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

Sex Differences in Management and Outcomes of Critical Limb Ischemia in the Medicare Population

BACKGROUND

Evidence about sex differences in management and outcomes of critical limb ischemia (CLI) is conflicting.

METHODS

We identified Fee-For-Service Medicare patients within the 5% enhanced sample file who were diagnosed with new incident CLI between 2015 and 2017. For each beneficiary, we identified all hospital admissions, outpatient encounters and procedures, and pharmacy prescriptions. Outcomes included 90-day mortality and major amputation.

RESULTS

Incidence of CLI declined from 2.80 (95% CI, 2.72-2.88) to 2.47 (95% CI, 2.40-2.54) per 1000 person from 2015 to 2017, P<0.01. Incidence was lower in women compared with men (2.19 versus 3.11 per 1000) but declined in both groups. Women had a lower prevalence of prescription of any statin (48.4% versus 52.9%, P<0.001) or high-intensity statins (15.3% versus 19.8%, P<0.01) compared with men. Overall, 90-day revascularization rate was 52%, and women were less likely to undergo revascularization (50.1% versus 53.6%, P<0.01) compared with men. Women had a similar unadjusted (9.9% versus 10.3%, P=0.5) and adjusted 90-day mortality (adjusted rate ratio, 0.98 [95% CI, 0.85-1.12], P=0.7) compared with men. Over the study period, unadjusted 90-day mortality remained unchanged for men (10.4% in 2015 to 9.9% in 2017, Pfor trend=0.3), and women (9.5% in 2015 to 10.6% in 2017, Pfor trend=0.2). Men had higher unadjusted (12.9% versus 8.9%, P<0.001) and adjusted risk of 90-day major amputation (adjusted rate ratio, 1.30 [95% CI, 1.14-1.48], P<0.001). One-third of patients with CLI underwent major amputation without a diagnostic angiogram or trial of revascularization in the preceding 90 days regardless of the sex.

CONCLUSIONS

Women with new incident CLI are less likely to receive statin or undergo revascularization at 90 days compared with men. However, the differences were small. There was no difference in risk of 90-day mortality between both sexes. Graphic Abstract: A graphic abstract is available for this article.

Home-Based Cardiac Rehabilitation: A SCIENTIFIC STATEMENT FROM THE AMERICAN ASSOCIATION OF CARDIOVASCULAR AND PULMONARY REHABILITATION, THE AMERICAN HEART ASSOCIATION, AND THE AMERICAN COLLEGE OF CARDIOLOGY

Cardiac rehabilitation (CR) is an evidence-based intervention that uses patient education, health behavior modification, and exercise training to improve secondary prevention outcomes in patients with cardiovascular disease. CR programs reduce morbidity and mortality rates in adults with ischemic heart disease, heart failure, or cardiac surgery but are significantly underused, with only a minority of eligible patients participating in CR in the United States. New delivery strategies are urgently needed to improve participation. One potential strategy is home-based CR (HBCR). In contrast to center-based CR services, which are provided in a medically supervised facility, HBCR relies on remote coaching with indirect exercise supervision and is provided mostly or entirely outside of the traditional center-based setting. Although HBCR has been successfully deployed in the United Kingdom, Canada, and other countries, most US healthcare organizations have little to no experience with such programs. The purpose of this scientific statement is to identify the core components, efficacy, strengths, limitations, evidence gaps, and research necessary to guide the future delivery of HBCR in the United States. Previous randomized trials have generated low- to moderate-strength evidence that HBCR and center-based CR can achieve similar improvements in 3- to 12-month clinical outcomes. Although HBCR appears to hold promise in expanding the use of CR to eligible patients, additional research and demonstration projects are needed to clarify, strengthen, and extend the HBCR evidence base for key subgroups, including older adults, women, underrepresented minority groups, and other higher-risk and understudied groups. In the interim, we conclude that HBCR may be a reasonable option for selected clinically stable low- to moderate-risk patients who are eligible for CR but cannot attend a traditional center-based CR program.

Management of cardiovascular disease in patients with systemic lupus erythematosus

INTRODUCTION

SLE is increasingly recognized as an important risk factor for cardiovascular disease. Premature CAD and several other cardiac manifestations are resulting in significant morbidity and premature death among young and older adults. There is a considerable unmet need for developing specific guidelines toward the primary and secondary prevention of cardiovascular disease in SLE patients.

AREAS COVERED

The authors describe the prevalence of various cardiovascular manifestations, associated with traditional and lupus-specific risk factors. They summarize the evidence behind various nonpharmacological and pharmacological options such as cardiac medications, antimalarials, anti-inflammatory, and immunosuppressant medications.

