An analysis of IN.PACT DEEP randomized trial on the limitations of the societal guidelines-recommended hemodynamic parameters to diagnose critical limb ischemia

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia).

METHODS

A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate.

STRUCTURE

Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia).

METHODS

A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate.

STRUCTURE

Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

Below-the-Knee Endovascular Revascularization: A Position Statement

Patients with chronic limb-threatening ischemia, the terminal stage of peripheral artery disease, are frequently afflicted by below-the-knee disease. Although all patients should receive guideline-directed medical therapy, restoration of inline flow is oftentimes necessary to avoid limb loss. Proper patient selection and proficiency in endovascular techniques for below-the-knee revascularization are intended to prevent major amputation and promote wound healing. This review, a consensus among an international panel of experienced operators, provides guidance on these challenges from an endovascular perspective and offers techniques to navigate this complex disease process.

Role of Hemodynamic Assessment and Limitations in Ankle-Brachial Pressure Index, Toe- Brachial Pressure Index to Predict Wound Healing After Revascularization

Chronic limb-threatening ischemia (CLTI) represents one of the most severe forms of peripheral arterial disease implying impaired wound healing and tissue loss at the same time posing a significant impact on the quality of life of patients and a serious economic burden on healthcare systems around the world. A major challenge in the management of patients with CLTI is the validity and role of non-invasive hemodynamic parameters in assessing their clinical status before and after revascularization. Traditionally, the diagnosis of CLTI is routinely based on clinical symptoms and confirmed by measurements of non-invasive limb hemodynamics including ankle-brachial pressure index (ABPI) and toe-brachial pressure index (TBPI). However, whether these indices alone can provide definitive treatment or be used as adjunctive tool along with the implementation of novel techniques to help guide revascularization for CLI patients still remains unclear.

Off-the-shelf percutaneous deep vein arterialization for no-option chronic limb-threatening ischemia related to Buerger disease

Percutaneous deep venous arterialization (pDVA) is an important technique in the pursuit of limb salvage for a certain high-risk subset of patients with chronic limb-threatening ischemia (CLTI) considered to have "no option" owing to the lack of tibial or pedal targets for revascularization. pDVA seeks to establish an arteriovenous connection at the level of the tibial vessels, in addition to tibial and/or pedal venoplasty, to provide a pathway for arterial perfusion via the tibial and/or plantar venous system. A commercial system for pDVA exists; however, it is not yet approved by the U.S. Food and Drug Administration. In the present report, we detail a method of pDVA that uses commercially available devices for a patient with no-option CLTI related to Buerger disease.

A Real-Time Blood Flow Measurement Device for Patients with Peripheral Artery Disease

PURPOSE

To evaluate the feasibility of a new optical device that measures peripheral blood flow as a diagnostic and monitoring tool for patients with peripheral artery disease (PAD).

MATERIALS AND METHODS

In this prospective study, 167 limbs of 90 patients (mean age, 76 y; 53% men) with suspected PAD were evaluated with the FlowMet device, which uses a new type of dynamic light-scattering technology to assess blood flow in real time. Measurements of magnitude and phasicity of blood flow were combined into a single-value flow-waveform score and compared vs ankle-brachial index (ABI), toe-brachial index (TBI), and clinical presentation of patients per Rutherford category (RC). Receiver operating characteristic curves were constructed to predict RC. Area under the curve (AUC), sensitivity, and specificity were compared among flow-waveform score, ABI, and TBI.

RESULTS

Qualitatively, the FlowMet waveforms were analogous to Doppler velocity measurements, and degradation of waveform phasicity and amplitude were observed with increasing PAD severity. Quantitatively, the flow, waveform, and composite flow-waveform scores decreased significantly with decreasing TBI. In predicting RC ≥ 4, the flow-waveform score (AUC = 0.83) showed a linear decrease with worsening patient symptoms and power comparable to that of TBI (AUC = 0.82) and better than that of ABI (AUC = 0.71). Optimal sensitivity and specificity pairs were found to be 56%/83%, 72%/81%, and 89%/74% for ABI, TBI, and flow-waveform score, respectively.

