Critical limb ischemia

Angiotensin Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers (ACEI/ARB) are Associated with Improved Limb Salvage after Infrapopliteal Interventions for Critical Limb Ischemia

BACKGROUND

Angiotensin-converting enzyme Inhibitors and Angiotensin II Receptor Blockers (ACEI/ARB) reduce the risk of cardiovascular events and mortality in patients with peripheral arterial disease (PAD). However, their effect on limb-specific outcomes is unclear. The objective of this study is to assess the effect of ACEI/ARB on patency and limb salvage in patients undergoing interventions for critical limb ischemia (CLI).

METHODS

Patients undergoing infrainguinal revascularization for CLI (Rutherford 4-6) between 06/2001 and 12/2014 were retrospectively identified. Primary Patency (PP), Secondary Patency (SP), Limb Salvage (LS), major adverse cardiac events (MACE), and survival rates were calculated using Kaplan-Meier. Multivariate analysis was performed using Cox regression.

RESULTS

A total of 755 limbs in 611 patients (311 ACEI/ARB, 300 No ACEI/ARB) were identified. Hypertension (86% vs. 70%, P < 0.001), diabetes (68% vs. 55%, P = 0.001) and statin use (61% vs. 45%, P < 0.001) were significantly greater in the ACEI/ARB group. Interventions were performed mostly for tissue loss (83% ACEI/ARB vs. 84% No ACEI/ARB, P = 0.73). Comparing ACEI/ARB versus No ACEI/ARB, in femoropopliteal interventions, 60-month PP (54% vs. 55%, P = 0.47), SP (76% vs. 75%, P = 0.83) and LS (84% vs. 87%, P = 0.36) were not significantly different. In infrapopliteal interventions, 60-month PP (45% vs. 46%, P = 0.66) and SP (62% vs. 75%, P = 0.96) were not significantly different. LS was significantly greater in ACEI/ARB (75%), as compared to No ACEI/ARB (61%) (P = 0.005). Cox regression identified diabetes (HR 2.4 (1.4-4.1), P = 0.002), ESRD (HR 3.5 (2.1-5.7), P < 0.001), hypertension (HR 0.4 (0.2-0.6), P < 0.001), and ACEI/ARB (HR 0.6 (0.4-0.9), P = 0.03), as factors independently associated with LS after infrapopliteal interventions. Freedom from MACE (ACEI/ARB 37% vs. 32%, P = 0.82) and overall survival (ACEI/ARB 42% vs. 35% No ACEI/ARB, P = 0.84) were not significantly different.

CONCLUSIONS

ACEI/ARB is associated with improved limb salvage in CLI patients undergoing infrapopliteal interventions, but not after femoropopliteal interventions. ACEI/ARB had no impact on patency rates. They were also associated with a trend toward improved survival and freedom from MACE. Our findings suggest that the use of ACEI/ARB may improve outcomes in the high-risk CLI patient population.

Retinal microvascular findings and risk of incident peripheral artery disease: An analysis from the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND AND AIMS

Lower-extremity peripheral artery disease (PAD) is usually considered large artery disease. Interestingly, retinal microvascular findings were shown to predict PAD progression in diabetes. However, it is unknown whether retinal microvascular parameters are associated with incident PAD and its severe form, critical limb ischemia (CLI), in a community-based cohort.

METHODS

Among 9371 ARIC participants (aged 49-72 years) free of a history of PAD, we quantified the associations of several retinal measures by retinal photography during the period 1993-1995 with PAD risk using Cox models. Incident PAD was defined as the first hospitalization with PAD diagnosis or leg revascularization (considered CLI if an additional diagnosis of ulcer, gangrene, or amputation).

RESULTS

During a median follow-up of 18.8 years, 303 participants developed PAD (including 91 CLI cases). Although generalized retinal arteriolar narrowing was not associated with PAD, most measures of retinopathy demonstrated strong associations with PAD beyond potential confounders including diabetes, with adjusted hazard ratios (HR) of 3.26 (95% CI 2.18-4.90) for blot-shaped hemorrhages, 3.11 (1.83-5.29) for hard exudates, and 2.18 (1.62-2.95) for any retinopathy. Adjusted HRs were significantly greater for CLI (ranging from 3.2 to 5.9) than for PAD (all p-values <0.05). Retinopathy measures showed particularly strong associations in participants with diabetes (p-value for interaction [vs. those without diabetes] <0.001).

CONCLUSIONS

Several retinopathy measures were strongly associated with PAD, especially with CLI and in diabetes. Our results support the contribution of microvascular abnormalities to the development and progression of PAD and would have implications on its preventive and therapeutic approaches.

Outcomes and safety of electronic consult use in vascular surgery

OBJECTIVE

The objective of this study was to determine how electronic consults (eConsults) are used in vascular surgery in a veterans health care setting and whether their use is safe for patients.

METHODS

A retrospective review was performed of all eConsults completed by the vascular surgery service at the Ann Arbor Veterans Affairs Healthcare System between October 10, 2012 and November 15, 2013. Patients' demographics and comorbidities were collected. eConsult recommendations and patient and provider compliance with recommendations were collected. Data on adverse outcomes up to 1 year after consultation and data on all-cause mortality at 1 year and 5 years were collected.

RESULTS

Between October 10, 2012 and November 15, 2013, of 350 eConsults completed, 123 (35%) were for peripheral artery disease, 93 (27%) for carotid stenosis, and 57 (16%) for abdominal aortic aneurysm. Unique recommendations were made for 291 consults (83%). Medication recommendations were made in 140 consults (40%). The most commonly recommended medication was cilostazol. Compliance with medication recommendations ranged from 30% to 61%. Noninvasive imaging was recommended in 220 consults (60.3%). Procedures overall were recommended in only six consults (1.7%). Five-year all-cause mortality for categorized diagnoses ranged from 8.3% for nonabdominal aneurysm to 28.1% for abdominal aortic aneurysm.

CONCLUSIONS

Within the Veterans Affairs vascular surgery service, eConsults provide a safe and effective means of triaging and providing recommendations for patients with vascular disease. eConsults used to augment traditional consultations may provide an important means of reducing clinic congestion for providers and reducing time and cost for patients.

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

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

miR-15a/-16 Inhibit Angiogenesis by Targeting the Tie2 Coding Sequence: Therapeutic Potential of a miR-15a/16 Decoy System in Limb Ischemia

MicroRNA-15a (miR-15a) and miR-16, which are transcribed from the miR-15a/miR-16-1 cluster, inhibit post-ischemic angiogenesis. MicroRNA (miRNA) binding to mRNA coding sequences (CDSs) is a newly emerging mechanism of gene expression regulation. We aimed to (1) identify new mediators of the anti-angiogenic action of miR-15a and -16, (2) develop an adenovirus (Ad)-based miR-15a/16 decoy system carrying a luciferase reporter (Luc) to both sense and inhibit miR-15a/16 activity, and (3) investigate Ad.Luc-Decoy-15a/16 therapeutic potential in a mouse limb ischemia (LI) model. LI increased miR-15a and -16 expression in mouse muscular endothelial cells (ECs). The miRNAs also increased in cultured human umbilical vein ECs (HUVECs) exposed to serum starvation, but not hypoxia. Using bioinformatic tools and luciferase activity assays, we characterized miR-15a and -16 binding to Tie2 CDS. In HUVECs, miR-15a or -16 overexpression reduced Tie2 at the protein, but not the mRNA, level. Conversely, miR-15a or -16 inhibition improved angiogenesis in a Tie2-dependent manner. Local Ad.Luc-Decoy-15a/16 delivery increased Tie2 levels in ischemic skeletal muscle and improved post-LI angiogenesis and perfusion recovery, with reduced toe necrosis. Bioluminescent imaging (in vivo imaging system [IVIS]) provided evidence that the Ad.Luc-Decoy-15a/16 system responds to miR-15a/16 increases. In conclusion, we have provided novel mechanistic evidence of the therapeutic potential of local miR-15a/16 inhibition in LI.

