Predicting delayed healing: The diagnostic accuracy of a venous leg ulcer risk assessment tool

Prognostic models for clinical outcomes in patients with venous leg ulcers: A systematic review

OBJECTIVE

The purpose of this review was to identify prognostic models for clinical application in patients with venous leg ulcers (VLUs).

METHODS

Literature searches were conducted in Embase, Medline, Cochrane, and CINAHL databases from inception to December 22, 2021. Eligible studies reported prognostic models aimed at developing, validating, and adjusting multivariable prognostic models that include multiple prognostic factors combined, and that predicted clinical outcomes. Methodological quality was assessed using the CHARMS checklist and PROBAST short form questionnaire.

RESULTS

Thirteen studies were identified, of which three were validation studies of previously published models, four reported derivation and validation of models, and the remainder reported derivation models only. There was substantial heterogeneity in the model characteristics, including 11 studies focused on wound healing outcomes reporting 91 different predictors. Three studies shared similar predicted outcomes, follow-up timepoint and used a Cox proportional hazards model. However, these models reported different predictor selection methods and different predictors and it was therefore not feasible to summarize performance, such as discriminative ability.

CONCLUSIONS

There are no standout risk prediction models in the literature with promising clinical application for patients with VLUs. Future research should focus on developing and validating high-performing models in wider VLU populations.

Evaluation of factors affecting the healing process of venous ulcers: A 12-week longitudinal study

The process of healing venous ulcers is complex and influenced by many factors. By identifying the risk factors that influence a slower healing process, it is possible to predict impending delays and plan an individualised care plan. We analysed our database of patients with venous ulcers and identified clinical and demographic factors that delay the healing process. The research analysed the medical records of 754 patients with VLUs at Chronic Wound Treatment Unit of the University Hospital treated between 2001 and 2019. In study, the majority (64.3%) were women, the mean age was 65.7 years. The median duration of Chronic Venous Insufficiency was 24 years, 52% patients had had the disease >20 years, and 296 (39.3%) had experienced ulceration >12 months. Most of the patients (85.8%) had comorbidities, 84% were obese. At 12-week follow-up, 432 of the 754 ulcers had healed. Identified independent predictors of slower ulcer healing rates: wound area greater than 8.25 cm2 , location of the ulceration other than the medial ankle area, underlying disease >20 years, the presence of multiple comorbidities, depth of the ulcer, the presence of an unpleasant smell and alert pathogens. The presence of redness resulted in faster healing of VLUc. Many factors influence the healing process of venous ulceration. The results of the study can help in planning patient care and implementing appropriate early strategies to promote healing.

Can Thermal Imaging Technique be Used to Predict the Healing Status of a Venous Leg Ulcer?

Venous leg ulcers (VLUs) are the most common chronic wound types in older populations, with many wounds not healing in the normal trajectory. Many older people with wounds are treated in their homes, currently assessed by monitoring the wound area over weeks to ascertain the potential for healing. A noncontact method using thermal imaging has been shown to predict the healing trajectory of diabetes-related foot ulcers, although has not been tested in VLU or the home setting. This project investigated the effectiveness of using thermal imaging to predict VLU healing in the homes of participants. Images of 78 ulcers were collected weekly using a thermal camera from 67 participants in their homes, at 5 consecutive time points. Final follow-up calls were undertaken at 12 weeks to ascertain healing status (healed/unhealed). Images were preprocessed and segmented and the area of the region of the wound was extracted. Kruskal-Wallis tests were performed to test the association of the change of areas over the 5 consecutive weeks with the healing status of the ulcers at 12 weeks. The 95% confidence interval plots were obtained to study the distribution of the area in the healed and unhealed cases. This study found that the difference in the imaged areas between unhealed ulcers at 12 weeks did not reach statistical significance using thermal imaging. Therefore, thermal images could not predict healing progression in VLUs when the images were taken in the homes of participants. Future research to improve the prediction of venous leg ulcer healing should include developing a protocol to standardize conditions, improve imaging process methods, and use machine learning.

