WIfI Classification Research Articles

Prognostic Ability of the Wound, Ischemia, Foot Infection (WIfI) Classification System in Diabetic Patients with Non-Healing Ulcer

Abstract Objectives Several classifications have been published to predict limb salvage in diabetic patients with non-healing ulcer to aid in the management plan. The Society for Vascular Surgery (SVS) Lower Extremity Guidelines Committee has composed a new classification system that reflects the three major factors that impact amputation risk and clinical management Our goal was to evaluate the predictive ability of this wound, ischemia and foot infection(WIfI) classification as a predictor of limb salvage in diabetic patients with non-healing ulcer Methods a prospective single arm observational cohort study conducted on 50 patients within 2022 at single center, Ain Shams University Hospitals, Patients are diabetics who had non healing ulcers some of the cases underwent angioplasty or debridement, then follow up of the wounds was done. Limbs were stratified into clinical stages 1 to 4 based on the SVS WIfI classification for amputation risk. Results Our study included 38 males (76%) and 12 females (24%). The age range between 35 years and 73 years with mean age of 59±8.81. All of the patients are diabetic. The percentage of patients with hypertensive ( 76 %), 54% of them were smoker & 7 were suffering from ESRD. limb salvage was achieved on 75 % of cases. All cases have been classified according to WIFI classification into clinical stages I-IV and their percentage were 6%,12%,40% and 42% respectively. WIfI classification was significant in predicting the major or minor amputation as well as ulcer healing. As Major amputation among each WIfI classification group low, moderate and high risk was 0%, 10%, 47% respectively. Risk of minor amputation was 22%, 40% and 76% respectively. While ulcer healing was 100%, 85% and 52% respectively. Conclusion The likelihood of an amputation after one year in patients with non healing ulcer increases with higher WIfI stages, so The WIfI classification is applicable in prediction of limb salvage in diabetic patients with non-healing ulcer. Smoking and aging also decreases the chance of limb salvageability

Examination of patients with diabetes mellitus and peripheral arterial disease according to the adapted ischaemic criteria of the WIfI classification

Objective. To combine the determination of ischemia class indicators according to the WIfI classification and simultaneous performance of ultrasound duplex scanning of the arteries of both lower extremities during the initial examination of patients with diabetes mellitus and peripheral arterial disease to predict healing, determine the risk of amputation and the need for revascularisation. Materials and methods. We treated 74 patients with diabetes mellitus and peripheral arterial disease who had signs of infection, ulceration or destruction of deep foot tissues. Patients were divided into two groups: the main group – 43 patients (ischaemia class was determined by the WIfI classification with simultaneous performance of ultrasound duplex scanning of the lower extremity arteries with assessment of lesions by ultrasound criteria) and the control group – 31 patients (ischaemia class according to the WIfI classification was determined only by portable Doppler). Patients in both groups received comprehensive treatment. Results. During the 1–year follow–up, the frequency of re–hospitalisation associated with deterioration of the condition due to limb ischaemia in the main group was statistically significantly (p=0.03) lower than in the control group. Conclusions. The integration of ultrasound duplex scanning at the initial stage of diagnosis allows to determine the degree of ischemia more accurately and to refer the patient for vascular correction in time.

RHEOLOGICAL THROMBUS EXTRACTION IN POSTOPERATIVE THROMBOSIS OF THE POPLITEAL-TIBIAL SEGMENT AFTER ENDOVASCULAR METHODS OF REVASCULARIZATION

