Systematic literature review comparing clinical utility of heparin-bonded expanded polytetrafluoroethylene graft to autologous saphenous vein graft for management of below-knee peripheral arterial disease.

INTRODUCTION: This systematic literature review compares the clinical outcomes of heparin-bonded expanded polytetrafluoroethylene with autologous saphenous vein in the management of patients undergoing below-the-knee bypass to treat peripheral arterial disease. METHODS: An electronic literature search was conducted in MEDLINE and EMBASE to identify comparative studies in patients undergoing below-the-knee surgical bypass. Studies were screened at abstract and full text review using pre-defined inclusion criteria by two independent reviewers and critically appraised for risk of bias. Meta-analyses were conducted using Review Manager 5 software (Nordic Cochrane Centre, Copenhagen, Denmark). RESULTS: Eight retrospective cohort studies were identified. Meta-analysis of primary patency demonstrated no significant difference between heparin-bonded expanded polytetrafluoroethylene and autologous saphenous vein grafts after one year (0.91 [0.52-1.59], P=0.74), two years (1.12 [0.60-2.10], P=0.77), three years (0.62 [0.26-1.48], P=0.28) and 4 years [0.36 -1.39], P=0.31). Similarly, for secondary patency, no significant difference was detected at one (0.62 [0.33-1.15], P=0.13), two (0.83 [0.32-2.13], P=0.69), three (0.60 [0.27-1.32], P=0.20) and 4 years (0.66 [0.32-1.36], P=0.26) respectively. There was no significant difference between autologous veins and heparin-bonded expanded polytetrafluoroethylene for limb salvage and mortality at all timepoints. A sensitivity analysis to compare outflow vessel was conducted in only tibial bypass identified no differences. All analyses were considered at high-risk bias due to heterogeneity in study populations and attrition in follow-up. CONCLUSION: This meta-analysis demonstrates similar outcomes between autologous saphenous vein and heparin-bonded expanded polytetrafluoroethylene for patency, limb salvage, and mortality through 4 years. Primary and secondary patency are superior at four years with autologous veins, but limb salvage and overall survival remained similar. The use of heparin-bonded expanded polytetrafluoroethylene synthetic grafts is a satisfactory option to prevent amputation, particularly when autologous saphenous vein grafts are not available. Controlled clinical studies are needed to further inform future decision making and economic modeling related to the choice of conduit for below-the-knee graft construction.

Management of peripheral arterial disease in the context of a multidisciplinary limb program.

Peripheral artery disease (PAD) continues to increase in prevalence worldwide due to risk factors such as advanced age, diabetes mellitus, and obesity. Critical limb ischemia (CLTI) is the advanced form of PAD that can result in a lack of healing and limb loss as the most devastating consequence. Patients with PAD, especially CLTI, benefit from multidisciplinary care to optimize outcomes by reducing cardiovascular morbidity and mortality and preventing lower extremity amputation. Collaboration between various specialties allows a focus on problems involved in treating the patient with PAD including prevention, screening, medical care, wound care, infection, and revascularization when needed. Although there is no clear definition or consensus on the structure of the PAD team, certain guidelines are applicable to most clinical scenarios emphasizing "provider champions" in leading a clinical program. A vascular specialist (vascular surgery, interventional radiology, interventional cardiology) and a soft tissue specialist (podiatry, plastic surgery) are the typical "champions," often involving orthopedics, general surgery, vascular medicine, diabetology/endocrinology, infectious disease, nephrology, and rehabilitation medicine. The team should also include wound nurses, nutritionists, occupational therapists, orthotists, pharmacists, physical therapists, prosthetists, and social workers. This paper presents a brief overview of the structure of the multidisciplinary team with key components and functions of such a team to optimize treatment outcomes for PAD and CLTI.

Surgical Deep Vein Arterialization: Adding to the Armamentarium of Complex Limb Salvage.