Critical limb ischemia: Current and novel therapeutic strategies

Critical limb ischemia (CLI) is the advanced stage of peripheral artery disease spectrum and is defined by limb pain or impending limb loss because of compromised blood flow to the affected extremity. Current conventional therapies for CLI include amputation, bypass surgery, endovascular therapy, and pharmacological approaches. Although these conventional therapeutic strategies still remain as the mainstay of treatments for CLI, novel and promising therapeutic approaches such as proangiogenic gene/protein therapies and stem cell-based therapies have emerged to overcome, at least partially, the limitations and disadvantages of current conventional therapeutic approaches. Such novel CLI treatment options may become even more effective when other complementary approaches such as utilizing proper bioscaffolds are used to increase the survival and engraftment of delivered genes and stem cells. Therefore, herein, we address the benefits and disadvantages of current therapeutic strategies for CLI treatment and summarize the novel and promising therapeutic approaches for CLI treatment. Our analyses also suggest that these novel CLI therapeutic strategies show considerable advantages to be used when current conventional methods have failed for CLI treatment.

Unclassified unilateral persistent sciatic artery in a patient with chronic intermittent claudication

Patients with persistent sciatic artery are at high risk for development of limb ischemia, aneurysm formation, and embolism. In this report, we identify a nonclassified left leg persistent sciatic artery in a patient with chronic limb ischemia. Vascular reconstruction was carried out by common iliac-deep femoral artery bypass to restore adequate arterial flow. Our approach to placement of the distal anastomosis on the deep femoral artery instead of on the popliteal artery, which is used in routine practice, may potentially increase treatment efficacy and decrease surgical complications. At 2-year follow-up, the patient remained asymptomatic and in good health.

Human adipose mesenchymal stem cells overexpressing dual chemotactic gene showed enhanced angiogenic capacity in ischaemic hindlimb model

Aims

In present study, we sought to characterize the angio-vasculogenic property of human adipose mesenchymal stem cells (ASCs) overexpressing dual chemokine GCP-2 and SDF-1α (ASC-G/S) and to determine the therapeutic potential of ASC-G/S in the context of experimental ischaemia.

Methods and results

We generated ASC-G/S line and performed flow cytometry, quantitative (q)-PCR, Matrigel tube formation, Matrigel plug assays, and in vivo therapeutic assays using hind limb ischaemia mouse model. Q-PCR results showed that the representative pro-angiogenic factors were highly upregulated in ASC-G/S compared with ASCs single chemokine overexpressing GCP-2 (ASC-G). In addition, ASC-G/S exhibited high expression of endothelium-specific genes shch as vWF and Flk-1 and showed robust in vitro micro-vascular formation. ASC-G/S was transplanted into ischaemic mouse hind limbs and compared with control groups. ASC-G/S injection prevented limb loss and augmented blood perfusion, suggesting that ASC-G/S enhances neovascularization in hind limb ischaemia. In addition, transplanted ASC-G/S revealed high vasculogenic potential in vivo compared with transplanted ASC-G.

Conclusion

Our data suggest that ASC-G/S has high therapeutic effects on hind limb ischaemia via robust angiogenic and vasculogenic action.

Risk stratification for low extremity amputation in critical limb ischemia patients who have undergone endovascular revascularization: A survival tree analysis

Patients with peripheral artery disease (PAD) are a heterogeneous population and differ in risk of mortality and low extremity amputation (LEA), which complicates clinical decision-making. This study aimed to develop a simple risk scale using decision tree methodology to guide physicians in managing critical limb ischemia (CLI) patients who will benefit from endovascular therapy (EVT).A total of 736 patients with CLI, Rutherford classification (RC) stage ≥4, and prior successful EVT were included. Variables significantly associated with LEA by univariate analysis (P < .05) were selected and put into classification tree analysis using the Classification and Regression Tree (CART) model with a dependent variable, amputation, and depth of tree = 3. Four risk groups were generated according to the order of amputation rate. The amputation-free survival (AFS) times between groups were compared using the Kaplan-Meier curve with the log-rank test.Patients were classified as high risk for amputation (G4) (WBC counts ≥10,000/μl, and platelet-lymphocyte ratio (PLR) ≥130.337); intermediate risk group 1 (G3) (WBC < 10,000/μl and RC stage before EVT > 5); intermediate risk group 2 (G2) (WBC count ≥ 10,000/μl, and PLR < 130.337) and low-risk group (G1) (WBC < 10,000/μl, RC before EVT ≤ 5). G2, G3, and G4 risk groups had shorter AFS time (range, 58.7 to 65.5 months) than the G1 risk group (100 months) (P < .05). Risk of LEA was significantly higher in the G4, G3, and G2 groups than in the G1 group (P ≤ .05). The G4 group had the highest risk of amputation (odds ratio = 6.84, P < .001).This simple risk scale model can help healthcare professionals more easily identify and appropriately treat patients with CLI who are at different levels of risk for LEA following endovascular revascularization.

Percutaneous Vascular Interventions Versus Bypass Surgeries in Patients With Critical Limb Ischemia: A Comprehensive Meta-analysis

OBJECTIVE

The aim of our study was to compare percutaneous vascular interventions (PVI) versus bypass surgeries (BSX) in patients with critical limb ischemia (CLI).

BACKGROUND

Previous relevant reviews with limited numbers of included studies did not strictly confine the inclusion criteria to CLI, also involving patients with severe claudication, which may introduce bias in the decision-making of CLI revascularization. Current treatment strategies for CLI still remain controversial.

METHODS

We performed a meta-analysis of all available randomized controlled trials and observational clinical studies comparing PVI with BSX in CLI patients. Primary endpoints included overall survival, amputation-free survival, 30-day mortality, and major adverse cardiovascular and cerebrovascular events.

RESULTS

We identified 45 cohorts and 1 RCT in over 20,903 patients. In overall population, PVI reduced the risks of 30-day mortality [odds ratio (OR) 0.69, 95% confidence interval (CI) 0.51-0.95), major adverse cardiovascular and cerebrovascular events (OR 0.42, 95% CI 0.29-0.61), and surgical site infection (OR 0.31, 95% CI 0.19-0.51), but increased the risks of long-term all-cause mortality [hazard ratio (HR) 1.16, 95% CI 1.05-1.27) and primary patency failure (HR 1.31, 95% CI 1.08-1.58). When compared with autogenous BSX, PVI was also associated with additional increased risks of long-term death or amputation (HR 1.41, 95% CI 1.02-1.94) and secondary patency failure (HR 1.51, 95% CI 1.17-1.95). In patients with infrapopliteal lesions, we found PVI had inferior primary patency (HR 1.39, 95% CI 1.10-1.75) compared with BSX.

CONCLUSION

For patients in good physical condition with long life-expectancy, BSX may represent a better choice compared with PVI, particularly when autogenous bypass is available. While enhanced perioperative care for cardiovascular events and surgical site should be considered in patients underwent BSX to achieve comparable short-term outcomes provided by PVI.

Endovascular Extra-Anatomic Femoro-Popliteal Bypass for Limb Salvage in Chronic Critical Limb Ischemia

PURPOSE

To report the initial clinical experience with fully endovascular extra-anatomic femoro-popliteal bypass (FPB) for limb salvage in patients with critical limb ischemia (CLI) and no traditional endovascular or surgical revascularization options.

METHODS

Between June 2013 and May 2018, endovascular procedure was proposed for limb salvage during multidisciplinary team meeting in fifteen hospitalized patients (median age 67 years; 73% men) with CLI and a high risk of major amputation. Primary outcome was amputation-free survival at 1 year. Secondary outcomes included mortality, cardiovascular (CV) events and major limb amputation at 1 year, primary/secondary bypass patency and wound healing at the last follow-up visit. Procedure-related complications (deaths, CV events, hemorrhages) were recorded through 30 days.

RESULTS

Technical procedure success rate was 100%. Major peri-procedural outcomes occurred in two patients (13%): One patient died secondary to cardiogenic shock; one patient suffered acute coronary syndrome associated with iliopsoas bleeding. No major amputation occurred through 30 days. Median follow-up period was 21.5 (18.25-45.5) months (last follow-up visits on April 2019). Amputation-free survival at 1-year and at the last follow-up visit was 80% and 53%, respectively. Cumulative mortality at 1-year and at the last follow-up visit was 13% and 33%, respectively. Primary and secondary bypass patency was 27% and 60%, respectively. Complete wound healing was achieved in 11 patients (73%).

