Peripheral Artery Disease: Evolving Role of Exercise, Medical Therapy, and Endovascular Options

Characteristics and outcomes of patients with peripheral artery disease undergoing endovascular revascularization: A community hospital perspective

BACKGROUND

There are limited data on outcomes for patients with peripheral artery disease undergoing endovascular revascularization by multi-disciplinary teams in a community hospital setting.

METHODS

From January 2015 through December 2015, we assembled a multi-disciplinary program comprised of cardiologists, surgeons, radiologists, nurses, and administrative staff for managing patients with peripheral artery disease undergoing endovascular revascularization. Demographic, procedural, and outcomes data were collected with use of a template from the Society for Vascular Surgery Vascular Quality Initiative database. We compared characteristics and outcomes of patients with intermittent claudication and critical limb ischemia. We used Kaplan-Meier methods to estimate the rate of overall survival and freedom from rehospitalization between groups.

RESULTS

After excluding patients with acute limb ischemia (n = 5), peripheral intervention to the upper extremity (n = 6), or abdominal aorta (n = 11), there were 82 patients in the study cohort; 45 had intermittent claudication and 37 had critical limb ischemia. Baseline and procedural characteristics were similar between groups, although critical limb ischemia patients were more likely to have hyperlipidemia (75.7% vs. 53.3%, P = .42). Procedural success was achieved in 91.3% of cases. Actionable access site bleeding occurred in 2.4% of patients. High rates of aspirin (91.5%) and statin (87.8%) were noted at discharge. After two years of post endovascular revascularization, survival was 57.5% for critical limb ischemia patients and 94.4% for intermittent claudication patients (P < .001). Freedom from rehospitalization was 32.7% for critical limb ischemia patients and 83.5% for intermittent claudication patients (P < .001).

CONCLUSIONS

We found that favorable outcomes may be achieved with a multi-disciplinary peripheral artery disease program at community hospitals. The incorporation of quality improvement practices may further help to develop standardized and regionalized approaches to care delivery for patients with peripheral artery disease.

Superficial Femoral Artery Pseudoaneurysm and Arterial Wall Destruction After Drug-Coated Balloon Treatment

Drug-coated balloon angioplasty may present an efficient alternative to traditional balloon angioplasty and stenting, which suffer from high rates of restenosis and increased risk of stent fractures in the anatomically unfavorable regions, such as the superficial femoral artery in the adductor canal. Although pseudoaneurysms are the most common vascular access site complications, they are considerably rarer at the site of the endovascular treatment. They can be caused by several mechanisms, including stent fractures, usage of oversized balloons, high-pressure inflations, and infections. In addition, paclitaxel, the drug released from drug-coated balloons, may also play a significant role in the formation and exacerbation of pseudoaneurysms. The exact pathophysiology remains unclear, but it may be due to a combination of paclitaxel's suppression of neointimal healing and immune response, cytotoxic properties, and hypersensitivity-related inflammation.

An overview and update on the epidemiology of flavonoid intake and cardiovascular disease risk

There is an accumulating body of literature reporting on dietary flavonoid intake and the risk of cardiovascular disease (CVD) in prospective cohort studies. This makes apparent the need for an overview and update on the current state of the science. To date, at least 27 prospective cohorts (in 44 publications) have evaluated the association between estimated habitual flavonoid intake and CVD risk. At this time, the totality of evidence suggests long-term consumption of flavonoid-rich foods may be associated with a lower risk of fatal and non-fatal ischemic heart disease (IHD), cerebrovascular disease, and total CVD; disease outcomes which are principally, though not exclusively, composed of cases of atherosclerotic CVD (ASCVD). To date, few studies have investigated outcome specific ASCVD, such as peripheral artery disease (PAD) or ischemic stroke. Of the flavonoid subclasses investigated, evidence more often implicates diets rich in anthocyanins, flavan-3-ols, and flavonols in lowering the risk of CVD. Although inferences are restricted by confounding and other inherent limitations of observational studies, causality appears possible based on biological plausibility, temporality, and the relative consistency of the reported associations. However, whether the associations observed represent a benefit of the isolated bioactives per se, or are a signal of the bioactives acting in concert with the co-occurring nutrient matrix within flavonoid-bearing foods, are issues of consideration. Thus, the simple interpretation, and the one most relevant for dietary advice, is that consumption of flavonoid-rich foods or diets higher in flavonoids, appear nutritionally beneficial in the prevention of CVD.

The risk factors for calcification vary among the different sections of the lower extremity artery in patients with symptomatic peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD) is associated with considerable mortality and morbidity worldwide. The present study explored the risk factors for arterial calcification among the different sections of the lower extremity in patients with PAD and analyzed their correlations with the extent of arterial stenosis at the corresponding section.

METHODS

This study enrolled symptomatic PAD patients from our hospital from March 2017 to March 2018. The lower extremity arterial calcification score (LEACS) and lower extremity arterial stenosis index (LEASI), representing the extent of arterial stenosis, were measured on computed tomography (CT) and the correlations between them were analyzed using Spearman's correlation analysis. The relationships between risk factors and calcification were analyzed among the different sections of the lower extremity artery.

RESULTS

In total, 209 patients were included. The LEACSs of the total lower extremity, aortoiliac artery, and femoropopliteal and infrapopliteal arteries were correlated with the LEASI (all P < 0.05), but their correlation was relatively weak in the aortoiliac artery. Univariate analysis showed that hypertension was associated with the total (P = 0.019) and aortoiliac (P = 0.012) LEACSs. Diabetes was related to both femoropopliteal (P = 0.001) and infrapopliteal (P = 0.002) LEACSs. The infrapopliteal LEACS was higher in male patients (P = 0.011). After adjustment for age, the above relationships were maintained among the different sections, but not in the total lower extremity artery.

CONCLUSIONS

The LEACS is associated with the LEASI in all arterial sections, but that of the aortoiliac artery was relatively weak. Different factors have different effects on calcification among the various sections of the lower extremity artery.

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

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

The role of dynamic contrast-enhanced MRI in evaluation of percutaneous transluminal angioplasty outcome in patients with critical limb ischemia

PURPOSE

Imaging modalities such as CTA and MRA provide significant information about the distribution of macrovascular lesions of the limbs in patients with peripheral arterial disease but not for the local microvascular perfusion of the feet. The purpose of this study is to evaluate foot perfusion in patients with critical limb ischemia (CLI) and estimate percutaneous transluminal angioplasty (PTA) results, using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

METHODS

Ten patients (6 male, median age 68 years) with CLI were examined. All patients underwent DCE-MRI of the lower limb before and within first month after PTA. Perfusion parameters such as blood flow (BF), Ktrans, Kep were analyzed and applied for statistical comparisons. The studies were also examined by a second observer to determine inter-observer reproducibility.

