint Elian have the same rates of major amputation, 0% and 8% (P = .66), but not of wound healing, 85% and 51% (P < .05). The optimal cut point for detecting major amputation in Saint Elian is 18, with a sensitivity of 90.9 and specificity of 84.9, but there is no recommended cut point for wound healing. These classifications are validated for their use in diabetic foot wounds and to assess amputation risk, helping physicians make decisions and talk to the patients about prognosis.

Increased Reintervention After Infrainguinal Revascularization for Chronic Limb-Threatening Ischemia in Women

BACKGROUND

The objective of this study was to determine if there are gender-based differences in major adverse limb events after revascularization for chronic limb-threatening ischemia (CLTI) and to identify potential associated factors.

METHODS

This was a single-center retrospective analysis of 151 patients who underwent infrainguinal revascularization for CLTI between April 2013 and December 2015. Only the first revascularized limb was included in patients with bilateral CLTI. Demographic data and clinical outcomes were collected using electronic medical records.

RESULTS

The mean age was 68.1 ± 12.1 years, and 55 of 151 (36%) were women. Women were less likely to carry a diagnosis of hyperlipidemia (60% vs. 83%; P = 0.003), less likely to be on a statin medication (58% vs. 81%; P = 0.004), and less likely to undergo an infrapopliteal revascularization (60% vs. 77%; P = 0.04) compared with men. There were no differences between genders with regard to the Society for Vascular Surgery Wound Ischemia and Foot Infection stage at presentation or utilization of open versus endovascular intervention. During the median follow-up time of 678 days (interquartile range, 167-1277 days), 48 of 151 patients (32%) underwent reintervention on the threatened limb and 23 of 151 patients (15%) underwent major amputation. Women were more likely than men to need reintervention (P = 0.02). There was no difference between genders for major amputation (P = 0.48) or overall survival (P = 0.65). In a multivariable Cox proportional hazards model for reintervention that included gender, preoperative body mass index, hyperlipidemia, preoperative anticoagulation, and ischemia score ≥2 (all P < 0.20 in univariate analysis), female gender (hazard ratio [HR], 1.96 [1.10-3.54]; P = 0.02) and hyperlipidemia (HR, 2.32 [1.07-5.03]; P = 0.03) were significantly associated with increased rates of reintervention.

CONCLUSIONS

Women undergoing lower extremity revascularization for CLTI were more likely to require reintervention compared with men but had similar rates of limb preservation. Further study is required to understand potential causative factors to improve treatment outcomes in women.

New Innovations and Devices in the Management of Chronic Limb-Threatening Ischemia

As the number of patients afflicted by chronic limb-threatening ischemia (CLTI) continues to grow, new solutions are necessary to provide effective, durable treatment options that will lead to improved outcomes. The diagnosis of CLTI remains mostly clinical, and endovascular revascularization remains mostly balloon-based. Multiple innovative techniques and technologies are in development or in early usage that may provide new solutions. This review categorizes areas of advancement, highlights recent developments in the management of CLTI and looks forward to novel devices that are currently under investigation.

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

The Society for Vascular Surgery has proposed a new classification system for the threatened lower limb, based on the three main factors that have an impact on limb amputation risk: Wound (W), Ischemia (I) and foot Infection ("fI") - the WIfI classification. The system also covers diabetic patients, previously excluded from the concept of critical limb ischemia because of their complex clinical condition. The classification's purpose is to provide accurate and early risk stratification for patients with threatened lower limbs; assisting with clinical management, enabling comparison of alternative therapies; and predicting risk of amputation at 1 year and the need for limb revascularization. The objective of this study is to collect together the main points about the WIfI classification that have been discussed in the scientific literature. Most of the studies conducted for validation of this classification system prove its association with factors related to limb salvage, such as amputation rates, amputation-free survival, prediction of reintervention, amputation, and stenosis (RAS) events, and wound healing.