CONCLUSION

Endovascular extra-anatomic FPB represents an innovative approach for limb salvage in CLI with no traditional endovascular or surgical revascularization options. Our clinical experience highlights that this technique remains challenging because of frequent comorbidities and fragility of this patient population.

LEVEL OF EVIDENCE

Level 4, Case series.

[Prolonged paravertebral analgesia in therapy of chronic pain syndrome in critical lower-limb ischaemia]

Chronic pain syndrome in patients presenting with lower-limb critical ischaemia may have considerable significance in progression of the degree of limb ischaemia, and quality of life of patients appears to be largely determined by adequate analgesia. Currently, there is no 'gold standard' of therapy for chronic pain syndrome in critical lower-limb ischaemia, which makes it necessary to search for new effective and safe methods of analgesia. The purpose of this study was to evaluate efficacy and safety of paravertebral analgesia compared with epidural analgesia in therapy of chronic pain syndrome in critical lower-limb ischaemia. Our prospective randomized double-centre study included a total of 40 patients suffering from atherosclerotic-genesis critical lower-limb ischaemia and pronounced unilateral pain syndrome. The patients were randomized into two equal groups comprising 20 patients each. They were comparable by the main clinical and demographic parameters, as well as by the scope of the comprehensive treatment performed. In the study group, therapy of chronic pain syndrome was provided by the method of paravertebral analgesia, with the comparison group patients receiving epidural analgesia. Paravertebral analgesia was performed with the use of ultrasound navigation, in the prolonged mode by means of using microinfusion elastomeric pumps, epidural analgesia - according to the standard technique. The use of various methods of analgesia was accompanied by a decrease in chronic pain syndrome according to the visual analogue scale by 60% within the first 24 hours, and by 65% at 72 hours thereafter, with the differences being statistically insignificant. The use of prolonged paravertebral analgesia was accompanied by neither considerable haemodynamic reactions nor the development of the motor block, however requiring significant expenditure of a local anaesthetic. The conclusion was drawn that paravertebral analgesia in lower-limb critical ischaemia turned out to be a safe and efficient method of comprehensive therapy of chronic pain syndrome.

Restenosis is associated with prothrombotic plasma fibrin clot characteristics in endovascularly treated patients with critical limb ischemia

INTRODUCTION

Hypolysible fibrin clots composed of tightly packed fibers characterize patients with peripheral artery disease (PAD) especially those with critical limb ischemia (CLI). Little is known about the impact of a prothrombotic clot phenotype on restenosis following endovascular revascularization in CLI. The goal of this study was to compare fibrin clot properties and their determinants in CLI patients with restenosis after endovascular treatment (ET) and those free of this complication.

METHODS

85 patients with CLI and restenosis within 1 year after ET on optimal pharmacotherapy and 47 PAD control patients without restenosis were included into the study. Plasma fibrin clot permeability (Ks, a measure of the average pore size in the fibrin network) and clot lysis time (CLT) with its potential determinants were determined. During follow-up, the composite endpoint including re-intervention, amputation and death was assessed.

RESULTS

Compared with the control group, patients with restenosis had reduced Ks (- 9.5%, p < 0.001), prolonged CLT (+ 12.4%, p = 0.003), higher thrombin generation (+ 7.9%, p < 0.001) and elevated von Willebrand factor (vWF) antigen (+ 14.2%, p < 0.001). During a 24 months follow-up the composite endpoint occurred in 54 CLI patients with restenosis (63.5%) and nine control patients (19.1%, p < 0.001) with no association with baseline Ks and CLT.

CONCLUSION

The increased thrombin formation and unfavorable fibrin clot properties occur in patients with CLI who experienced restenosis despite optimal endovascular and pharmacological therapy.

Review of the Current Basic Science Strategies to Treat Critical Limb Ischemia

Critical limb ischemia (CLI) is a highly morbid disease with many patients considered poor surgical candidates. The lack of treatment options for CLI has driven interest in developing molecular therapies within recent years. Through these translational medicine studies in CLI, much has been learned about the pathophysiology of the disease. Here, we present an overview of the macrovascular and microvascular changes that lead to the development of CLI, including impairment of angiogenesis, vasculogenesis, and arteriogenesis. We summarize the randomized clinical controlled trials that have used molecular therapies in CLI, and discuss the novel imaging modalities being developed to assess the efficacy of these therapies.

Assessment of the Severity of Ischaemia and the Outcomes of Revascularisation in Peripheral Arterial Disease Patients Based on the Skin Microcirculatory Response to a Thermal Load Test

Objective

This study investigated the skin microcirculatory response to a thermal load test using a laser Doppler flowmetry device to evaluate the severity of limb ischaemia and the outcomes of revascularisation in patients with peripheral arterial disease (PAD).

Methods

A total of 34 PAD patients (39 limbs) including 17 critical limb ischaemia (CLI) patients (21 limbs) who underwent revascularisation were enrolled. The skin microcirculation of the dorsal side of the affected foot was investigated for 15 minutes after local heating. The tests were performed both before and after revascularisation, and several parameters gleaned from the microcirculatory fluctuations were analysed and compared with the ankle brachial pressure index and the transcutaneous oxygen tension (tcPO₂) values.

Results

Among the parameters, significant differences were observed between the CLI patients and patients with claudication with regard to the increasing phase time (T_inc), the difference in the perfusion values at the onset and the peak of the transient increase in blood perfusion (PΔ), the slope of the transient increase in blood perfusion (S_in), and the slope of the decrease in blood perfusion after the peak (S_de). In CLI patients, the PΔ, S_in, and S_de values increased significantly after revascularisation. In the patients with claudication, the changes in the parameters after revascularisation were not statistically significant. The S_de showed the most statistically significant correlation with the tcPO₂ value (ρ .759, p < .001).

Conclusions

Thermal load testing can be used to evaluate the severity of limb ischaemia in patients with PAD.

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New thermal load testing for evaluation of the severity of limb ischaemia is presented.

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Skin blood flow response to thermal load was investigated by laser Doppler flowmetry.

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Thermal load testing can be used to evaluate the severity of limb ischaemia.

Prognostic Factors in Patients Treated with Drug-Coated Balloon Angioplasty for Symptomatic Peripheral Artery Disease

Purpose

Aim of this study is to report real-life experience on the treatment of peripheral artery disease (PAD) with a specific drug-coated balloon (DCB), and to evaluate potential prognostic factors for outcomes.

Materials and Methods

This is a retrospective study reporting outcomes in patients with PAD who were treated with the Lutonix DCB during a four-year period. Major outcomes included: all-cause mortality, amputation, clinical improvement, wound healing and target lesion revascularization (TLR). Mean follow-up was 24.2±2.3 months.

Results

Overall, 149 patients (mean age: 68.6±8.3 years; 113 males) were treated, either for intermittent claudication (IC) (n=86) or critical limb ischemia (CLI) (n=63). More than half the target lesions (n=206 in total) were located in the superficial femoral artery and 18.0% were below-the-knee lesions. CLI patients presented more frequently with infrapopliteal (P=0.002) or multilevel disease (P=0.0004). Overall, all-cause mortality during follow-up was 10.7%, amputation-free survival was 81.2% and TLR-free survival was 96.6%. CLI patients showed higher all-cause mortality (P=0.007) and total amputation (P=0.0001) rates as well as lower clinical improvement (P=0.0002), compared to IC patients. Coronary artery disease (CAD), gangrene and infrapopliteal disease were found to be predictors for death whereas CLI and gangrene were found to be predictors for amputation, during follow-up.

Conclusion

PAD treatment with Lutonix DCBs seems to be an efficient and safe endovascular strategy yielding promising results. However, CAD, gangrene, CLI and infrapopliteal lesions were found to be independent predictors for adverse outcomes. Larger series are needed to identify additional prognostic factors.

