Direct Revascularization With the Angiosome Concept for Lower Limb Ischemia: A Systematic Review and Meta-Analysis

The Double Burden: Deciphering Chronic Limb-Threatening Ischemia in End-Stage Renal Disease

BACKGROUND

Chronic limb-threatening ischemia (CLTI) in patients with end-stage renal disease (ESRD) poses significant challenges in clinical management due to its unique pathology and poor treatment outcomes. This review calls for a tailored classification and risk assessment for these patients to guide better revascularization choices with early minor amputation as a first-line strategy in advanced stages.

METHODS

This review consolidates key findings from recent literature on CLTI in ESRD, focusing on disease mechanisms, treatment options, and patient outcomes. It evaluates the literature to clarify the decision-making process for managing CLTI in ESRD.

RESULTS

CLTI in ESRD patients often results in worse clinical outcomes, such as nonhealing wounds, increased limb loss, and higher mortality rates. While the literature reveals ongoing debates regarding the optimal revascularization method, recent retrospective studies and meta-analyses suggest potential benefits of endovascular treatment (EVT) over open bypass surgery (OB) in reducing mortality and wound complications, with comparable amputation-free survival rates.

CONCLUSIONS

The selection of revascularization methods in ESRD patients with CLTI is complex, necessitating individualized strategies. The importance of early detection and timely intervention is critical to decelerate disease progression and improve revascularization outcomes. There is a shift in these treatment strategies toward less invasive endovascular procedures, acknowledging the limitations these patients face with open revascularization surgeries. Considering early minor amputations after revascularization could prevent worse consequences, reflecting a shift in the approach to managing CLTI in ESRD patients.

Confounding factors in peripheral thermal recovery time after active cooling

OBJECTIVES

The effectiveness of normal physiological thermoregulation complicates differentiation between pathologic changes in medical thermography associated with peripheral artery disease and a number of other clinical conditions. In this study we investigate a number of potential confounding factors to the thermal recovery rate after active limb cooling, with the main focus on age and sex.

APPROACH

The source data consists of 53 healthy individuals with no diagnosed cardiovascular disease or reported symptoms and with a mean age of 38.4 (± 12.1) years. The sample population was further divided into male (N = 14) and female groups (N = 39). The thermal recovery time was measured using two thermal cameras from both lower limbs on plantar and dorsal sides. The active cooling was achieved using moldable cold pads placed on the plantar and dorsal side of the lower limb. The recovery was measured until the temperature had reached a stable level. The recovery time was determined from an exponential fit to the measured data.

RESULTS

The correlation between the thermal recovery time constant and age varied from low to moderate linear correlation (0.31 ≤ ⍴ ≤ 70), depending on the inspected region of interest, with a higher statistically significant correlation in the medial regions. The contralateral limb temperature differences or the thermal time constants did not have statistically significant differences between the male and female sexes. Further, the secondary metrics such as participant's body mass, body-mass index, or systolic blood pressure had low or no correlation with the thermal recovery time in the study group.

CONCLUSION

The thermal recovery time constant after active cooling appears as a relatively independent metric from the majority of the measured potential confounding factors. Age should be accounted for when performing thermal recovery measurements. However, dynamic thermal imaging and its methodologies require further research and exploration.

Risk Factors for 30-day Hospital Readmissions After Peripheral Vascular Interventions in Peripheral Artery Disease Patients at the US-Mexico Border

Peripheral artery disease (PAD) is associated with high rates of readmission following endovascular interventions and contributes to a significant hospital readmission burden. Quality metrics like hospital readmissions affect hospital performance, but must adjust to local trends. Our primary goal was to evaluate risk factors and readmission rates post-percutaneous peripheral intervention in a US-Mexico border city, at a single tertiary university hospital. We performed a retrospective review of patients with PAD undergoing first time peripheral intervention from July 2015 to June 2020. Among 212 patients, 58% were readmitted with median 235-day follow-up (inter-quartile range (IQR) 42-924); 35.3% of readmissions occurred within 30 days, and 30.2% of those were within 7 days. Median time to readmission was 62 days. Active smokers had 84% higher risk of readmission (hazard ratio (HR) 1.84, 95% CI 1.23-2.74, P < .01). Other significant factors noted were insurance status-Medicaid or uninsured (HR 1.94, 95% CI 1.22-3.09), prior amputation (HR 1.69, 95% CI 1.13-2.54), heart failure, both preserved (HR 4.35, 95% CI 2.07-9.16) and reduced ejection fraction (HR 1.88, 95% CI 1.14-3.10). Below the knee, interventions were less likely to be readmitted (adjusted HR .64, 95% CI 0.42-.96). Readmission rates were unrelated to medication adherence.