Diabetic Foot Ulcers: Appraising Standard of Care and Reviewing New Trends in Management

Diabetic foot ulcers (DFU) are one of the most common diabetes complications and are associated with significant morbidity and mortality. Current DFU standard of care (SOC) involves four principles: (1) pressure relief, (2) debridement, (3) infection management, and (4) revascularization when indicated. Despite the current SOC, many DFU persist, warranting a new approach for the management of these complex wounds. This review aims to summarize the current SOC as well as the latest trends in adjunctive therapies that may become the new SOC in DFU management. These include negative pressure wound therapy and hyperbaric oxygen therapy, bioengineered skin substitutes, growth factors, shockwave therapy, and several others. These novel therapies have shown significant DFU clinical improvement among subsets of DFU patients. However, much of the literature comes from smaller trials with inconsistent patient selection and outcomes measured, making it difficult to assess the true clinical benefit of these treatments. While novel therapies are promising for the interdisciplinary approach to DFU management, many still lack sufficient evidence, and their efficacy remains to be determined.

Using the epidemiology of critical limb ischemia to estimate the number of patients amenable to endovascular therapy

Critical limb ischemia represents the advanced stage of peripheral artery disease, a health problem with increasing prevalence. Critical limb ischemia is associated with significant mortality, limb loss, pain, and diminished health-related quality of life. Public awareness and early diagnosis are necessary for an effective treatment with early risk factor modification, smoking cessation, and exercise therapy. Herein, we present an overview of the epidemiology as well as the clinical stages of the disease, and estimate that there are 6.5 million patients with critical limb ischemia in the US, Europe, and Japan based on global population-based studies. At least 75% of these patients, accounting for approximately 4.8 million patients, are amenable to endovascular therapy.

Additional Risk Stratification Using Local and Systemic Factors for Patients with Critical Limb Ischaemia Undergoing Endovascular Therapy in the WIfI Era

OBJECTIVES

While current guidelines describe the importance of assessing limb characteristics for predicting limb prognosis in patients with critical limb ischaemia (CLI), several reports have also suggested that systemic factors are associated with limb prognosis. The aim of this study was to evaluate whether systemic factors have the same impact on wound healing as limb characteristics in CLI patients undergoing endovascular therapy.

METHODS

A total of 735 patients who were treated for the first time for CLI with tissue loss between April 2010 and December 2015 were extracted from a prospective registry and data for the Wound, Ischaemia, and foot Infection (WIfI) classification were searched retrospectively. The predictors of wound healing were explored with Cox proportional hazards regression.

RESULTS

The one year wound healing rate was 60.2% in WIfI stage 1-3 patients and 53.6% in WIfI stage 4 (p = .01). In WIfI stage 1-3, no systemic factors were significantly associated with wound healing, whereas, in WIfI stage 4 patients, non-ambulatory status [hazard ratio (HR) 1.98; 95% confidence interval (CI) 1.37-2.84], haemodialysis (HR 1.90; 95% CI 1.33-2.72) and an albumin level under 3.0 g/dL (HR 1.53; 95% CI 1.02-2.31), were identified as independent risk factors for failure to achieve wound healing. If none or one of these risk factors were present, wound healing was comparable with WIfI 4 and WIfI 1-3 patients (67.7% vs. 63.6%, p = .89), whereas in patients with two or more risk factors wound healing was worse in WIfI 4 than in WIfI 1-3 patients (35.7% vs. 49.5%, p = .01).

CONCLUSION

Non-ambulatory status, haemodialysis, and a low albumin level were additional systemic risk factors for impaired wound healing in patients with WIfI stage 4. The wound healing rate in WIfI stage 4 patients with one or fewer of these risk factors was comparable to that in WIfI stage 1-3.

Global Vascular Guidelines on the Management of Chronic Limb-Threatening Ischemia

GUIDELINE SUMMARY

Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

Global vascular guidelines on the management of chronic limb-threatening ischemia

Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

Utility of skin perfusion pressure values with the Society for Vascular Surgery Wound, Ischemia, and foot Infection classification system

OBJECTIVE

The addition of skin perfusion pressure (SPP) might enhance the predictive value of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system. The purpose of the present study was to evaluate the SPP for each WIfI classification stage among patients with foot wounds by cross-referencing the results of prospectively monitored limb outcomes and to derive the SPP criteria that could be combined with other measurements to grade ischemia for the WIfI classification.