Plasma Total Ascorbic Acid and Serum 25-Hydroxy-Vitamin-D Status in Patients with Venous Leg Ulcers: A Case-Control Study

Venous leg ulcers (VLUs) pose a significant burden on patients, health care systems, and national economies. Nutritional health is an important determinant of wound healing. Vitamin C and D levels and additional biochemical markers, C-reactive protein, and albumin in a group of patients with VLUs, were compared with a control group without VLUs. No significant difference in either nutrient marker was found with the presence, size, or duration of VLUs. Obesity was significantly more common in the VLU group, as noted in other studies. Additional controlled studies should be performed with measures of VLU size and duration to assess long-term outcomes with nutritional therapy.

Electrical stimulation for pain reduction in hard-to-heal wound healing

OBJECTIVE

Despite treatment advances over the past 30 years, the societal impact of hard-to-heal wounds is increasingly burdensome. An unresolved issue is wound pain, which can make many treatments, such as compression in venous leg ulcers, intolerable. The aim of this review is to present the evidence and stimulate thinking on the use of electrical stimulation devices as a treatment technology with the potential to reduce pain, improve adherence and thus hard-to-heal wound outcomes.

METHOD

A literature search was conducted for clinical studies up to August 2020 reporting the effects of electrical stimulation devices on wound pain. Devices evoking neuromuscular contraction or direct spinal cord stimulation were excluded.

RESULTS

A total of seven publications (three non-comparative and four randomised trials) were identified with four studies reporting a rapid (within 14 days) reduction in hard-to-heal wound pain. Electrical stimulation is more widely known for accelerated healing and is one of the most evidence-based technologies in wound management, supported by numerous in vitro molecular studies, five meta-analyses, six systematic reviews and 30 randomised controlled trials (RCTs). Despite this wealth of supportive evidence, electrical stimulation has not yet been adopted into everyday practice. Some features of electrical stimulation devices may have hampered adoption in the past.

CONCLUSION

As new, pocket-sized, portable devices allowing convenient patient treatment and better patient adherence become more widely available and studied in larger RCTs, the evidence to date suggests that electrical stimulation should be considered part of the treatment options to address the challenges of managing and treating painful hard-to-heal wounds.

Thermal imaging potential and limitations to predict healing of venous leg ulcers

Area analysis of thermal images can detect delayed healing in diabetes foot ulcers, but not venous leg ulcers (VLU) assessed in the home environment. This study proposes using textural analysis of thermal images to predict the healing trajectory of venous leg ulcers assessed in home settings. Participants with VLU were followed over twelve weeks. Digital images, thermal images and planimetry of wound tracings of the ulcers of 60 older participants was recorded in their homes by nurses. Participants were labelled as healed or unhealed based on status of the wound at the 12th week follow up. The weekly change in textural features was computed and the first two principal components were obtained. 60 participants (aged 80.53 ± 11.94 years) with 72 wounds (mean area 21.32 ± 51.28cm2) were included in the study. The first PCA of the change in textural features in week 2 with respect to week 0 were statistically significant for differentiating between healed and unhealed cases. Textural analysis of thermal images is an effective method to predict in week 2 which venous leg ulcers will not heal by week 12 among older people whose wounds are being managed in their homes.

Why Venous Leg Ulcers Have Difficulty Healing: Overview on Pathophysiology, Clinical Consequences, and Treatment