Proximal Arterial Inflow Revascularization Improves Pedal Arch Quality and Its Impact on Ischemic Diabetic Foot Ulcer Healing

BACKGROUND

Arterial perfusion is a key factor in diabetic foot ulcer (DFU) healing. Although it is associated with pedal arch patency, not all patients are amenable to pedal artery angioplasty. This study aims to determine the impact of angiographic improvement of the pedal arch quality after proximal arterial inflow revascularization (PAIR) and its association with wound healing.

METHODS

One hundred and fifty diabetic patients with tissue loss in 163 limbs who had digital subtraction angiography were studied. Cox regression analysis was used to determine independent predictors of wound healing. Wound healing rates in association with pedal arch patency were calculated by Kaplan-Meier analysis.

RESULTS

End-stage renal disease, minor amputation, and complete pedal arch patency were significant independent predictors of wound healing following PAIR with hazard ratios for failure: 3.02 (P = 0.008), 0.54 (P = 0.023), and 0.40 (P = 0.039), respectively. The prevalence of complete pedal arches increased by 24.1% with successful intervention (P < 0.001). The overall rates of wound healing at 6, 12, and 24 months were 36%, 64%, and 72%, respectively. The wound healing rate at 1 year in patients with a complete pedal arch was 73% compared to 45% in those with an absent pedal arch (P = 0.017).

CONCLUSIONS

PAIR increases complete pedal arch patency, a significant predictor of wound healing in DFU.

Evaluation of the Angiosome Concept Using Near-Infrared Fluorescence Imaging with Indocyanine Green

BACKGROUND

The angiosome concept is defined as the anatomical territory of a source artery within all tissue layers. When applying this theory in vascular surgery, direct revascularization (DR) is preferred to achieve increased blood flow toward the targeted angiosome of the foot in patients with lower extremity arterial disease (LEAD). This study evaluates the applicability of the angiosome concept using quantified near-infrared (NIR) fluorescence imaging with indocyanine green (ICG).

METHODS

This study included patients undergoing an endovascular- or surgical revascularization of the leg between January 2019 and December 2021. Preinterventional and postinterventional ICG NIR fluorescence imaging was performed. Three angiosomes on the dorsum of the foot were determined: the posterior tibial artery (hallux), the anterior tibial artery (dorsum of the foot) and the combined angiosome (second to fifth digit). The angiosomes were classified from the electronic patient records and the degree of collateralization was classified based on preprocedural computed tomography angiography and/or X-ray angiography. Fluorescence intensity was quantified in all angiosomes. A subgroup analysis based on endovascular or surgical revascularized angiosomes, and within critical limb threatening ischemia (CLTI) patients was performed.

RESULTS

ICG NIR fluorescence measurements were obtained in 52 patients (54 limbs) including a total of 157 angiosomes (121 DR and 36 indirect revascularizations [IR]). A significant improvement of all perfusion parameters in both the directly and indirectly revascularized angiosomes was found (P-values between <0.001-0.007). Within the indirectly revascularized angiosomes, 90.6% of the scored collaterals were classified as significant. When comparing the percentual change in perfusion parameters between the directly and indirectly revascularized angiosomes, no significant difference was seen in all perfusion parameters (P-values between 0.253 and 0.881). Similar results were shown in the CLTI patients subgroup analysis, displaying a significant improvement of perfusion parameters in both the direct and indirect angiosome groups (P-values between <0.001 and 0.007), and no significant difference when comparing the percentual parameter improvement between both angiosome groups (P-values between 0.134 and 0.359). Furthermore, no significant differences were observed when comparing percentual changes of perfusion parameters in directly and indirectly revascularized angiosomes for both endovascular and surgical interventions (P-values between 0.053 and 0.899).

CONCLUSIONS

This study proves that both DR and IR of an angiosome leads to an improvement of perfusion. This suggests that interventional strategies should not only focus on creating in-line flow to the supplying angiosome. One can argue that the angiosome concept is not applicable in patients with LEAD.

Angiosome-directed endovascular intervention and infrapopliteal disease: Intraoperative evaluation of distal hemodynamic changes and foot blood volume of lower extremity

Objectives

To evaluate foot blood volume and hemodynamics and explore whether quantitative techniques can guide revascularization.

Materials and methods

A prospective single-center cohort study included thirty-three patients with infrapopliteal artery occlusion who underwent percutaneous transluminal angioplasty (PTA) between November 2016 and May 2020. The time-to-peak (TTP) from color-coded quantitative digital subtraction angiography (CCQ-DSA) and parenchymal blood volume (PBV) were used to evaluate the blood volume and hemodynamic changes in different regions of the foot before and after the operation.