RESULTS

Revascularization was technically successful in all patients and mean ankle brachial index (ABI) increased from 0.37 ± 0.18 to 0.76 ± 0.23, p < 0.05. After PTA, mean BF increased from 6.232 ± 2.867-9.867 ± 2.965 mL/min/100 g, K^trans increased from 0.060 ± 0.022 to 0.107 ± 0.041 min^-1 and K_ep increased from 0.103 ± 0.024 to 0.148 ± 0.024 min^-1, p < 0.05. All measurements demonstrated very good inter-observer reliability with an ICC > 0.85 for all perfusion parameters.

CONCLUSIONS

DCE-MRI is a safe and reproducible modality for the diagnosis of foot hypo-perfusion. It seems also to be a promising tool for evaluation of PTA outcome, as significant restitution of perfusion parameters was observed after successful revascularization.

Vascular Regeneration in Peripheral Artery Disease

Peripheral artery disease is a common disorder and a major cause of morbidity and mortality worldwide. Therapy is directed at reducing the risk of major adverse cardiovascular events and at ameliorating symptoms. Medical therapy is effective at reducing the incidence of myocardial infarction and stroke to which these patients are prone but is inadequate in relieving limb-related symptoms, such as intermittent claudication, rest pain, and ischemic ulceration. Limb-related morbidity is best addressed with surgical and endovascular interventions that restore perfusion. Current medical therapies have only modest effects on limb blood flow. Accordingly, there is an opportunity to develop medical approaches to restore limb perfusion. Vascular regeneration to enhance limb blood flow includes methods to enhance angiogenesis, arteriogenesis, and vasculogenesis using angiogenic cytokines and cell therapies. We review the molecular mechanisms of these processes; briefly discuss what we have learned from the clinical trials of angiogenic and cell therapies; and conclude with an overview of a potential new approach based upon transdifferentiation to enhance vascular regeneration in peripheral artery disease.

Polonsky T, Leeuwenburgh C, Ferrucci L, Peterson CA. Correlations of Calf Muscle Macrophage Content With Muscle Properties and Walking Performance in Peripheral Artery Disease

Background Peripheral artery disease (PAD) is a manifestation of atherosclerosis characterized by reduced blood flow to the lower extremities and mobility loss. Preliminary evidence suggests PAD damages skeletal muscle, resulting in muscle impairments that contribute to functional decline. We sought to determine whether PAD is associated with an altered macrophage profile in gastrocnemius muscles and whether muscle macrophage populations are associated with impaired muscle phenotype and walking performance in patients with PAD. Methods and Results Macrophages, satellite cells, and extracellular matrix in gastrocnemius muscles from 25 patients with PAD and 7 patients without PAD were quantified using immunohistochemistry. Among patients with PAD, both the absolute number and percentage of cluster of differentiation (CD) 11b+CD206+ M2-like macrophages positively correlated to satellite cell number (r=0.461 [P=0.023] and r=0.416 [P=0.042], respectively) but not capillary density or extracellular matrix. The number of CD11b+CD206- macrophages negatively correlated to 4-meter walk tests at normal (r=-0.447, P=0.036) and fast pace (r=-0.510, P=0.014). Extracellular matrix occupied more muscle area in PAD compared with non-PAD (8.72±2.19% versus 5.30±1.03%, P<0.001) and positively correlated with capillary density (r=0.656, P<0.001). Conclusions Among people with PAD, higher CD206+ M2-like macrophage abundance was associated with greater satellite cell numbers and muscle fiber size. Lower CD206- macrophage abundance was associated with better walking performance. Further study is needed to determine whether CD206+ macrophages are associated with ongoing reparative processes enabling skeletal muscle adaptation to damage with PAD. Registration URL: https://www.clini​caltr​ials.gov; Unique identifiers: NCT00693940, NCT01408901, NCT0224660.

Biomarkers of Muscle Metabolism in Peripheral Artery Disease: A Dynamic NIRS-Assisted Study to Detect Adaptations Following Revascularization and Exercise Training

We assessed whether muscle metabolism biomarkers (MMb) identified by near-infrared spectroscopy (NIRS) are valid for determining adaptations following revascularization or exercise training in peripheral artery disease (PAD). Eighteen patients (males n = 13; 69 ± 7 years) were randomized to receive revascularization (Rev = 6) or pain-free home-based exercise (Ex = 12). MMb were safely collected via a NIRS-assisted treadmill test as area-under-curve for the spectra of oxygenated (-oxy), deoxygenated (-deoxy), differential (-diff) and total (-tot) hemoglobin traces. MMb, ankle–brachial index (ABI), pain-free (PFWD) and 6-min (6MWD) walking distances were assessed at baseline and after four months. MMb were correlated at baseline with ABI (MMb-oxy r = 0.46) and 6MWD (MMb-tot r = 0.51). After treatments, MMb-oxy showed an expected increase, which was more relevant for Rev group than the Ex (56% vs. 20%), with trends towards normalization for the other MMb. These changes were significantly correlated with variations in ABI (MMb-oxy r = 0.71; p = 0.002) and 6MWD (MMb-tot r = 0.58; p = 0.003). The MMb-diff in Rev group and MMb-deoxy in Ex group at baseline predicted clinical outcomes being correlated with PFWD improvements after 4-month (r = −0.94; p = 0.005 and r = −0.57; p = 0.05, respectively). A noninvasive NIRS-based test, feasible in a clinical setting, identified muscle metabolism biomarkers in PAD. The novel MMb were associated with validated outcome measures, selectively modified after different interventions and able to predict long-term functional improvements after surgery or exercise training.

Device Selection in Femoral-Popliteal Arterial Interventions

Endovascular intervention devices for femoral-popliteal arterial disease have evolved in the last decade to more effectively treat patients with symptoms of claudication, improve tissue healing, and prevent amputation in patients with critical limb ischemia. Drug-eluting stents and drug-coated balloon therapies have demonstrated significant improvements in short- and mid-term patency and decreases in future target vessel interventions over uncoated balloon angioplasty. Adjunctive lesion preparation options including atherectomy devices are available to treat more complex and calcified lesions, but comparative data are still required.

