Interventions for lower extremity peripheral artery disease

Recruitment Feasibility of Patients with Peripheral Artery Disease for a Multidisciplinary Intervention: Findings from the TEAM-PAD Trial

INTRODUCTION

Peripheral Arterial Disease (PAD) is a chronic progressive vascular condition with high morbidity and mortality, often necessitating comprehensive management to mitigate cardiovascular risk.

AIMS

This study assessed the feasibility of recruiting patients with PAD for a multidisciplinary team (MDT)-based care intervention, comparing its effectiveness to standard care within a clinical trial setting.

METHODS

Conducted as a cross-sectional analysis nested within the ongoing TEAM-PAD trial, this study targeted the recruitment of 30 patients within 12 weeks and evaluated recruitment, consent, and retention rates to assess feasibility.

RESULTS

A total of 30 participants were consented within 11 weeks, with an overall recruitment rate of 36.4% and retention rate of 90%. Baseline characteristics were balanced between groups. Participants had a mean age of 68.9 years and a high prevalence of comorbidities. The mean 10-year cardiovascular risk (SMART-REACH) was 42.8%. In the intervention group, implementing MDT recommendations is projected to reduce this risk by 12.1%.

CONCLUSION

Recruitment of patients with PAD into an MDT intervention was feasible and timely, with strong retention and well-balanced baseline characteristics. While modelled estimates suggest a potential benefit from MDT recommendations, these findings are preliminary and based on a small interim cohort. Evaluation of clinical effectiveness within the larger ongoing randomised controlled trial is needed to evaluate the medium and long-term impacts of integrated vascular care.

Proteomic Analysis and 2-Hydroxyisobutyrylation Profiling in Metabolic Syndrome Induced Restenosis

Restenosis is the primary complication following stenting for coronary and peripheral arterial disease, posing an ongoing clinical challenge. Metabolic syndrome (MetS), characterized by metabolic disturbances, has been identified as an independent predictor for postoperative restenosis in coronary and carotid arteries, potentially due to endothelial dysfunction and augmented oxidative stress in cells, while its specific regulatory mechanism is still largely unknown. Lysine 2-hydroxyisobutyrylation (Khib), a recently identified posttranslational modification, plays a crucial role in transcriptional regulation and cellular metabolism. However, there is a lack of comprehensive analysis of the proteome and Khib modifications within restenotic vessels in the context of MetS, as well as in the understanding of the associated pathophysiology. In this study, we observed a significant upregulation of Khib in restenotic arteries induced by MetS, confirmed by animal and cellular experiments. Further, using high-throughput liquid chromatography-mass spectrometry, we catalogued 15,558 Khib sites across 2568 proteins, implicating a multitude of biological functions. Analysis revealed 2007 Khib sites on 1002 proteins with considerable differential modifications which are present within the cytoplasm and nucleus. Interestingly, proteins located in the mitochondria, endoplasmic reticulum, and cell membrane also exhibit distinct expression and modification profiles to varying extents that related to vascular smooth muscle contraction, platelet activation, and the PI3K-Akt signaling pathway. Notably, the level of COL1A1 protein detected in the protein-protein interaction pathway network and the level of Khib modification are diametrically opposed, suggesting a significant role in the disease's pathogenesis. This study provides the first comprehensive proteomic and Khib modification overview of MetS-related in-stent restenosis vasculature, offering key insights to inform novel therapeutic approaches for restenosis mitigation.

A randomised controlled trial of a multidisciplinary TEAM-based approach to guide secondary cardiovascular risk reduction for patients with Peripheral Artery Disease (TEAM-PAD) study protocol

BACKGROUND

Peripheral arterial disease (1) is a vascular condition associated with significant cardiovascular morbidity and mortality. Effective secondary prevention strategies are essential to improve cardiovascular outcomes in patients with PAD. The TEAM-PAD study aims to determine if a centralised virtual multidisciplinary team (MDT) model of care is effective in improving guideline-recommended secondary cardiovascular risk reduction for outpatients with PAD.

METHODS

TEAM-PAD is a multicentre, randomised controlled trial involving patients with PAD. Participants will be randomised into two groups: the intervention group, who will receive care supported by cardiovascular risk reduction recommendations from a centralised MDT; and the control group, who will receive usual care by their vascular surgeon. The MDT will consist of the following clinicians: vascular surgeon, cardiologist, endocrinologist, nephrologist, geriatrician, drug health physician and clinical pharmacist. The primary outcome is the change in a composite measure of an individual's 10-year cardiovascular risk between baseline to 9-months follow-up. Secondary outcomes include control of modifiable cardiovascular risk factors and medication optimisation, cardiovascular and limb outcomes, PAD symptom control, quality of life outcomes, and health-service use outcomes.

CONCLUSION

This article details the TEAM-PAD trial protocol, which will provide robust evidence on the benefits of an MDT-based approach to cardiovascular risk reduction in PAD patients. TEAM-PAD has the potential to inform clinical practice by demonstrating whether coordinated, personalised care recommendations can improve cardiovascular risk and potentially reduce cardiovascular events in this high-risk population.

TRIAL REGISTRATION

This study has been registered at the Australia New Zealand Clinical Trial Registry (Registration number: ACTRN12623000995673).

IVUS Improves Outcomes With SUPERA Stents for the Treatment of Superficial Femoral-Popliteal Artery Disease

BACKGROUND

Nitinol interwoven bare metal stents represent an advancement in stent technology; however, nominal deployment remains an area of focus. Intravascular ultrasound (IVUS) has been shown to improve outcomes in both the coronary and peripheral vasculature by providing the operator with greater vessel detail; however, the use of adjunctive IVUS with nitinol bare metal stents has not been widely studied. This studies aims to determine the effect of IVUS when used adjunctively with nitinol interwoven bare metal stents in the management of femoropopliteal lesions.

DESIGN

Retrospective study.

METHODS

This study included a cohort of 200 consecutive patients with peripheral artery disease. All patients were treated with ≥1 Supera bare metal stent, and 91 received adjunctive IVUS imaging prior to stent deployment. Deployment conditions of nominal, compressed, and elongated were measured, and the primary clinical outcomes included target lesion reintervention, amputation, and mortality. This study also showed that 8.3 number needed to treat (NNT) patients must be treated with IVUS to avoid an additional revascularization event.

RESULTS

The patients who received IVUS had a significantly greater number of nominally deployed stents (p<0.001). Patients who had IVUS imaging also had significantly lower reintervention rates compared with those who did not receive IVUS imaging (p=0.047).

CONCLUSION

The IVUS and angiography decreases clinically-driven target lesion reintervention and increases nominal deployment compared with angiography alone in femoropopliteal lesions treated with interwoven bare metal nitinol stents.Clinical ImpactEndovascular surgones may conisder the adjuctive use of IVUS when using the Supera stent for the treatment of infra inguinal superficial femoral artery lesions. The adjunct use of IVUS may lead to improved sizing, vessel prep, deployment, and ultiamtely reduction in CD-TLR.

Biomaterial-based vascularization strategies for enhanced treatment of peripheral arterial disease

Peripheral arterial disease (PAD) poses a global health challenge, particularly in its advanced stages known as critical limb ischemia (CLI). Conventional treatments often fail to achieve satisfactory outcomes. Patients with CLI face high rates of morbidity and mortality, underscoring the urgent need for innovative therapeutic strategies. Recent advancements in biomaterials and biotechnology have positioned biomaterial-based vascularization strategies as promising approaches to improve blood perfusion and ameliorate ischemic conditions in affected tissues. These materials have shown potential to enhance therapeutic outcomes while mitigating toxicity concerns. This work summarizes the current status of PAD and highlights emerging biomaterial-based strategies for its treatment, focusing on functional genes, cells, proteins, and metal ions, as well as their delivery and controlled release systems. Additionally, the limitations associated with these approaches are discussed. This review provides a framework for designing therapeutic biomaterials and offers insights into their potential for clinical translation, contributing to the advancement of PAD treatments.

Transplantation of engineered endothelial progenitor cells with H19 overexpression promotes arterial reendothelialization and inhibits neointimal hyperplasia

Endothelial injury is a key factor initiating in-stent restenosis (ISR) following peripheral artery stent implantation. Genetically modified endothelial progenitor cells (EPCs) can promote reendothelialization of injured arteries and inhibit neointimal hyperplasia. However, the role of engineered EPCs overexpressing lncRNA H19 in these processes remains unclear. We constructed EPCs overexpressing lncRNA H19 and investigated their effects and mechanisms in promoting reendothelialization and inhibiting neointimal hyperplasia both in vitro and in vivo. Compared to the normal control group, ISR patients exhibited a significant reduction in circulating EPCs. Engineered EPCs overexpressing lncRNA H19 promoted reendothelialization and inhibited neointimal hyperplasia in injured arteries. Exogenous overexpression of lncRNA H19 significantly upregulated the endothelial repair-related gene S1PR3 in EPCs, while the opposite was also observed. Additionally, engineered EPCs overexpressing S1PR3 promoted reendothelialization and inhibited neointimal hyperplasia in injured arteries. S1PR3 overexpression enhanced EPCs proliferation, migration, and tube formation in vitro; these effects were lost with S1PR3 inhibition. Binding sites for H3K27 acetylation were identified on the S1PR3 promoter. Mechanistically, we found that lncRNA H19 directly interacted with HDAC2, a known H3K27ac deacetylase, disrupting its binding to H3K27 acetylation. Our findings suggest that lncRNA H19 positively regulates S1PR3 expression by disrupting HDAC2 / H3K27ac binding, thereby promoting reendothelialization of injured arteries and inhibiting neointimal hyperplasia.