Six-Month Freedom From Amputation Rates and Quality of Life Following Tibial and Pedal Endovascular Revascularization for Critical Limb Ischemia

Objective:

Patients with critical limb ischemia (CLI) and gangrene have a 10% to 38% rate of major amputation at 6 months. The purpose of this study is to report short- and mid-term major and minor amputation rates for patients who underwent tibial and pedal revascularization in addition to quality-of-life (QoL) scores.

Methods:

All patients who presented to a single institution with CLI (defined as rest pain or nonhealing wounds) and underwent antegrade or retrograde tibial access, atherectomy and angioplasty of the tibial circulation, and angioplasty of pedal circulation (antegrade or retrograde) from June 2016 to September 2017 were included. The Stark QoL questionnaire was used at each visit. Patients were scored at 1, 3, and 6 months postprocedure. Amputation rates were recorded.

Results:

Forty-two patients with CLI and gangrene underwent 57 peripheral interventions for limb salvage between June 2016 and September 2017. Thirty-two limbs had dry gangrene along the dorsalis pedis angiosome, 14 limbs had dry gangrene along the posterior tibial angiogram, and 11 limbs had a combined disease pattern. Twelve limbs underwent angioplasty of the superficial femoral artery (SFA), 18 limbs underwent angioplasty and stenting of the SFA, and 14 limbs underwent atherectomy, angioplasty, and stenting of the SFA. All patients had 1 or 2 tibial vessel runoff and high-grade stenosis of the pedal circulation. Immediate technical success defined as 3-vessel outflow to the foot occurred in 49 limbs (86%) with zero 30-day complications (30-day readmission, major amputation, or sepsis). Major amputation rate at 1, 3, and 6 months was 0%, 2%, and 4%, respectively. Patient satisfaction in terms of QoL increased over the 6-month follow-up period.

Conclusion:

Aggressive tibial and pedal revascularization may improve freedom from minor and major amputation at 6 months and may be associated with a short- and mid-term higher QoL.

The multi-functional roles of menstrual blood-derived stem cells in regenerative medicine

Menstrual blood-derived stem cells (MenSCs) are a novel source of mesenchymal stem cells (MSCs). MenSCs are attracting more and more attention since their discovery in 2007. MenSCs also have no moral dilemma and show some unique features of known adult-derived stem cells, which provide an alternative source for the research and application in regenerative medicine. Currently, people are increasingly interested in their clinical potential due to their high proliferation, remarkable versatility, and periodic acquisition in a non-invasive manner with no other sources of MSCs that are comparable in adult tissue. In this review, the plasticity of pluripotent biological characteristics, immunophenotype and function, differentiative potential, and immunomodulatory properties are assessed. Furthermore, we also summarize their therapeutic effects and functional characteristics in various diseases, including liver disease, diabetes, stroke, Duchenne muscular dystrophy, ovarian-related disease, myocardial infarction, Asherman syndrome, Alzheimer’s disease, acute lung injury, cutaneous wound, endometriosis, and neurodegenerative diseases. Subsequently, the clinical potential of MenSCs is investigated. There is a need for a deeper understanding of its immunomodulatory and diagnostic properties with safety concern on a variety of environmental conditions (such as epidemiological backgrounds, age, hormonal status, and pre-contraceptive). In summary, MenSC has a great potential for reducing mortality and improving the quality of life of severe patients. As a kind of adult stem cells, MenSCs have multiple properties in treating a variety of diseases in regenerative medicine for future clinical applications.

Modified VEGF-A mRNA induces sustained multifaceted microvascular response and accelerates diabetic wound healing

Capable of mediating efficient transfection and protein production without eliciting innate immune responses, chemically modified mRNA holds great potential to produce paracrine factors at a physiologically beneficial level, in a spatiotemporally controlled manner, and with low toxicity. Although highly promising in cardiovascular medicine and wound healing, effects of this emerging therapeutic on the microvasculature and its bioactivity in disease settings remain poorly understood. Here, we longitudinally and comprehensively characterize microvascular responses to AZD8601, a modified mRNA encoding vascular endothelial growth factor A (VEGF-A), in vivo. Using multi-parametric photoacoustic microscopy, we show that intradermal injection of AZD8601 formulated in a biocompatible vehicle results in pronounced, sustained and dose-dependent vasodilation, blood flow upregulation, and neovessel formation, in striking contrast to those induced by recombinant human VEGF-A protein, a non-translatable variant of AZD8601, and citrate/saline vehicle. Moreover, we evaluate the bioactivity of AZD8601 in a mouse model of diabetic wound healing in vivo. Using a boron nanoparticle-based tissue oxygen sensor, we show that sequential dosing of AZD8601 improves vascularization and tissue oxygenation of the wound bed, leading to accelerated re-epithelialization during the early phase of diabetic wound healing.

Functional prognosis of critical limb ischemia and efficacy of restoration of direct flow below the ankle

Objective

Patients with critical limb ischemia have serious systemic comorbidities and are at high risk of impairment of limb function. In this study, we assessed the prognostic factors of limbs after revascularization.

Methods

In this retrospective single-center cohort study, from April 2008 to December 2012, we treated 154 limbs of 121 patients with critical limb ischemia by the endovascular therapy-first approach based on the patients’ characteristics. The primary end point was amputation-free survival. Secondary end points were patency of a revascularized artery, major adverse limb events, or death. Furthermore, we investigated the ambulatory status one year after revascularization as prognosis of limb function.

Results

Endovascular therapy was performed in 85 limbs in 65 patients as the initial therapy (endovascular therapy group) and surgical reconstructive procedures (bypass group) were performed in 69 limbs in 56 patients. Early mortality within 30 days was not observed in either group. The primary patency rate was significantly better in the bypass group than in the endovascular therapy group ( p < 0.0001). Furthermore, the secondary patency rate was similar between the two groups ( p = 0.0096). There were no significant differences in amputation-free survival and major adverse limb event between the two groups. Univariate analysis showed that ulcer healing ( p < 0.0001), no hypoalbuminemia ( p = 0.0019), restoration of direct flow below the ankle ( p = 0.0219), no previous cerebrovascular disease ( p = 0.0389), and Rutherford 4 ( p = 0.0469) were predictive factors for preservation of ambulatory status one year after revascularization. In multivariate analysis, ulcer healing ( p < 0.0001) and restoration of direct flow below the ankle ( p = 0.0060) were significant predictors.

Conclusions

Ulcer healing and restoration of direct flow below the ankle are independently associated with prognosis of limb functions in patients who undergo infrainguinal arterial reconstruction.

Comparison of Ankle Pressure, Systolic Toe Pressure, and Transcutaneous Oxygen Pressure to Predict Major Amputation After 1 Year in the COPART Cohort

The hemodynamic definition of critical limb ischemia (CLI) has evolved over time but remains controversial. We compared the prediction of major amputation by 3 hemodynamic methods. Patients were selected from the Cohorte des Patients ARTériopathes cohort of patients hospitalized for peripheral arterial disease. Patients with CLI were enrolled according to the Trans-Atlantic Inter-Society Consensus Document on Management of Peripheral Arterial Disease II definition and followed up for at least 1 year. We compared the major amputation rate according to initial ankle pressure (AP), systolic toe pressure (STP), and forefoot transcutaneous oxygen pressure (TcPO2); 556 patients were included and divided into surgical (264) and medical (292) groups. The AP failed to identify 42% of patients with CLI. After 1 year, 27% of medical and 17% of surgical patients had undergone major amputation. The TP <30 mm Hg predicted major amputation in the whole sample and in the medical group (odds ratio [OR] 3.5 [1.7-7.1] and OR 5 [2-12.4], respectively), but AP did not. The TcPO2 <10 mm Hg also predicted major amputation (OR 2.3 [1.5-3.5] and OR 3.8 [2.1-6.8]). The best predictive thresholds to predict major amputation were STP <30 mm Hg and TcPO2 <10 mm Hg. None of these methods performed before surgery was able to predict outcome in the revascularized patients.