Entering Cardiac Rehabilitation With Peripheral Artery Disease: A RETROSPECTIVE COMPARISON TO CORONARY ARTERY DISEASE

PURPOSE

Supervised exercise is recommended for patients with peripheral artery disease (PAD) and patients with coronary artery disease (CAD). Both conditions share common etiology as atherosclerotic diseases. The clinical profile, cardiorespiratory fitness, and exercise prescriptions of PAD, CAD, and patients with concomitant PAD and CAD (BOTH) have yet to be compared upon entry into cardiac rehabilitation (CR).

METHODS

Cardiopulmonary, demographic, and anthropometric assessments were conducted at entry to CR between January 2006 and December 2017.

RESULTS

Among 9701 consecutively enrolled patients, there were 94.6% with CAD (n = 9179), 1.5% with PAD (n = 143), and 3.9% with BOTH (n = 379). Only 5.4% (n = 522) of all patients entering CR had a diagnosis of PAD. Compared with CAD, patients with PAD and BOTH were older (mean ± SD = 62.5 ± 11.1 vs 67.9 ± 11.4 and 69.2 ± 9.8 yr, P < .01), had higher resting systolic blood pressure (124 ± 17 vs 130 ± 17 and 133 ± 18 mm Hg, P < .01), had lower cardiorespiratory fitness (19.7 ± 6.3 vs 15.6 ± 4.8 and 15 ± 4.5 mL/kg/min, P < .01), and were more likely to have diabetes (25% vs 35% and 41%, P < .01), abdominal obesity (39% vs 54% and 51%, P < .01), and initially prescribed lower-intensity exercise (84.4 ± 14.1 vs 74.1 ± 15.7 and 70.0 ± 14.6 m/min exercise pace, P < .01), reflecting the complex nature of patients diagnosed with PAD.

CONCLUSIONS

Patients referred with PAD have a cardiovascular risk profile that places them at a greater risk for a repeat or first cardiac event compared with patients with CAD. Referral to structured exercise and risk factor modification programs should be considered to aid in the management of PAD.

Neutrophils promote venular thrombosis by shaping the rheological environment for platelet aggregation

In advanced inflammatory disease, microvascular thrombosis leads to the interruption of blood supply and provokes ischemic tissue injury. Recently, intravascularly adherent leukocytes have been reported to shape the blood flow in their immediate vascular environment. Whether these rheological effects are relevant for microvascular thrombogenesis remains elusive. Employing multi-channel in vivo microscopy, analyses in microfluidic devices, and computational modeling, we identified a previously unanticipated role of leukocytes for microvascular clot formation in inflamed tissue. For this purpose, neutrophils adhere at distinct sites in the microvasculature where these immune cells effectively promote thrombosis by shaping the rheological environment for platelet aggregation. In contrast to larger (lower-shear) vessels, this process in high-shear microvessels does not require fibrin generation or extracellular trap formation, but involves GPIbα-vWF and CD40-CD40L-dependent platelet interactions. Conversely, interference with these cellular interactions substantially compromises microvascular clotting. Thus, leukocytes shape the rheological environment in the inflamed venular microvasculature for platelet aggregation thereby effectively promoting the formation of blood clots. Targeting this specific crosstalk between the immune system and the hemostatic system might be instrumental for the prevention and treatment of microvascular thromboembolic pathologies, which are inaccessible to invasive revascularization strategies.

Neuromuscular stimulation ameliorates ischemia-induced walking impairment in the rat claudication model

Intermittent claudication (IC) is the most common symptom of peripheral arterial disease which significantly deteriorates the quality of life of patients. Exercise training is by far the most effective treatment for IC; however, the underlying mechanisms remain elusive. To determine the local mechanisms by which exercise training improves walking performance in claudicants, we developed an implantable device to locally induce ischemic skeletal muscle contraction mimicking exercise via electrical stimulation (ES). Rats were assigned to four groups, Sham, Ischemia (Isch), Isch + exercise and Isch + ES groups. Following both unilateral femoral and iliac artery occlusion, rats showed sustained impairment of walking performance in the treadmill test. Chronic low-frequency ES of ischemic skeletal muscles for 2 weeks significantly recovered the occlusion-induced walking impairment in the rat claudication model. We further analyzed the ischemic skeletal muscles immunohistochemically following ES or exercise training; both ES and exercise training significantly increased capillaries in the ischemic skeletal muscles and shifted the muscle fibers toward oxidative types. These findings demonstrate that ES takes on common features of exercise in the rat claudication model, which may facilitate investigations on the local mechanisms of exercise-induced functional recovery.

Morbidity and mortality associated with atherosclerotic peripheral artery disease: A systematic review

BACKGROUND AND AIMS

It is unclear whether improvements in the detection/treatment of peripheral artery disease (PAD) affect overall survival and morbidity. We undertook a systematic review to describe survival and morbidity in contemporary PAD cohorts.

METHODS

Electronic databases were searched for randomised and observational studies reporting mortality/morbidity events between 1 May 2003 and 31 December, 2017 in patients with PAD, diagnosed by intermittent claudication (IC), critical limb ischaemia (CLI), or an ankle brachial index (ABI) < 0.9. Pooled event rates for all-cause and cardiovascular (CV) mortality, non-fatal myocardial infarction (MI), non-fatal stroke, major CV events (MACE; non-fatal MI/stroke, CV death), and major amputation were calculated per 1000 person-years.

RESULTS

124 eligible studies were identified (570,856 patients; 855,894 person-years of follow-up). Statin use was reported in 67% of the overall cohort and antiplatelet use in 79%. Pooled event rates for all-cause and CV mortality, MI, stroke, MACE, and major amputation were 113, 39, 20, 12, 71, and 70 per 1000 person-years, respectively. Compared with patients with an ABI <0.9, the presence of CLI was associated with increased rates of all-cause and CV mortality, MI, MACE, and major amputation. Event rates for stroke were similar between patients with an ABI <0.9 and CLI.

CONCLUSIONS

Our data show PAD patients have a high risk of all-cause and CV mortality, and imply the risk of stroke or MI is at least equivalent to the risk in patients with coronary artery disease. Moreover, our data underline the need for improved treatments to attenuate CV risk in PAD patients.