Study on mid-term outcomes of atherectomy for patients with femoral popliteal artery lesions with different Global Limb Anatomic Staging System grades

Objective

To investigate the mid-term efficacy and patency rate of TurboHawk peripheral plaque excision system in the treatment of femoral popliteal artery lesions with different Global Limb Anatomic Staging System (GLASS) grades.

Methods

The clinical data of 141 patients with femoral popliteal arteriosclerosis obliterans who were treated with TurboHawk from January 2018 to July 2022 in our institution were retrospectively analyzed. There were 109 male patients and 32 female patients. Recordings were made of the patient's symptoms of limb ischemia, technical success rate, primary patency rate of target vessels, ankle brachial index (ABI), GLASS grades, postoperative complications, and a statistical analysis with the patient's preoperative treatment was conducted.

Results

All patients had improved limb ischemia symptoms to varying degrees after surgery, with a technical success rate of 100% (femoral artery puncture and superficial femoral artery recanalization) without bleeding, hematoma, pseudoaneurysm, arteriovenous fistula or other complications. The follow-up period was 1-24 months, during which the severity of claudication, resting pain, and toe ulcers significantly improved. The primary patency rate of the target vessel was 98.58% (139/141), and the ABI significantly increased on the second day, three months, and six months after surgery compared to before surgery. No major adverse events were found during follow-up. The patency rates at 1, 6, 12 and 24 months after intervention were 100%, 80%, 75% and 60% respectively.

Conclusion

The mid-term efficacy and patency rate of TurboHawk in the treatment of femoral popliteal artery lesions with GLASS I patients have the best mid-term prognosis, the highest mid-term survival rate, and the highest vascular patency. The plaque removal system has proven to be an effective treatment for individual localized chronic total occlusion lesions. Additionally, the TurboHawk system provides a safe and minimally invasive treatment alternative for superficial femoral artery conditions, achieving significant therapeutic results within a brief period.

Maglev-fabricated long and biodegradable stent for interventional treatment of peripheral vessels

While chronic limb-threatening ischemia is a serious peripheral artery disease, the lack of an appropriate stent significantly limits the potential of interventional treatment. In spite of much progress in coronary stents, little is towards peripheral stents, which are expected to be both long and biodegradable and thus require a breakthrough in core techniques. Herein, we develop a long and biodegradable stent with a length of up to 118 mm based on a metal-polymer composite material. To achieve a well-prepared homogeneous coating on a long stent during ultrasonic spraying, a magnetic levitation is employed. In vivo degradation of the stent is investigated in rabbit abdominal aorta/iliac arteries, and its preclinical safety is evaluated in canine infrapopliteal arteries. First-in-man implantation of the stent is carried out in the below-the-knee artery. The 13 months' follow-ups demonstrate the feasibility of the long and biodegradable stent in clinical applications.

The Association Between Triglyceride-Glucose Index and Its Combination with Obesity Indicators and Lower Extremity Peripheral Artery Disease in Patients with Type 2 Diabetes Mellitus: A Cross-Sectional Study

Background

Lower extremity peripheral artery disease (LEAD) is a significant chronic complication of type 2 diabetes mellitus (T2DM) that significantly contributes to disability and mortality. The subtle presentation of LEAD symptoms often leads to underrecognition and misdiagnosis. Therefore, identifying simple and effective evaluation indicators is essential for the early detection and management of LEAD. Insulin resistance is closely associated with diabetes and its complications. However, the specific relationship between insulin resistance-measured by the triglyceride-glucose (TyG) index-and obesity indicators in relation to LEAD remains unclear.

Objective

This study aims to investigate the association between the TyG index and its combination with obesity indicators in participants with T2DM and LEAD.

Methods

We performed a univariate analysis on 3176 T2DM patients to identify risk factors for LEAD. Patients were then divided into quartiles based on the TyG index combined with various obesity indicators. The chi-square test was used to compare the prevalence of LEAD across these groups. Logistic regression analysis was conducted to examine the association between the TyG index, in combination with different obesity indicators, and the occurrence of LEAD. Finally, we assessed the predictive ability of the TyG index combined with obesity indicators for LEAD by comparing the area under the ROC curve (AUC).

Results

The study included 3176 T2DM patients (1691 males and 1485 females) with a mean age of 56.16±10.60 years. Among them, 106 individuals had LEAD. The prevalence of LEAD varied significantly across quartiles of the TyG index, TyG-WC, and TyG-WHR (Q4 > Q3 > Q2 > Q1; P < 0.05). Multiple logistic regression analysis showed that the TyG index, TyG-WC, and TyG-WHR were positively associated with the risk of LEAD in T2DM patients. ROC curve analysis identified the best cutoff values for predicting LEAD: 9.8059 for the TyG index (sensitivity: 49.1%, specificity: 67.9%, AUC: 0.583), 808.8397 for TyG-WC (sensitivity: 70.8%, specificity: 47.8%, AUC: 0.603), and 8.8543 for TyG-WHR (sensitivity: 75.5%, specificity: 44.6%, AUC: 0.607).

Conclusion

In T2DM patients, the TyG index, TyG-WHR, and TyG-WC are positively associated with the occurrence of LEAD. TyG-WHR and TyG-WC exhibit a stronger correlation with LEAD compared to the TyG index alone, indicating their superior diagnostic value.

Generation of Autologous Vascular Endothelial Cells for Patients with Peripheral Artery Disease

Peripheral artery disease (PAD) is a prevalent cardiovascular disease with risks of limb loss. Our objective is to establish an autologous cell source for vascular regeneration to achieve limb salvage in PAD. Six PAD patients (age 50-80) were enrolled with their peripheral blood collected to derive vascular endothelial cells (ECs) with two different approaches: (1) endothelial progenitor cell (EPC) approach and (2) induced pluripotent stem cell (iPSC) approach. The iPSC approach successfully generated patient-specific ECs for all PAD patients, while the EPC approach did not yield any colony-forming ECs in any of the patients. The patient-derived iPSC-ECs expressed endothelial markers and exhibited endothelial functions. However, elevated inflammatory status with VCAM-1 expression was observed in the patient-derived cells. Pharmacological treatment with resveratrol resulted in patient-specific responses in cell viability and VCAM-1 expression. Our study demonstrates the potential of iPSC-ECs for autologous regenerative therapy in PAD, offering promise for personalized treatments for ischemic PAD.

Macrophage scavenger receptor A1 promotes skeletal muscle regeneration after hindlimb ischemia

The macrophage-mediated inflammatory response is crucial for the recovery of skeletal muscle following ischemia. Therefore, macrophage-based therapeutic targets need to be explored for ischemic disease. In the current study, we found that the mRNA levels of scavenger receptor A1 ( Sr-a1) were elevated in patients with critical limb ischemia, based on an analysis of the Gene Expression Omnibus data. We then investigated the role and underlying mechanisms of macrophage SR-A1 in a mouse hindlimb ischemia (HLI) model. Compared with the Sr-a1 fl/fl mice, the Lyz Cre/+/ Sr-a1 flox/flox ( Sr-a1 ΔMΦ) mice showed significantly reduced laser Doppler blood flow in the ischemic limb on day seven after HLI. Consistently, histological analysis revealed that the ischemic limb of the Sr-a1 ΔMΦ mice exhibited more severe and prolonged necrotic morphology, inflammation, fibrosis, decreased vessel density, and delayed regeneration than that of the control Sr-a1 fl/fl mice. Furthermore, restoring wild-type myeloid cells to the Sr-a1 knockout mice effectively improved the Doppler perfusion in the ischemic limb and mitigated skeletal muscle damage seven days after HLI. Consistent with these in vivo findings, co-cultivating macrophages with the mouse myoblast cell line C2C12 revealed that the Sr-a1 -/- bone marrow macrophages significantly inhibited myoblast differentiation in vitro. Mechanistically, SR-A1 enhanced the skeletal muscle regeneration in response to HLI by inhibiting oncostatin M production via suppression of the NF-κB signaling activation. These findings indicate that SR-A1 may be a promising candidate protein to improve tissue repair and regeneration in peripheral ischemic arterial disease.

Liquid Drug Delivery Approaches for the Treatment of Occlusive Arterial Disease: A Systematic Review

OBJECTIVE

Local Liquid drug (LLD) delivery devices have recently emerged as a novel approach to treat peripheral arterial disease. This systemic review aims to identify and evaluate the clinical utility of the most commonly used delivery devices.