BACKGROUND: Patients with severe peripheral arterial disease with limited or nonexistent arterial runoff, the so-called "desert foot", challenge efforts at limb preservation. Deep vein arterialization (DVA) involves incorporating a venous target as an outflow to achieve revascularization in these complex patients. We report outcomes in an initial series of patients undergoing DVA as a component of surgical bypass. METHODS: Over a 2-year period, 10 patients underwent bypass incorporating DVA due to severely disadvantaged runoff using a heparin-bonded expanded polytetrafluoroethylene conduit. Indications for surgery included tissue loss (8) or ischemic rest pain (2) in patients who had failed endovascular (3) or surgical (7) revascularization. Inflow arteries for bypass ranged from external iliac to below knee popliteal. Outflow anastomoses incorporated a common ostium arteriovenous fistula between anterior tibial (5), posterior tibial (2), peroneal (1) or plantaris pedis (2) arteries, and corresponding tibial veins. Prior to anastomotic completion, tibial vein valves were lysed to allow venous arterialization by a way of retrograde flow. Postoperative medical regimen included dual antiplatelet (2), antiplatelet plus anticoagulation (7), or anticoagulation alone (1). RESULTS: Primary patency was maintained in 7 of 10 grafts (average: 4.1 months, range: 1-18 months). Limb salvage was achieved in 8 of 10 patients (average: 6 months, range: 1-18 months). Two below knee amputations were performed after graft occlusion due to extensive tissue loss and infection, whereas 1 patient maintained limb salvage despite graft occlusion after successful wound healing. CONCLUSIONS: This initial experience describes surgical DVA using a prosthetic conduit in conjunction with an arteriovenous fistula at the distal anastomosis in patients with threatened limb loss and severely disadvantaged tibial runoff. Although evidence for long-term efficacy is uncertain, preliminary outcomes warrant further investigation as this technique may allow for surgical revascularization resulting in limb preservation for patients with no other alternative than amputation.

Novel Therapies for Critical Limb-Threatening Ischemia.

PURPOSE OF REVIEW: This review intends to discuss the latest endovascular and surgical advancement in the treatment of critical limb-threatening ischemia (CLTI). RECENT FINDINGS: We discuss novel endovascular technological advancements such as intravascular lithotripsy, the Tack endovascular stent, the PQ Bypass DETOUR system, and the LimFlow System for deep venous arterialization (DVA) in the very high risk "no-option" CLTI population. We also discuss the increasing adoption of radial and pedal approaches for endovascular revascularization and the tibiopedal arterial minimally invasive (TAMI) technique. On the surgical front, we discuss the distal vein patch technique and surgical and hybrid DVA. Recent advancements in the treatment options of CLTI will likely lead to reducing the rate of major amputations if they are adopted in a collaborative environment in order to apply the most appropriate treatment option to each individual patient based on the anatomy, comorbidities, functional status, and local expertise.

Learning curve and proficiency metrics for transcarotid artery revascularization.

BACKGROUND: When introduced to a new procedure, physicians improve their performance and reduce their procedural adverse event rates rapidly during the initial cases and then improvement slows, signaling that proficiency has been achieved. Determining when they have acquired proficiency has important implications for procedural innovation, education, credentialing, and patient safety. We analyzed the worldwide experience with transcarotid artery revascularization (TCAR), a hybrid approach to carotid revascularization, to identify the (1) procedural performance measures associated with clinical and technical adverse events; (2) target levels of performance measures that minimize adverse event rates; and (3) number of TCAR cases needed to achieve the target levels for the performance measures. METHODS: The patient, lesion, and physician characteristics were collected for each TCAR procedure performed by each physician worldwide in an international quality assurance database. Four procedural performance measures were recorded for each procedure: flow-reversal time, fluoroscopy time, contrast volume, and total skin-to-skin time. Composite clinical adverse events (ie, transient ischemic attack, stroke, myocardial infarction, death) and composite technical adverse events (ie, aborted procedure, conversion to surgery, bleeding, dissection, cranial nerve injury, device failure), occurring within 24 hours were also recorded. Correlations between each performance measure and the clinical and technical adverse event rates were computed. The inflection points in the performance measures were identified at which no further improvements occurred in the adverse event rates. Finally, the minimum number of TCAR cases required to achieve the target performance measure levels was computed. RESULTS: A total of 18,240 procedures performed by 1273 physicians were analyzed. Of the 18,240 patients, 34.9% were women and 62.5% were asymptomatic. The flow-reversal time correlated with clinical adverse events adjusted for age, sex, and symptomatic status (R2 = 0.91; P < .0001) and adjusted technical adverse events (R2 = 0.86; P < .0001). The skin-to-skin time correlated with adjusted technical adverse events (R2 = 0.92; P < .0001). A reduction in flow-reversal times to <13.1 minutes and the skin-to-skin time to <81 minutes did not translate into further improvements in the adverse event rates. A minimum of 26 TCAR cases was required to achieve the target flow-reversal time, and a minimum of 15 cases was required to achieve the target skin-to-skin time. CONCLUSIONS: The flow-reversal time and skin-to-skin time are appropriate performance measures for establishing the level of expertise of physicians as they acquire skills to perform TCAR. A target time of ≤13.1 minutes for flow-reversal and 81 minutes for skin-to-skin time minimized the adverse event rates. Familiarity with the steps involved in performing TCAR was achieved after ≥15 cases, and minimizing clinical adverse events occurred after ≥26 cases.