National survey of current practice and opinions on rehabilitation for intermittent claudication in the Danish Public Healthcare System

Objective. International guidelines recommend rehabilitation including supervised exercise therapy in patients with Intermittent Claudication (IC), but knowledge of the implementation in clinical practice is limited. This study aims to investigate current practice and opinions on rehabilitation for patients with IC among vascular surgeons and rehabilitation departments in the municipalities and hospitals. Design. Three electronic cross-sectional surveys were distributed nationally to the Danish vascular surgeons (n = 131) and to rehabilitation departments in the municipalities (n = 92) and hospitals (n = 33). Results. The response rates were 70% among the vascular surgeons, 98% among the municipalities and 94% among the hospitals. Vascular surgeons utilize oral advice to exercise by self-administered walking, pharmacological treatment, and revascularization to improve walking distance in patients with IC. Currently, only 12% of the vascular surgeons referred to rehabilitation to improve walking distance, while almost all vascular surgeons (96%) would refer their patients to IC rehabilitation, if it was available. Only 14% of municipalities and none of the hospitals, who treat patients with IC, have a rehabilitation program designed specifically for patients with IC. However, 59% of the rehabilitation departments in the municipalities and 26% in the hospitals included patients with IC in rehabilitation program designed for other patient groups - mostly cardiac patients. There was consensus among the groups of respondents that future IC specific rehabilitation should include an initial conversation, supervised exercise therapy, smoking cessation, and patient education according to guidelines. Conclusion. Vascular surgeons support referral and participation in IC rehabilitation to improve walking distance in patients with IC. Despite some hospitals and municipalities included patients with IC in rehabilitation nearly all services fail to meet current guideline as specific services tailored to patient with IC is almost non-existent in Denmark. Our findings call for action for services to comply with current recommendations of structured, systematic rehabilitation for patients with IC.

Evaluation of Risk Factors for Major Amputation in Patients With Diabetes and Peripheral Artery Disease Receiving Antiplatelet Therapy - Post Hoc Analysis of a Prospective Observational Multicenter Cohort Study (SEASON)

BACKGROUND

Guidelines for peripheral arterial disease (PAD) recommend long-term antiplatelet therapy in symptomatic patients to reduce cardiovascular morbidity and mortality risk. Although diabetes is a known risk factor for PAD, PAD has been undertreated in these patients. This study aimed to evaluate risk factors for major amputation in patients with diabetes undergoing antiplatelet therapy for PAD.Methods and Results:This retrospective analysis of a 2-year observational cohort study (1,745 clinics in Japan, September 2009-2013) evaluated predictors of amputation in patients with diabetes undergoing antiplatelet therapy for PAD. Among 4,016 eligible patients, 52 had an amputation during follow-up. Amputation risk (Cox regression analysis) was predicted at baseline by history of lower extremity revascularization/amputation (hazard ratio [HR]: 2.92; 95% confidence interval [CI]: 1.39, 6.14), chronic kidney disease (HR: 4.19; 95% CI: 1.95, 8.97), and comorbid cerebrovascular and heart disease (HR: 3.32; 95% CI: 1.19, 9.30), and was unaffected by choice of oral antiplatelet therapy. In patients with PAD and diabetes, amputation event rate was highest for those with ankle-brachial pressure index (ABI) <0.40 and progressively decreased at higher ABI cut-offs.

CONCLUSIONS

These findings inform real-world understanding of PAD in diabetic patients receiving antiplatelet therapy in Japan, and showed that ABI <0.4 was the strongest risk factor for amputation.

A Novel, Individualized Exercise Program for Patients with Peripheral Arterial Disease Recovering from Bypass Surgery

The effectiveness of an individual six-month-long physical exercise program in improving health-related quality of life (HRQOL) is unclear. There is some evidence that an individual exercise program can be effective for this aim. The goal of this study was to compare an individual six-month-long physical exercise program for patients with PAD (Peripheral Arterial Disease) with a traditional exercise program and find the effect of these programs on HRQOL and PAD risk factors. The study included patients who underwent femoral–popliteal artery bypass grafting surgery. Patients were divided into three groups: patients participating in an individual six-month-long physical exercise program (group I), in the standard physical activity program (group II), and in a control group (group III), with no subjects participating in rehabilitation II. Results: group I patients had a significantly (p < 0.001) higher HRQOL at 6 months after their surgery compared with groups II and III. The HRQOL scores were significantly (p < 0.05) lower after surgery among older (≥ 65), overweight participants, as well as among patients with diabetes mellitus and cardiovascular diseases when comparing study results with patients without these risk factors.

Supervised exercise therapy and revascularization: Single-center experience of intermittent claudication management

Guidelines recommend supervised exercise therapy (SET) as first-line treatment for intermittent claudication. However, the use of revascularization is widespread. We addressed the effectiveness of preventing (additional) invasive revascularization after primary SET or revascularization based on lesion and patient characteristics. In this single-center, retrospective, cohort study, 474 patients with intermittent claudication were included. Patients with occlusive disease of the aortoiliac tract and/or common femoral artery (inflow) were primarily considered for revascularization, while patients with more distal disease (outflow) were primarily considered for SET. In total, 232 patients were referred for SET and 242 patients received revascularization. The primary outcome was freedom from (additional) intervention, analyzed by Kaplan–Meier estimates. Secondary outcomes were survival, critical ischemia, freedom from target lesion revascularization (TLR), and an increase in maximum walking distance. In the SET-first strategy, 71% of patients had significant outflow lesions. Freedom from intervention was 0.90 ± 0.02 at 1-year and 0.82 ± 0.03 at 2-year follow-up. In the primary revascularization group, 90% of patients had inflow lesions. Freedom from additional intervention was 0.78 ± 0.03 at 1-year and only 0.65 ± 0.04 at 2-year follow-up, despite freedom from TLR of 0.91 ± 0.02 and 0.85 ± 0.03 at 1- and 2-year follow-up, respectively. In conclusion, SET was effective in preventing invasive treatment for patients with mainly outflow lesions. In contrast, secondary intervention rates following our strategy of primary revascularization for inflow lesions were unexpectedly high. These findings further support the guideline recommendations of SET as first-line treatment for all patients with intermittent claudication irrespective of level of disease.

