Implementing global chronic limb-threatening ischemia guidelines in clinical practice: Utility of the Society for Vascular Surgery Threatened Limb Classification System (WIfI)

Current Status and Principles for the Treatment and Prevention of Diabetic Foot Ulcers in the Cardiovascular Patient Population: A Scientific Statement From the American Heart Association

Despite the known higher risk of cardiovascular disease in individuals with type 2 diabetes, the pathophysiology and optimal management of diabetic foot ulcers (DFUs), a leading complication associated with diabetes, is complex and continues to evolve. Complications of type 2 diabetes, such as DFUs, are a major cause of morbidity and mortality and the leading cause of major lower extremity amputation in the United States. There has recently been a strong focus on the prevention and early treatment of DFUs, leading to the development of multidisciplinary diabetic wound and amputation prevention clinics across the country. Mounting evidence has shown that, despite these efforts, amputations associated with DFUs continue to increase. Furthermore, due to increasing patient complexity of management secondary to comorbid conditions, such as cardiovascular disease, the management of peripheral artery disease associated with DFUs has become increasingly difficult, and care delivery is often episodic and fragmented. Although structured, process-specific approaches exist at individual institutions for the management of DFUs in the cardiovascular patient population, there is insufficient awareness of these principles in the general medicine communities. Furthermore, there is growing interest in better understanding the mechanistic underpinnings of DFUs to better define personalized medicine to improve outcomes. The goals of this scientific statement are to provide salient background information on the complex pathogenesis and current management of DFUs in cardiovascular patients, to guide therapeutic and preventive strategies and future research directions, and to inform public policy makers on health disparities and other barriers to improving and advancing care in this expanding patient population.

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.

Relationship between WIfI stage and quality of life at revascularization in the BEST-CLI trial

OBJECTIVE

The WIfI (Wound, Ischemia, foot Infection) stage measures the extent of wounds, ischemia, and foot infection in patients with chronic limb threatening ischemia (CLTI) and has been associated with the risk of major amputation. Patients with CLTI have impaired health-related quality of life (HRQoL), which can be multifactorial. We hypothesized that the severity of the limb threat (WIfI stage) would be associated with poor HRQoL among patients with CLTI presenting for revascularization.

METHODS

The dataset of the BEST-CLI (best endovascular versus best surgical therapy in patients with CLTI) trial, a prospective, randomized trial comparing open and endovascular revascularization strategies, was queried for HRQoL assessments at patient enrollment. The HRQoL assessments included (1) Vascular Quality of Life; (2) 12-item short form survey (SF-12), containing the utility index score (short-form six-dimension R2 utility index, incorporating physical, emotional, and mental well-being) and mental and physical components; and (3) the EQ-5D. Multivariable regression analysis was used to identify the independent associations with the baseline HRQoL assessments.

RESULTS

A total of 1568 patients with complete WIfI data were analyzed, of whom 71.5% were men. The WIfI distribution was 35.5% with stage 4, 29.6% with stage 3, 28.6% with stage 2, and 6.3% with stage 1. Patients presenting with WIfI stage 4, compared with stage 1 to 3, were more often men (74.9% vs 69.6%) and current smokers (25.4% vs. 17.6%), had had end-stage renal disease (13.3% vs 8.5%) and diabetes (83.6% vs 60.2%), were not independently ambulatory (56.8% vs 38.5%), and had had higher median morbidity scores (4 vs 3; P < .05 for all). On multivariable analysis, WIfI stage 4, compared with stage 1 to 3, was associated with lower SF-12 mental component scale scores (estimate, -2.43; 95% confidence interval, -3.73 to -1.13; P < .001) and short-form six-dimension R2 utility index scores (estimate, -0.02; 95% confidence interval, -0.03 to 0.001; P = .04). The WIfI stage was not independently associated with the baseline Vascular Quality of Life, SF-12 physical component scale, or EQ-5D assessments.

CONCLUSIONS

WIfI stage was independently associated with poorer quality of life because of mental, rather than physical, health for patients with CLTI. Clinicians should be aware of the burden of mental stress borne by those with the greatest limb impairment.

Evolution of WIfI: Expansion of WIfI Notation After Intervention

Nearly a decade ago, the Society for Vascular Surgery (SVS)'s wound, ischemia, and foot Infection (WIfI) classification was first developed to help assess overall limb threat. However, managing conditions such as diabetic foot ulcer and chronic limb-threatening ischemia can be complex. For instance, certain investigative findings might initially be pending such as the level of ischemia or extent of infection before the final classification is established. In addition, wounds evolve rapidly, and the current classification does not allow for tracking their progression over time during treatment. Therefore, we propose a supplemental consistent notation for scoring WifI re-assessment during treatment of a threatened limb inspired by the cancer staging before and after neoadjuvant treatment classification system. Thus, we describe the re-scoring system and how to use it. Our suggestion supports a coherent method to longitudinally communicate characteristics of a threatened limb. This has potential to support high quality interdisciplinary, patient-centered care and enhance the use of this classification in research. Further work is required to validate this modification of a common language of risk.