METHODS

A systemic review was performed using the Medical Subjects Heading terms of "drug delivery," "liquid," "local," and "cardiovascular disease" in PubMed, Google Scholar, and Scopus.

RESULTS

Four commonly used delivery devices were identified, including (1) the Bullfrog Micro-Infusion Device, (2) the ClearWay RX Catheter, (3) the Occlusion Perfusion Catheter, and (4) the Targeted Adjustable Pharmaceutical Administration. All have shown to successfully deliver liquid therapeutic into the target lesion and have exhibited favorable safety and efficacy profiles in preclinical and clinical trials. The LLD devices have the ability to treat very long or multiple lesions with a single device, providing a more economical option. The safety profile in LLD clinical studies is also favorable in view of recent concerns regarding adverse events with crystalline-paclitaxel-coated devices.

CONCLUSION

There is clear clinical evidence to support the concept of local liquid delivery to treat occlusive arterial disease.

CLINICAL IMPACT

The 'leave nothing behind' strategy has been at the forefront of the most recent innovations in the field of interventional cardiology and vascular interventions. Although drug coated balloons have overcome limitations associated with plain old balloon angioplasty and peripheral stents, recent safety concerns and cost considerations have impacted their usage. In this review, various liquid drug delivery devices are presented, showcasing their capabilities and success in both preclinical and clinical settings. These innovative liquid delivery devices, capable of targeted delivery and their ability to be re-used for multiple treatment sites, may provide solutions for current unmet clinical needs.

Comparing Endovascular Approaches in Lower Extremity Artery Disease: Insights from a Network Meta-Analysis

BACKGROUND

Endovascular therapy offers an alternative for treating femoropopliteal (FP) and infrapopliteal (IP) lesions related to occlusive lower extremity artery disease. Despite numerous trials, the effectiveness of restenosis prevention using local drug delivery devices remains a topic of debate.

OBJECTIVES

An updated systematic review and network meta-analysis was conducted. Our overall aim was to summarize the most recent clinical evidence regarding endovascular approaches for FP and IP atherosclerotic lesions.

METHODS

We conducted a search for randomized trials in the MEDLINE database, and extracted data related to clinical endpoints. Our primary focus was on the rate of major adverse events (MAEs), including mortality, amputation, and target lesion revascularization (TLR). A multiple treatment network meta-analysis supplemented with component network analyses was performed to examine the impact of combined treatment.

RESULTS

Our search yielded 33 randomized controlled trials encompassing 5766 patients. This included 19 studies focused on femoropopliteal and 14 on IP lesions, accounting for 3565 and 2201 patients, respectively. Drug-coated balloons (DCBs) and drug-eluting stents (DESs) displayed a reduced MAE risk in comparison to plain old balloon angioplasty (POBA)-RR for DCB: 0.64 (95% CI: 0.52-0.77) and for DES: 0.71 (95% CI: 0.51-0.99). The bare-metal stent (BMS) group manifested the most substantial MAE risk, being 59% higher relative to the DCB cohort (BMS vs. DCB RR: 1.59; 95% CI: 1.03-2.47). For FP lesions, DES was the standout performer, curtailing MAE risk by 55% relative to POBA. Within IP lesions, DES mitigated the MAE risk by 25% versus POBA. DCB did not exhibit any notable MAE reduction when pitted against POBA.

CONCLUSION

In FP arteries, both DESs and DCBs yielded significantly diminished MAEs, thus outpacing other techniques. Regarding IP arteries, only DESs resulted in significantly fewer MAEs. In alignment with contemporary research, our findings revealed no signs of elevated mortality in patients undergoing treatment with drug-eluting apparatuses.

Corilagin relieves atherosclerosis via the toll-like receptor 4 signaling pathway in vascular smooth muscle cells

INTRODUCTION

Corilagin possesses a diverse range of pharmacologic bioactivities. However, the specific protective effects and mechanisms of action of corilagin in the context of atherosclerosis remain unclear. In this study, we investigated the impact of corilagin on the toll-like receptor (TLR)4 signaling pathway in a mouse vascular smooth muscle cell line (MOVAS) stimulated by oxidized low-density lipoprotein (ox-LDL). Additionally, we examined the effects of corilagin in Sprague-Dawley rats experiencing atherosclerosis.

METHODS

The cytotoxicity of corilagin was assessed using the CCK8 assay. MOVAS cells, pre-incubated with ox-LDL, underwent treatment with varying concentrations of corilagin. TLR4 expression was modulated by either downregulation through small interfering (si)RNA or upregulation via lentivirus transfection. Molecular expression within the TLR4 signaling pathway was analyzed using real-time polymerase chain reaction (PCR) and Western blotting. The proliferation capacity of MOVAS cells was determined through cell counting. In a rat model, atherosclerosis was induced in femoral arteries using an improved guidewire injury method, and TLR4 expression in plaque areas was assessed using immunofluorescence. Pathological changes were examined through hematoxylin and eosin staining, as well as Oil-Red-O staining.

RESULTS

Corilagin demonstrated inhibitory effects on the TLR4 signaling pathway in MOVAS cells pre-stimulated with ox-LDL, consequently impeding the proliferative impact of ox-LDL. The modulation of TLR4 expression, either through downregulation or upregulation, similarly influenced the expression of downstream molecules. In an in vivo context, corilagin exhibited the ability to suppress TLR4 and MyD88 expression in the plaque lesion areas of rat femoral arteries, thereby alleviating the formation of atherosclerotic plaques.

CONCLUSION

Corilagin can inhibit the TLR4 signaling pathway in VSMCs, possibly by downregulating TLR4 expression and, consequently, relieving atherosclerosis.

Primary aldosteronism and lower-extremity arterial disease: a two-sample Mendelian randomization study

BACKGROUND AND AIMS

Primary aldosteronism (PA) is an adrenal disorder of autonomous aldosterone secretion which promotes arterial injury. We aimed to explore whether PA is causally associated with lower-extremity arterial disease (LEAD).

METHODS

We included 39,713 patients with diabetes and 419,312 participants without diabetes from UK Biobank. We derived a polygenic risk score (PRS) for PA based on previous genome-wide association studies (GWAS). Outcomes included LEAD and LEAD related gangrene or amputation. We conducted a two-sample Mendelian randomization analysis for PA and outcomes to explore their potential causal relationship.

RESULTS

In whole population, individuals with a higher PA PRS had an increased risk of LEAD. Among patients with diabetes, compared to the subjects in the first tertile of PA PRS, subjects in the third tertile showed a 1.24-fold higher risk of LEAD (OR 1.24, 95% CI 1.03-1.49) and a 2.09-fold higher risk of gangrene (OR 2.09, 95% CI 1.27-3.44), and 1.72-fold higher risk of amputation (OR 1.72, 95% CI 1.10-2.67). Among subjects without diabetes, there was no significant association between PA PRS and LEAD, gangrene or amputation. Two-sample Mendelian randomization analysis indicated that genetically predictors of PA was significantly associated with higher risks of LEAD and gangrene (inverse variance weighted OR 1.20 [95% CI 1.08-1.34]) for LEAD, 1.48 [95% CI 1.28-1.70] for gangrene), with no evidence of significant heterogeneity or directional pleiotropy.

CONCLUSIONS

Primary aldosteronism is genetically and causally associated with higher risks of LEAD and gangrene, especially among patients with diabetes. Targeting on the autonomous aldosterone secretion may prevent LEAD progression.

Potentially active compounds that improve PAD through angiogenesis: A review

Peripheral arterial disease (PAD) has been historically neglected, which has resulted in a lack of effective drugs in clinical practice. However, with the increasing prevalence of diseases like atherosclerosis and diabetes, the incidence of PAD is rising and cannot be ignored. Researchers are exploring the potential of promoting angiogenesis through exogenous compounds to improve PAD. This paper focuses on the therapeutic effect of natural products (Salidroside, Astragaloside IV, etc.) and synthetic compounds (Cilostazol, Dapagliflozin, etc.). Specifically, it examines how they can promote autocrine secretion of vascular endothelial cells, enhance cell paracrine interactions, and regulate endothelial progenitor cell function. The activation of these effects may be closely related to PI3K, AMPK, and other pathways. Overall, these exogenous compounds have promising therapeutic potential for PAD. This study aims to summarize the potential active compounds, provide a variety of options for the search for drugs for the treatment of PAD, and bring light to the treatment of patients.

Biofunctionalized Electrospun Vascular Scaffolds for Enhanced Antithrombotic Properties and In Situ Endothelialization

The development of innovative vascular substitutes has become increasingly significant due to the prevalence of vascular diseases. In this study, we designed a biofunctionalized electrospun vascular scaffold by chemically conjugating heparin molecules as an antithrombotic agent with an endothelial cell (EC)-specific antibody to promote in situ endothelialization. To optimize this biofunctionalized electrospun vascular scaffolding system, we examined various parameters, including material compositions, cross-linker concentrations, and cross-linking and conjugation processes. The findings revealed that a higher degree of heparin conjugation onto the vascular scaffold resulted in improved antithrombotic properties, as confirmed by the platelet adhesion test. Additionally, the flow chamber study demonstrated that the EC-specific antibody immobilization enhanced the scaffold's EC-capturing capability compared to a nonconjugated vascular scaffold. The optimized biofunctionalized vascular scaffolds also displayed exceptional mechanical properties, such as suture retention strength and tensile properties. Our research demonstrated that the biofunctionalized vascular scaffolds and the directed immobilization of bioactive molecules could provide the necessary elements for successful acellular vascular tissue engineering applications.