Rehabilitative Exercise Reduced the Impact of Peripheral Artery Disease on Vascular Outcomes in Elderly Patients with Claudication: A Three-Year Single Center Retrospective Study

The study retrospectively evaluated the association between rehabilitative outcomes and risk of peripheral revascularizations in elderly peripheral artery disease (PAD) patients with claudication. Eight-hundred thirty-five patients were enrolled. Ankle-brachial index (ABI) and maximal walking speed (S_max) were measured at baseline and at discharge from a structured home-based rehabilitation program. For the analysis, patients were divided according to a baseline ABI value (severe: ≤0.5; moderate: ≥0.5) and according to hemodynamic or functional rehabilitative response (responder: ABI ≥ 0.10 and/or S_max > 0.5 km/h). Three-year outcomes were collected from the regional registry. According to the inclusion criteria (age 60–80, ABI < 0.80; program completion) 457 patients, 146 severe and 311 moderate, were studied. The whole population showed significant functional and hemodynamic improvements at discharge, with 56 revascularizations and 69 deaths at follow-up. Compared to the moderate group, the severe group showed a higher rate of revascularizations (17% vs. 10%, p < 0.001) and deaths (29% and 8%, respectively; p < 0.001). However, patients with severe PAD who were ABI responders after rehabilitation showed less revascularizations than non-responders (13% vs. 21%; hazard ratio (HR): 0.52) and were not different from patients with moderate disease (9%). Superimposable rates were observed for S_max responders (13% vs. 21%; HR: 0.55; moderate 10%). In conclusion, elderly patients with severe PAD empowered by better rehabilitation outcomes showed lower rates of peripheral revascularizations and deaths that were comparable to patients with moderate PAD.

One-Year Results of the LIBERTY 360 Study: Evaluation of Acute and Midterm Clinical Outcomes of Peripheral Endovascular Device Interventions

Purpose: To report the 1-year results of a multicenter study of peripheral artery disease (PAD) treatment with a variety of endovascular treatment strategies employed in routine practice. Materials and Methods: The LIBERTY trial (ClinicalTrials.gov identifier NCT01855412) is a prospective, observational, core laboratory–assessed, multicenter study of endovascular device intervention in 1204 subjects (mean age 69.8±10.7 years; 770 men) stratified by Rutherford category (RC): claudicants (RC2,3; n=501) and critical limb ischemia (CLI) with no/minimal tissue loss (RC4,5; n=603) or significant tissue loss (RC6; n=100). Key outcomes included quality of life (QoL) measures (VascuQol and EuroQol) and freedom from major adverse events (MAE), defined as death (within 30 days), major amputation, and target vessel revascularization based on Kaplan-Meier analysis. Results: Successful revascularization was beneficial, with RC improvement noted across all groups. Thirty-day freedom from MAE estimates were high across all groups: 99.2% in RC2,3, 96.1% in RC4,5, and 90.8% in RC6. At 12 months, the freedom from MAE was 82.6% in RC2,3, 73.2% in RC4,5, and 59.3% in RC6 patients. Estimates for freedom from major amputation at 12 months were 99.3%, 96.0%, and 81.7%, respectively. QoL scores improved significantly across all domains in all groups with 12-month VascuQol total scores of 5.3, 5.0, and 4.8 for RC2,3, RC4,5, and RC6, respectively. Conclusion: The results indicate that peripheral endovascular intervention is a viable treatment option for RC2,3, RC4,5, and RC6 patients as evidenced by the high freedom from major amputation, as well as the improvement in QoL and the RC at 12 months. Furthermore, primary unplanned amputation is often not necessary in RC6.

Disease-specific characteristics of vascular cell adhesion molecule-1 levels in patients with peripheral artery disease

Peripheral arterial disease (PAD) is one of the most common manifestations of systemic atherosclerosis. The prevalence of unrecognized PAD is high, leading to a lack of opportunity to detect subjects at a high risk for cardiovascular events. Inflammatory processes play an important role in the disease initiation as well as in the disease progression. Vascular cell adhesion molecule 1 (VCAM-1), a biomarker of endothelial dysfunction, appears to be an important mediator in inflammatory processes. Therefore, we hypothesized that in patients with PAD, circulating VCAM-1 might be elevated due to its function in mediating adhesion of immune cells to the vascular endothelium in the process of endothelial dysfunction and inflammation, and, therefore, applicable as a diagnostic biomarker. A total of 126 non-consecutive patients were enrolled in this study, of whom 51 patients had typical clinical manifestations of PAD and as controls 75 patients with no history of PAD or cardiovascular disease. All serum samples were obtained either during hospitalization or during out-patient visits and analyzed for VCAM-1 by the ELISA. Compared with controls, median levels of VCAM-1 were significantly elevated in patients suffering from PAD (953 vs. 1352 pg/ml; p < 0.001). Furthermore, VCAM-1 appeared to be highly discriminative for the detection of PAD (AUC = 0.76; CI 0.67-0.83). We could not observe dynamics related to increasing disease stages according to Rutherford classes in patients with apparent PAD. VCAM-1 was shown to be a potential discriminator and biomarker for the severity of systemic atherosclerosis. In a logistic regression analysis, VCAM-1 was robustly associated with the diagnosis of PAD, even after correction for clinically relevant cofounders (namely age, arterial hypertension, diabetes and LDL levels). Thusly, VCAM-1 might serve as a biomarker for PAD screening and detection.

Comparison of Outcomes and Cost of Endovascular Management Versus Surgical Bypass for the Management of Lower Extremities Peripheral Arterial Disease

The management of lower extremities peripheral arterial disease (LE-PAD) has always been debatable. We sought to explore in-hospital outcomes in hospitalizations that underwent endovascular or bypass surgery for LE-PAD from nation's largest, publicly available database. The National Inpatient Sample from 2012 to 2014 was queried to identify adult hospitalizations underwent endovascular management and bypass surgery for LE-PAD. Appropriate International Classification of Diseases, Ninth Revision, Clinical Modification diagnostic and procedural codes were utilized to identify hospitalizations. A total of 89,256 hospitalizations were identified having endovascular management or bypass surgery for LE-PAD. More hospitalizations underwent endovascular intervention as compared with bypass surgery. Overall, hospitalizations for endovascular management had higher baseline co-morbidities and older age. A propensity score matched analysis was performed to compare in-hospital outcomes. After matching, 28,791 hospitalizations were included in each group. In-hospital mortality was significantly lower with endovascular intervention procedure as compared with surgical bypass group (1.5% vs 2.5%, p ≤0.001). All other secondary outcomes were noted lower with endovascular management except stroke and postprocedural infection. Taken together, these may account for higher discharges to home, lower length of stay, and less cost of hospitalizations associated with endovascular management. In conclusion, endovascular management is associated with lower in-hospital morbidity, mortality, length of stay, and cost when compared with bypass surgery in this study.

Long-term survival and fate of the leg in de novo intermittent claudication

Aims

The long-term life expectancy and fate of the leg, including progression rate to critical limb ischaemia (CLI), were analysed in de novo patients with intermittent claudication (IC).