CONCLUSIONS

The technology tested in this pilot study showed a high predictive value for diagnosis of critical limb ischemia. The device showed promise as a diagnostic tool capable of providing clinical feedback in real time.

Toe pressure should be part of a vascular surgeon's first-line investigation in the assessment of lower extremity artery disease and cardiovascular risk of a patient

OBJECTIVE

Toe pressure (TP) is an accurate indicator of the peripheral vascular status of a patient and thus cardiovascular risk, with less susceptibility to errors than ankle-brachial index (ABI). This study aimed to analyze how ABI and TP measurements associate with overall survival and cardiovascular death and to analyze the TP of patients with ABI of 0.9 to 1.3.

METHODS

The first ABI and TP measurements of a consecutive 6784 patients treated at the Helsinki University Hospital vascular surgery clinic between 1990 and 2009 were analyzed. Helsinki University Vascular Registry and the national Cause of Death Registry provided the data.

RESULTS

The poorest survival was in patients with ABI >1.3 (10-year survival, 15.3%; hazard ratio, 2.2; 95% confidence interval, 1.9-2.6; P < .0001; reference group, ABI 0.9-1.3), followed by the patients with TP <30 mm Hg (10-year survival, 19.6%; hazard ratio, 2.0; 95% confidence interval, 1.7-2.2; P < .0001; reference group, TP ≥80 mm Hg). The best 10-year survival was in patients with TP ≥80 mm Hg (43.9%). Of the 642 patients with normal ABI (0.9-1.3), 18.7% had a TP <50 mm Hg. The highest cardiovascular death rate (64.6%) was in the patients with TP <30 mm Hg, and it was significantly lower than for the patients with TP >50 mm Hg.

CONCLUSIONS

Low TP is associated significantly with survival and cardiovascular mortality. Patients with a normal ABI may have lower extremity artery disease (LEAD) and a considerable risk for a cardiovascular event. If only the ABI is measured in addition to clinical examination, a substantial proportion of patients may be left without LEAD diagnosis or adequate treatment of cardiovascular risk factors. Thus, especially if ABI is normal, LEAD is excluded only if TPs are also measured and are normal.

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.

Heel Pressure Injuries: Consensus-Based Recommendations for Assessment and Management

Significance: A systematic approach to develop experts-based recommendations could have a favorable impact on clinical problems characterized by scarce and low-quality evidence as heel pressure ulcers. Recent Advances: A systematic approach was used to conduce a formal consensus initiative. A multidisciplinary panel of experts identified relevant clinical questions, performed a systematic search of the literature, and created a list of statements. GRADE Working Group guidelines were followed. An independent international jury reviewed and voted recommendations for clinical practice. Consent was developed according to Delphi rules and GRADE method was used to attribute grade of strength. Critical Issues: The extensive search of the literature retrieved 42 pertinent articles (26 clinical studies, 7 systematic reviews or meta-analysis, 5 other reviews, 2 consensus-based articles, and 2 in vitro studies). Thirty-five recommendations and statements were created. Only 1 of 35, concerning ankle-brachial pressure index reliability in diabetic patients, was rejected by the panel. No sufficient agreement was achieved on toe brachial index test to rule out the orphan heel syndrome, removing dry eschar in adult patients without vascular impairment, and using an antimicrobial dressing in children with infected heel pressure injuries. Eleven recommendations were approved with a weak grade of strength. Experts strongly endorsed 20 recommendations. Offloading, stages I and II pressure injuries, and referral criteria were areas characterized by higher level of agreement. Future Directions: We believe that the results of our effort could improve practice, especially in areas where clear and shared opinions emerged. Barriers and limits that could hinder implementation are also discussed in the article.