Results

After the intervention procedure, the overall blood volume significantly increased from 25.15 ± 21.1 ml/1,000 ml to 72.33 ± 29.3 ml/1,000 ml (p &lt; 0.001, with an average increase of 47.18 ml/1,000 ml. The overall TTP decrease rate, postoperative blood flow time significantly faster than those preoperatively, from 22.93 ± 7.83 to 14.85 ± 5.9 s (p &lt; 0.001, with an average decrease of 8.08 s). Direct revascularization (DR) resulted in significant blood volume improvement than compared with indirect revascularization (IR) [188% (28, 320) vs.51% (10, 110), p = 0.029]. Patients with DR had a significantly faster blood flow time than those with IR [80% (12, 180) vs. 26% (5, 80), p = 0.032]. The ankle-brachial index (ABI) of the affected extremity also showed an significant change from 0.49 ± 0.3 to 0.63 ± 0.24 (p &lt; 0.001) after the intervention. The relative values of ΔTTP and ΔABI showed a weak correlation (r = −0.330).

Conclusions

The quantitative measurement results based on PBV and CCQ-DSA techniques showed that the overall blood volume increased significantly and that the foot distal hemodynamics were significantly improved after endovascular treatment. DR in the ischemic area could r improve foot perfusion.

Evaluation of Tissue Perfusion by Wound Blush and 2D Color-Coded Digital Subtraction Angiography During Endovascular Intervention and Its Impact on Limb Salvage in Critical Limb Ischemia

PURPOSE

Critical limb ischemia (CLI) is an entity with high mortality if not properly treated. The primary aim of CLI revascularization is to enhance wound healing, which greatly depends on microvascular circulation. The available tools for assessment of revascularization success are deficient in the evaluation of local microvascular tissue perfusion, that wound blush (WB) reflects. A reliable technique that assesses capillary flow to foot lesions is needed. This study aims to assess WB angiographically at sites of interest in the foot after revascularization and its impact on limb salvage in CLI.

MATERIALS AND METHODS

198 CLI patients (Rutherford category 5/6) with infrainguinal atherosclerotic lesions amenable for endovascular revascularization (EVR) were included. Limbs were directly or indirectly revascularized by EVR. Direct revascularization meant that successful revascularization of the area of interest according to the angiosome concept was achieved. A completion angiographic run was taken to assess WB. Patients were divided into 2 groups; positive and negative WB groups. In the event of a disagreement between the observational investigators, the digital subtraction angiography (DSA) series was analyzed for hemodynamic changes with a computerized 2D color-coded DSA (Syngo iFlow).

RESULTS

176 limbs had successful revascularization in 157 patients. The successful revascularization rate was 88.9% (176/198), with technical failure encountered in 22 limbs. 121 patients had positive WB and 55 patients had negative WB. Direct revascularization of target areas was obtained in 98 limbs (55.7%). There was a significant difference in the rate of achieving direct flow to the lesion between the positive WB and negative WB groups (36.4% vs 19.3%, p≤0.001). We noticed a nonsignificant difference between patients who had direct revascularization of the foot lesion(s) and those who had indirect revascularization as regards limb salvage. Patients were followed up for 25.2 ± 12.7 months. By the end of the first year, limb salvage rate was significantly higher in patients who had positive WB (98% vs 63%, p<0.001, after 2 years (97% vs 58%, p<0.001) and after 3 years (94% vs 51.5%, p<0.001).

CONCLUSIONS

WB is an important predictor and a prognostic factor for wound healing in CLI patients with soft tissue lesions.

Advances in Revascularization for Peripheral Artery Disease: Revascularization in PAD

Effective revascularization of the patient with peripheral artery disease is about more than the procedure. The approach to the patient with symptom-limiting intermittent claudication or limb-threatening ischemia begins with understanding the population at risk and variation in clinical presentation. The urgency of revascularization varies significantly by presentation; from patients with intermittent claudication who should undergo structured exercise rehabilitation before revascularization (if needed) to those with acute limb ischemia, a medical emergency, who require revascularization within hours. Recent years have seen the rapid development of new tools including wires, catheters, drug-eluting technology, specialized balloons, and biomimetic stents. Open surgical bypass remains an important option for those with advanced disease. The strategy and techniques employed vary by clinical presentation, lesion location, and lesion severity. There is limited level 1 evidence to guide practice, but factors that determine technical success and anatomic durability are largely understood and incorporated into decision-making. Following revascularization, medical therapy to reduce adverse limb outcomes and a surveillance plan should be put in place. There are many hurdles to overcome to improve the efficacy of lower extremity revascularization, such as restenosis, calcification, microvascular disease, silent embolization, and tools for perfusion assessment. This review highlights the current state of revascularization in peripheral artery disease with an eye toward technologies at the cusp, which may significantly impact current practice.