Introduction. The use of endovascular methods of revascularization of the atherosclerotic stenotic-occlusive process of the femoral-distal arterial bed leads in 1/4 of the primary surgical interventions to the need for repeated surgical intervention, in 6-32% of cases it is complicated by the development of thrombosis of the reconstruction segment, restenosis of the surgical intervention segment [6, 7]. Aim. The main goal of the study was to improve the results of endovascular methods of revascularization of multi-level stenotic-occlusive femoral-distal arterial bed by performing rheological thrombus extraction with the Angiojet system in postoperative thrombosis of the popliteal-tibial segment. Materials and methods. 164 patients with multilevel stenotic-occlusive atherosclerotic lesions of the femoral-distal arterial bed were under observation. Thrombosis of the popliteal segment was diagnosed in 17 (73.9%) cases in patients with endovascular angioplasty of one of the tibial arteries, in 6 (26.1%) cases with endovascular angioplasty of two arteries of the tibial segment. Surgical treatment of thrombosis of the popliteal segment was performed by the method of minimally invasive rheological thrombus extraction using the Angiojet device (Possies, USA). Results. A patient with a multilevel stenotic-occlusive process of the femoral-distal arterial bed at clinical stage 3 (according to WIFI classification) had a two-level endovascular angioplasty of the infrainguinal arterial channel. Rheological thrombus extraction from the popliteal-tibial segment using the Angiojet system was used in 14 (60.9%) patients who underwent two-level endovascular angioplasty of the femoral-distal arterial bed. Rheological thrombus extraction from the popliteal-tibial segment with the Angiojet system was used in 9 (34.8%) patients who underwent revascularization of the infrainguinal arterial bed by the hybrid revascularization method. Conclusions. 1. Endovascular methods of revascularization of multilevel stenotic-occlusive femoral-distal arterial bed are complicated in 14.0% of observations by the development of postoperative thrombosis of the popliteal-tibial segment. The effectiveness of the application of rheological thrombus extraction by the Angiojet system of postoperative thrombosis from the popliteal-tibial segment after endovascular methods of revascularization of multilevel stenotic-occlusive femoral-distal arterial bed is at the level of 82.6%.

Features of diagnostics and treatments of the patient with type 2 diabetes mellitus and chronic ischtmia with threating lower limb loss

The article presents the result of our own observation of the patient with a poor control of type 2 diabetes mellitus (DM) for a long period, complicated by obliterating atherosclerosis of the arteries of the lower extremities, Menckeberg’s sclerosis and chronic ischemia threatening loss of the lower extremity (CLLI). A feature of the clinical manifestation are complications associated with potentially regional (angiosomal) ischemia of the foot, as well as variant anatomy, represented by hypoplasia of the vascular lower leg in the patient. The clinical consequences of vascular calcification due to long-term decompensation of carbohydrate metabolism and the development of diabetic distal polyneuropathy (DDP) led to falsely high values of the cuff test in the patient. Disadvantages of non-invasive methods for diagnosing limb ischemia and advantages of the complex application of tests for diseases of the arteries of the lower extremities are discussed. Using WIFI classification according to the degree of ulceration, the degree of ischemia, and the degree of infection on the foot (Wound, Ischemia and Foot Infection), the tactics of managing the patient are presented. The important role of ultrasonic duplex scanning (USDS) in the visualization of the arteries of the legs and feet in patients with DM is substantiated. The importance of a multidisciplinary approach in the management of a comorbid patient with type 2 diabetes and CLTI is emphasized.

Evaluating the correlation between WIFI score and outcome of intervention in infrainguinal artery in chronic limb threatening ischemia

Overview: The WIfI score was first introduced as an initial assessment, helping to predict the risk of limb amputation, the feasibility, and the benefit of revascularization in patients with chronic limb-threatening ischemia. Objectives: Determining the correlation between WIfI score and the outcome of endovascular intervention in the lower limb in chronic ischemia threatening limb stage. Methods: A retrospective study was conducted to identify the cases with chronic limb threatening ischemia of the infrainguinal artery occlusion, treated by endovascular intervention at the Department of Vascular Surgery, Cho Ray Hospital from August 2020 to May 2021. Results: There were 80 patients with 80 limbs that were treated, with mean age of 71.5, male gender accounted for 67.5%. Patients were admitted to the hospital with Rutherford stages 4,5,6 respectively 42.5%, 42.5% and 15%. WIfI stages 1,2,3,4 respectively 6.3%, 46.3%, 23.8%, 23.8%. The technical success rate was 96.3%, the wound healing rate was 79.1%, the primary patency rate was 64.9%, the limb salvage rate was 89.7%, the survival rate was 97.5%. The higher WIfI stage before intervention was associated with lower primary patency and limb salvage rates, statistically significant with p<0.05. There was no correlation between WIfI stage and mortality rate. Conclusions: The WIfI classification system is very important in chronic limb-threatening ischemia, as it helps to estimate the limb salvage rate, predict the need for revascularization and wound healing.

Modified tibial cortex transverse transport for diabetic foot ulcers with Wagner grade ≥ II: a study of 98 patients.