Methods and results

A prospective cohort study was performed in 1107 patients with de novo IC. The endpoints were overall survival (OS), freedom from major adverse cardiovascular events (MACE), freedom from major adverse cardiovascular and limb events (MACLE), and fate of the leg. The 5-, 10-, 15-, and 20-year rates were 73.3, 47.8, 28.1, and 14.9% for OS, and 63.0, 35.6, 18.5, and 5.7% for freedom from MACE, respectively. In Cox multivariable analysis, body mass index, diabetes, haemodialysis, and C-reactive protein (CRP) level were correlated with OS (P < 0.05). Ankle brachial pressure index, diabetes, coronary artery disease, haemodialysis, and CRP level were independently correlated with freedom from MACE and MACLE. Statins improved mortality, MACE, and MACLE (P < 0.05). Revascularization did not improve mortality and MACE, and femoropopliteal revascularization increased MACLE (P < 0.05). There was no deterioration of claudication in 881 patients (79.6%). Worsening claudication was noted in 211 patients (14.8% per 5 years), and 15 patients (1.1% per 5 years) worsened to CLI. Diabetes and haemodialysis were independent predictors of CLI. A history of cerebral infarction and femoropopliteal revascularization tended to increase CLI.

Conclusions

Life expectancy in patients with IC was poor, but the rate of IC progression to CLI was low. Statins improved mortality and morbidity, revascularization did not improve mortality and MACE, and femoropopliteal revascularization reduced freedom from MACLE with a risk of CLI.

Incidence and Endovascular Treatment of Isolated Atherosclerotic Popliteal Artery Disease: Outcomes from the IPAD Multicenter Study

PURPOSE

To report the incidence and long-term outcomes following endovascular treatment of symptomatic, atherosclerotic isolated popliteal artery disease (IPAD).

MATERIALS AND METHODS

This retrospective, multicenter study included all patients who underwent endovascular treatment of IPAD between January 2010 and December 2016 because of intermittent claudication or critical limb ischemia (CLI), in three tertiary University Hospitals. In total, 4717 peripheral arterial disease (PAD) procedures were analyzed. The study's primary outcome measures were: IPAD incidence, binary restenosis rate and freedom from target lesion revascularization (TLR). Secondary outcome measures included technical success, limb salvage rate and the identification of predictors of outcomes.

RESULTS

The incidence of IPAD was 0.98% (46/4717 PAD procedures). In total, 46 patients (38 male; mean age 73 ± 12 years) underwent plain balloon (69.5%) or bail-out stenting (30.5%) procedures. Most patients suffered from CLI (65.2%). Mean lesion length was 52.5 ± 32.0 mm and 45.6% of the cases were occlusions. Severe calcifications were noted in 26.1%. Technical success was 100%. Mean time follow-up was 32.6 ± 25.6 months. According to Kaplan-Meier analysis, restenosis was 15.8, 40.9, 45.8% and TLR-free rate was 90.5, 79.0, 74.1%, at 1, 2 and 3 years, respectively. Survival and limb salvage rates were 73.6 and 88.1%, at 5 years, respectively. The major amputation rate for CLI patients was 10.0% (3/29 limbs), while no major amputations occurred in the claudication subgroup. Cox multivariable analysis detected baseline occlusion as an independent predictor of increased restenosis (HR 5.3; 95% CI 0.21-0.66, p = 0.02).

CONCLUSIONS

Isolated popliteal lesions requiring treatment appear in nearly 1% of patients with PAD. Balloon angioplasty and bail-out stenting resulted in acceptable long-term clinical outcomes. Treatment of occlusions was correlated with increased restenosis rate.

ImmunoPET of CD146 in a Murine Hindlimb Ischemia Model

Peripheral arterial disease (PAD) consists of a persistent obstruction of lower-extremity arteries further from the aortic bifurcation attributable to atherosclerosis. PAD is correlated with an elevated risk of morbidity and mortality as well as of deterioration of the quality of life with claudication and chronic leg ischemia being the most frequent complications. Therapeutic angiogenesis is a promising therapeutic strategy that aims to restore the blood flow to the ischemic limb. In this context, assessing the efficacy of pro-angiogenic treatment using a reliable noninvasive imaging technique would greatly benefit the implementation of this therapeutic approach. Herein, we describe the angiogenesis and perfusion recovery characteristics of a mouse model of PAD via in vivo positron emission tomography (PET) imaging of CD146 expression. For that, ischemia was generated by ligation and excision of the right femoral artery of Balb/C mice and confirmed through laser Doppler imaging. The angiogenic process, induced by ischemia, was noninvasively monitored and quantified through PET imaging of CD146 expression in the injured leg using a ⁶⁴Cu-labeled anti-CD146 monoclonal antibody, ⁶⁴Cu-NOTA-YY146, at post-operative days 3, 10, and 17. The CD146-specific character of ⁶⁴Cu-NOTA-YY146 was verified via a blocking study performed in another cohort at day 10 after surgery. Tracer uptake was correlated with in situ CD146 expression by histological analysis. PET scan results indicated that ⁶⁴Cu-NOTA-YY146 uptake in the injured leg was significantly higher, with the highest uptake with a value of 14.1 ± 2.0 %ID/g at post-operative day 3, compared to the normal contralateral hindlimb, at all time points (maximum uptake of 2.2 ± 0.2 %ID/g). The pre-injection of a blocking dose resulted in a significantly lower tracer uptake in the ischemic hindlimb on day 10 after surgery, confirming tracer specificity. CD146/CD31 immunofluorescent co-staining showed an excellent correlation between the high uptake of the tracer with in situ CD146 expression levels and a marked co-localization of CD146 and CD31 signals. In conclusion, persistent and CD146-specific tracer accumulation in the ischemic hindlimb was observed, confirming the feasibility of ⁶⁴Cu-NOTA-YY146 to be used as an imaging agent to monitor the progression of angiogenesis and recovery in future PAD research.

Microfibrillar-associated protein 4 variation in symptomatic peripheral artery disease

Background

Symptomatic peripheral artery disease (PAD) is an atherosclerotic occlusive disease affecting the lower extremities. The cause of symptomatic PAD is atherosclerosis, vascular dysfunctions, impaired angiogenesis and neointima formation. Microfibrillar-associated protein 4 (MFAP4) is an extracellular matrix protein, which is highly expressed in the heart and arteries and recently introduced as a potential mediator of pathological vascular remodeling and neointima formation. We aimed to investigate the relationship between serum MFAP4 (sMFAP4) and symptomatic PAD outcomes.