Angiosomal Vascular Occlusions, Deep-Tissue Pressure Injuries, and Competing Theories: A Case Report

ABSTRACT

Compression of the soft tissue between a support surface and a bony prominence has long been the accepted primary mechanism of pressure injury (PrI) formation, with the belief that said compression leads to capillary occlusion, ischemia, and tissue necrosis. This explanation presupposes an "outside-in" pathophysiologic process of tissue damage originating at the local capillary level. Despite advances in prevention protocols, there remains a stubbornly consistent incidence of severe PrIs including deep-tissue injuries, the latter usually evolving into stage 4 PrIs with exposed bone or tendon. This article presents just such a perioperative case with the aim of providing further evidence that these more severe PrIs may result from ischemic insults of a named vessel within specific vascular territories (labeled as angiosomes). Pressure is indeed a factor in the formation of severe PrIs, but these authors postulate that the occlusion occurred at the level of a named artery proximal to the lesion. This vascular event was likely attributable to low mean arterial pressure. The authors suggest that the terminology proposed three decades ago to call both deep-tissue injuries and stage 4 PrIs "vascular occlusion pressure injuries" should be the topic of further research and expert consensus.

Prognostic Value of Radiotracer-Based Perfusion Imaging in Critical Limb Ischemia Patients Undergoing Lower Extremity Revascularization

OBJECTIVES

The purpose of this study was to evaluate the prognostic value of single-photon emission computed tomography (SPECT)/computed tomography (CT) imaging of angiosome foot perfusion for predicting amputation outcomes in patients with critical limb ischemia (CLI) and diabetes mellitus (DM).

BACKGROUND

Radiotracer imaging can assess microvascular foot perfusion and identify regional perfusion abnormalities in patients with critical limb ischemia CLI and DM, but the relationship between perfusion response to revascularization and subsequent clinical outcomes has not been evaluated.

METHODS

Patients with CLI, DM, and nonhealing foot ulcers (n = 25) were prospectively enrolled for SPECT/CT perfusion imaging of the feet before and after revascularization. CT images were used to segment angiosomes (i.e., 3-dimensional vascular territories) of the foot. Relative changes in radiotracer uptake after revascularization were evaluated within the ulcerated angiosome. Incidence of amputation was assessed at 3 and 12 months after revascularization.

RESULTS

SPECT/CT detected a significantly lower microvascular perfusion response for patients who underwent amputation compared with those who remained amputation free at 3 (p = 0.01) and 12 (p = 0.01) months after revascularization. The cutoff percent change in perfusion for predicting amputation at 3 months was 7.55%, and 11.56% at 12 months. The area under the curve based on the amputation outcome was 0.799 at 3 months and 0.833 at 12 months. The probability of amputation-free survival was significantly higher at 3 (p = 0.002) and 12 months (p = 0.03) for high-perfusion responders than low-perfusion responders to revascularization.

CONCLUSIONS

SPECT/CT imaging detects regional perfusion responses to lower extremity revascularization and provides prognostic value in patients with CLI (Radiotracer-Based Perfusion Imaging of Patients With Peripheral Arterial Disease; NCT03622359).

Foot Angiosomes: Instructions for Use

In the last 15 years an abundance of literature has demonstrated that angiosome-targeted revascularization, either endovascular or open, can lead to better clinical results in patients with chronic limb-threatening ischemia. According to this literature, the angiosome concept should guide our treatment strategy in every chronic limb-threatening ischemia patient. However, in our daily practice, its application is often difficult or impossible. Most foot wounds spread over multiple angiosomes and, moreover, the value of an angiosome-guided revascularization approach can vary according to vascular anatomy, collateral vessel network, type of revascularization, and wound. The aim of this article is to explore values and limits of the angiosome concept, and to propose some “instructions for use” regarding its application in our daily practice.

Involvement of microcirculation in critical ischemia: how to identify it?

Critical limb ischemia represents the most severe pattern of peripheral arterial disease (PAD) associated with the high risk of major amputation, cardiovascular events and death. The diagnosis and management of critical limb ischemia (CLI) is often challenging. Systolic ankle and toe pressure measurements are considered to be the basic techniques for the identification of PAD. However, they provide rough insight into the dependent local tissue perfusion. Furthermore, those techniques do not enable investigation of microcirculation which has crucial role in the pathogenesis of CLI. Some patients with mild deterioration of macrocirculation develop CLI if microcirculation is affected. Investigation of perfusion on macro- and local microcirculatory level enables more effective treatment: revascularization of the angiosome-related artery. The technologies capable of assessing limb tissue oxygenation or perfusion on microcirculatory level enable direct assessment of distant tissue oxygenation. Transcutaneous oxygen tension (TcPO2) measurement which was introduced in clinical practice represents one of the objective criteria for the diagnosis of CLI. Main weakness of this technique as well as laser Doppler flow measurement is low penetrance from the skin surface. Measurement of tissue blood flow on microcirculatory level can be performed with indocyanine green fluorescent imaging (ICG), contrast-enhanced magnetic resonance and vital microscopy. ICG is promising method which provides excellent informative image of tissue perfusion. However, it offers little quantitative information. Investigation of microcirculation in patients with CLI is of outmost importance because it enables insight in local tissue perfusion and oxygenation, which represents the basis of identification of most ischemic regions and provide more successful angiosome related revascularization of an affected artery.