Diabetic foot ulcers constitute a substantial healthcare burden on a global scale and present challenges in achieving healing. Our objective was to assess the efficacy of modified tibial cortex transverse transport surgery in managing refractory diabetic foot ulcers. We retrospectively analyzed clinical data from 98 patients suffering from diabetic foot ulcers classified as Wagner grade ≥II who were admitted to our medical facility between January 2020 and June 2022. All the patients were treated by modified tibial cortex transverse transport surgery, wherein the osteotomy scope was reduced to two rectangular bone windows measuring 1.5cm × 1.5cm each. Record the patient's general information and ulcer healing time; ulcer area, ankle-brachial index, WIFi classification, and visual analogue scale before and 3 months following the surgical intervention. The average duration of diabetes of 98 patients with diabetic foot ulcer was 20.22 ± 8.02 years, 52 patients had more than one toe gangrene on admission. The postoperative wound healing rate was 95.83% and the average healing time was 53.18 ± 20.18 days. The patients showed significant improvement in ankle-brachial index, WIFi classification, and visual analogue scale at 3 months postoperatively compared to preoperatively, with statistically significant differences (P< 0.05). Eight patients experienced complications, and the incidence of complications was 8.16%. Throughout the follow-up period, there were no instances of ulcer recurrence noted. Modified tibial cortex transverse transport surgery demonstrates effectiveness in the management of diabetic foot ulcers by enhancing lower limb microcirculation and facilitating the process of wound healing.

Learning curve of tibial cortex transverse transport: a cumulative sum analysis

ObjectiveThis study aimed to describe the learning curve of surgeons performing tibial cortex transverse transport (TTT) and explore its safety and effectiveness during the initial stages of surgeon’s learning.MethodsThe clinical data of patients with diabetic foot ulcers classified as Wagner grade ≥ 2, who underwent TTT at our hospital from January 2020 to July 2021, were included in this retrospective analysis. The same physician performed all procedures. Patients were numbered according to the chronological order of their surgery dates. The cumulative sum and piecewise linear regression were used to evaluate the surgeon's learning curve, identify the cut-off point, and divide the patients into learning and mastery groups. A minimum follow-up period of 3 months was ensured for all patients. Baseline data, perioperative parameters, complications, and efficacy evaluation indicators were recorded and compared between the two groups.ResultsSixty patients were included in this study based on the inclusion and exclusion criteria. After completing 20 TTT surgeries, the surgeon reached the cut-off point of the learning curve. Compared to the learning group, the mastery group demonstrated a significant reduction in the average duration of the surgical procedure (34.88 min vs. 54.20 min, P < 0.05) along with a notable decrease in intraoperative fluoroscopy (9.75 times vs. 16.9 times, P < 0.05) frequency, while no significant difference was found regarding intraoperative blood loss (P = 0.318). Of the patients, seven (11.7%) experienced complications, with three (15%) and four cases (10%) occurring during the learning phase and the mastery phase, respectively. The postoperative ulcer area was significantly reduced, and the overall healing rate was 94.8%. Significant improvements were observed in postoperative VAS, ABI, and WIFI classification (P < 0.05). There were no significant differences in the occurrence of complications or efficacy indicators between the learning and mastery groups (P > 0.05).ConclusionSurgeons can master TTT after completing approximately 20 procedures. TTT is easy, secure, and highly efficient for treating foot ulcers. Furthermore, TTT’s application by surgeons can achieve almost consistent clinical outcomes in the initial implementation stages, comparable to the mastery phase.

Wi-CL: Low-Cost WiFi-Based Detection System for Nonmotorized Traffic Travel Mode Classification