Methods

A total of 286 PAD patients were analyzed if they had either intermittent claudication or critical lower-extremity ischemia (CLI) and followed for 7 years. The level of serum MFAP4 (sMFAP4) was measured by alphaLISA. Kaplan–Meier, Cox proportional hazard and logistic regression analysis were used to analyze the associations between upper tertile sMFAP4 and symptomatic PAD outcomes.

Results

Patients with upper tertile sMFAP4 had an odds ratio (OR) of 2.65 (p < 0.001) for having CLI diagnosis. Further analysis indicated that patients with upper tertile sMFAP4 had a hazard ratio (HR) of 1.97 (p = 0.04) for cardiovascular death during the 7-years follow-up. However, analysis of 2-year primary patency showed that patients with upper tertile sMFAP4 had decreased risk of vascular occlusion after reconstructive surgery with HR of 0.15 (p = 0.02).

Conclusions

sMFAP4 has potential as a prognostic marker for cardiovascular death, primary patency of reconstructed vessels and CLI diagnosis in symptomatic PAD patients. Confirmation of observations in larger cohorts is warranted.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1523-6) contains supplementary material, which is available to authorized users.

Cardiopulmonary Exercise Testing Limitation in Peripheral Arterial Disease

BACKGROUND

Peripheral artery disease (PAD) is associated with a markedly increased risk of cardiovascular mortality and remains underrecognized and undertreated. New screening approaches are needed to prevent disability in patients with PAD.

METHODS

We performed a retrospective analysis of clinically stable cardiovascular patients who were referred for cardiopulmonary exercise testing (CPET) due to a variety of cardiovascular complaints. Angiograms were assessed for patients who prematurely terminated CPET. Estimated functional capacity in metabolic equivalents was also obtained from monitored bicycle exercise at the visit.

RESULTS

According to our analysis, 351 patients were unable to complete the CPET test due to some limiting factor. Of these patients, a total of 216 had available angiographic assessment conducted, of whom 42.6% were males, 57.4% were females, and the mean age was 67 years. A total of 135 patients with a similar gender distribution and a mean age of 53 years did not undergo angiography for various reasons including feasibility. Most patients who underwent assessment were found to have lesions. Across all patients, 284 arterial lesions were identified: 55 were iliac, 67 were femoral, and 162 were below the knee. PAD was diagnosed in 165 of these lesions. There was a significant difference observed in the VO₂ max in patients with lesions depending on location of lesion. In all vessel groups, the existence of PAD was associated with a significantly reduced VO₂ max during CPET testing.

CONCLUSIONS

The data obtained in this study provides a preliminary understanding of the underlying effects of PAD and provides a basis for further utilization of CPET termination as a potential screening signal for further PAD investigation in appropriate patients.

Antiplatelet and anticoagulant for prevention of reocclusion in patients with atrial fibrillation undergoing endovascular treatment for low extremity ischemia

Background

The purpose of this study is to report the efficacy of the mono antiplatelet plus anticoagulation therapy for prevention of reocclusion in patients with atrial fibrillation (AF) undergoing endovascular treatment for lower extremity ischemia.

Methods

From March 2014 to July 2016, 32 (21 males; range, 68-84 years) patients were submitted to endovascular therapy for low extremity ischemia with AF and all were treated with endovascular treatments to correct underlying lesions. Then 20 patients receive aspirin plus rivaroxaban post-operation and 12 patients receive aspirin plus warfarin to prevent reocclusion.

Results

Complete reconstruction of occluded femopopliteal arteries with unimpeded blood flow to legs were successfully obtained in all 32 patients; 12 (37.5%) patients had acute ischemia, 17 (53.1%) patients had chronic ischemia, 3 (9.4%) patients had acute on chronic ischemia. Endovascular treatments including percutaneous transluminal angioplasty (PTA) and stenting were performed to correct residual lesions after the thrombolytic/thrombectomy procedure or to correct native lesions for chronic patients. All 32 patients showed significant improvements in symptoms and 4 patients improved completely. The mean ankle-brachial index (ABI) had risen from 0.43±0.21 preoperatively to 0.81±0.16 postoperatively (P<0.01), and the primary patency rates were 88.9% at 12 months, and 81.5% at 24 months. No episodes of major bleeding and only one patient showed positive fecal occult blood tests during the follow-up.

Conclusions

The mono antiplatelet plus anticoagulation therapy offers a safe and effective alternative for prevention of reocclusion in patients with AF undergoing endovascular treatment for lower extremity ischemic.

The heart matters in diabetes: 10-Year outcomes of peripheral artery disease

Objectives:

Mortality rates at 10 years are higher in diabetic patients with chronic lower extremity peripheral arterial disease than in non-diabetic peripheral arterial disease patients. We tested the hypothesis that the predictors of mortality differ between diabetic and non-diabetic peripheral arterial disease patients.

Methods:

We studied 331 consecutive patients who were <75 years of age, symptomatic for peripheral arterial disease, and admitted to a tertiary care hospital. Our cohort included 216 patients without diabetes mellitus and 115 with diabetes mellitus. The outcome measure was all-cause mortality at 10 years post-admission.

Results:

Mortality rates at 10 years were 29% among non-diabetic peripheral arterial disease patients and 58% among diabetic peripheral arterial disease patients. We identified the following independent predictors of death in the 216 peripheral arterial disease patients without diabetes: age ≥65 years (risk ratio: 2.15; 95% confidence interval: 1.28–3.59), ankle brachial index <0.60 mmHg/mmHg (risk ratio: 1.88; 95% confidence interval: 1.14–3.08), history of peripheral arterial disease-specific intervention (risk ratio: 1.81; 95% confidence interval: 1.10–2.97), and high-sensitivity C-reactive protein ≥5.0 mg/L (risk ratio: 2.11; 95% confidence interval: 1.28–3.47). For the 115 peripheral arterial disease patients with diabetes, independent predictors of mortality were as follows: age ≥65 years (risk ratio: 1.72; 95% confidence interval: 1.05–2.83) and amino-terminal pro-B-type natriuretic peptide ≥125 ng/L (risk ratio: 2.10; 95% confidence interval: 1.22–3.60).

Conclusion:

In this study, the predictors of death at 10 years differed between peripheral arterial disease patients with and without diabetes. Among the biomarkers tested, high-sensitivity C-reactive protein was independently associated with outcomes in non-diabetic patients, whereas amino-terminal pro-B-type natriuretic peptide was an independent predictor of death in patients with diabetes. Our findings suggest that in future studies, risk assessment and treatment strategies should be differentially applied to the two peripheral arterial disease subgroups.