SPECT/CT Imaging: A Noninvasive Approach for Evaluating Serial Changes in Angiosome Foot Perfusion in Critical Limb Ischemia

Objective: To investigate the feasibility of serial radiotracer-based imaging as a noninvasive approach for quantifying volumetric changes in microvascular perfusion within angiosomes of the foot following lower extremity revascularization in the setting of critical limb ischemia (CLI).

Approach: A CLI patient with a nonhealing foot ulcer underwent single-photon emission computed tomography (SPECT)/computed tomography (CT) imaging of the feet before and after balloon angioplasty of the superficial femoral artery (SFA) and popliteal artery. SPECT/CT imaging was used to evaluate serial changes in angiosome perfusion, which was compared to quantitative changes in peripheral vascular anatomy and hemodynamics, as assessed by standard clinical tools that included digital subtraction angiography (DSA), ankle-brachial index (ABI), and toe-brachial index (TBI).

Results: Following revascularization, upstream quantitative improvements in stenosis of the SFA (pre: 35.4% to post: 11.9%) and popliteal artery (pre: 59.1% to post: 21.7%) shown by DSA were associated with downstream angiosome-dependent improvements in SPECT microvascular foot perfusion that ranged from 2% to 16%. ABI measurement was not possible due to extensive arterial calcification, while TBI values decreased from 0.26 to 0.16 following revascularization.

Innovation: This is the first study to demonstrate the feasibility of assessing noninvasive volumetric changes in angiosome foot perfusion in response to lower extremity revascularization in a patient with CLI by utilizing radiotracer-based imaging.

Conclusion: SPECT/CT imaging allows for quantification of serial perfusion changes within angiosomes containing nonhealing ulcers and provides physiological assessment that is complementary to conventional anatomical (DSA) and hemodynamic (ABI/TBI) measures in the evaluation of lower extremity revascularization.

Radiotracer Imaging Allows for Noninvasive Detection and Quantification of Abnormalities in Angiosome Foot Perfusion in Diabetic Patients With Critical Limb Ischemia and Nonhealing Wounds

Background:

Single photon emission computed tomography (SPECT)/computed tomography (CT) imaging allows for assessment of skeletal muscle microvascular perfusion but has not been quantitatively assessed in angiosomes, or 3-dimensional vascular territories, of the foot. This study assessed and compared resting angiosome foot perfusion between healthy subjects and diabetic patients with critical limb ischemia (CLI). Additionally, the relationship between SPECT/CT imaging and the ankle–brachial index—a standard tool for evaluating peripheral artery disease—was assessed.

Methods and Results:

Healthy subjects (n=9) and diabetic patients with CLI and nonhealing ulcers (n=42) underwent SPECT/CT perfusion imaging of the feet. CT images were segmented into angiosomes for quantification of relative radiotracer uptake, expressed as standardized uptake values. Standardized uptake values were assessed in ulcerated angiosomes of patients with CLI and compared with whole-foot standardized uptake values in healthy subjects. Serial SPECT/CT imaging was performed to assess uptake kinetics of technetium-99m-tetrofosmin. The relationship between angiosome perfusion and ankle–brachial index was assessed via correlational analysis. Resting perfusion was significantly lower in CLI versus healthy subjects (P=0.0007). Intraclass correlation coefficients of 0.95 (healthy) and 0.93 (CLI) demonstrated excellent agreement between serial perfusion measurements. Correlational analysis, including healthy and CLI subjects, demonstrated a significant relationship between ankle–brachial index and SPECT/CT (P=0.01); however, this relationship was not significant for diabetic CLI patients only (P=0.2).

Conclusions:

SPECT/CT imaging assesses regional foot perfusion and detects abnormalities in microvascular perfusion that may be undetectable by conventional ankle–brachial index in patients with diabetes mellitus. SPECT/CT may provide a novel approach for evaluating responses to targeted therapies.