Traffic travel mode identification and classification are crucial for the development of intelligent transportation systems (ITSs). At present, scholars have investigated the classification of motorized and nonmotorized traffic travel in various road environments; however, the classification of walking and bicycle modes in nonmotorized travel has been largely ignored. Therefore, in this paper, we investigate nonmotorized traffic travel and propose a new low-cost nonmotorized traffic travel mode classification system, known as the Wi-Fi classification (Wi-CL) system that uses Wi-Fi signal detectors and the refined characteristics of nonmotorized travel modes. The Wi-CL system includes four modules: data acquisition module, data processing module, feature extraction module, and mode classification module. In the data acquisition module, the proposed system detects the Wi-Fi signals of traffic participants in road environments. In addition, we propose a received signal strength indicator (RSSI) filtering algorithm for hybrid traffic networks that effectively addresses surrounding obstacles and environmental noise. In the feature extraction module, we extract relevant traffic features to construct a mode classification model. Finally, a recurrent neural network (RNN) framework based on the long short-term memory (LSTM) algorithm is successfully implemented in the mode classification module for traffic travel mode identification. To validate the effectiveness of the Wi-CL system, extensive experiments were conducted using field data collected by Wi-Fi detectors installed at the South China University of Technology (SCUT). The experimental results show that the proposed RSSI filtering algorithm achieves excellent signal filtering results in real road traffic environments. In addition, the constructed travel speed estimation algorithm outperforms other baseline models in four different scenarios (flat-peak walking, midday peak walking, flat-peak cycling, and midday peak cycling), achieving an overall classification accuracy of 97.92%. In summary, our Wi-CL system is a feasible approach for nonmotorized traffic travel mode classification.

Prognostic factors for delayed healing of complex wounds in adults: A scoping review.

Complex or hard-to-heal wounds continue to be a challenge because of the negative impact they have on patients, caregivers, and all the associated costs. This study aimed to identify prognostic factors for the delayed healing of complex wounds. Five databases and grey literature were the sources used to research adults with pressure ulcers/injuries, venous leg ulcers, critical limb-threatening ischaemia, or diabetic foot ulcers and report the prognostic factors for delayed healing in all care settings. In the last 5 years, a total of 42 original peer-reviewed articles were deemed eligible for this scoping review that followed the JBI recommendations and checklist PRISMA-ScR. The most frequent prognostic factors found with statistical significance coinciding with various wound aetiologies were: gender (male), renal disease, diabetes, peripheral arterial disease, the decline in activities of daily life, wound duration, wound area, wound location, high-stage WIfI classification, gangrene, infection, previous ulcers, and low ankle brachial index. It will be essential to apply critical appraisal tools and assessment risk of bias to the included studies, making it possible to make recommendations for clinical practice and build prognostic models. Future studies are recommended because the potential for healing through identification of prognostic factors can be determined, thus allowing an appropriate therapeutic plan to be developed.

WIfI Classification Based Analysis of Risk Factors for Outcomes in Patients with Chronic Limb Threatening Ischaemia after Endovascular Revascularisation Therapy

Evaluating limb status with WIfI classifications and assessing patient risks combined with systemic factors were recommended in patients with chronic limb-threatening ischemic (CLTI). However, there was little application evidence of WIfI in the Chinese population. This study aimed to verify the utilization of the WIfI classification in a China patient population, and further identify local and systemic independent predictors for adverse outcomes of CLTI. A total of 474 patients who underwent endovascular therapy (EVT) for CLTI in a tertiary hospital between July 2017 and September 2020 were included in this retrospective study. The outcomes included 1-year major adverse limb events (MALEs), 1-year all-cause mortality, and 1-year amputation-free survival (AFS). Cox regression was used to analyze the association between risk factors and adverse outcomes. There were 104 (21.9%) all-cause mortalities observed. The MALEs rate was 17.5%, while AFS rate was 71.9%. The multivariate analysis revealed that a BMI < 18.5 kg/㎡ (P = .002), a left ventricular ejection fraction (LVEF) < 50 % (P < .001), and WIfI-Wound Grade (P < .001) were independent risk factors for MALEs, while age ≥ 77 years (P = .031), a BMI < 18.5 kg/㎡ (P < .001), coronary heart disease (P = .040), and WIfI clinical stages (P = .021) were independent risk factors for mortality in CLTI patients. Besides, age ≥ 77 years (P = .003), a BMI < 18.5 kg/㎡ (P < .001), coronary heart disease (P = .012), a LVEF < 50 % (P < .001), WIfI-Wound Grade (P = .004) and WIfI clinical stages (P = .044) were independently associated with a decreased AFS rate. This study confirms the predictive ability of WIfI classification for Chinese CLTI patients who underwent EVT. Wound grade was the most sensitive and important risk factor among the three components of WIfI. In addition, systemic factors should also be considered to ensure a more accurate prognosis prediction and appropriate clinical decision-making in CLTI patients.