Peripheral Artery Disease: Underappreciated Impact and Residual Cardiovascular Risk Despite Revascularization

This Commentary highlights the under-recognized prevalence and heavy burden of peripheral artery disease (PAD) and its important role as a harbinger of complications of atherosclerotic cardiovascular disease. Although increasing in prevalence globally, PAD is being further accelerated with diabetes, and patients with advanced PAD are at high risk for chronic limb-threatening ischemia. The need for (repeated) revascularization and amputation places a heavy social burden on patients and family, and a heavy financial burden on the health care system, exceeding the cost of coronary artery and cerebrovascular diseases. Clinical trial research in PAD will be enhanced by widely agreed-upon definitions of major adverse cardiovascular events and major adverse limb events. Antithrombotic and lipid-lowering therapies are recommended but underutilized, while the optimal peri-interventional antithrombotic regimen is still under debate. Additional antiinflammatory treatment is currently an unaddressed strategy in the management of patients with PAD, and there is a strong case for the evaluation of widely available antiinflammatory agents such as colchicine.

A systematic review and meta-analysis of primary bypass surgery compared with bypass surgery after endovascular treatment in peripheral artery disease patients

OBJECTIVE

Both bypass surgery and endovascular treatment are well-recognized interventions for the treatment of peripheral artery disease; however, the effect of failed endovascular treatment on subsequent surgeries remains controversial. A systematic review was conducted to compare the outcomes of primary bypass and bypass surgery after endovascular treatment.

METHODS

Three academic databases (Embase, PubMed, and Scopus) were searched from their inception to August 2022. Two independent investigators searched for studies that reported the outcomes of primary bypass surgery and bypass surgery after endovascular treatment in patients with peripheral artery disease. Abstracts and full-text studies were screened independently using duplicate data abstraction. Dichotomous outcome measures were reported using a random-effects model to generate a summary odds ratio (OR) and 95% confidence interval (CI). The risk of bias was assessed using the Newcastle-Ottawa Scale.

RESULTS

Seventeen retrospective observational studies were selected from 3911 articles and included 8064 patients, 6252 of whom underwent primary bypass surgery and 1812 underwent bypass surgery after endovascular treatment. The mean age was 69.0 years and 61.2% (n = 4938) were male. For perioperative outcomes, the 30-day results showed no difference in mortality (OR, 0.76; 95% CI, 0.53-1.10), or amputation (OR, 0.89; 95% CI, 0.67-1.20). For short- to mid-term outcomes, primary patency did not differ at 6 months (OR, 0.98; 95% CI, 0.81-1.19), 1 year (OR, 1.12; 95% CI, 0.97-1.30), or 2 years (OR, 1.17; 95% CI, 0.85-1.61) follow-up. Amputation-free survival did not differ at 6 months (OR, 1.03; 95% CI, 0.82-1.30), 1 year (OR, 1.09; 95% CI, 0.89-1.32), 2 years (OR, 1.18; 95% CI, 0.93-1.50), or 3 years (OR, 1.09; 95% CI, 0.84-1.40) of follow-up. No significant difference was found in overall survival or second patency.

CONCLUSIONS

This meta-analysis of retrospective, nonrandomized, observational studies suggests that prior endovascular treatment of lower extremity arterial disease does not result in worse perioperative, short-term, or mid-term clinical outcomes of subsequent infrainguinal bypass surgery compared with patients without prior endovascular treatment.

Poor Below Knee Runoff Impacts Femoropopliteal Stent Failure and Fluoropolymer Antithrombotic Effect in Healthy Swine Model

OBJECTIVE

Poor below knee (BTK) runoff is a predictor of stent failure after endovascular femoropopliteal artery treatment; however, lack of pathological evaluation has prevented characterisation of stent failure. The study aimed to investigate the impact of poor BTK runoff and the antithrombotic effect of the polymer of fluoropolymer coated paclitaxel eluting stents (FP-PESs) in a healthy swine femoropopliteal artery model.

METHODS

FP-PESs and bare metal stents (BMSs) and FP-PES and polymer free paclitaxel coated stents (PF-PCSs) were implanted in the bilateral femoral arteries of healthy swine (n = 6, respectively) following coil embolisation in both tibial arteries to induce poor BTK runoff. Histological assessment and intravascular imaging device evaluation were performed at one month. The Japanese Association for Laboratory Animal Science approved the study protocol (reference number: IVT22-90).

RESULTS

Optical coherence tomography showed significantly lower percent area stenosis in FP-PES compared with BMS (37.3%, [interquartile range (IQR), 25.6 - 54.3] % vs. 92.5% [IQR, 75.5 - 96.1] %, respectively, p = .031), and PF-PCS (8.3% [IQR, 4.5 - 27.0] % vs. 31.2% [IQR, 23.3 - 52.2] %, respectively, p = .031). Histopathological evaluation demonstrated that thin fibrin attachment without re-stenosis was the most dominant neointimal tissue characteristic in FP-PES. On the other hand, neointimal tissue characteristics with significant restenosis of BMS and PF-PCS were mainly organising or organised thrombus.

CONCLUSION

Organising and or organised thrombus attachment due to poor BTK runoff was the main cause of in stent restenosis of the swine femoral artery. FP-PES demonstrated the least percent area stenosis, suggesting the importance of the antithrombotic effect of polymer.

Editor's Choice - Infra-inguinal Endovascular Revascularisation and Bypass Surgery for Chronic Limb Threatening Ischaemia: a Retrospective European Multicentre Cohort Study with Propensity Score Matching

OBJECTIVE

The aim of this study was to compare the long term efficacy of lower limb bypass with that of endovascular treatment (EVT) in patients with chronic limb threatening ischaemia (CLTI).

METHODS

This retrospective, multicentre study evaluated the outcomes of patients with CLTI who underwent first time infra-inguinal bypass or EVT. The primary outcome was to compare amputation free survival (AFS) rates between the two propensity score matched groups. The secondary outcome was to compare wound healing within the first six months. Major adverse events were compared according to the type of revascularisation.

RESULTS

Overall, 793 patients fulfilled the eligibility criteria, from whom 236 propensity score matched pairs were analysed. The mean follow up was 52 months. The 236 bypass procedures included 190 autogenous bypass grafts (80.5%), 151 (64.0%) of which were infrapopliteal. Among the 236 EVT procedures, the target lesion was the femoropopliteal segment in 81 patients (34.3%), the femoropopliteal and infrapopliteal segments in 101 patients (42.8%), and the infrapopliteal segment in 54 patients (22.9%). AFS was significantly better in the bypass group at five years (60.5 ± 3.6%) compared with the EVT group (35.3 ± 3.6%) (p < .001). Major amputation occurred in 61 patients (25.8%) in the bypass group and 85 patients (36.0%) in the EVT group (HR 0.66, 95% CI 0.47 - 0.92; p = .014). The probability of healing was significantly better in the bypass group at six months compared with the EVT group (p = .003). The median length of stay was shorter for the EVT group (4 days) than for the bypass group (8 days) (p = .001). Urgent re-intervention and re-admission rates were high and did not differ significantly between the groups.

CONCLUSION

This study has shown that lower limb bypass surgery offered a significantly higher probability of AFS and wound healing compared with EVT in patients with CLTI.

Tissue factor targeting peptide enhances nanoparticle binding and delivery of a synthetic specialized pro-resolving lipid mediator to injured arteries

Background

Specialized pro-resolving lipid mediators (SPM) such as resolvin D1 (RvD1) attenuate inflammation and exhibit vasculo-protective properties.

Methods

We investigated poly-lactic-co-glycolic acid (PLGA)-based nanoparticles (NP), containing a peptide targeted to tissue factor (TF) for delivery of 17R-RvD1 and a synthetic analog 17-R/S-benzo-RvD1 (benzo-RvD1) using in vitro and in vivo models of acute vascular injury. NPs were characterized in vitro by size, drug loading, drug release, TF binding, and vascular smooth muscle cell migration assays. NPs were also characterized in a rat model of carotid angioplasty.