METHODS

From July 2015 to June 2017, patients with foot wounds that met the WIfI classification criteria were prospectively enrolled. We assessed the limbs using the WIfI ischemia grade without measuring the transcutaneous oxygen pressure but measured the SPP. After monitoring for 1 year, the predictability of the WIfI stages was analyzed according to whether the limbs had not healed (unchanged or worsened wounds, minor or major amputation, all-cause death) or had healed (improved or healed wounds) by comparing stages 1 and 2 with stages 3 and 4. We also statistically analyzed the SPP values that could be the boundary values between each ischemia grade and reevaluated the predictability of the WIfI stages with the boundary SPP values.

RESULTS

We enrolled a total of 91 limbs for 76 patients (mean age, 70.5 ± 12.0 years). The mean SPP values stratified by ischemia grade 0 to 3 were 52.1, 41.1, 27.1, and 18.8 mm Hg, respectively (an SPP of <30 mm Hg indicates severe ischemia). After monitoring for 1 year, 19 of 48 limbs in stage 1 and 2 and 35 of 43 in stage 3 and 4 were in the nonhealed group and 29 limbs in stage 1 and 2 and 8 limbs in stage 3 and 4 were in the healed group. The SPP boundary values between each ischemia (I) grade were calculated as 45 mm Hg for I-0/I-1, 35 for I-1/I-2, and 25 for I-2/I-3. When jointly using the boundary SPP values, the ischemia grade changed for 23 limbs, altering the distribution of the WIfI stages and limb outcomes: 11 of 38 limbs in stage 1 and 2 and 43 of 53 in stage 3 and 4 were transferred to the nonhealed group. The sensitivity, efficiency, and negative predictive value of WIfI staging improved when staging with SPP: from 65% to 80%, 70% to 77%, and 60% to 71%, respectively.

CONCLUSIONS

The SPP boundary values that could be used with ischemia grade in the WIfI classification were identified as 45, 35, and 25 mm Hg. The addition of SPP could improve the accuracy of the evaluation.

Using the Society for Vascular Surgery Wound, Ischemia, and foot Infection classification to identify patients most likely to benefit from revascularization

BACKGROUND

The Society of Vascular Surgery Wound Ischemia foot Infection (WIfI) classification system for chronic limb-threatening ischemia was intended to predict 1-year major lower extremity amputation (LEA) risk and to identify which patients benefit most from revascularization. We aimed to identify which WIfI presentations benefited most from revascularization to explore whether a cluster analysis could identify a more data-driven WIfI score, and to quantify which component of the WIfI score was most strongly associated with 1-year LEA after revascularization.

METHODS

Composite multi-institutional nested cohort data from centers who previously validated WIfI were reviewed retrospectively. We collected each patient's WIfI component grades and whether LEA was performed. To examine the benefit of revascularization, the predicted LEA rates were subtracted from observed LEA rates. We used k-means cluster analysis to model predicted vs observed LEA rates after revascularization. Multivariable linear regression analysis was performed to quantify which WIfI score component(s) best predicted LEA.