The Infrapopliteal Global Limb Anatomic Staging System Predicts Wound Healing and Pain Relief after Partial Revascularization

Chronic limb-threatening ischemia (CLTI) is frequently associated with crural artery occlusion. Complete revascularization beyond the diseased crural artery is preferable; however, complete revascularization is challenging in many cases for various reasons. On the other hand, partial reconstruction for inflow disease sometimes leads to complete relief of symptoms. It is not elucidated which patients may recover from CLTI with partial revascularization (PR). Therefore, we aimed to evaluate the factors affecting outcomes after PR. We retrospectively reviewed the medical records of patients who underwent first-attempt PR, for CLTI, for limb salvage, in our institution, between April 2012 and December 2020. We divided these 103 cases into 2 groups: the salvage group (who achieved wound healing or relief from rest pain with PR; n=81) and the nonsalvage group (who ended with major amputation or additional distal revascularization; n=22). We evaluated the factors affecting the outcome of PR in terms of patient risk, limb severity (Society for Vascular Surgery Lower Extremity Threatened Limb Classification System; wound, ischemia, and foot infection [WIfI] classification), and anatomical pattern (Global Limb Anatomic Staging System; GLASS classification). Although patient risk between the 2 groups was not statistically significant, hypoalbuminemia (< 3.0mg/dL) was more prevalent in the nonsalvage group without significance (P=0.068). Regarding limb severity status, there was no significant difference in WIfI grades. Wound grade showed the strongest correlation (P=0.11) and reduced wound grade suggested future wound healing. In terms of GLASS, infrapopliteal grade was statistically significant (P=0.033). Upon a multivariate analysis, among infrapopliteal grade, hypoalbuminemia, and wound grade, infrapopliteal grade (P=0.0096) and hypoalbuminemia (P=0.2512) revealed significant differences. Wound grade also showed correlation (P=0.085). The usefulness of the WIfI classification and GLASS classification to predict wound healing after PR for CLTI was validated.

IDF21-0620 Results of split thickness skin grafts in revascularized diabetic foot ulcers patients

Background: Split thickness skin grafts (STSG) have been shown to improve healing of diabetic foot ulcers (DFU) in non-ischemic patients. There were no previous studies to assess the results of STSG in ischemic revascularized legs. Aim: To assess the results of STSG in patients presenting with DFU and critical limb threatening ischemia (CLTI), who underwent revascularization, in comparison with non-ischemic patients. Method: Retrospective case control study. The data of all consecutive patients who had STSG for DFU at our center between 1st of January 2020 and 31 of December 2020 were reviewed. They were divided into two groups: group A included patients with CTLI who underwent revascularization prior to STSG, and group B included non-ischemic patients who had STSG. DFU were treated along standard lines regarding debridement, off-loading of plantar ulcers, and treatment of infection. DFU in CLTI were treated by revascularization, using endovascular approach mainly. Optimization of the general condition was performed prior to STSG. Negative pressure wound therapy was applied until the wound was covered with healthy granulations, then STSG was performed. All patients were followed for a minimum of 6 months. End points were rate of healing, duration of complete wound healing, major amputation and death. Results: There were 61 patients: Group A: 37 & Group B 24. 78% were male and all were diabetics. No statistical differences were found between both groups regarding the demographic factors and risk factors, and the local wound condition regarding size, location, and wound class according to WIFI classification. Complete wound healing was achieved in 80% in group A versus 92.3% for group B within 6 months (NS). The mean time to complete healing was 31.5 (SD 44.7) days in Group A and 22.2 (SD 21.5) days in group B (NS). One patient had major amputation due to infection and 2 patients died due to unrelated causes, all were in group A. Discussion: STSG was not previous reported following revascularization in patients suffering CLTI and DFU. Although this study showed longer time to achieve complete wound healing in revascularized patients as compared to non-ischemic DFU, the healing rate of the revascularized group (80%) and the mean healing time (31.5 days) were still improved as compared to our own historical data of non-ischemic patients with DFU who did not receive STSG.