Results

PLGA NPs based on a 75/25 lactic to glycolic acid ratio demonstrated optimal loading (507.3 pg 17R-RvD1/mg NP; P = ns) and release of RvD1 (153.1 pg 17R-RvD1/mg NP; P < .05). NPs incorporating the targeting peptide adhered to immobilized TF with greater avidity than NPs with scrambled peptide (50 nM: 41.6 ± 0.52 vs 32.66 ± 0.34; 100 nM: 35.67 ± 0.95 vs 23.5 ± 0.39; P < .05). NPs loaded with 17R-RvD1 resulted in a trend toward blunted vascular smooth muscle cell migration in a scratch assay. In a rat model of carotid angioplasty, 16-fold more NPs were present after treatment with TF-targeted NPs compared with scrambled NPs (P < .01), with a corresponding trend toward higher tissue levels of 17R-RvD1 (P = .06). Benzo-RvD1 was also detectable in arteries treated with targeted NP delivery and accumulated at 10 times higher levels than NP loaded with 17R-RvD1. There was a trend toward decreased CD45 immunostaining in vessels treated with NP containing benzo-RvD1 (0.76 ± 0.38 cells/mm2 vs 122.1 ± 22.26 cells/mm2; P = .06). There were no significant differences in early arterial inflammatory and cytokine gene expression by reverse transcription-polymerase chain reaction.

Conclusions

TF-targeting peptides enhanced NP-mediated delivery of SPM to injured artery. TF-targeted delivery of SPMs may be a promising therapeutic approach to attenuate the vascular injury response.

Double-layered blood vessels over 3 mm in diameter extruded by the inverse-gravity technique

One of the most promising techniques for treating severe peripheral artery disease is the use of cellular tissue-engineered vascular grafts (TEVGs). This study proposes an inverse-gravity (IG) extrusion technique for creating long double-layered cellular TEVGs with diameters over 3 mm. A three-layered coaxial laminar hydrogel flow in an 8 mm-diameter pipe was realised simply by changing the extrusion direction of the hydrogel from being aligned with the direction of gravity to against it. This technique produced an extruded mixture of human aortic smooth muscle cells (HASMCs) and type-I collagen as a tubular structure with an inner diameter of 3.5 mm. After a 21 day maturation period, the maximal burst pressure, longitudinal breaking force, and circumferential breaking force of the HASMC TEVG were 416 mmHg, 0.69 N, and 0.89 N, respectively. The HASMC TEVG was endothelialised with human umbilical vein endothelial cells to form a tunica intima that simulated human vessels. Besides subcutaneous implantability on mice, the double-layered blood vessels showed a considerably lower adherence of platelets and red blood cells once exposed to heparinised mouse blood and were considered nonhaemolytic. The proposed IG extrusion technique can be applied in various fields requiring multilayered materials with large diameters.

Association between fibrinogen level and length of stay in patients with lower extremity atherosclerotic disease: a retrospective cohort study

The level of fibrinogen in patients with lower extremity atherosclerosis (LEAD) has been widely identified as a risk factor contributing to adverse outcomes. However, some knowledge gaps remain regarding fibrinogen levels and downstream adverse outcomes, such as length of stay (LOS). We conducted this study to examine the association between fibrinogen level and LOS in LEAD patients. The retrospective cohort study included 1428 LEAD patients between January 2014 and November 2021 in China. Several generalized linear models with a negative binomial link function were used to evaluate the association between fibrinogen level and LOS. The area under the curve (AUC) was used to evaluate the predicting effect of fibrinogen level on a LOS greater than 10 days (median LOS). The median age of the patients was 70 years old, and 1153 (80.74%) were males. Fibrinogen level was positively associated with LOS (β = 1.14; 95% CI, 0.42-1.86; p = 0.002) in LEAD patients after controlling for age, gender, number of historical hospitalizations, surgical history, vascular disease history, drinking history, smoking history, insurance type, surgical approach, lesion site, weight loss, Fontaine classification, age-adjusted Charlson comorbidity index, urea, total protein, activated partial thromboplastin time, thrombin time, prothrombin time-international normalized ratio, calcium, triglyceride, albumin/globulin ratio, phosphorus, and D-dimer. The fibrinogen-added prediction model demonstrated good discrimination and calibration, with an AUC value of 0.807. Fibrinogen level was positively associated with LOS in LEAD patients. The fibrinogen level is a widely available and easy-to-measure biochemical indicator, and it could be used as a suitable indicator for the prognosis and prophylaxis of prolonged LOS in patients with LEAD during hospitalization.

Syndecan-4 Proteoliposomes Enhance Revascularization in a Rabbit Hind Limb Ischemia Model of Peripheral Ischemia

Regenerative therapeutics for treating peripheral arterial disease are an appealing strategy for creating more durable solutions for limb ischemia. In this work, we performed preclinical testing of an injectable formulation of syndecan-4 proteoliposomes combined with growth factors as treatment for peripheral ischemia delivered in an alginate hydrogel. We tested this therapy in an advanced model of hindlimb ischemia in rabbits with diabetes and hyperlipidemia. Our studies demonstrate enhancement in vascularity and new blood vessel growth with treatment with syndecan-4 proteoliposomes in combination with FGF-2 or FGF-2/PDGF-BB. The effects of the treatments were particularly effective in enhancing vascularity in the lower limb with a 2-4 increase in blood vessels in the treatment group in comparison to the control group. In addition, we demonstrate that the syndecan-4 proteoliposomes have stability for at least 28 days when stored at 4°C to allow transport and use in the hospital environment. In addition, we performed toxicity studies in the mice and found no toxic effects even when injected at high concentration. Overall, our studies support that syndecan-4 proteoliposomes markedly enhance the therapeutic potential of growth factors in the context of disease and may be promising therapeutics for inducing vascular regeneration in peripheral ischemia. STATEMENT OF SIGNIFICANCE: Peripheral ischemia is a common condition in which there is a lack of blood flow to the lower limbs. This condition can lead to pain while walking and, in severe cases, critical limb ischemia and limb loss. In this study, we demonstrate the safety and efficacy of a novel injectable therapy for enhancing revascularization in peripheral ischemia using an advanced large animal model of peripheral vascular disease using rabbits with hyperlipidemia and diabetes.

Engineering orthotopic tumor spheroids with organ-specific vasculatures for local chemoembolization evaluation

Developing a three-dimensional (3D) in vitro tumor model with vasculature systems suitable for testing endovascular interventional therapies remains a challenge. Here we develop an orthotopic liver tumor spheroid model that captures the organ-level complexity of vasculature systems and the extracellular matrix to evaluate transcatheter arterial chemoembolization (TACE) treatment. The orthotopic tumor spheroids are derived by seeding HepG2 cell colonies with controlled size and location surrounding the portal triads in a decellularized rat liver matrix and are treated by clinically relevant drug-eluting beads embolized in a portal vein vasculature while maintaining dynamic physiological conditions with nutrient and oxygen supplies through the hepatic vein vasculature. The orthotopic tumor model exhibits strong drug retention inside the spheroids and embolization location-dependent cellular apoptosis responses in an analogous manner to in vivo conditions. Such a tumor spheroid model built in a decellularized scaffold containing organ-specific vasculatures, which closely resembles the unique tumor microenvironment, holds the promise to efficiently assess various diagnostic and therapeutic strategies for endovascular therapies.

Alleviating iatrogenic effects of paclitaxel via anti-inflammatory treatment

Background

Paclitaxel is touted as an essential medicine due to its extensive use as a chemotherapeutic for various cancers and an antiproliferative agent for restenosis. Due to recent concerns related to long-term mortality, paclitaxel (PTX)-based endovascular therapy is now surrounded by controversies.

Objective

Examine the inflammatory mediators driven by the systemic administration of PTX and explore the means to suppress these effects.

Methods

RNAseq analysis, cell and mouse models.

Results

RNAseq analysis of primary human endothelial cells (ECs) treated with PTX demonstrated transcriptional perturbations of a set of pro-inflammatory mediators, including monocyte chemoattractant protein-1 (MCP-1) and CD137, which were validated in EC lysates. These perturbations were abrogated with dexamethasone, a prototypic anti-inflammatory compound. The media of ECs pre-treated with PTX showed a significant increase in MCP-1 levels, which were reverted to baseline levels with DEX treatment. A group of mice harvested at different time points after PTX injection were analyzed for immediate and delayed effects of PTX. A 3-fold increase in MCP-1 was noted in blood and aortic ECs after 12 hours of PTX treatment. Similar changes in CD137 and downstream mediators such as tissue factor, VCAM-1 and E-selectin were noted in aortic ECs.

Conclusions

Our study shows that systemic PTX exposure upregulates atherothrombotic markers, and co-delivery of DEX can subdue the untoward toxic effects. Long-term studies are needed to probe the mechanisms driving systemic complications of PTX-based therapies and evaluate the clinical potential of DEX to mitigate risk.

Peri-therapeutic multi-modal hemodynamic assessment and detection of predictors for symptomatic in-stent restenosis after percutaneous transluminal angioplasty and stenting

Backgrounds

This study performed multi-modal hemodynamic analysis including quantitative color-coded digital subtraction angiography (QDSA) and computational fluid dynamics (CFD) to delineate peri-therapeutic hemodynamic changes and explore the risk factors for in-stent restenosis (ISR) and symptomatic ISR (sISR).

Methods

Forty patients were retrospectively reviewed. Time to peak (TTP), full width at half maximum (FWHM), cerebral circulation time (CCT), angiographic mean transit time (aMTT), arterial stenosis index (ASI), wash-in gradient (WI), wash-out gradient (WO) and stasis index were calculated with QDSA and translesional pressure ratio (PR) and wall shear stress ratio (WSSR) were quantified from CFD analysis. These hemodynamic parameters were compared between before and after stent deployment and multivariate logistic regression model was established to detect predictors for ISR and sISR at follow-up.