The impact of the SARS-CoV-2 pandemic on the management of chronic limb-threatening ischemia and wound care.

In the wake of the coronavirus pandemic, the critical limb ischemia (CLI) Global Society aims to develop improved clinical guidance that will inform better care standards to reduce tissue loss and amputations during and following the new SARS-CoV-2 era. This will include developing standards of practice, improve gaps in care, and design improved research protocols to study new chronic limb-threatening ischemia treatment and diagnostic options. Following a round table discussion that identified hypotheses and suppositions the wound care community had during the SARS-CoV-2 pandemic, the CLI Global Society undertook a critical review of literature using PubMed to confirm or rebut these hypotheses, identify knowledge gaps, and analyse the findings in terms of what in wound care has changed due to the pandemic and what wound care providers need to do differently as a result of these changes. Evidence was graded using the Oxford Centre for Evidence-Based Medicine scheme. The majority of hypotheses and related suppositions were confirmed, but there is noticeable heterogeneity, so the experiences reported herein are not universal for wound care providers and centres. Moreover, the effects of the dynamic pandemic vary over time in geographic areas. Wound care will unlikely return to prepandemic practices. Importantly, Levels 2-5 evidence reveals a paradigm shift in wound care towards a hybrid telemedicine and home healthcare model to keep patients at home to minimize the number of in-person visits at clinics and hospitalizations, with the exception of severe cases such as chronic limb-threatening ischemia. The use of telemedicine and home care will likely continue and improve in the postpandemic era.

The Significance of the Global Vascular Guidelines for Podiatrists: Answers to Key Questions in the Diagnosis and Management of the Threatened Limb.

The publication of the Global Vascular Guidelines in 2019 provide evidence-based, best practice recommendations on the diagnosis and treatment of chronic limb-threatening ischemia (CLTI). Certainly, the multidisciplinary team, and more specifically one with collaborating podiatrists and vascular specialists, has been shown to be highly effective at improving the outcomes of limbs at risk for amputation. This article uses the Guidelines to answer key questions for podiatrists who are caring for the patient with CLTI.

Modern multidisciplinary team approach is crucial in treatment for critical limb threatening ischemia.

The aim of this study was to provide a brief overview of the history the multidisciplinary team approach, highlighting the benefit to the patient with critical limb threatening ischemia in relation to health care economics. Furthermore, we provided a description of the requisites and key components, showing how to build a multidisciplinary team.

Digital Subtraction Angiography Prior to an Amputation for Critical Limb Ischemia (CLI): An Expert Recommendation Statement From the CLI Global Society to Optimize Limb Salvage.

Despite recent guideline updates on peripheral artery disease (PAD) and critical limb ischemia (CLI) treatment, the optimal treatment for CLI is still being debated. As a result, care is inconsistent, with many CLI patients undergoing an amputation prior to what many consider to be mandatory: consultation with an interdisciplinary specialty care team and a comprehensive imaging assessment. More importantly, quality imaging is critical in CLI patients with below-the-knee disease. Therefore, the CLI Global Society has put forth an interdisciplinary expert recommendation for superselective digital subtraction angiography (DSA) that includes the ankle and foot in properly indicated CLI patients to optimize limb salvage. A recommended imaging algorithm for CLI patients is included.