SVS WIfI score as a predictor of amputation after onset of CLI: Validation in an Irish tertiary vascular unit

IntroductionCritical limb ischemia (CLI) in diabetic patients is defined by non-healing foot ulcer or rest pain for more than 2 weeks with ankle pressure of less than 40 mmHg. The SVS WIfI classification system stratifies CLI on the basis of perfusion, extent of wound and superadded infection to provide a composite score which guides further management and predicts final prognosis ObjectiveThe aim of the study was to use the SVS WIfI scoring system to predict the need for early revascularization versus early amputation depending on the composite WIfI score at presentation. MethodologyThis was a retrospective observational study. Data was collected on patients admitted with CLI, in the last 2 years, to calculate composite WIfI score. The WIfI categories according to risk of limb loss were identified with endpoint being major or minor amputation. ResultsAmong the 87 patients reviewed, 35 patients (40%) required major amputation, and 29 of those underwent vascular intervention (83%) as part of their care. Median age of the cohort was 72 and 71% were male patients. Comparative analysis between major amputations and minor amputation showed the median score on initial clinical presentation to be 7 in major amputation and 5 in minor amputations (p < 0.0001). ConclusionThe composite WIFi score (a summation of the Wound, Ischaemia, and Infection sub-scores) was a good predictor of need for an amputation WIfI scoring system is a useful tool and should be used early in the management of infected ischaemic limbs.

Angiography Is an Important Adjunct to WIfI Clinical Staging

The SVS Threatened Limb Classification System (“WIfI”) is used to predict risk of limb loss and potentially predict benefit of revascularization in the setting of chronic limb-threatening ischemia (CLTI). We sought to analyze angiographic findings by WIfI classification in patients with CLTI.

Biomedical cell products in patients with diabetic foot syndrome using feasibility (literature review)

Today, the rapid and cost-effective treatment of patients with diabetic foot syndrome (DFS) is still challenging. The use of biomedical cell products (BCP) in this patients category has a clear pathogenetic orientation, but it remains not fully understood and generally accepted. The review presents the results of numerous studies confirming the efficacy of BCP for the treatment of predominantly superficial trophic defects in patients with neuropathic DFS. However, these technologies are still classified as adjuvant therapies. There are no clear algorithms and regulations for the use of BCP. It has been shown that their use accelerates the reparative processes in superficial trophic defects in patients with neuropathic DFS in combination with standard therapy and shortens the time of wound epithelialization. Considering the laboriousness and high cost of BCPs, the possibility of their use for the treatment of patients with neuroischemic form of DFS of various grades according to the WIfI classification should be considered.

Опыт эндоваскулярного лечения пациентов с хронической ишемией, угрожающей потерей конечности

The aim of the study was to assess the technical feasibility of endovascular revascularization of the arteries of the lower extremities in the development of critical ischemia of the lower extremities (chronic ischemia with threatening limb loss), including diabetic foot syndrome. Two clinical cases of endovascular revascularization of lower limb arteries with the development of chronic ischemia with threatening limb loss and diabetic foot syndrome were analyzed. Median age was 61 (60–62) years; there was 1 male (50 %). Upon hospitalization, the risk of limb loss according to the WIfI classification was assessed in one case as high, in the other as medium. The efficiency of revascularization was 100 %. In 1 case (50 %), a second intervention was required. High amputation after surgery during the next year of follow-up was 100 % not necessary. The duration of the operation was 120–150 minutes. The survival rate during the year of follow-up after surgery was 100 %. Clinical observation demonstrates that even with the correct selection of patients, stratification of risk factors for both possible loss of a limb and the risk of surgery, as well as the correctness of the chosen tactics for revascularization of the CPR, only with an increase in the number of procedures performed, routing training and the creation of specialized centers is it possible to achieve satisfactory results in treatment of this problem, which, as the global trend shows, will worsen as the incidence of diabetes increases and the population ages

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

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. 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. 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). 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.