Venous leg ulcers (VLUs) are one of the most common ulcers of the lower extremity. VLU affects many individuals worldwide, could pose a significant socioeconomic burden to the healthcare system, and has major psychological and physical impacts on the affected individual. VLU often occurs in association with post-thrombotic syndrome, advanced chronic venous disease, varicose veins, and venous hypertension. Several demographic, genetic, and environmental factors could trigger chronic venous disease with venous dilation, incompetent valves, venous reflux, and venous hypertension. Endothelial cell injury and changes in the glycocalyx, venous shear-stress, and adhesion molecules could be initiating events in VLU. Increased endothelial cell permeability and leukocyte infiltration, and increases in inflammatory cytokines, matrix metalloproteinases (MMPs), reactive oxygen and nitrogen species, iron deposition, and tissue metabolites also contribute to the pathogenesis of VLU. Treatment of VLU includes compression therapy and endovenous ablation to occlude the axial reflux. Other interventional approaches such as subfascial endoscopic perforator surgery and iliac venous stent have shown mixed results. With good wound care and compression therapy, VLU usually heals within 6 months. VLU healing involves orchestrated processes including hemostasis, inflammation, proliferation, and remodeling and the contribution of different cells including leukocytes, platelets, fibroblasts, vascular smooth muscle cells, endothelial cells, and keratinocytes as well as the release of various biomolecules including transforming growth factor-β, cytokines, chemokines, MMPs, tissue inhibitors of MMPs (TIMPs), elastase, urokinase plasminogen activator, fibrin, collagen, and albumin. Alterations in any of these physiological wound closure processes could delay VLU healing. Also, these histological and soluble biomarkers can be used for VLU diagnosis and assessment of its progression, responsiveness to healing, and prognosis. If not treated adequately, VLU could progress to non-healed or granulating VLU, causing physical immobility, reduced quality of life, cellulitis, severe infections, osteomyelitis, and neoplastic transformation. Recalcitrant VLU shows prolonged healing time with advanced age, obesity, nutritional deficiencies, colder temperature, preexisting venous disease, deep venous thrombosis, and larger wound area. VLU also has a high, 50-70% recurrence rate, likely due to noncompliance with compression therapy, failure of surgical procedures, incorrect ulcer diagnosis, progression of venous disease, and poorly understood pathophysiology. Understanding the molecular pathways underlying VLU has led to new lines of therapy with significant promise including biologics such as bilayer living skin construct, fibroblast derivatives, and extracellular matrices and non-biologic products such as poly-N-acetyl glucosamine, human placental membranes amnion/chorion allografts, ACT1 peptide inhibitor of connexin 43, sulodexide, growth factors, silver dressings, MMP inhibitors, and modulators of reactive oxygen and nitrogen species, the immune response and tissue metabolites. Preventive measures including compression therapy and venotonics could also reduce the risk of progression to chronic venous insufficiency and VLU in susceptible individuals.

The Wound Healing Index for Predicting Venous Leg Ulcer Outcome

Objective: To develop a venous leg ulcer (VLU) risk stratification system for use in research and clinical practice. Approach: U.S. Wound Registry data were examined retrospectively and assigned an outcome. Bivariate analysis identified significant variables (p < 0.05) that were used to create a multivariable logistic regression model. Ulcers with data for wound area at the first visit before debridement were included in regression analysis, which was based on a 90% development sample. The model was validated on a hold-out 10% data sample. Results: The original dataset included 26,713 VLUs, of which 11,773 ulcers were eligible for preliminary analysis and 10,942 ulcers were eligible for regression analysis. The 90% development model included 9,898 ulcers, of which 7,498 healed (75.8%). The 10% validation sample included 1,044 ulcers, of which 809 healed (77.5%). The following variables significantly predicted healing: number of concurrent wounds of any etiology, wound size, wound age (in days), evidence of bioburden/infection, being nonambulatory, and hospitalization for any reason. Innovation: The VLU Wound Healing Index (WHI) is a comprehensive, validated risk stratification model for predicting VLU healing that incorporates patient- and wound-specific variables. Conclusions: The WHI can identify which VLUs most likely require adjunctive therapies to heal, prioritize referral to venous experts, risk-stratify ulcers to create more generalizable clinical trials and understand the impact of clinical interventions. The Centers for Medicare and Medicaid Services accepts this method for reporting VLU outcome under the Quality Payment Program.

Infrared thermography to prognose the venous leg ulcer healing process-preliminary results of a 12-week, prospective observational study

Venous leg ulcers are complex, and their multifactorial etiology make successful treatment a difficult and long process. Nonhealing ulcers are the greatest challenge because they are resistant to standard therapies. In this study, we analyzed whether monitoring the temperature of the ulcered limb wound area could benefit the diagnosis of the wound's tendency to heal (estimating the presence of a healing or nonhealing wound) in patients with two-sided venous leg ulcers. This prospective, 12-week observational study included 57 adult individuals with chronic venous leg ulcers. The dynamics of wound healing was assessed by planimetry and infrared thermography every two weeks. We analyzed temperatures measured at three marked areas-the wound, the periwound skin, and the reference area. An initial wound area larger than 1 cm² was associated with a temperature increase of 0.027 °C in the periwound skin. A 1-cm² decrease in the wound area was associated with a 0.04 °C decrease in the temperature difference between the periwound skin and wound. A strong positive relationship was identified for both the bacteriology variables (the presence of bacteria: temperature increase in the periwound skin of 0.4 °C, p < 0.001; the number of bacterial species in a wound, temperature increase of 0.95 °C, p < 0.001). The temperature in the reference area was significantly correlated with the failure of the superficial and perforating veins (temperature increase of 0.69 °C, p = 0.04). This study reports that the assessment of the temperature a limb may be beneficial in predicting whether an ulcer is a healing or a nonhealing ulcer. The decrease in the temperature differences between the areas referred to as healing wounds was the only beneficial prognostic marker. Other temperature differences in the periwound skin were caused by disorders, such as multibacterial wound infections and superficial venous inflammation.