Outcomes after Open Lower Extremity Revascularization in Patients with Critical Limb Ischemia

BACKGROUND

For decades, open intervention was the treatment of choice in patients requiring lower extremity revascularization. In the endovascular era, however, open and endovascular revascularization are options. The implications of prior revascularization on the outcomes for subsequent revascularization are not known. In the present study, we evaluated 30-day outcomes after open lower extremity revascularization for critical limb ischemia (CLI) in those who had previous interventions.

METHODS

The 2012-2017 open lower extremity bypass Participant User Data Files from the National Surgical Quality Improvement Program were used to identify a cohort of patients with CLI. Patients whose operation was considered emergent were excluded from the analysis. Patients were stratified on whether they had a previous open or endovascular intervention or undergoing a primary revascularization. The primary outcome measure was 30-day major adverse limb events (MALEs). Secondary outcomes included major adverse cardiac events (MACEs) and wound complications.

RESULTS

A total of 12,668 patients met study criteria with 59.6% (n = 7,549) undergoing a primary open revascularization, 22.4% (n = 2,839) having a prior endovascular intervention, and 18.0% (n = 2,280) having a prior open revascularization. There were notable differences in the baseline characteristics between the 3 groups. In addition, there were differences in the reason for intervention (rest pain versus tissue loss), type of revascularization, and type of conduit used between the 3 groups. After adjustment, a prior open revascularization was significantly associated with 30-day MALE when compared with a primary revascularization (adjusted odds ratio, 1.69; 95% confidence interval, 1.47-1.94; P < 0.001) and prior endovascular intervention (adjusted odds ratio, 1.76; 95% confidence interval, 1.46-2.12; P < 0.001). There were no differences in outcomes between primary revascularization and prior endovascular patients. There were no differences between MACEs or wound complications between the 3 groups.

CONCLUSIONS

A prior endovascular intervention does not seem to accrue any additional short-term risk when compared with primary revascularization, suggesting an endovascular-first approach may be a safe strategy in patients with CLI. However, a prior open intervention is significantly associated with 30-day MALE in patients undergoing redo open revascularization, which may be related to the rapid decline in patients once they have exhausted their best open revascularization option.

Diagnostic and Therapeutic Approaches in the Management of Infrapopliteal Arterial Disease

Chronic limb-threatening ischemia represents end-stage peripheral artery disease. It is underdiagnosed; it relies on clinical symptoms and traditional noninvasive tests, which significantly underestimate the severity of disease. Innovative techniques, approaches, technologies, and risk-assessment tools have significantly improved our ability to treat these patients and to better understand their complex disease process. For patients with chronic limb-threatening ischemia considered without options, the reengineering of deep venous arterialization procedures has shown promising results. Finally, the creation of interactive and multidisciplinary teams in centers of excellence is of paramount importance to significantly improve the care and outcomes of these patients.

Microvascular Disease Increases Amputation in Patients With Peripheral Artery Disease

It is estimated that >2 million patients are living with an amputation in the United States. Peripheral artery disease (PAD) and diabetes mellitus account for the majority of nontraumatic amputations. The standard measurement to diagnose PAD is the ankle-brachial index, which integrates all occlusive disease in the limb to create a summary value of limb artery occlusive disease. Despite its accuracy, ankle-brachial index fails to well predict limb outcomes. There is an emerging body of literature that implicates microvascular disease (MVD; ie, retinopathy, nephropathy, neuropathy) as a systemic phenomenon where diagnosis of MVD in one capillary bed implicates microvascular dysfunction systemically. MVD independently associates with lower limb outcomes, regardless of diabetic or PAD status. The presence of PAD and concomitant MVD phenotype reveal a synergistic, rather than simply additive, effect. The higher risk of amputation in patients with MVD, PAD, and concomitant MVD and PAD should prompt aggressive foot surveillance and diagnosis of both conditions to maintain ambulation and prevent amputation in older patients.