Shared Spectrum Monitoring Using Deep Learning

Shared spectrum usage is inevitable due to the ongoing increase in wireless services and bandwidth requirements. Spectrum monitoring is a key enabler for efficient spectrum sharing by multiple radio access technologies (RATs). In this paper, we present signal classification using deep neural networks to identify various radio technologies and their associated interferences. We use Convolutional Neural Networks (CNN) to perform signal classification and employ six well-known CNN models to train for ten signal classes. These classes include LTE, Radar, WiFi and FBMC (Filter Bank Multicarrier) and their interference combinations, which include, LTE + Radar, LTE + WiFi, FBMC + Radar, FBMC + WiFi, WiFi + Radar and Noise. The CNN models include, AlexNet, VGG16, ResNet18, SqueezeNet, InceptionV3 and ResNet50. The radio signal data sets for training and testing of CNN-based classifiers are acquired using a USRP-based experimental setup. Extensive measurements of these radio technologies (LTE, WiFi, Radar and FBMC) are done over different locations and times to generate a robust dataset. We propose a novel (spectrogram) representation called the Quarter-spectrogram (Q-spectrogram) that squeezes temporal and frequency information for input to CNN models. While considering classification accuracy, model complexity and prediction time for a single input Q-spectrogram (image), ResNet18 (CNN model) gives the best overall performance with 98% classification accuracy. While SqueezeNet (CNN model) offers the lowest model complexity which makes it very suitable for resource-constrained radio monitoring devices and also offers the least prediction time of 110 msec. Moreover, we also propose a simple WiFi classification scheme that buffers several WiFi Q-spectrograms and then makes a decision about WiFi’s presence and also gives a quantified measure of WiFi traffic density.

Pedal Acceleration Time (PAT): A Novel Predictor of Limb Salvage

In the setting of Peripheral Arterial Disease (PAD), pedal arch interrogation by ultrasound has not been well described. Patients with noncompressible vessels and/or open wounds of the foot may preclude the use of ankle-brachial indices, toe pressure measurements, or TcPO2, respectively. We propose that pedal artery interrogations with Pedal Acceleration Time (PAT) can be a predictor for limb salvage in patients with Chronic Limb-Threatening Ischemia (CLTI). A retrospective review of a prospectively kept database was performed from 2018 to 2019. Patients with pending amputation due to severe infection (WIFI infection class 2 and 3) were excluded from the study. We identified 73 limbs with CLTI that fit the inclusion criteria. Data included WIFI classification, age, gender, cardiovascular risk factors, PAT, ABI, and TBI when reliable, were collected. PAT measurements were categorized into 4 classifications; 1 (40-120 msec), 2 (121-180 msec), 3 (181-224 msec), and 4 (Greater than 225 msec). Statistical analyses were performed. Seventy-three limbs with CLTI were included in our study. All patients underwent arterial revascularization with either percutaneous technique or arterial bypass. Limb salvage was achieved in 59 (81%) of the 73 limbs. All 59 limbs had a 2-classification improvement in their PAT following interventions. A total of 14 (19%) limbs without improvement in their PAT underwent above ankle level amputations. An improvement in PAT classes to class 1 or 2 is associated with limb salvage. Patients with noncompressible ankle pressures or nonobtainable toe pressures poses a challenge in the complete assessment of WIFI classification. Our group has shown that PAT can be used in the scoring system for severity of ischemia in conjunction with current WIFI classification. Our data suggests that limb salvage correlates with post procedure PAT in category 1 and 2. Therefore we propose that PAT be added as part of the WIFI classification.

A prognostic risk score for major amputation in dialysis patients with chronic limb-threatening ischemia after endovascular revascularization.

Almost 38% of all patients with end-stage chronic kidney disease (CKD) have peripheral arterial disease of the lower limbs that can lead to chronic limb threatening ischemia (CLTI). The aim of this study was to assess the impact of several factors to conduct a stratification of the amputation risk in CKD patients with CLTI receiving endovascular revascularization. Observational, retrospective, single-center study of patients treated from 2010 to 2016. The primary endpoint was the major amputation. The study included adult CKD dialysis patients affected by CLTI (rest pain and/or trophic lesions) with indication to endovascular revascularization and excluded for open repair. A total of 82 patients were considered (58 men [70.7%], 24 women [29.3%] mean age 70.4±15.0 years). The number of major amputations was 28 (34.1%). The arterial lesion severity (TASC II-classification) and the trophic lesions extension (WIfI classification) were significantly associated with major amputation (OR and 95%CI, 1.20 [1.07-1.34], P=0.001; 2.65 [1.49-4.72], P=0.001; respectively). Based on the above-mentioned characteristics, a prognostic score was proposed to predict the major amputation risk. A score ≥23 was associated with a 67.6% probability of amputation in the following 12 months. The CLTI revascularization is associated with poor outcomes in CKD patients. The present clinical score provided a pragmatic tool to calculate the major amputation risk. An elevated score could facilitate the decision-making process in order to perform an endovascular treatment vs. conservative approach.