The chaos of hospitalisation for patients with critical limb ischaemia approaching major amputation

AIMS AND OBJECTIVES

To illuminate the hospital experience for patients and families when major amputation has been advised for critical limb ischaemia (CLI).

BACKGROUND

CLI creates significant burden to the health system and the family, particularly as the person with CLI approaches amputation. Major amputation is often offered as a late intervention for CLI in response to the marked deterioration of an ischaemic limb, and functional decline from reduced mobility, intractable pain, infection and/or toxaemia. While a wealth of clinical outcome data on CLI and amputation exists internationally, little is known about the patient/family-centred experience of hospitalisation to inform preservation of personhood and patient-centred care planning.

DESIGN

Longitudinal qualitative study using Heideggerian phenomenology.

METHODS

Fourteen patients and 13 family carers provided a semistructured interview after advice for major amputation. Where amputation followed, a second interview (6 months postprocedure) was provided by eight patients and seven family carers. Forty-two semistructured interviews were audio-recorded and transcribed verbatim. Hermeneutic phenomenological analysis followed.

RESULTS

Hospitalisation for CLI, with or without amputation, created a sense of chaos, characterised by being fragile and needing more time for care (fragile body and fragile mind, nurse busyness and carer hypervigilance), being adrift within uncontrollable spaces (noise, unreliable space, precarious accommodation and unpredictable scheduling) and being confused by missed and mixed messages (multiple stakeholders, information overload and cultural/linguistic diversity).

CONCLUSIONS

Patients and families need a range of strategies to assist mindful decision-making in preparation for amputation in what for them is a chaotic process occurring within a chaotic environment. Cognitive deficits increase the care complexity and burden of family advocacy.

RELEVANCE TO CLINICAL PRACTICE

A coordinated, interprofessional response should improve systems for communication, family engagement, operation scheduling and discharge planning to support preparation, adjustment and allow a sense of safety to develop. Formal peer support for patients and caregivers should be actively facilitated.

High-sensitivity cardiac troponin and natriuretic peptide with risk of lower-extremity peripheral artery disease: the Atherosclerosis Risk in Communities (ARIC) Study

Aims

Cardiac troponin T (cTnT) is suggested as a predictor of amputation in patients with peripheral artery disease (PAD). However, cTnT-PAD association has not been systematically studied in a large study. This study evaluated the association of high-sensitivity cTnT (hs-cTnT) with PAD incidence and also explored whether natriuretic peptide (NT-proBNP), another representative cardiac marker, predicts PAD risk.

Methods and results

Among 12 288 middle-aged adults, the associations of hs-cTnT and NT-proBNP with incident PAD (hospitalizations with PAD diagnosis or leg revascularization [cases with rest pain or tissue loss considered as critical limb ischaemia (CLI)]) were quantified with multivariable Cox regression models. The risk discrimination was assessed by c-statistic. During a follow-up over 22 years, 454 participants developed PAD (164 CLI cases). In demographically adjusted models, the highest category of hs-cTnT (≥14 vs. <3 ng/L) and NT-proBNP (≥258.3 vs. <51.5 pg/mL) showed ∼8- and 10-20-fold higher risk of PAD and CLI, respectively. Even after adjusting for potential confounders and each other, hazard ratios were greater for CLI than for PAD (7.74 95% confidence interval [95% CI 4.43-13.55] vs. 2.84 [2.02-4.00] for the highest vs. reference hs-cTnT category and 4.63 [2.61-8.23] vs. 3.16 [2.23-4.49] for the highest vs. reference NT-proBNP category). The addition of these cardiac markers improved c-statistics for CLI.

Conclusion

High-sensitivity cTnT and NT-proBNP were independently associated with incident PAD, particularly its severe form, CLI. Although future studies are warranted to investigate pathophysiological mechanisms behind these associations, our study suggests the usefulness of cardiac markers to identify individuals at high risk of CLI.

Impact of Frailty on Clinical Outcomes in Patients With Critical Limb Ischemia

Background:

The predictive ability of patient frailty on clinical outcomes after revascularization in patients with critical limb ischemia remains largely unknown.

Methods and Results:

We enrolled 643 patients with critical limb ischemia treated with endovascular therapy (N=486) or bypass surgery (N=157) in January 2010 to January 2016, and prospectively assessed them using a 9-level clinical frailty scale (CFS). Patients were divided into 3 groups according to CFS levels: low (CFS level, 1–3; N=234), intermediate (CFS level, 4–6; N=196), and high (CFS level, 7–9; N=213) groups. Clinical follow-up rate was 95.8% at 2 years. In the low, intermediate, and high CFS groups, 2-year overall survival rates were 80.5%, 63.1%, and 49.3% ( P <0.001) and amputation-free survival rates were 77.9%, 60.5%, and 46.2% ( P <0.001), respectively. In multivariable analysis, higher frailty was independently associated with all-cause death (intermediate CFS group: adjusted hazard ratio, 1.64; 95% confidence interval, 1.12–2.42; P =0.01; high CFS group: adjusted hazard ratio, 2.22; 95% confidence interval, 1.52–3.23; P <0.001) and a composite of all-cause death and major amputation (intermediate CFS group: adjusted hazard ratio, 1.72; 95% confidence interval, 1.19–2.48; P =0.004; high CFS group: adjusted hazard ratio, 2.34; 95% confidence interval, 1.64–3.35; P <0.001). Frailty was also independently associated with overall survival and amputation-free survival in patients aged ≤75 and >75 years, those who underwent endovascular therapy or bypass surgery, and those with or without chronic renal failure, without significant interactions.

Conclusions:

Frailty was independently associated with 2-year overall survival and amputation-free survival in patients with critical limb ischemia treated with revascularization, irrespective of age, revascularization mode, and chronic renal failure status.

Fatigability and functional performance among older adults with low-normal ankle-brachial index: Cross-sectional findings from the Baltimore Longitudinal Study of Aging

BACKGROUND AND AIMS

Peripheral artery disease (PAD) is associated with poor mobility and fatigue, but the relationship between preclinical ankle-brachial index (ABI) and early markers of fatigue and functional decline has not been defined.

METHODS

570 adults, 50 and older, from the Baltimore Longitudinal Study of Aging (N = 570), with normal values of ABI (1-1.39), were classified into ABI tertiles. Perceived fatigability was assessed after a 5-min, treadmill walk (1.5 mph) using the Borg rating of perceived exertion (RPE, range 6-20). Functional evaluation included the Health, Aging and Body Composition Physical Performance Battery (HABC PPB), time to complete a 400-m corridor walk (LDCW), and VO₂ peak (ml/kg/min). High RPE and poor walking endurance (PWE) were defined as RPE≥10 and taking >5 min for the LDCW, respectively. Differences between tertiles in fatigability and functional measures were tested adjusting for demographics, behavioral characteristics, self-reported fatigue, and medical history.

RESULTS

Mean LDCW time and RPE were greater for participants in the lowest tertile compared to those in the highest; mean VO₂ peak and HABC PPB scores were lower, suggesting hierarchical associations between fatigability, functional performance, and ABI (p < 0.05 for all). Odds of PWE were greater for those in the lowest ABI tertile compared to the highest; odds of reporting high RPE were greater for those in the middle tertile.

CONCLUSIONS

Lower ABI is associated with poorer physical function and increased fatigability, suggesting that early changes in ABI may infer greater risk of functional decline, even among those who may not progress to PAD.

Myocardial injury after endovascular revascularization in critical limb ischemia predicts 1-year mortality: a prospective observational cohort study

BACKGROUND

Patients with critical limb ischemia (CLI) are at increased risk of cardiovascular complications and mortality. To determine (1) incidence of myocardial injury following endovascular revascularization, and (2) relationship between myocardial injury with 1-year mortality and major adverse cardiovascular events (MACE; i.e., composite of myocardial infarction, stroke, and death).