RESULTS

Data from 10 centers, accumulated between 2005 and 2015 were collated (2878 limbs at risk; 314 LEAs performed). The subset of patients who underwent revascularization comprised the study base (1654 limbs; 169 LEAs). Of 64 potential WIfI grade combinations, 15 were never reported and were excluded from the analysis. By original WIfI stages, the observed LEA rate after revascularization was: stage 1, 10.8% (14/130); stage 2, 4.9% (5/103); stage 3, 5.1% (25/487); and stage 4, 13.4% (125/934). Based on the difference between predicted and observed LEA risk for those who underwent revascularization, the WIfI scores were placed into quartiles from greatest to no benefit of revascularization. Cluster analysis identified four clusters with the following 1-year LEA rates: cluster 1, 4.4% (46/1038); cluster 2, 14.8% (66/447); cluster 3, 28.1% (36/128); and cluster 4, 51.2% (21/41). The between sum of squares/total sum of squares was 93.9%. Multiple linear regression revealed the wound grade most strongly predicted LEA (F-value, 17.25; P < .001). Ischemia (F-value, 6.51; P = .001) and infection (F-value, 5.7; P = .003) were similarly associated with LEA risk. Interaction terms between each component of the WIfI score were not statistically significant.

CONCLUSIONS

WIfI can identify which patients with chronic limb-threatening ischemia are most likely to benefit from revascularization and may provide improved prognostication, risk stratification, and equitable outcome assessments. After revascularization, wound severity is most strongly associated with LEA risk. Ischemic and infectious grades confer additive, but not synergistic, risk. Future cluster analyses comparing specific WIfI presentations treated with and without revascularization will be required to further refine WIfI.

Association between stress hormones and perioperative risk in patients with critical limb ischemia undergoing revascularization

BACKGROUND

It is well known that the clinical outcome of patients with critical limb ischemia (CLI) is poor. However, the relationship between stress-related hormone levels and CLI outcome remains unclear. The aim of this study was to reveal the association of stress hormones with the risk of a perioperative major adverse cardiovascular event (pMACE) in CLI patients undergoing surgical and endovascular revascularization.

METHODS

The study analyzed 467 CLI patients who had levels of stress-related hormones (epinephrine, norepinephrine, dopamine, and cortisol) measured before undergoing revascularization. The primary end point was pMACE, including all-cause mortality, myocardial infarction, and stroke within 30 days after revascularization. Propensity score matching was used to try to control for potential confounding.

RESULTS

Of the 467 patients analyzed, pMACE was observed in 21 patients (4.5%). The crude comparison of stress-related hormone levels between those with and those without pMACE showed that those with pMACE had a higher level of epinephrine, dopamine, and cortisol compared with those without pMACE. After propensity matching (20 patients with pMACE and 192 patients without pMACE), epinephrine and cortisol levels were significantly higher in those with pMACE. Multivariate analysis confirmed that both epinephrine and cortisol levels were related to the risk of pMACE independently of each other. The Cox proportional hazards regression model demonstrated that both hormones were associated with 30-day mortality but not with longer term mortality.

CONCLUSIONS

Stress-related hormone (epinephrine and cortisol) levels were significantly associated with the risk of pMACE in CLI patients undergoing revascularization. Both hormones were related to 30-day mortality.

Outcomes of Wound Healing and Limb Loss After Transmetatarsal Amputation in the Presence of Peripheral Vascular Disease

Transmetatarsal amputation (TMA) is the procedure of choice in treating forefoot gangrene and infection. Foot and ankle and vascular surgeons work closely together in limb salvage, but little is known about the timing of vascular intervention to achieve a healed amputation site. This study retrospectively looked at 153 patients with peripheral vascular disease who underwent TMA with a minimum of a 3-year follow-up. A total of 102 patients received vascular intervention: 79 endovascular and 23 open bypass. The primary focus of this study was to look at the timing of vascular intervention, incidence of wound healing, and incidence of limb loss. There was an overall 44% rate of limb loss. Patients who underwent open bypass did better than those who underwent endovascular intervention with a lower incidence of limb loss (87% compared with 51%), and quicker time to wound healing. The timing of vascular intervention, performed either before or after TMA, had no association with wound healing or limb loss. Similarly, the time interval between vascular intervention and TMA had no association with wound healing or limb loss. Comorbidities, including end-stage renal disease on hemodialysis, hyperlipidemia, and congestive heart failure, showed a significant association with TMA stump nonhealing and limb loss. Body mass index ≥30, end-stage renal disease on hemodialysis, and hyperlipidemia were all risk factors for limb loss.