Results

It was found that stenting generally reduced TTP, stasis index, CCT, aMTT and translesional WSSR while significantly increased translesional PR. ASI decreased after stenting, and during the mean follow-up time of 6.48 ± 2.86 months, lower ASI (<0.636) as well as larger stasis index were corroborated to be independently associated with sISR. aMTT showed a linear correlation with CCT before and after stenting.

Conclusion

PTAS not only improved cerebral circulation and blood flow perfusion but also changed local hemodynamics significantly. ASI and stasis index derived from QDSA were proved to play a prominent role in risk stratification for sISR. Multi-modal hemodynamic analysis could facilitate intraoperative real-time hemodynamic monitoring and help the determination of the end point of intervention.

Bioadhesive Perivascular Microparticle-Gel Drug Delivery System for Intimal Hyperplasia Prevention: In Vitro Evaluation and Preliminary Biocompatibility Assessment

Intimal hyperplasia (IH) is an undesirable pathology occurring after peripheral or coronary bypass surgery. It involves the proliferation and migration of vascular smooth muscle cells, leading to a reduction in the diameter of the vascular lumen, which can lead to stenosis and graft failure. Topically applied atorvastatin (ATV) has been shown to slow down this process. To be effective, the drug delivery system should remain at the perivascular site for 5-8 weeks, corresponding to the progression of IH, and be capable of releasing an initial dose of the drug followed by a sustained release. Ideally, bioadhesion would anchor the gel to the application site. To meet these needs, we encapsulated ATV in a 2-component system: a hyaluronic acid-dopamine bioadhesive gel for rapid release and biodegradable microparticles for sustained release. The system was characterized by scanning electron microscopy, rheology, bioadhesion on porcine arteries, and a release profile. The rheological properties were adequate for perivascular application, and we demonstrated superior bioadhesion and cohesion compared to the control HA formulations. The release profile showed a burst, generated by free ATV, followed by sustained release over 8 weeks. A preliminary evaluation of subcutaneous biocompatibility in rats showed good tolerance of the gel. These results offer new perspectives on the perivascular application towards an effective solution for the prevention of IH.

Insulin-Like Growth Factor-Binding Protein 7 (IGFBP-7)-New Diagnostic and Prognostic Marker in Symptomatic Peripheral Arterial Disease?-Pilot Study

The aim of our study was to evaluate the importance of insulin-like growth-factor-binding protein 7 (IGFBP-7) as a potential marker of symptomatic peripheral artery disease (PAD) occurrence. The study group consisted of 145 patients with diagnosed PAD, who qualified for the invasive treatment. The control group consisted of 67 individuals representing the local population and an ischemic heart disease (IHD) group of 88 patients after myocardial infarction or percutaneous coronary intervention. Patients with PAD had significantly higher IGFBP-7 concentrations than control group (1.80 ± 1.62 vs. 1.41 ± 0.45 ng/mL, p = 0.04). No significant differences between PAD patients and IHD patients were found (1.80 ± 1.62 vs. 1.76 ± 1.04 ng/mL, p = 0.783). Patients with multilevel PAD presented significantly higher IGFBP-7 concentrations than patients with aortoiliac PAD-median 1.18 (IQR 0.48-2.23) vs. 1.42 ng/mL (0.71-2.63), p = 0.035. In the group of patients who died or had a major adverse cardiovascular event (MACE) during six months of follow-up, a statistically significant higher IGFBP-7 concentration was found (median 2.66 (IQR 1.80-4.93) vs. 1.36 ng/mL (IQR 0.65-2.34), p = 0.004). It seems that IGFBP-7 is elevated in patients with atherosclerotic lesions-regardless of their locations. Further research should be conducted to verify IGFBP-7 usefulness as a predictor of MACE or death.

Frailty and outcomes following revascularization of lower-extremity peripheral artery disease: Insights from the Vascular Quality Initiative (VQI)

BACKGROUND

Multiple frailty screening tools are implemented; however, it is unclear whether they perform in a comparable way for both frailty detection and prediction of perioperative outcomes in patients undergoing lower-extremity revascularization.

METHODS

Patients undergoing lower-extremity revascularization were identified from the Vascular Quality Initiative (VQI) national database. Two cohorts were established based on the revascularization type (percutaneous vascular interventions (PVI) or lower-extremity bypass). Frailty was assessed by the 5-item modified frailty index (mFI-5) and the VQI-derived risk analysis index (RAI).

RESULTS

Out of 134,081 patients undergoing PVI, frailty was identified in 67% by mFI-5 and 28% by RAI. Similarly, out of 41,316 patients in the bypass cohort, frailty was identified in 69% by mFI-5 and 16% by RAI. There was little agreement between the two frailty tools for both vascular cohorts (PVI: kappa: 0.17; bypass: kappa: 0.13). In an adjusted analysis, frailty as assessed by mFI-5 and RAI was associated with higher odds of mortality in both cohorts (p < 0.001). A significant association between frailty and unplanned amputations was only noted in the bypass cohort when RAI was applied (OR: 1.50, p < 0.01). The addition of frailty to traditional PAD risk factors marginally improved model performance to predict mortality and unplanned major amputations.

CONCLUSION

There was significant variation in frailty detection by mFI-5 and RAI. Although frailty was associated with mortality, the predictive value of these tools in predicting outcomes in PAD was limited. Future research should focus on designing new frailty screening tools specific to the PAD population.

Delivery of VEGF and delta-like 4 to synergistically regenerate capillaries and arterioles in ischemic limbs

Vascularization of the poorly vascularized limbs affected by critical limb ischemia (CLI) is necessary to salvage the limbs and avoid amputation. Effective vascularization requires forming not only capillaries, but also arterioles and vessel branching. These processes rely on the survival, migration and morphogenesis of endothelial cells in the ischemic limbs. Yet endothelial cell functions are impaired by the upregulated TGFβ. Herein, we developed an injectable hydrogel-based drug release system capable of delivering both VEGF and Dll4 to synergistically restore endothelial cellular functions, leading to accelerated formation of capillaries, arterioles and vessel branching. In vitro, the Dll4 and VEGF synergistically promoted the human arterial endothelial cell (HAEC) survival, migration, and formation of filopodial structure, lumens, and branches under the elevated TGFβ1 condition mimicking that of the ischemic limbs. The synergistic effect was resulted from activating VEGFR2, Notch-1 and Erk1/2 signaling pathways. After delivering the Dll4 and VEGF via an injectable and thermosensitive hydrogel to the ischemic mouse hindlimbs, 95% of blood perfusion was restored at day 14, significantly higher than delivery of Dll4 or VEGF only. The released Dll4 and VEGF significantly increased density of capillaries and arterioles, vessel branching point density, and proliferating cell density. Besides, the delivery of Dll4 and VEGF stimulated skeletal muscle regeneration and improved muscle function. Overall, the developed hydrogel-based Dll4 and VEGF delivery system promoted ischemic limb vascularization and muscle regeneration. STATEMENT OF SIGNIFICANCE: Effective vascularization of the poorly vascularized limbs affected by critical limb ischemia (CLI) requires forming not only capillaries, but also arterioles and vessel branching. These processes rely on the survival, migration and morphogenesis of endothelial cells. Yet endothelial cell functions are impaired by the upregulated TGFβ in the ischemic limbs. Herein, we developed an injectable hydrogel-based drug release system capable of delivering both VEGF and Dll4 to synergistically restore endothelial cell functions, leading to accelerated formation of capillaries, arterioles and vessel branching.

Dual-Resonance (16/32 MHz) Piezoelectric Transducer With a Single Electrical Connection for Forward-Viewing Robotic Guidewire

Peripheral artery disease (PAD) affects more than 200 million people globally. Minimally invasive endovascular procedures can provide relief and salvage limbs while reducing injury rates and recovery times. Unfortunately, when a calcified chronic total occlusion is encountered, ~25% of endovascular procedures fail due to the inability to advance a guidewire using the view provided by fluoroscopy. To enable a sub-millimeter, robotically steerable guidewire to cross these occlusions, a novel single-element, dual-band transducer is developed that provides simultaneous multifrequency, forward-viewing imaging with high penetration depth and high spatial resolution while requiring only a single electrical connection. The design, fabrication, and acoustic characterization of this device are described, and proof-of-concept imaging is demonstrated in an ex vivo porcine artery after integration with a robotically steered guidewire. Measured center frequencies of the developed transducer were 16 and 32 MHz, with -6 dB fractional bandwidths of 73% and 23%, respectively. When imaging a 0.2-mm wire target at a depth of 5 mm, measured -6 dB target widths were 0.498 ± 0.02 and 0.268 ± 0.01 mm for images formed at 16 and 32 MHz, respectively. Measured SNR values were 33.3 and 21.3 dB, respectively. The 3-D images of the ex vivo artery demonstrate high penetration for visualizing vessel morphology at 16 MHz and ability to resolve small features close to the transducer at 32 MHz. Using images acquired simultaneously at both frequencies as part of an integrated forward-viewing, guidewire-based imaging system, an interventionalist could visualize the best path for advancing the guidewire to improve outcomes for patients with PAD.