Propensity Score-Adjusted Comparison of Long-Term Outcomes Among Revascularization Strategies for Critical Limb Ischemia.

BACKGROUND: Few studies have compared long-term outcomes among specific treatment modalities for critical limb ischemia. The aim of this study was to compare long-term outcomes with percutaneous transluminal angioplasty (PTA), stent placement, atherectomy, or surgical bypass in patients diagnosed with critical limb ischemia. METHODS: In this observational study using Medicare claims data, we identified incident cases with a primary critical limb ischemia diagnosis who received PTA, stent placement, atherectomy, or surgical bypass. We used propensity score weighting to determine the association of treatment type with all-cause mortality and major (above ankle) amputation over 4 years follow-up. RESULTS: Among 36 860 patients (10 904 PTA; 11 295 stent placement; 4422 atherectomy; 10 239 surgical bypass), all-cause mortality over 4 years was 49.3% with atherectomy, 51.4% with surgical bypass, 53.7% with stent placement, and 54.7% with PTA (P<0.05 for all pairwise comparisons). Major amputation rates over 4 years were 6.8% with atherectomy, 7.8% with stent placement, 8.1% with PTA, and 10.8% with surgical bypass (P<0.05 for all pairwise comparison except PTA versus stent). CONCLUSIONS: Among Medicare beneficiaries who received PTA, stent placement, atherectomy, or surgical bypass for critical limb ischemia, high mortality and major amputation rates were observed with minor differences among treatment groups. Statistically significant group differences of uncertain clinical importance were observed for several comparisons. Results from observational research may be susceptible to bias because of unmeasured confounders and, therefore, these comparative results should be interpreted with caution.

Hypogastric Preservation During Treatment of Aortoiliac Aneurysms.

The advent of endovascular technology for treating aortoiliac aneurysms has sometimes necessitated the occlusion of the hypogastric artery to prevent an endoleak or to achieve an adequate distal seal, resulting in significant morbidity for some patients. The use of iliac branch devices, in conjunction with aortic stent grafts, has made it possible to preserve the hypogastric arteries in select patients with suitable anatomy. The purpose of this review will be to discuss the indications for hypogastric preservation during treatment of aortoiliac aneurysms, as well as highlight the key procedural steps and potential technical challenges encountered during this procedure.

Determinants of Long-Term Outcomes and Costs in the Management of Critical Limb Ischemia: A Population-Based Cohort Study.

Background The optimal treatment for critical limb ischemia remains controversial owing to conflicting conclusions from previous studies. Methods and Results We obtained administrative claims on Medicare beneficiaries with initial critical limb ischemia diagnosis in 2011. Clinical outcomes and healthcare costs over 4 years were estimated among all patients and by first treatment (endovascular revascularization, surgical revascularization, or major amputation) in unmatched and propensity-score-matched samples. Among 72 199 patients with initial primary critical limb ischemia diagnosis in 2011, survival was 46% (median survival, 3.5 years) and freedom from major amputation was 87%. Among 9942 propensity-score-matched patients (8% rest pain, 26% ulcer, and 66% gangrene), survival was 38% with endovascular revascularization (median survival, 2.7 years), 40% with surgical revascularization (median survival, 2.9 years), and 23% with major amputation (median survival, 1.3 years; P<0.001 for each revascularization procedure versus major amputation). Corresponding major amputation rates were 6.5%, 9.6%, and 10.6%, respectively ( P<0.001 for all pair-wise comparisons). The cost per patient year during follow-up was $49 700, $49 200, and $55 700, respectively ( P<0.001 for each revascularization procedure versus major amputation). Conclusions Long-term survival and cost in critical limb ischemia management is comparable between revascularization techniques, with lower major amputation rates following endovascular revascularization. Primary major amputation results in shorter survival, higher risk of subsequent major amputation, and higher healthcare costs versus revascularization. Results from this observational research may be susceptible to bias because of the influence of unmeasured confounders.