Potential prognostic factors for delayed healing of common, non-traumatic skin ulcers: A scoping review

Healing of non-traumatic skin ulcers is often suboptimal. Prognostic tools that identify people at high risk of delayed healing within the context of routine ulcer assessments may improve this, but robust evidence on which factors to include is lacking. Therefore, we scoped the literature to identify which potentially prognostic factors may warrant future systematic reviews and meta-analyses. We conducted electronic searches in MEDLINE and Embase to identify studies in English published between 1997 and 2017 that tested the association between healing of the three most common non-traumatic skin ulcers encountered by health care professionals (venous leg, diabetic foot, and pressure ulcers) and patient characteristics, ulcer characteristics, and results from clinical investigations. We included 42 studies that investigated factors which may be associated with the healing of venous leg ulcers (n = 17), diabetic foot ulcers (n = 15), and pressure ulcers (n = 10). Across ulcer types, ulcer characteristics were most commonly reported as potential prognostic factors for healing (n = 37), including the size of the ulcer area (n = 29) and ulcer duration at first assessment (n = 16). A total of 35 studies investigated the prognostic value of patient characteristics (n = 35), including age (n = 31), gender (n = 30), diabetes (n = 22), smoking status (n = 15), and history of deep vein thrombosis (DVT) (n = 13). Of these studies, 23 reported results from clinical investigations as potential prognostic factors, with the majority regarding vessel quality. Age, gender, diabetes, smoking status, history of DVT, ulcer area, and ulcer duration at time of first assessment warrant a systematic review and meta-analysis to quantify their prognostic value for delayed ulcer healing.

T.I.M.E. to improve patient outcomes: use of a clinical decision support tool to optimise wound care

Patients with wounds pose an important healthcare challenge. Many of these wounds are managed in community care and can take weeks or months to resolve. Delays in wound healing can be perpetuated by clinicians who make poor treatment choices, fail to recognise complications and/or do not seek timely advice. Improving patient outcomes requires a proactive approach to care that includes accurate and timely assessment and re-assessment, treatment of the underlying cause using a multidisciplinary team approach and the use of evidence-based practice and clinical judgement to develop an appropriate treatment plan. A structured approach to care, such as the newly developed T.I.M.E. clinical decision support tool, has the potential to improve wound healing outcomes and reduce the burden of chronic wounds in community nursing services.

Predicting delayed healing: The diagnostic accuracy of a venous leg ulcer risk assessment tool

The aim of this study was to validate a newly developed tool that can predict the risk of failure to heal of a venous leg ulcer in 24 weeks. The risk assessment tool was validated, and performance of the tool was assessed using Area Under the Receiver Operating Characteristic Curve (AUC) analysis. Retrospective and prospective validation was conducted through multi-site, longitudinal studies. In the retrospective study (n = 318), 30% of ulcers did not heal within 24 weeks, with the tool demonstrating an AUC of 0.80 (95% CI, 0.68-0.93, P < .001) for the total score. In the prospective study across 10 clinical sites (n = 225), 31% (n = 68) of ulcers did not heal within 24 weeks. Participants were classified with the RAT at enrolment as being at low risk (27%), moderate risk (53%) or high risk (20%) of delayed healing; the proportion of wounds unhealed at 24 weeks was 6%, 29% and 59%, respectively. Validation results of the total score indicated good discrimination and goodness of fit with an AUC of 0.78 (95% CI, 0.71-0.85, P < .001). Validation of this risk assessment tool offers assurance that realistic outcomes can be predicted for patients, and scores can guide early decisions on interventions to address specific risk factors for failing to heal, thus promoting timely healing.