METHODS AND RESULTS

Single-center, prospective cohort study of CLI patients ≥ 45 years of age, who underwent endovascular revascularization with overnight hospitalization. High-sensitive troponins T (hsTnTs) were measured on admission, 3-6 h after endovascular revascularization and the subsequent morning. Myocardial injury after endovascular revascularization was defined as an hsTnT ≥ 14 ng/L with a relative increase ≥ 30% from the baseline value. We also evaluated other myocardial injury hsTnT thresholds (i.e., ≥ 30, ≥ 40, ≥ 60, and ≥ 80 ng/L). 239 consecutive patients (56% male, mean age 71.5 ± 10.1 years) were included; one patient was lost to follow-up. At 1 year, there were 34 deaths (14.2%), and 48 MACE (20.5%). Myocardial injury with the hsTnT threshold of 14 ng/L and relative increase by ≥ 30% from the baseline level occurred in 61 patients (25.5%). Myocardial injury was independently associated with 1-year mortality ([aHR], 2.44; 95% CI 1.18-5.06, for hsTnT ≥ 14 ng/L to aHR, 3.34; 95% CI 1.29-8.65 for hsTnT ≥ 80 ng/L). Myocardial injury was also independently associated with 1-year MACE ([AOR] 2.89; 95% CI 1.41-5.92 for hsTnT ≥ 14 ng/L to AOR, 6.69; 95% CI 2.17-20.68 for hsTnT ≥ 80 ng/L). 85.2% patients who had myocardial injury did not have ischemic clinical symptoms or electrocardiography changes. In sensitive analysis with exclusion of symptomatic patients that developed myocardial injury for the hsTnT ≥ 14 ng/L threshold, both the 1-year mortality (aHR: 2.19; CI 1.02-4.68; p = 0.04), and 1-year MACE (OR 2.25; CI 1.06-4.77; p = 0.036) remained significant.

CONCLUSIONS

Myocardial injury is common following endovascular revascularization for CLI and associated with the risk of 1-year mortality and MACE.

Reduced amputation rate with isovolemic hemodilution in critical limb ischemia patients

AIMS

Critical limb ischemia (CLI) patients are characterized by intractable pain in spite of medication, non-healing ulcers, and gangrene. The objective of this study was to investigate whether or not isovolemic hemodilution treatment can reduce the rate of major amputations in CLI.

METHODS

28 patients were studied who had tissue loss on Rutherford Grade III, Category 5 or 6. The subjects were divided into two arms: standard-of-care, conventional therapy (CT) (n = 15) as a control group and hemodilution therapy (HT) (n = 13) as a study group. For the HT group, weekly isovolemic hemodilution was performed over 4 consecutive weeks, removing 250 ml of whole blood with the infusion of hydroxyl-ethyl starch solution. Blood viscosity, hematocrit, hemoglobin, ankle-brachial index, VA pain scale, time-to-amputation from admission, and survival time were measured.

RESULTS

The mean Hct gradually decreased from 36.6 to 35.1, whereas the WBV at a shear rate of 1 s-1 significantly decreased from 18.2 to 10.5 during the same period. Subsequently, tissue oxygen delivery index, defined as the ratio of Hct to WBV at a shear rate of 1 s-1, increased from 24.4 to 37.0 by 51.7%, suggesting improvements in oxygen delivery in the patients. The average rate of lower limb major amputation in the control group was 93% (14/15), whereas that in the study group was 31% (4/13) (p = 0.001). Amputation-free median survival time and amputation-free 5-year survival rate in the control group were 1.2 months and 7%, while those in the study group were 30.2 months and 44% (p = 0.001). There were no adverse effects from repetitive hemodilution in the study group.

CONCLUSIONS

Isovolemic hemodilution treatment of CLI patients was found to be well-tolerated and reduced the rate of major amputation resulting from the deterioration of CLI.

Arginine pretreatment enhances circulating endothelial progenitor cell population and attenuates inflammatory response in high-fat diet-induced obese mice with limb ischemia

Obesity is a global health problem with an up-regulated inflammatory reaction. Obesity-induced endothelial progenitor cells (EPCs) dysfunction is associated with vascular complications that may contribute to critical limb ischemia. Arginine (Arg) is an amino acid with immune-modulatory property and has been found to promote EPCs mobilization in disease conditions. Thus in the present investigation, we hypothesized that arginine given to a murine model of diet-induced obesity would increase circulating EPCs and mitigate the inflammatory reactions in response to limb ischemia. Mice were divided into normal group (NC), high-fat group (HC), and high-fat Arg group (HA). Mice in the HC group were fed with a diet containing 60% energy as fat for 8 weeks, while HA group were initially fed with the same high-fat diet for 4 weeks and later shifted to a high-fat diet enriched with 2% Arg for the remaining 4 weeks. Then mice in the HC and HA groups underwent ischemic operations and were euthanized at either day 1 or day 7 after limb ischemia. The results showed that, compared to the ischemic HC group, the ischemic HA group had higher circulating EPCs at day 1 post-ischemia and higher muscle stromal cell-derived factor-1 and interleukin (IL)-10 mRNA expressions at day 7 after ischemia. In contrast, plasma leptin concentration and expressions of IL-1β and tumor necrosis factor-α mRNAs by adipocytes were down-regulated. These findings suggest that obese mice treated with Arg-containing high-fat diet enhanced circulating EPCs percentage and attenuated inflammatory reaction in response to limb ischemia.

The Effect of Malignancy on Outcomes Following Revascularization for Critical Limb Ischemia: A Case-Control Study

AIM

Malignancy is common in patients presenting with critical lower limb ischemia (CLI). However, outcomes in patients with concomitant active malignancy and CLI have not been well defined in comparative prospective analyses. Using contemporary prospective data, we aimed to assess outcomes following revascularization in patients with CLI and active malignancy.

METHODS

A nested case-control study was performed using data from 2 tertiary referral centers for vascular disease. A total of 48 consecutive patients undergoing intervention for CLI who had a diagnosis of active malignancy were identified and matched to patients with CLI but no malignancy for age, sex, diabetes, and smoking. Patency rates and morbidity/mortality were assessed using duplex ultrasonography and regular clinical review.

RESULTS

A total of 48 consecutive patients (median age: 74.5 years; interquartile range: 68-80 years) with active malignancy and CLI were identified and case-matched (age, sex, diabetes, and smoking) to 48 patients undergoing intervention for CLI who had no malignancy. Major cardiovascular risk factors did not differ. All-cause mortality was 23% versus 12% ( P = .41) at 6 months and 54% versus 15% ( P < .001) at 12 months. None of the patients died due to complications relating directly to the lower limb intervention or within 30 days of the intervention. A total of 4 (8.3%) patients had required a major limb amputation at 6 months in both groups, compared with 5 (10.4%) patients with malignancy versus 4 (8.3%) patients without ( P = .73) at 12 months. Patency rates were similar at 12 months (73% vs 80%). Three patients had required reintervention in both groups (endovascular in all cases) at 12 months.

CONCLUSION

Revascularization can be offered safely in selected patients with active malignancy; patency rates in those surviving to 1 year are similar to patients without malignancy.

Efficacy Outcomes of Endovascular Versus Surgical Revascularization in Critical Limb Ischemia: Results From a Prospective Cohort Study

Data on efficacy outcomes of endovascular versus surgical revascularization in patients with critical limb ischemia (CLI) in contemporary practice are limited. In this prospective cohort study, 353 consecutive patients with CLI were enrolled and allocated to endovascular (PTA [percutaneous transluminal angioplasty]), surgical (SURG), or no revascularization (No REVASC) after interdisciplinary consensus. Outcome measures were sustained primary clinical success (sPCS; survival without major amputation, repeated target extremity revascularization, and freedom from CLI), limb salvage, and amputation-free survival. Propensity-matched Kaplan-Meier analyses and stratified log-rank tests were performed. The PTA, SURG, and No REVASC groups consisted of 264, 62, and 27 patients, respectively. Compared to SURG patients, PTA patients were significantly older, had more risk factors, and more often had ischemic lesions. Propensity score-adjusted analyses showed no significant differences: sPCS was 51.3%/52.2%, limb salvage rate 91.5%/93.7%, and major amputation-free survival 90.5%/87.2% at 12 months for PTA and SURG, respectively. Amputation-free survival for the No REVASC group was 69% at 12 months. In conclusion, endovascular and surgical revascularization in CLI has comparable efficacy outcomes after 12 months. Contemporary overall outcome of patients with CLI is considerably better compared to earlier studies.