Kissing Balloon Technique for Infrapopliteal Angioplasty in Patients with Critical Limb Ischemia

BACKGROUND

This study aimed to analyze the technical aspects and follow-up findings regarding patients with critical limb ischemia who underwent the kissing balloon technique (KBT).

METHODS

Thirty patients (34 bifurcations) were enrolled in this retrospective analysis between September 2010 and February 2017. All patients were submitted to infrapopliteal intervention for critical limb ischemia. The KBT is the primary treatment in 3 situations: for cases with >70% stenosis of the main artery located less than 1 cm of the bifurcation, occlusion of one branch with greater than 50% stenosis of the contralateral branch, or greater than 50% bilateral stenosis. Stents were considered in cases of recoil greater than 30% or flow-limiting recoil and were used in 7 of the 34 bifurcations (20.5%).

RESULTS

Primary patency at 30 days, 1 year, and 2 years was 100%, 68.1%, and 68.1, respectively. Limb salvage rates at 30 days, 1 year, and 2 years were 100%, 86.6%, and 65.0%, respectively. Wound healing rates at 30 days, 6 months, 1 year, and 2 years were 7.1%, 34.4%, 44.5%, and 68.7%, respectively. The bifurcations of the V-shape and T-shape groups were compared in terms of wound healing, primary patency, and limb salvage. No differences were observed in wound healing (P = 0.268), primary patency (P = 0.394), and limb salvage (P = 0.755).

CONCLUSIONS

The KBT is a feasible bifurcation approach for infrapopliteal angioplasties to maintain the patency of both branches after ballooning. The comparison between the anterior tibial artery and tibioperoneal trunk bifurcation and the peroneal artery and posterior tibial artery bifurcation revealed no difference in wound healing, primary patency, and limb salvage.

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.

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

GUIDELINE SUMMARY

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

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

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

SDF-1 plasmid treatment for patients with peripheral artery disease (STOP-PAD): Randomized, double-blind, placebo-controlled clinical trial

The efficacy of biologic therapies in critical limb ischemia (CLI) remains elusive, in part, due to limitations in trial design and patient selection. Using a novel design, we examined the impact of complementing revascularization therapy with intramuscular JVS-100 – a non-viral gene therapy that activates endogenous regenerative repair pathways. In this double-blind, placebo-controlled, Phase 2B trial, we randomized 109 patients with CLI (Rutherford class V or VI) to 8 mg or 16 mg intramuscular injections of placebo versus JVS-100. Patients were eligible if they persistently had reduced forefoot perfusion, by toe–brachial index (TBI) or skin perfusion pressure (SPP), following successful revascularization with angiographic demonstration of tibial arterial flow to the ankle. The primary efficacy end point was a 3-month wound healing score assessed by an independent wound core laboratory. The primary safety end point was major adverse limb events (MALE). Patients’ mean age was 71 years, 33% were women, 79% had diabetes, and 8% had end-stage renal disease. TBI after revascularization was 0.26, 0.27, and 0.26 among the three groups (placebo, 8 mg, and 16 mg injections, respectively). Only 26% of wounds completely healed at 3 months, without any differences between the three groups (26.5%, 26.5%, and 25%, respectively). Similarly, there were no significant changes in TBI at 3 months. Three (2.8%) patients died and two (1.8%) had major amputations. Rates of MALE at 3 months were 8.8%, 20%, and 8.3%, respectively. While safe, JVS-100 failed to improve wound healing or hemodynamic measures at 3 months. Only one-quarter of CLI wounds healed at 3 months despite successful revascularization, highlighting the need for additional research in therapies that can improve microcirculation in these patients. ClinicalTrials.gov Identifier: NCT02544204

Multidisciplinary Care for Critical Limb Ischemia: Current Gaps and Opportunities for Improvement