Superlow Dosage of Intrinsically Bioactive Zinc Metal-Organic Frameworks to Modulate Endothelial Cell Morphogenesis and Significantly Rescue Ischemic Disease

Despite long-term efforts for ischemia therapy, proangiogenic drugs hardly satisfy therapy/safety/cost/mass production multiple evaluations and meanwhile with a desire to minimize dosages, thereby clinical applications have been severely hampered. Recently, metal ion-based therapy has emerged as an effective strategy. Herein, intrinsically bioactive Zn metal-organic frameworks (MOFs) were explored by bridging the dual superiorities of proangiogenic Zn²⁺ and facile/cost-effective/scalable MOFs. Zn-MOFs could enhance the morphogenesis of vascular endothelial cells (ECs) via the PI3K/Akt/eNOS pathway. However, high dosage is inevitable and Zn-MOFs suffer from insolubility and low stability, which lead to the bioaccumulation of Zn-MOFs and seriously potential toxicity risks. To alleviate this, it is required to decrease the dosage, but this can be entrapped into the dosage/therapy/safety contradiction and disappointing therapy effect. To address these challenges, the bioavailability of Zn-MOFs is urgent to improve for the minimization of dosage and significant therapy/safety. The mitochondrial respiratory chain is Zn²⁺ active, which inspired us to codecorate EC-targeted and mitochondria-localizing-sequence peptides onto Zn-MOF surfaces. Interestingly, after codecoration, a 100-fold reduced dosage acquired equally powerful vascularization, and the superlow dosage significantly rescued ischemia (4.4 μg kg^-1, about one order of magnitude lower than the published minimal value). Additionally, no obvious muscle injury was found after treatment. Potential toxicity risks were alleviated, benefiting from the superlow dosage. This advanced drug simultaneously satisfied comprehensive evaluations and dosage minimization. This work utilizes engineering thought to rationally design "all-around" bioactive MOFs and is expected to be applied for ischemia treatment.

Distribution of Mobile Health Applications amongst Patients with Symptomatic Peripheral Arterial Disease in Germany: A Cross-Sectional Survey Study

Background: Broadly available digital and mobile health applications (also known as mHealth) have recently gained increasing attention by the vascular community, but very little is known about the dissemination and acceptance of such technologies in certain target populations. The current study aimed to determine the user behaviour and acceptance of such digital technologies amongst patients with peripheral arterial disease (PAD). Methods: A cross-sectional survey of consecutively treated inpatients at 12 university institutions, as well as one non-university institution, was conducted. All admitted patients with symptomatic PAD were surveyed for 30 consecutive days within a flexible timeframe between 1 July and 30 September 2021. The factors associated with smartphone use were estimated via backward selection within a logistic regression model with clustered standard errors. Results: A total of 326 patients participated (response rate 96.3%), thereof 102 (34.0%) were treated for intermittent claudication (IC, 29.2% women, 70 years in median) and 198 were treated for chronic limb-threatening ischaemia (CLTI, 29.5% women, 70 years in median). Amongst all of the patients, 46.6% stated that they had not changed their lifestyle and health behaviour since the index diagnosis (four years in median), and 33.1% responded that they were not aware of the reasons for all of their medication orders. Amongst all those surveyed, 66.8% owned a smartphone (IC: 70.6%, CLTI: 64.1%), thereof 27.9% needed regular user support. While 42.5% used smartphone apps, only 15.0% used mobile health applications, and 19.0% owned wearables. One out of five patients agreed that such technologies could help to improve their healthy lifestyle. Only higher age was inversely associated with smartphone possession. Conclusions: The current survey showed that smartphones are prevalent amongst patients with peripheral arterial disease, but only a small proportion used mobile health applications and a considerable number of patients needed regular user support. Almost half of the patients did not change their lifestyle and one third were not aware of the reasons for their medication orders, emphasising room for improvement. These findings can further help to guide future projects using such applications to identify those target populations that are reachable with digital interventions.

Update on the pathophysiology and medical treatment of peripheral artery disease

Approximately 6% of adults worldwide have atherosclerosis and thrombosis of the lower limb arteries (peripheral artery disease (PAD)) and the prevalence is rising. PAD causes leg pain, impaired health-related quality of life, immobility, tissue loss and a high risk of major adverse events, including myocardial infarction, stroke, revascularization, amputation and death. In this Review, I describe the pathophysiology, presentation, outcome, preclinical research and medical management of PAD. Established treatments for PAD include antithrombotic drugs, such as aspirin and clopidogrel, and medications to treat dyslipidaemia, hypertension and diabetes mellitus. Randomized controlled trials have demonstrated that these treatments reduce the risk of major adverse events. The drug cilostazol, exercise therapy and revascularization are the current treatment options for the limb symptoms of PAD, but each has limitations. Novel therapies to promote collateral and new capillary growth and treat PAD-related myopathy are under investigation. Methods to improve the implementation of evidence-based medical management, novel drug therapies and rehabilitation programmes for PAD-related pain, functional impairment and ischaemic foot disease are important areas for future research.

Buyang Huanwu Decoction Enhances Revascularization via Akt/GSK3β/NRF2 Pathway in Diabetic Hindlimb Ischemia

Background

Peripheral arterial disease (PAD) is a typical disease of atherosclerosis, most commonly influencing the lower extremities. In patients with PAD, revascularization remains a preferred treatment strategy. Buyang Huanwu decoction (BHD) is a popular Chinese herbal prescription which has showed effects of cardiovascular protection through conducting antioxidant, antiapoptotic, and anti-inflammatory effects. Here, we intend to study the effect of BHD on promoting revascularization via the Akt/GSK3β/NRF2 pathway in diabetic hindlimb ischemia (HLI) model of mice.

Materials and Methods

All db/db mice (n = 60) were randomly divided into 6 groups by table of random number. (1) Sham group (N = 10): 7-0 suture thread passed through the underneath of the femoral artery and vein without occlusion. The remaining 5 groups were treated differently on the basis of the HLI (the femoral artery and vein from the inguinal ligament to the knee joint were transected and the vascular stump was ligated with 7-0 silk sutures) model: (2) HLI+NS group (N = 15): 0.2 ml NS was gavaged daily for 3 days before modeling and 14 days after occlusion; (3) HLI+BHD group (N = 15): 0.2 ml BHD (20 g/kg/day) was gavaged daily for 3 days before modeling and 14 days after occlusion; (4) HLI+BHD+sh-NC group (N = 8): local injection of adenovirus vector carrying the nonsense shRNA (Ad-GFP) in the hindlimbs of mice before treatment; (5) HLI+BHD+sh-NRF2 group (N = 8): knockdown of NRF2 in the hindlimbs of mice by local intramuscular injection of adenovirus vector carrying NRF2 shRNA (Ad-NRF2-shRNA) before treatment; and (6) HLI+BHD+LY294002 group (N = 4): intravenous injection of LY294002 (1.5 mg/kg) once a day for 14 days on the basis of the HLI+BHD group. Laser Doppler examination, vascular cast, and immunofluorescence staining were applied to detect the revascularization of lower limbs in mice. Western blot analysis was used to detect the expression of vascular endothelial growth factor (VEGF), interleukin-1beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor- (TNF-) α, heme oxygenase-1 (HO-1), NAD(P)H dehydrogenase quinone-1 (NQO-1), catalase (CAT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphorylated protein kinase B (p-AKT), and phosphorylated glycogen synthase kinase-3 beta (p-GSK3β). HE staining was used to assess the level of muscle tissue damage and inflammation in the lower extremities. Local multipoint injection of Ad-NRF2-shRNA was used to knock down NRF2, and qPCR was applied to detect the mRNA level of NRF2. The blood glucose, triglyceride, cholesterol, MDA, and SOD levels of mice were tested using corresponding kits. The SPSS 20.0 software and GraphPad Prism 6.05 were used to do all statistics. Values of P < 0.05 were considered as statistically significant. Results and Conclusions. BHD could enhance the revascularization of lower limbs in HLI mice, while BHD has no effect on blood glucose and lipid level in db/db mice (P > 0.05). BHD could elevate the protein expression of VEGF, HO-1, NQO-1, and CAT (P < 0.05) and decrease the expression of IL-1β, IL-6, and TNF-α (P < 0.05) in HLI mice. Meanwhile, BHD could activate NRF2 and promote the phosphorylation of AKT/GSK3β during revascularization (P < 0.05). In contrast, knockdown of NRF2 impaired the protective effects of BHD on HLI (P < 0.05). LY294002 inhibited the upregulation of NRF2 activated by BHD through inhibiting the phosphorylation of the AKT/GSK3β pathway (P < 0.05). The present study demonstrated that BHD could promote revascularization on db/db mice with HLI through targeting antioxidation, anti-inflammation, and angiogenesis via the AKT/GSK3β/NRF2 pathway.