Current Status of Arterial Revascularization for the Treatment of Critical Limb Ischemia in Infrainguinal Atherosclerotic Disease

Critical limb ischemia (CLI) is the most severe form of peripheral arterial disease (PAD) that may result in limb loss and even death; thus, the fast and proper treatment should be employed as earlier as possible to prevent these catastrophic consequences. Arterial revascularization is almost always an indispensable treatment option for CLI. Although both endovascular and surgical revascularization procedures have an important role, nowadays, the hybrid revascularization as a combination of these revascularization procedures has also gained increasing popularity in the treatment of patients with CLI. This review provides an update on the arterial revascularization strategies for the treatment of CLI.

Switch to Ticagrelor in critical limb ischemia antiplatelet study (STT-CLIPS)

OBJECTIVE

To investigate platelet reactivity in patients with critical limb ischemia (CLI) after switching from clopidogrel to ticagrelor.

BACKGROUND

High on-treatment platelet reactivity (HPR) is highly prevalent in patients with CLI treated with clopidogrel. The effect of ticagrelor in patients with CLI is not known, however.

METHODS

We performed P2Y12 platelet receptor inhibition studies (VASP and VerifyNow) in 50 patients with CLI. Tests were performed before and 6±1h after daily 75mg clopidogrel dose. Patients were then switched to ticagrelor 90mg twice daily for two weeks and platelet assays repeated. Patients were divided based on VerifyNow P2Y12 reaction units (PRU). Group 1: HPR defined as PRU ≥208 and Group 2: Appropriate platelet inhibition (API), PRU <208.

RESULTS

After two weeks of uninterrupted antiplatelet therapy, mean PRU results were 173 PRU and 71 PRU at baseline (p<0.0001) and 140 PRU and 63 PRU after 6h (p<0.0001) for clopidogrel and ticagrelor, respectively. Before daily clopidogrel dose, 36% of patients (n=18) demonstrated HPR and after 6h, 30% (n=15). One patient (2%) had HPR on ticagrelor. Ninety-four percent of patients with HPR on clopidogrel demonstrated appropriate platelet inhibition after switching to ticagrelor and all patients with API on clopidogrel remained with API after switching to ticagrelor. Six hours after daily dosing, VASP-PRI >50% was found in 42% of clopidogrel and 2% of ticagrelor treated patients.

CONCLUSIONS

Among patients with CLI, ticagrelor achieved greater platelet inhibition than clopidogrel during maintenance treatment and at 6h after daily dosing. High on-treatment platelet reactivity to clopidogrel in patients with CLI can be overcome by switching to ticagrelor.

The Use of the Profunda Femoral Artery as the Sole Target Vessel to Bypass Aortoiliac Disease in Patients with Critical Limb Ischemia and Concomitant Unreconstructable Infrainguinal Disease

BACKGROUND

Critical limb ischemia (CLI) often results from multilevel occlusive disease. There are occasions where a patent profunda femoral artery (PFA) is the only target artery that can be used as outflow during reconstruction to bypass aortoiliac disease (AOID), with no further option for infrainguinal revascularization. We aim to report results of the use of PFA as the sole target vessel for the treatment of these patients.

METHODS

This is a retrospective, single-center study including CLI patients treated during 36 months. All procedures were included regardless of inflow site. The outcomes examined were hemodynamic improvement, clinical status change, amputation-free and overall survival, and patency of the prosthesis. Univariate analysis was performed to identify possible predictors of adverse outcomes.

RESULTS

Twenty-three patients and 27 limbs were included (2 female, mean age 70.6). Sixteen limbs presented rest pain and 11 tissue loss. Inflow was obtained from the axillary (n = 9), contralateral femoral (n = 8), abdominal aorta (n = 2), thoracic aorta (n = 1), ipsilateral external iliac (n = 2), and contralateral external iliac artery (n = 1). Immediately postoperatively ankle-brachial index significantly increased from 0.15 (0-0.5) to 0.50 (0.25-0.9), (P-value < 0.001). Twenty-four limbs presented clinical improvement (3 minimally, 18 moderately, and 3 markedly improved) and 3 presented no change. During a mean follow-up of 15.8 (2-36) months, we recorded 4 deaths and 4 major amputations. Mean predicted overall survival and amputation-free survival were 29.8 (95% confidence interval [CI] 24.5-35.1) and 26.5 months (95% CI 21.1-31.8), respectively. Predicted primary patency was 76% at 3 years. Univariate analysis revealed significant associations only between bypass patency and limp loss (P-value = 0.021).

CONCLUSIONS

In the presence of CLI due to AOID and unreconstructable infrainguinal disease, the use of PFA as the sole target vessel during bypass is associated with significant rates of clinical improvement and limb salvage.

Perfusion measures for symptom severity and differential outcome of revascularization in limb ischemia: Preliminary results with arterial spin labeling reactive hyperemia

BACKGROUND

Previously, a theoretical model based on microvascular physiology was established to facilitate the interpretation of calf perfusion dynamics recorded by arterial spin labeling (ASL).

PURPOSE

To investigate the clinical relevance of novel perfusion indices by comparing them to the symptoms, response to revascularization, and short-term functional outcome in patients with peripheral arterial disease (PAD).

STUDY TYPE

Prospective cohort study.

POPULATION

Nineteen patients with PAD.

FIELD STRENGTH/SEQUENCE

Pulsed ASL at 3T.

ASSESSMENT

The mid-calf reactive hyperemia induced by 2 minutes of arterial occlusion was recorded in PAD patients. The perfusion responses were characterized by the peak, time-to-peak, and physiological model-derived indices including the baseline perfusion f_r , arterial resistance R_a , and compliance C_a , and sensitivity g_ATP and response time τ_ATP of downstream microvasculature to metabolic stress. These indices were compared to the disease severity and outcome within 6 months after revascularization assessed by self-reported symptoms and the ankle-brachial index. Disease severity was categorized as asymptomatic, claudication, or critical limb ischemia. The outcome was categorized as symptom resolved or limited improvement.

STATISTICAL TESTS

Severity and outcome groups were compared using Mann-Whitney and Kruskal-Wallis tests with Holm-Sidak adjustments.

RESULTS

The peak perfusion decreased and model arterial resistance increased progressively with increasing severity of limb ischemia (P = 0.0402 and 0.0413, respectively). Eleven patients had a successful endovascular procedure, including six patients who had symptoms resolved, four patients who had remaining leg pain, and one patient lost to follow-up. The subjects with limited improvement had significantly lower preintervention microvascular sensitivity g_ATP than those with symptoms resolved (8.72 ± 1.46 vs. 4.93 ± 0.91, P = 0.0466).

DATA CONCLUSION

ASL reactive hyperemia reflects multiple aspects of the pathophysiology. Measures of macrovascular arterial disease are related to the manifested symptom severity, whereas preintervention g_ATP associated with microvascular dysfunction is related to prognosis following revascularization.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2018;47:1578-1588.

Stem Cell Therapies in Peripheral Vascular Diseases — Current Status

Peripheral artery diseases include all arterial diseases with the exception of coronary and aortic involvement, more specifically diseases of the extracranial carotids, upper limb arteries, mesenteric and renal vessels, and last but not least, lower limb arteries. Mononuclear stem cells, harvested from various sites (bone marrow, peripheral blood, mesenchymal cells, adipose-derived stem cells) have been studied as a treatment option for alleviating symptoms in peripheral artery disease, as potential stimulators for therapeutic angiogenesis, thus improving vascularization of the ischemic tissue. The aim of this manuscript was to review current medical literature on a novel treatment method — cell therapy, in patients with various peripheral vascular diseases, including carotid, renal, mesenteric artery disease, thromboangiitis obliterans, as well as upper and lower limb artery disease.

A Reliable Mouse Model of Hind limb Gangrene

BACKGROUND

Lack of a reliable hind limb gangrene animal model limits preclinical studies of gangrene, a severe form of critical limb ischemia. We develop a novel mouse hind limb gangrene model to facilitate translational studies.