Critical limb ischemia (CLI), defined as ischemic rest pain or nonhealing ulceration due to arterial insufficiency, represents the most severe and limb-threatening manifestation of peripheral artery disease. A major challenge in the optimal treatment of CLI is that multiple specialties participate in the care of this complex patient population. As a result, the care of patients with CLI is often fragmented, and multidisciplinary societal guidelines have not focused specifically on the care of patients with CLI. Furthermore, multidisciplinary care has the potential to improve patient outcomes, as no single medical specialty addresses all the facets of care necessary to reduce cardiovascular and limb-related morbidity in this complex patient population. This review identifies current gaps in the multidisciplinary care of patients with CLI, with a goal toward increasing disease recognition and timely referral, defining important components of CLI treatment teams, establishing options for revascularization strategies, and identifying best practices for wound care post-revascularization.

Evaluation and Perioperative Management of the Diabetic Patient

Diabetes mellitus is a devastating disease that has reached epidemic proportions. The surgical patient with diabetes is at increased risk for developing complications when compared with patients without diabetes. A comprehensive preoperative work-up must be performed, including ancillary studies, with optimization of the patient's glucose levels during the perioperative period to decrease the chance of developing surgical complications. A multispecialty team approach for the care of patients with diabetes should be used to produce successful surgical outcomes.

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.

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.

Hemodynamic Assessment Before and After Endovascular Therapy for Critical Limb Ischemia and Association With Clinical Outcomes

OBJECTIVES

This study sought to determine the relationship between change in ankle-brachial index (ABI) and toe-brachial index (TBI) and outcomes following revascularization of critical limb ischemia (CLI).

BACKGROUND

An increase in ABI of 0.15 after revascularization for peripheral artery disease with claudication is considered significant. However, the utility of using change in ABI or TBI to predict outcomes in patients with CLI is unproven.

METHODS

This was an observational study of 218 patients with Rutherford class V or VI CLI that underwent endovascular therapy. Receiver-operating characteristic curve analysis determined cutpoints in post-procedure ABI and TBI, as well as change in these values for endpoints of wound healing, major adverse limb events (MALE), and repeat revascularization.

RESULTS

After multivariable Cox proportional hazards analysis adjusting for age, diabetes, glomerular filtration rate, smoking, Rutherford class, and baseline ABI or TBI, neither static post-procedure ABI nor post-procedure TBI were associated with wound healing (hazard ratio [HR]: 1.21; 95% confidence interval [CI]: 0.77 to 1.89; p = 0.40; HR: 1.49; 95% CI: 0.98 to 2.27; p = 0.065, respectively). However, change in ABI ≥0.23 was independently associated with wound healing (HR: 1.87; 95% CI: 1.12 to 3.15; p = 0.018) and less repeat revascularization (HR: 0.40; 95% CI: 0.19 to 0.84; p = 0.015), but not MALE. Increase in TBI ≥0.21 was independently associated with wound healing (HR: 1.63; 95% CI: 1.02 to 2.59; p = 0.039), and reduced MALE (HR: 0.27; 95% CI: 0.09 to 0.77; p = 0.014), but not repeat revascularization.

CONCLUSIONS

A change in ABI and TBI from pre-procedural values provides prognostic value in determining which patients may have wound healing and reduced MALE.

Prevalence of Tibial Artery and Pedal Arch Patency by Angiography in Patients With Critical Limb Ischemia and Noncompressible Ankle Brachial Index

Background—

Approximately 20% of patients undergoing ankle brachial index testing for critical limb ischemia have noncompressible vessels because of tibial artery calcification. This represents a clinical challenge in determining tibial artery patency. We sought to identify the prevalence of tibial artery and pedal arch patency by angiography in these patients.