Trimetazidine ameliorates hindlimb ischaemic damage in type 2 diabetic mice

BACKGROUND

Ischaemia caused by lower extremity artery stenosis is the main cause of peripheral artery disease (PAD) in patients with diabetes. Trimetazidine (TMZ) has traditionally been used as an anti-ischaemic drug for coronary artery disease. The effect of TMZ on PAD in a diabetic animal model and the underlying molecular mechanisms remain unclear.

METHODS

The db/db mice were challenged with femoral artery ligation (FAL), followed by TMZ treatment for 2 weeks. Scores on hindlimb ischaemia and function were evaluated. Histological and capillary density analyses of gastrocnemius were performed. The expression of vascular endothelial growth factor (VEGF) and myogenic regulators was also confirmed by Western blotting. We also detected serum intercellular adhesion molecule 1 (ICAM-1) level through ELISA.

RESULTS

Diabetic mice exhibited limb ulceration and motor dysfunction after FAL while TMZ-treated db/db mice exhibited milder ischaemic impairment. Furthermore, decreased capillary density in the gastrocnemius muscles of ischaemic hindlimb and reduced expressions of VEGF, myogenic markers, and serum ICAM-1 could be partially reversed by TMZ treatment.

CONCLUSION

TMZ may alleviate hindlimb ischaemic damage in db/db mice, at least partly, through enhancing angiogenesis and promoting myogenesis in ischaemia region.Key messagesTMZ intervention could alleviate hindlimb ischaemic damage in db/db mice.TMZ intervention could enhance angiogenesis and stimulate myogenesis in ischaemia region.

In-patient care trends in peripheral artery disease in the German healthcare system over the past decade

OBJECTIVES

To analyze trends of in-hospital treatment of patients admitted due to peripheral artery disease (PAD) from 2009 to 2018 with special focus on comorbidities, revascularization procedures, resulting costs, and outcome.

METHODS

Using data from the research data center of the German Federal Statistical Office, we included all hospitalizations due to PAD Fontaine stage IIb or higher from 2009 to 2018. To analyze comorbidities, Elixhauser diagnostic groups and linear van Walraven score (vWS) were assessed.

RESULTS

A total of 1.8 million hospitalizations resulting in €10.3 billion in reimbursement costs were included. From 2009 to 2018, the absolute number of hospitalizations due to PAD increased by 13.3% (163,547 to 185,352). The average cost per hospitalization increased by 20.8% from €5,261 to €6,356. The overall in-hospital mortality decreased from 3.1 to 2.6%. Median vWS of all PAD cases increased by 3 points (2 to 5). The number of percutaneous transluminal angioplasties (PTA) increased by 43.9% while some surgical procedures such as bypasses and embolectomies decreased by 30.8% and 6.8%, respectively. Many revascularization procedures showed a disproportionate increase of those performed in vessels below the knee for example in PTA (+ 68.5%) or in endarterectomies (+ 38.8%).

CONCLUSIONS

This decade-long nationwide analysis shows a rising number of hospitalizations due to PAD with more comorbid patients resulting in increasing reimbursement costs. Interventions are shifting from surgical to endovascular approaches with a notable trend towards interventions in smaller vessels below the knee.

KEY POINTS

• The number of hospitalizations due to peripheral artery disease is rising and it is associated with increasing reimbursement costs. • Admitted patients are older and show an increasing number of comorbidities while overall in-hospital mortality is decreasing. • Revascularization procedures are shifting from surgical to endovascular approaches and show a trend towards intervention in smaller vessels below the knee. • Major amputations are decreasing while the number of minor amputations is increasing.

Digital Subtraction Angiography Contrast Material Transport as a Direct Assessment for Blood Perfusion of Middle Cerebral Artery Stenosis

Digital subtraction angiography (DSA) is a fluoroscopic technique used extensively in interventional radiology for visualizing blood vessels. It has also been used to evaluate blood perfusion. However, the perfusion obtained in previous techniques was extracted from signal intensity rather than by the transport of contrast material (CM) through blood flow. The main aim of this study is to evaluate the morphological effects on the hemodynamics and the CM concentration in the middle cerebral artery (MCA) stenosis. We proposed a quantitative parameter, i.e., contrast material remaining time (CMRT), to describe the variation in the transport of CM over time. Computational fluid dynamics simulations were performed on both reconstructive synthetic and patient-derived models. In the synthetic models, we evaluated the variation of flow patterns and the transport of CM with different degrees of stenosis and the location of the lesion. It was found that an increase in the degree of stenosis (from 30 to 80%) resulted in a significant increase in CMRT at the anterior cerebral artery (ACA) outlet (p = 0.0238) and a significant decrease in CMRT at the MCA outlet (p = 0.012). The patient-derived models were reconstructed from the pre- and post-interventional DSA images of a patient with MCA stenosis. Both blood flow velocity and CMRT increased at the ACA outlet but decreased at the MCA outlet. The perfusion analysis demonstrated that the perfusion function was improved after interventional surgery. In conclusion, changes in stenotic degree at MCA may lead to apparent differences in the hemodynamic distribution and the transport of CM. CMRT could be a quantitative indicator to evaluate the changes in blood perfusion after the intervention for MCA stenosis.

Peripheral Vascular Disease and Kidney Transplant Outcomes: Rethinking an Important Ongoing Complication

Peripheral vascular disease (PVD) is highly prevalent in patients on the waiting list for kidney transplantation (KT) and after transplantation and is associated with impaired transplant outcomes. Multiple traditional and nontraditional risk factors, as well as uremia- and transplant-related factors, affect 2 processes that can coexist, atherosclerosis and arteriosclerosis, leading to PVD. Some pathogenic mechanisms, such as inflammation-related endothelial dysfunction, mineral metabolism disorders, lipid alterations, or diabetic status, may contribute to the development and progression of PVD. Early detection of PVD before and after KT, better understanding of the mechanisms of vascular damage, and application of suitable therapeutic approaches could all minimize the impact of PVD on transplant outcomes. This review focuses on the following issues: (1) definition, epidemiological data, diagnosis, risk factors, and pathogenic mechanisms in KT candidates and recipients; (2) adverse clinical consequences and outcomes; and (3) classical and new therapeutic approaches.

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.

Heme Oxygenase-1 in Macrophages Impairs the Perfusion Recovery After Hindlimb Ischemia by Suppressing Autolysosome-Dependent Degradation of NLRP3

[Figure: see text].

[General Treatment Strategy for Intervention in Lower Extremity Arterial Disease]

The prevalence of lower extremity disease is increasing with age. With recent technological advancements, endovascular treatment is being performed more frequently. The treatment goal of intermittent claudication is to improve walking and reduce claudication. To achieve these goals, anatomical durability and patency are important. In patients with critical limb ischemia, the lesions are diffuse and particularly severe in below-the-knee arteries. The treatment goal of critical limb ischemia is to promote wound healing and to prevent major amputation, which is evaluated by the limb salvage rate. Primary stenting using covered or bare metal stents is a widely accepted endovascular treatment. While drug-eluting technologies with or without atherectomy are widely used in the treatment of femoropopliteal disease, balloon angioplasty is the mainstay treatment for below-the-knee intervention. CT angiography provides a road map for planning endovascular treatment in patients without absolute contraindications.

Long-term outcomes following endovascular and surgical revascularization for peripheral artery disease: a propensity score-matched analysis

AIMS

Peripheral artery disease (PAD) revascularization can be performed by either endovascular or open surgical approach. Despite increasing use of endovascular revascularization, it is still uncertain which strategy yields better long-term outcomes.

METHODS AND RESULTS

This retrospective cohort study evaluated patients hospitalized with PAD in Australia and New Zealand who underwent either endovascular or surgical revascularization between 2008 and 2015, and compared procedures using a propensity score-matched analysis. Hybrid interventions were excluded. The primary endpoint was mortality or major adverse limb events (MALE), defined as a composite endpoint of acute limb ischaemia, urgent surgical or endovascular reintervention, or major amputation, up to 8 years post-hospitalization using time-to-event analyses 75 189 patients fulfilled eligibility (15 239 surgery and 59 950 endovascular), from whom 14 339 matched pairs (mean ± SD age 71 ± 12 years, 73% male) with good covariate balance were identified. Endovascular revascularization was associated with an increase in combined MALE or mortality [hazard ratio (HR) 1.13, 95% confidence interval (CI): 1.09-1.17, P < 0.001]. There was a similar risk of MALE (HR 1.04, 95% CI: 0.99-1.10, P = 0.15), and all-cause urgent rehospitalizations (HR 1.01, 95% CI: 0.98-1.04, P = 0.57), but higher mortality (HR 1.16, 95% CI: 1.11-1.21, P < 0.001) when endovascular repair was compared to surgery. In subgroup analysis, these findings were consistent for both claudication and chronic limb-threatening ischaemia presentations.

CONCLUSION

Although the long-term risk of MALE was comparable for both approaches, enduring advantages of surgical revascularization included lower long-term mortality. This is at odds with some prior PAD studies and highlights contention in this space.