Development of a Limb-Preservation Program.

In the global scenario, as the prevalence of renal failure and diabetes increases, healing and limb preservation assume increasing clinical importance for patients and healthcare systems. Unfortunately, there continues to be variation in the care delivered to patients at risk of losing a limb based on geography, race, socioeconomic status, and insurance status. There are also a variety of therapeutic approaches to patients with limb-threatening ischemia; 25% undergo primary amputation, 25% undergo medical therapy, and only 50% undergo any attempt at revascularization. Nearly 50% of patients undergoing major amputation have not had a simple diagnostic arteriogram to assess the possibility of limb preservation. The Society of Vascular Surgery and the American Podiatric Medical Association have recognized the benefits of a multidisciplinary approach to limb preservation. Benefits to the patient include rapid assessment, improved healing, and enhanced revascularization. Advantages for the providers include the ability to efficiently manage complex patients with help from the appropriate specialties, an increase in referrals, enhanced identity of the institution, and clinical research and trials. Such a program requires the coordinated effort of physicians, nurses, allied health professionals, and administrators dedicated to the preservation of functional limbs. Beneficial components include identifiable space, a vascular laboratory, hyperbaric oxygen therapy, and protocol-driven care involving diagnostic and therapeutic modalities such as endovascular revascularization, open bypass, and soft tissue reconstruction. Prosthetic expertise is also important to maintain function in those patients for whom amputation is appropriate. But, the key to a program is cooperation and communication among the participants who have a passion for limb preservation. Video Journal Club 'Cappuccino with Claudio Ronco' at http://www.karger.com/?doi=452746.

Initial in vitro and in vivo evaluation of a self-monitoring prosthetic bypass graft.

OBJECTIVE: Prosthetic grafts used for lower extremity revascularization and dialysis access fail because of hyperplastic stenosis and thrombosis. Graft surveillance is advocated to monitor function; however, graft failure can occur between episodic examinations. An innovative sensor with wireless, microchip technology allows automated surveillance with assessment of graft function using a "cloud"-based algorithm. We performed proof-of-concept experiments with in vitro and in vivo models to assess the feasibility such a real-time graft surveillance system. METHODS: A self-monitoring graft system was evaluated consisting of a prosthetic conduit of expanded polytetrafluoroethylene and a sensor unit, and a microsensor, microelectronics, battery, and remote processor with a monitor. The sensor unit was integrated on the extraluminal surface of expanded polytetrafluoroethylene grafts without compromise to the lumen of the conduit. The grafts were tested in vitro in a pulsatile, recirculating flow system under physiologic flow parameters. The hemodynamic parameters were varied to assess the ability to obtain wireless signal acquisition reflecting real-time flow properties in vitro. Segments of custom tubing with reduced diameters were inserted into the model to mimic stenosis proximal and distal to the grafts. After characterization of the initial data, the self-monitoring grafts were implanted in an ovine carotid model to assess proof of concept in vivo with 30-day follow-up of signal acquisition as well as arteriographic and histologic analysis. RESULTS: In vitro flow data demonstrated the device was able to determine factors related to prosthetic graft function under varied hemodynamic flow conditions. Wireless signal acquisition using Bluetooth technology (Bluetooth SIG, Inc, Kirkland, Wash) allowed remote data analysis reflecting graft flow parameters through changes in microsensor voltage and frequency. Waveform analysis was applied to construct an algorithm using proprietary software and determine a parameter for graft flow characteristics. This algorithm allowed determination of the degree of stenosis and location of stenosis location (proximal or distal) for display on a remote monitor in real time. Subsequent in vivo experiments confirmed the ability of the system to generate signal acquisition through skin and soft tissue under biologic conditions with no arteriographic stenosis and a favorable healing response at 30-day harvest. CONCLUSIONS: Initial in vitro and in vivo experiments demonstrate the ability for a self-monitoring graft system to remotely monitor hemodynamic parameters reflecting graft function using wireless data transmission. This automated system shows promise to deliver real-time data that can be analyzed by cloud-based algorithms alerting the clinician of a change in graft function or development of stenosis for further diagnostic study or intervention before graft failure.