Perfusion Assessment in Critical Limb Ischemia: Principles for Understanding and the Development of Evidence and Evaluation of Devices: A Scientific Statement From the American Heart Association

There are >12 million patients with peripheral artery disease in the United States. The most severe form of peripheral artery disease is critical limb ischemia (CLI). The diagnosis and management of CLI is often challenging. Ethnic differences in comorbidities and presentation of CLI exist. Compared with white patients, black and Hispanic patients have higher prevalence rates of diabetes mellitus and chronic renal disease and are more likely to present with gangrene, whereas white patients are more likely to present with ulcers and rest pain. A thorough evaluation of limb perfusion is important in the diagnosis of CLI because it can not only enable timely diagnosis but also reduce unnecessary invasive procedures in patients with adequate blood flow or among those with other causes for ulcers, including venous, neuropathic, or pressure changes. This scientific statement discusses the current tests and technologies for noninvasive assessment of limb perfusion, including the ankle-brachial index, toe-brachial index, and other perfusion technologies. In addition, limitations of the current technologies along with opportunities for improvement, research, and reducing disparities in health care for patients with CLI are discussed.

Angiosome-Guided Intervention in Critical Limb Ischemia

The goals of treatment for critical limb ischemia (CLI) are alleviation of ischemic rest pain, healing of arterial insufficiency ulcers, and improving quality of life, thereby preventing limb loss and CLI-related mortality. Arterial revascularization is the foundation of a contemporary approach to promote amputation-free survival. Angiosome-directed revascularization has become a popular theory of reperfusion, whereby anatomically directed arterial flow is restored straight to the wound bed. Innovations in endovascular revascularization combined with a multidisciplinary strategy of wound care accelerate progress in CLI management. This article highlights advances in CLI management, including the clinical relevance of angiosome-directed revascularization, and provides considerations for future treatment of CLI.

Non-contact dynamic diffuse optical tomography imaging system for evaluating lower extremity vasculature

A novel multi-view non-contact dynamic diffuse optical tomographic imaging system for the clinical evaluation of vasculature in the lower extremities is presented. The system design and implementation are described in detail, including methods for simultaneously obtaining and reconstructing diffusely reflected and transmitted light using a system of mirrors and a single CCD camera. The system and its performance using numeric simulations and optical phantoms. Measurements of a healthy foot in vivo demonstrates the potential of the system in assessing perfusion within the foot.

Current concepts for the evaluation and management of diabetic foot ulcers

The lifetime risk for diabetic patients to develop a diabetic foot ulcer (DFU) is 25%. In these patients, the risk of amputation is increased and the outcome deteriorates.More than 50% of non-traumatic lower-extremity amputations are related to DFU infections and 85% of all lower-extremity amputations in patients with diabetes are preceded by an ulcer; up to 70% of diabetic patients with a DFU-related amputation die within five years of their amputation.Optimal management of patients with DFUs must include clinical awareness, adequate blood glucose control, periodic foot inspection, custom therapeutic footwear, off-loading in high-risk patients, local wound care, diagnosis and control of osteomyelitis and ischaemia. Cite this article: EFORT Open Rev 2018;3:513-525. DOI: 10.1302/2058-5241.3.180010.

Heel Wounds Predict Mortality but Not Amputation after Infrapopliteal Revascularization

BACKGROUND

Ischemic heel ulcerations are generally thought to carry a poor prognosis for limb salvage. We hypothesized that patients undergoing infrapopliteal revascularization for heel wounds, either bypass or endovascular intervention, would have lower wound healing rates and amputation-free survival (AFS) than patients with forefoot wounds.

METHODS

A retrospective chart review was performed on patients who presented between 2006 and 2013 to our institution with ischemic foot wounds and infrapopliteal arterial disease and underwent either pedal bypass or endovascular tibial artery intervention. Data were collected on patient demographics, comorbidities, wound characteristics, procedural details, and postoperative outcomes then analyzed by initial wound classification. The primary outcome was major amputation or death.

RESULTS

Three hundred ninety-eight limbs underwent treatment for foot wounds; accurate wound data were available in 380 cases. There were 101 bypasses and 279 endovascular interventions, with mean follow-up of 24.6 and 19.9 months, respectively (P = 0.02). Heel wounds comprised 12.1% of the total with the remainder being forefoot wounds; there was no difference in treatment modality by wound type (P = 0.94). Of 46 heel wounds, 5 (10.9%) had clinical or radiographic evidence of calcaneal osteomyelitis. Patients with heel wounds were more likely to have diabetes mellitus (DM) (P = 0.03) and renal insufficiency (P = 0.004). 43.1% of wounds healed within 1 year, with no difference by wound location (P = 0.30). Major amputation rate at 1 year was 17.8%, with no difference by wound location (P = 0.81) or treatment type (P = 0.33). One- and 3-year AFS was 66.2% and 44.0% for forefoot wounds and 45.7% and 17.6% for heel wounds, respectively (P = 0.001). In a multivariate analysis, heel wounds and endovascular intervention were both predictors of death; however, there was significant interaction such that endovascular intervention was associated with higher mortality in patients with forefoot wounds (hazard ratio 2.25, P < 0.001) but not those with heel wounds (hazard ratio 0.67, P = 0.31).