Methods and Results—

One hundred twenty-five limbs (of 89 patients) with critical limb ischemia and ankle brachial index ≥1.4 who underwent lower extremity angiograms within 1 year were included. Reviewers of angiography were blinded to results of physiological testing. Tibial artery vessels were classified as completely occluded, significantly stenosed (≥50%), or patent (<50% stenosis). The sensitivity of toe brachial index and pulse volume recording to predict tibial artery disease was also determined. Of 125 limbs with noncompressible ankle brachial index, 72 (57.6%) anterior tibial and 80 (64%) posterior tibial arteries were occluded. Another 23 (18.4%) anterior tibial and 13 (10.4%) posterior tibial arteries had ≥50% stenosis. Pulse volume recording was moderate to severely dampened in 54 of 119 (45.4%) limbs. Toe brachial index <0.7 was found in 75 of 83 (90.4%) limbs. Moderate to severe pulse volume recording dampening was 43.6% sensitive, whereas toe brachial index <0.7 was 89.7% sensitive in diagnosing occluded or significantly stenotic tibial artery disease. The pedal arch was absent or incomplete in 86 of 103 (83.5%) limbs.

Conclusions—

Among patients with critical limb ischemia and noncompressible ankle brachial index results, the prevalence of occlusive tibial and pedal arch disease is very high. Toe brachial index <0.7 is more sensitive in diagnosing occluded and significantly stenotic tibial artery disease in these patients compared with ankle pulse volume recording.

2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

Since 1980, the American College of Cardiology (ACC) and American Heart Association (AHA) have translated scientific evidence into clinical practice guidelines with recommendations to improve cardiovascular health. These guidelines, based on systematic methods to evaluate and classify evidence, provide a cornerstone of quality cardiovascular care.

In response to reports from the Institute of Medicine1 ,2 and a mandate to evaluate new knowledge and maintain relevance at the point of care, the ACC/AHA Task Force on Clinical Practice Guidelines (Task Force) modified its methodology.3 –5 The relationships among guidelines, data standards, appropriate use criteria, and performance measures are addressed elsewhere.5

2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

Since 1980, the American College of Cardiology (ACC) and American Heart Association (AHA) have translated scientific evidence into clinical practice guidelines with recommendations to improve cardiovascular health. These guidelines, based on systematic methods to evaluate and classify evidence, provide a cornerstone of quality cardiovascular care.

In response to reports from the Institute of Medicine1 ,2 and a mandate to evaluate new knowledge and maintain relevance at the point of care, the ACC/AHA Task Force on Clinical Practice Guidelines (Task Force) modified its methodology.3 –5 The relationships among guidelines, data standards, appropriate use criteria, and performance measures are addressed elsewhere.5

Critical Limb Ischemia: An Expert Statement

Critical limb ischemia (CLI), the most advanced form of peripheral artery disease, is associated with significant morbidity, mortality, and health care resource utilization. It is also associated with physical, as well as psychosocial, consequences such as amputation and depression. Importantly, after a major amputation, patients are at heightened risk of amputation on the contralateral leg. However, despite the technological advances to manage CLI with minimally invasive technologies, this condition often remains untreated, with significant disparities in revascularization and amputation rates according to race, socioeconomic status, and geographic region. Care remains disparate across medical specialties in this rapidly evolving field. Many challenges persist, including appropriate reimbursement for treating complex patients with difficult anatomy. This paper provides a comprehensive summary that includes diagnostic assessment and analysis, endovascular versus open surgical treatment, regenerative and adjunctive therapies, and other important aspects of CLI.

Key Concepts in Critical Limb Ischemia: Selected Proceedings from the 2015 Vascular Interventional Advances Meeting

Over 500,000 patients each year are diagnosed with critical limb ischemia (CLI), the most severe form of peripheral artery disease. CLI portends a grim prognosis; half the patients die from a cardiovascular cause within 5 years, a rate that is 5 times higher than a matched population without CLI. In 2014, the Centers for Medicare and Medicaid Services paid approximately $3.6 billion for claims submitted by hospitals for inpatient and outpatient care delivered to patients with CLI. Although significant advances in diagnosis, treatment, and follow-up of patients with CLI have been made, many challenges remain. In this article, we summarize selected presentations from the 2015 Vascular Interventional Advances Conference related to the modern demographics, diagnosis, and management of patients with CLI.