Conservative Management of Non-Infected Diabetic Foot Ulcers Achieves Reliable Wound Healing and Limb Salvage in the Setting of Mild-Moderate Ischemia

OBJECTIVE

The Society for Vascular Surgery (SVS) Wound, Ischemia, and foot Infection (WIfI) classification system has been validated to predict wound healing among patients with critical limb threatening ischemia (CLTI). Our goal was to analyze the use of a previously reported conservative wound care approach to non-infected (foot infection score of zero), diabetic foot ulcers (DFU) with mild-moderate peripheral arterial disease (PAD) enrolled in a conservative tier of a multidisciplinary limb preservation program.

METHODS

Veterans with CLTI and tissue loss were prospectively enrolled into our Prevention of Amputation in Veterans Everywhere (PAVE) program. All patients with wounds were stratified to a conservative approach based on perfusion evaluation and a validated pathway of care. Retrospective analysis of a prospectively maintained database was performed to evaluate all conservatively managed patients presenting without foot infection for the primary outcome of wound healing as well as secondary outcomes of time to wound healing, delayed revascularization, wound recurrence, and limb loss.

RESULTS

Between January 2006 and December 2019, 1113 patients were prospectively enrolled into the PAVE program. A total of 241 limbs with 281 wounds (217 patients) were stratified to the conservative approach. Of these, 122 limbs (89 patients) met criteria of having diabetic foot wounds without infection at the time of enrollment and are analyzed in this report. Of the 122 limbs, 97 (79.5%) healed their index wound with a mean time to healing of 4.6 months (0.5-20 months). Wound recurrence ensued in 44 (45.4%) limbs, 93.2% of which healed again after recurrence. There were three (3.1%) limbs requiring major amputation in this group (one due to uncontrolled infection and two due to ischemic tissue loss). Of the 25 (20.5%) limbs that did not heal initially, four (16%) required amputation due to progressive symptoms of CLTI.

CONCLUSIONS

In patients` with diabetes and lower extremity wounds without infection in the setting of mild to moderate PAD, there appears to be an acceptable rate of index wound healing, and appropriate rate of recurrent wound healing with a low risk of limb loss. While wound recurrence is frequent, this can be successfully treated without the need for revascularization.

Participation in a Chronic Limb Threatening Ischemia Randomized Trial Is Inversely Correlated With Regional Amputation Rate in Limb Threatening Ischemia Patients

OBJECTIVE

The National Health Service demonstrated that regions of the United Kingdom with the highest number of patients enrolled in research studies had the lowest risk-adjusted mortality when patients were admitted to the hospital. Our goal was to investigate if this correlation was evident for patients with chronic limb threatening ischemia (CLI) treated in the United States (US). Accordingly, we examined correlations among sites participating in the Best Endovascular versus best Surgical Therapy in patients with Critical (BEST-CLI) trial, a multicenter, National Institute of Health-sponsored, international randomized controlled trial (RCT) comparing revascularization strategies in patients with CLI, and regional rates of major amputation from CLI.

METHODS

We measured regional participation in the BEST-CLI trial by evaluating trial participation and enrollment rosters. To determine regional rates of lower limb amputation, we queried the Medicare database (2007-2016) for patients with concurrent peripheral arterial disease (PAD) and diabetes, then assessed how many had lower extremity amputations. Correlation of regional amputation rates with distribution of BEST-CLI sites in four US geographical regions was calculated using Pearson's correlation coefficients. Simple regression equations were used to calculate the significance of these correlation coefficients.

RESULTS

Of 9,231,909 CLI patients, 342,406 underwent amputation in the Medicare dataset. Amputation rates per 1000 CLI patients differed by region (South 40.42, Midwest 40.12, West 34.81, Northeast 31.14). There were 116 US vascular centers, selected by volume and expertise that participated in BEST-CLI with the following distribution: South (n = 30, 26%), Midwest (n = 26, 22%), West (n = 29, 25%), and Northeast (n = 31, 27%). There was a negative correlation between the number of amputations per 1000 for Medicare CLI patients with diabetes and PAD and the number of BEST-CLI sites in the region which trended toward significance (Pearson R= -0.61, P = 0.39).

CONCLUSIONS

Amputation rate among Medicare CLI patients is inversely correlated with US BEST-CLI site distribution. Higher participation in clinical research, especially within large RCTs, may be a marker of optimal PAD management.