New Innovations in Drug-Eluting Stents for Peripheral Arterial Disease

PURPOSE OF REVIEW

The purpose of this paper was to provide a review of the burden of peripheral arterial disease; to examine older therapies and their limitations; and especially to highlight new treatment innovations as well as the data supporting their use.

RECENT FINDINGS

Building on the success of paclitaxel in the prevention of restenosis in the peripheral circulation, the newest generation drug-eluting stent is presented, which combines paclitaxel with a polymer-allowing the drug to be eluted slowly over 12 months. The positive results of the pilot MAJESTIC study led to the ongoing IMPERIAL trial. Limited data of bioresorbable scaffolds in above and below-the-knee applications are also reviewed. Endovascular therapy of peripheral arterial disease has had many advances in the preceding two decades. However, drug-eluting stent technology has had the greatest impact to date and holds great promise for the future.

Lower limb arterial calcification (LLAC) scores in patients with symptomatic peripheral arterial disease are associated with increased cardiac mortality and morbidity

AIMS

The association of coronary arterial calcification with cardiovascular morbidity and mortality is well-recognized. Lower limb arterial calcification (LLAC) is common in PAD but its impact on subsequent health is poorly described. We aimed to determine the association between a LLAC score and subsequent cardiovascular events in patients with symptomatic peripheral arterial disease (PAD).

METHODS

LLAC scoring, and the established Bollinger score, were derived from a database of unenhanced CT scans, from patients presenting with symptomatic PAD. We determined the association between these scores outcomes. The primary outcome was combined cardiac mortality and morbidity (CM/M) with a secondary outcome of all-cause mortality.

RESULTS

220 patients (66% male; median age 69 years) were included with follow-up for a median 46 [IQR 31-64] months. Median total LLAC scores were higher in those patients suffering a primary outcome (6831 vs. 1652; p = 0.012). Diabetes mellitus (p = 0.039), ischaemic heart disease (p = 0.028), chronic kidney disease (p = 0.026) and all-cause mortality (p = 0.012) were more common in patients in the highest quartile of LLAC scores. The area under the curve of the receiver operator curve for the LLAC score was greater (0.929: 95% CI [0.884-0.974]) than for the Bollinger score (0.824: 95% CI [0.758-0.890]) for the primary outcome. A LLAC score ≥ 4400 had the best diagnostic accuracy to determine the outcome measure.

CONCLUSION

This is the largest study to investigate links between lower limb arterial calcification and cardiovascular events in symptomatic PAD. We describe a straightforward, reproducible, CT-derived measure of calcification-the LLAC score.

Advances in Percutaneous Therapies for Peripheral Artery Disease: Drug-Coated Balloons

PURPOSE OF REVIEW

This review paper provides a summary on the use of drug-coated balloons in peripheral artery disease. It covers the main drug-coated balloon (DCB) trials. It is divided into categories of lesions: superficial femoral artery and popliteal lesions, infra-popliteal lesions and in-stent restenosis. It also includes an overview of the future of DCBs, highlighting the main ongoing trials.

RECENT FINDINGS

The latest research on DCB focuses on newer types of DCBs, mainly paclitaxel-coated but with lower doses. Another area of latest DCB research is its use in superficial femoral artery and popliteal artery in-stent restenosis, with superior outcomes. Drug-coated balloons produce better outcomes than percutaneous transluminal angioplasty alone in de novo and in-stent restenosis lesions of superficial femoral artery and popliteal arteries. More data are needed to demonstrate efficacy and safety of DCBs in infrapopliteal disease. Newer DCBs and adjunctive therapy may provide improved outcomes for peripheral artery disease interventions.

Usefulness of Lipoprotein(a) for Predicting Clinical Outcomes After Endovascular Therapy for Aortoiliac Atherosclerotic Lesions

PURPOSE

To evaluate the usefulness of serum lipoprotein(a) as a biomarker of clinical outcomes after endovascular therapy (EVT) for atherosclerotic aortoiliac lesions.

METHODS

Serum lipoprotein(a) concentrations were measured at admission in 189 consecutive patients (median age 72 years; 160 men) with peripheral artery disease who underwent EVT for aortoiliac occlusive disease. The patients were dichotomized into 2 groups based on serum lipoprotein(a) levels ≤40 mg/dL (LOW; n=135) or >40 mg/dL (HIGH; n=54). After EVT, the incidences of major adverse limb events (MALE) were analyzed. Predictors of MALE were sought with a Cox proportional hazards analysis; results are presented as the hazard ratio (HR) and 95% confidence interval.

RESULTS

At the median follow-up of 33 months (interquartile range 11, 54), MALE occurred in 44 (23.3%) patients. The MALE-free survival estimate was significantly lower in patients in the HIGH group (55.6% vs 85.2%, p<0.001). Independent predictors of MALE after EVT were hemodialysis (HR 2.23, 95% CI 1.04 to 4.78, p=0.039) and high lipoprotein(a) levels (HR 2.80, 95% CI 1.44 to 5.45, p=0.003).

CONCLUSION

High lipoprotein(a) levels were associated with a higher incidence of MALE after EVT for patients with aortoiliac lesions.

Serum-derived extracellular vesicles (EVs) impact on vascular remodeling and prevent muscle damage in acute hind limb ischemia

Serum is an abundant and accessible source of circulating extracellular vesicles (EVs). Serum-EV (sEV) pro-angiogenic capability and mechanisms are herein analyzed using an in vitro assay which predicts sEV angiogenic potential in vivo. Effective sEVs (e-sEVs) also improved vascular remodeling and prevented muscle damage in a mouse model of acute hind limb ischemia. e-sEV angiogenic proteomic and transcriptomic analyses show a positive correlation with matrix-metalloproteinase activation and extracellular matrix organization, cytokine and chemokine signaling pathways, Insulin-like Growth Factor and platelet pathways, and Vascular Endothelial Growth Factor signaling. A discrete gene signature, which highlights differences in e-sEV and ineffective-EV biological activity, was identified using gene ontology (GO) functional analysis. An enrichment of genes associated with the Transforming Growth Factor beta 1 (TGFβ1) signaling cascade is associated with e-sEV administration but not with ineffective-EVs. Chromatin immunoprecipitation analysis on the inhibitor of DNA binding I (ID1) promoter region, and the knock-down of small mother against decapentaplegic (SMAD)1–5 proteins confirmed GO functional analyses. This study demonstrates sEV pro-angiogenic activity, validates a simple, sEV pro-angiogenic assay which predicts their biological activity in vivo, and identifies the TGFβ1 cascade as a relevant mediator. We propose serum as a readily available source of EVs for therapeutic purposes.