METHODS

BALB/c, FVB, and C57BL/6 mice underwent femoral artery ligation (FAL) with or without administration of N^G-nitro-L-arginine methyl ester (L-NAME), an endothelial nitric oxide synthase inhibitor. Gangrene was assessed using standardized ischemia scores ranging from 0 (no gangrene) to 12 (forefoot gangrene). Laser Doppler imaging (LDI) and DiI perfusion quantified hind limb reperfusion postoperatively.

RESULTS

BALB/c develops gangrene with FAL-only (n = 11/11, 100% gangrene incidence), showing mean limb ischemia score of 12 on postoperative days (PODs) 7 and 14 with LDI ranging from 0.08 to 0.12 on respective PODs. Most FVB did not develop gangrene with FAL-only (n = 3/9, 33% gangrene incidence) but with FAL and L-NAME (n = 9/9, 100% gangrene incidence). Mean limb ischemia scores for FVB undergoing FAL with L-NAME were significantly higher than for FVB receiving FAL-only. LDI score and capillary density by POD 28 were significantly lower in FVB undergoing FAL with L-NAME. C57BL/6 did not develop gangrene with FAL-only or FAL and L-NAME.

CONCLUSIONS

Reproducible murine gangrene models may elucidate molecular mechanisms for gangrene development, facilitating therapeutic intervention.

Critical Limb Ischemia: A Practical Up-To-Date Review

Critical limb ischemia (CLI) is the most advanced form of peripheral artery disease. It is associated with significant morbidity and mortality and high management costs. It carries a high risk of amputation and local infection. Moreover, cardiovascular complications remain a major concern. Although it is a well-known entity and new technological and therapeutic advances have been made, this condition remains poorly addressed, with significantly heterogeneous management, especially in nonexperienced centers. This review, from a third-level dedicated inpatient and outpatient cardioangiology structure, aims to provide an updated summary on the topic of CLI of its complexity, encompassing epidemiological, social, economical and, in particular, diagnostic/imaging issues, together with potential therapeutic strategies (medical, endovascular, and surgical), including the evaluation of cardiovascular risk factors, the diagnosis, and treatment together with prognostic stratification.

Effect of direct cold atmospheric plasma (diCAP) on microcirculation of intact skin in a controlled mechanical environment

OBJECTIVE

The microcirculatory response of intact human skin to exposure with diCAP for different durations with a focus on the effect of implied mechanical pressure during plasma treatment was investigated.

METHODS

Local relative hemoglobin, blood flow velocity, tissue oxygen saturation, and blood flow were monitored noninvasively for up to 1 hour in 1-2 mm depth by optical techniques, as well as temperature, pH values, and moisture before and after skin stimulation. The experimental protocol (N = 10) was set up to differentiate between pressure- and plasma-induced effects.

RESULTS

Significant increases in microcirculation were only observed after plasma stimulation but not after pressure stimulus alone. For a period of 1 h after stimulation, local relative hemoglobin was increased by 5.1% after 270 seconds diCAP treatment. Tissue oxygen saturation increased by up to 9.4%, whereas blood flow was doubled (+106%). Skin pH decreased by 0.3 after 180 seconds and 270 seconds diCAP treatment, whereas skin temperature and moisture were not affected.

CONCLUSIONS

diCAP treatment of intact skin notably enhances microcirculation for a therapeutically relevant period. This effect is specific to the plasma treatment and not an effect of the applied pressure. Prolonged treatment durations lead to more pronounced effects.

Measures of chronic kidney disease and risk of incident peripheral artery disease: a collaborative meta-analysis of individual participant data

BACKGROUND

Some evidence suggests that chronic kidney disease is a risk factor for lower-extremity peripheral artery disease. We aimed to quantify the independent and joint associations of two measures of chronic kidney disease (estimated glomerular filtration rate [eGFR] and albuminuria) with the incidence of peripheral artery disease.

METHODS

In this collaborative meta-analysis of international cohorts included in the Chronic Kidney Disease Prognosis Consortium (baseline measurements obtained between 1972 and 2014) with baseline measurements of eGFR and albuminuria, at least 1000 participants (this criterion not applied to cohorts exclusively enrolling patients with chronic kidney disease), and at least 50 peripheral artery disease events, we analysed adult participants without peripheral artery disease at baseline at the individual patient level with Cox proportional hazards models to quantify associations of creatinine-based eGFR, urine albumin-to-creatinine ratio (ACR), and dipstick proteinuria with the incidence of peripheral artery disease (including hospitalisation with a diagnosis of peripheral artery disease, intermittent claudication, leg revascularisation, and leg amputation). We assessed discrimination improvement through c-statistics.

FINDINGS

We analysed 817 084 individuals without a history of peripheral artery disease at baseline from 21 cohorts. 18 261 cases of peripheral artery disease were recorded during follow-up across cohorts (median follow-up was 7·4 years [IQR 5·7-8·9], range 2·0-15·8 years across cohorts). Both chronic kidney disease measures were independently associated with the incidence of peripheral artery disease. Compared with an eGFR of 95 mL/min per 1·73 m2, adjusted hazard ratios (HRs) for incident study-specific peripheral artery disease was 1·22 (95% CI 1·14-1·30) at an eGFR of 45 mL/min per 1·73 m2 and 2·06 (1·70-2·48) at an eGFR of 15 mL/min per 1·73 m2. Compared with an ACR of 5 mg/g, the adjusted HR for incident study-specific peripheral artery disease was 1·50 (1·41-1·59) at an ACR of 30 mg/g and 2·28 (2·12-2·44) at an ACR of 300 mg/g. The adjusted HR at an ACR of 300 mg/g versus 5 mg/g was 3·68 (95% CI 3·00-4·52) for leg amputation. eGFR and albuminuria contributed multiplicatively (eg, adjusted HR 5·76 [4·90-6·77] for incident peripheral artery disease and 10·61 [5·70-19·77] for amputation in eGFR <30 mL/min per 1·73 m2 plus ACR ≥300 mg/g or dipstick proteinuria 2+ or higher vs eGFR ≥90 mL/min per 1·73 m2 plus ACR <10 mg/g or dipstick proteinuria negative). Both eGFR and ACR significantly improved peripheral artery disease risk discrimination beyond traditional predictors, with a substantial improvement prediction of amputation with ACR (difference in c-statistic 0·058, 95% CI 0·045-0·070). Patterns were consistent across clinical subgroups.

INTERPRETATION

Even mild-to-moderate chronic kidney disease conferred increased risk of incident peripheral artery disease, with a strong association between albuminuria and amputation. Clinical attention should be paid to the development of peripheral artery disease symptoms and signs in people with any stage of chronic kidney disease.

FUNDING

American Heart Association, US National Kidney Foundation, and US National Institute of Diabetes and Digestive and Kidney Diseases.

Biodegradable Carriers for Delivery of VEGF Plasmid DNA for the Treatment of Critical Limb Ischemia

The safe and efficient delivery of therapeutic nucleic acid is a prerequisite for an effective DNA therapy. In this study, we condensed the low molecular weight polyethylenimine (PEI, 1.8k Da) with 2,6-pyridinedicarboxaldehyde (PDA), both of which are degradable in vivo, to synthesize a biodegradable polycationic material (PDAPEI) to deliver vascular endothelial growth factor (VEGF) plasmid DNA (pDNA). Particle size and zeta potential of this novel degradable PEI derivatives-pDNA nanoparticle were investigated and in vitro cytotoxicity was estimated on human umbilical vein endothelial cells (HUVECs). Using pDNA-encoding VEGF-A and green fluorescence protein (GFP), we also checked transfection efficiency of the vector (PDAPEI) and found its excellent performance at 40 w/w ratio. We successfully established peripheral ischemia animal model on C57/BL6J mice to evaluate the therapeutic effect of PDAPEI/pVEGF-A polyplex system on ischemic disease and a conclusion was made that PDAPEI is a promising gene vector in the treatment of peripheral ischemic artery disease (PAD).