CONCLUSIONS

Patients presenting with heel ulceration who undergo infrapopliteal revascularization are prone to higher mortality despite equivalent rates of amputation and wound healing and regardless of treatment modality. These patients may benefit from an endovascular-first strategy.

Heterogeneity of Ankle-Brachial Indices in Patients Undergoing Revascularization for Critical Limb Ischemia

OBJECTIVES

This study sought to describe the distribution of pre-intervention treated-limb ankle-brachial indices (ABIs) among patients with critical limb ischemia (CLI) undergoing percutaneous vascular intervention (PVI) or surgical revascularization (SR).

BACKGROUND

CLI is diagnosed by the presence of rest pain, tissue ulceration, or gangrene due to chronic arterial insufficiency. It is unclear what fraction of patients with suspected CLI have severe peripheral artery disease (PAD) on noninvasive functional testing.

METHODS

The study included patients who underwent lower extremity revascularization for CLI in a multicenter registry in Michigan from January 2012 through June 2015. ABIs were classified as normal (ABI: 0.91 to 1.40), mild-moderate (ABI: 0.41 to 0.90), and severe (ABI: ≤0.40). Pre- and post-intervention Peripheral Artery Questionnaire summary scores were assessed in a subset of patients.

RESULTS

Among 10,756 patients with signs or symptoms of CLI, 9,113 (84.7%) underwent PVI and 1,643 (15.3%) underwent SR. ABIs were recorded in 4,972 (54.6%) PVI and 1,012 (61.6%) SR patients. Patients undergoing PVI had higher ABIs than those undergoing SR, with substantial variation in both groups (PVI: 0.72 ± 0.29 vs. SR: 0.61 ± 0.29; p < 0.001). Nearly a quarter of patients with compressible arteries had normal ABIs (24.0%), whereas severe PAD was uncommon (16.5%). A significant improvement in Peripheral Artery Questionnaire scores was noted after intervention across all ABI categories.

CONCLUSIONS

Among patients undergoing revascularization for CLI in contemporary practice, the authors found substantial heterogeneity in pre-intervention ABIs. The disconnect between ABI results and clinical diagnosis calls into question the utility of ABIs in this population and suggests the need for standardization of functional PAD testing.

The comparative efficacy of angiosome-directed and indirect revascularisation strategies to aid healing of chronic foot wounds in patients with co-morbid diabetes mellitus and critical limb ischaemia: a literature review

BACKGROUND

Ischaemic ulcerations have been reported to persist and/or deteriorate despite technically successful revascularisations; a higher incidence of which affects patients with diabetes and critical limb ischaemia. In the context of wound healing, it is unclear if applications of the angiosome concept in 'direct revascularisation' (DR) would be able to aid the healing of chronic foot ulcerations better than the current 'best vessel' or 'indirect revascularisation' (IR) strategy in patients with co-morbid diabetes and critical limb ischaemia.

METHODS

A literature search was conducted in eight electronic databases, namely AMED, CINAHL, The Cochrane Library, ProQuest Health & Medicine Complete, ProQuest Nursing & Allied Health Source, PubMed, ScienceDirect and TRIP database. Articles were initially screened against a pre-established inclusion and exclusion criteria to determine eligibility and subsequently appraised using the Newcastle-Ottawa Scale.

RESULTS

Five retrospective studies of varying methodological quality were eligible for inclusion in this review. Critical analysis of an aggregated population (n = 280) from methodologically stronger studies indicates better wound healing outcomes in subjects who had undergone DR as compared to IR (p < 0.001; p = 0.04). DR also appears to result in a nearly twofold increase in probability of wound healing within 12 months (hazard ratio, 1.97; 95% CI, 1.34-2.90). This suggests that achieving direct arterial perfusion to the site of ulceration may be important for the healing of chronic diabetic foot ulcerations.

CONCLUSION

Incorporating an angiosome-directed approach in the lower limb revascularisation strategy could be a very useful adjunct to a solely indirect approach, which could increase the likelihood of wound healing. With the limited data currently available, findings appear promising and merit from further investigation. Additional research to form a solid evidence base for this revised strategy in patients with co-morbid diabetes and critical limb ischaemia is warranted.

Angiosome-directed revascularization in patients with critical limb ischemia

OBJECTIVE

Direct revascularization (DR), according to the angiosome concept, provides direct blood flow to the site of tissue loss in patients with critical limb ischemia (CLI). DR may lead to improved outcomes; however, evidence for this is controversial. This systematic review and meta-analysis investigated the outcomes of surgical and endovascular DR compared with indirect revascularization (IR) in patients with CLI.

METHODS

A systematic review was undertaken using the Cochrane Collaboration specified tool, and a meta-analysis was done according to the MOOSE (Meta-analysis of Observational Studies in Epidemiology) criteria. The electronic databases of MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials were systematically searched for studies of DR compared with IR in patients with CLI with tissue loss. All articles were critically assessed for relevance, validity, and availability of data regarding patient and lesion characteristics and outcomes. When possible, data were systematically pooled, and a meta-analysis was performed for wound healing, major amputation, amputation-free survival, and overall survival.

RESULTS

Of 306 screened abstracts, 19 cohort studies with 3932 patients were included. Nine scored 7 or higher on the Newcastle-Ottawa score. DR significantly improved wound healing (risk ratio [RR], 0.60; 95% confidence interval [CI], 0.51-0.71), major amputation (RR, 0.56; 95% CI, 0.47-0.67), and amputation-free survival rates (RR, 0.83; 95% CI, 0.69-1.00) compared with IR. This significance was lost in major amputation on sensitivity analysis for bypass studies. No significant difference was found in overall survival. In studies stratifying for collaterals, no differences between DR and IR were found in wound healing or major amputations in the presence of collaterals.

CONCLUSIONS

DR significantly improves wound healing and major amputation rates after endovascular treatment in patients with CLI, supporting the angiosome theory. In the presence of collaterals, outcomes after IR are similar to outcomes after DR. Alternatively, patients without collaterals may benefit even more from DR as a primary treatment strategy. The angiosome theory is less applicable in bypass surgery, because bypasses are generally anastomosed to the least affected artery, with runoff passing the ankle to maintain bypass patency.

Midterm Outcomes After Infrapopliteal Interventions in Patients With Critical Limb Ischemia Based on the TASC II Classification of Below-the-Knee Arteries

Purpose: To analyze the relationship between the new TransAtlantic Inter-Society Consensus (TASC II) infrapopliteal classification and limb outcomes among patients with critical limb ischemia (CLI). Methods: A single-center retrospective study was performed on 166 consecutive CLI patients (mean age 71 years; 113 men) undergoing endovascular treatment of 244 infrapopliteal lesions from 2006 to 2013. Patient, procedural, angiographic, and limb outcomes were compared for the new TASC A/B vs C/D classification for infrapopliteal lesions. Binary restenosis was determined by a peak systolic velocity ratio >2.0 by duplex ultrasound on follow-up at 1, 3, 6, and 12 months. Results: Seventy-two (43.4%) patients had TASC A/B lesions, while 94 (56.6%) had TASC C/D patterns of infrapopliteal disease. Baseline demographics and tissue loss (93% vs 94%, p=0.59) were similar between the groups. TASC A/B lesions were shorter (53±35 vs 170±83 mm, p<0.001), less severely stenosed (77%±24% vs 93%±14%, p<0.001), had a larger target vessel diameter (2.9±0.5 vs 2.6±0.5 mm, p<0.001), and were less frequently chronic total occlusions (24% vs 64%, p<0.001) compared with the TASC C/D group. Three-year freedom from both amputation (85% vs 67%, p=0.02) and major adverse limb events (79% vs 61%, p=0.02) were significantly higher in the TASC A/B group. Technical success rates (95% vs 80%, p<0.001) and 1-year primary patency (58% vs 51%, p=0.04) were higher in the A/B group. Overall 3-year survival was similar between the groups (96% A/B vs 88% C/D, p=0.2). Conclusion: TASC C/D infrapopliteal lesions are associated with higher amputation and major adverse limb events rates and lower primary patency compared with TASC A/B infrapopliteal lesions. Further studies are needed to assess the association between TASC C/D infrapopliteal lesions and clinical outcomes in patients with CLI.

Is Angiosome-Targeted Angioplasty Effective for Limb Salvage and Wound Healing in Diabetic Foot? : A Meta-Analysis

PURPOSE

Given that the efficacy of employing angiosome-targeted angioplasty in the treatment of diabetic foot remains controversial, this study was conducted to examine its efficacy.

METHODS

We performed a systematic literature review and meta-analysis using core databases, extracting the treatment modality of angiosome-targeted angioplasty as the predictor variable, and limb salvage, wound healing, and revision rate as the outcome variables. We used the Newcastle-Ottawa Scale to assess the study quality, along with the Cochrane Risk of Bias Tool. We evaluated publication bias using a funnel plot.

RESULTS

The search strategy identified 518 publications. After screening these, we selected four articles for review. The meta-analysis revealed that overall limb salvage and wound healing rates were significantly higher (Odds ratio = 2.209, 3.290, p = 0.001, p<0.001) in patients who received angiosome-targeted angioplasty than in those who received nonangiosome-targeted angioplasty. The revision rate between the angiosome and nonangiosome groups was not significantly different (Odds ratio = 0.747, p = 0.314).

CONCLUSION

Although a further randomized controlled trial is required for confirmation, angiosome-targeted angioplasty in diabetic foot was more effective than nonangiosome-targeted angioplasty with respect to wound healing and limb salvage.