EXPERT OPINION

There is considerable literature claiming that the traditional Framingham score used to calculate the risk in the general population would not clearly predict the 10-year risk among SLE patients as they do not include lupus-specific risk factors such as accelerated inflammation, immunometabolic changes, thrombosis, vasospasm, vasculitis, and endothelial dysfunction into account. Identifying potential risk factors among SLE patients and treating hyperlipidemia regardless of their risk scores may be the first step in reducing mortality. Blocking lupus-specific inflammatory pathways by targeting validated biomarkers of pathogenesis has great future potential and more studies are needed on their cardiovascular benefits.

Long-Term Results of Distal Bypass for Intermittent Claudication

BACKGROUND

Distal bypass (DB) is the optimal treatment for patients with critical limb ischemia (CLI). However, effectiveness of DB for patients with intermittent claudication (IC) remains uncertain. This study aimed to analyze long-term results of DB for IC patients (IC-DB) compared with those of DB for CLI patients (CLI-DB).

METHODS

Patients undergoing DB from January 2009 to July 2018 at a single institution were retrospectively reviewed. Operative details, primary and secondary patency, amputation free survival rate (AFS), and long-term exercise capacity using Barthel index were analyzed.

RESULTS

Out of 302 DB (245 patients), 49 IC-DB were performed in 43 patients: 38 males, mean age 70.3 ± 8.0 years, diabetes mellitus 51%, chronic renal failure with hemodialysis 7%. The Great saphenous vein was used in 47 limbs, the small saphenous vein in 1, and the arm vein in 1. These grafts were bypassed in a non-reversed fashion for 35 limbs, in an in-situ fashion in 9, and in a reversed fashion in 5. The mean operative time was 173 min. The mean follow-up was 25 ± 26 months. Primary and secondary patency of IC-DB was 79% and 94% at 1 year, 71% and 90% at 3 years, 65% and 90% at 5 years, which were significantly higher than those of CLI-DB (primary patency: P = .007, secondary patency: P = .025). AFS of IC-DB and CLI-DB was 100% and 77% at 1 year, 93% and 52% at 3 years, and 90% and 43% at 5 years (IC-DB vs. CLI-DB, p < .0001). Barthel index of IC-DB unchanged at discharge (median 100) and at the last visit (median 100), showing daily activity was maintained adequately.

CONCLUSIONS

DB could offer a promising approach for patients with IC because of durable graft patency, acceptable AFS, and maintenance of daily activity.

Experimental Validation of Perfusion Imaging With HOSVD Clutter Filters

Novel pulsed-Doppler methods for perfusion imaging are validated using dialysis cartridges as perfusion phantoms. Techniques that were demonstrated qualitatively at 24 MHz, in vivo, are here examined quantitatively at 5 and 12.5 MHz using phantoms with the blood-mimicking fluid flow within cellulose microfibers. One goal is to explore a variety of flow states to optimize measurement sensitivity and flow accuracy. The results show that 2-3-s echo acquisitions at roughly 10 frames/s yield the highest sensitivity to flows of 1-4 mL/min. A second goal is to examine methods for setting the parameters of higher order singular value decomposition (HOSVD) clutter filters. For stationary or moving clutter, the velocity of the blood-mimicking fluid in the microfibers is consistently estimated within measurement uncertainty (mean coefficient of variation = 0.26). Power Doppler signals were equivalent for stationary and moving clutter after clutter filtering, increasing approximately 3 dB/mL/min of blood-mimicking fluid flow for 0 ≤ q ≤ 4 mL/min. Comparisons between phantom and preclinical images show that peripheral perfusion imaging can be reliably achieved without contrast enhancement.

Modes of exercise training for intermittent claudication

BACKGROUND

According to international guidelines and literature, all patients with intermittent claudication should receive an initial treatment of cardiovascular risk modification, lifestyle coaching, and supervised exercise therapy. In the literature, supervised exercise therapy often consists of treadmill or track walking. However, alternative modes of exercise therapy have been described and yielded similar results to walking. This raises the following question: which exercise mode produces the most favourable results? This is the first update of the original review published in 2014.

OBJECTIVES

To assess the effects of alternative modes of supervised exercise therapy compared to traditional walking exercise in patients with intermittent claudication.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 4 March 2019. We also undertook reference checking, citation searching and contact with study authors to identify additional studies. No language restriction was applied.

SELECTION CRITERIA

We included parallel-group randomised controlled trials comparing alternative modes of exercise training or combinations of exercise modes with a control group of supervised walking exercise in patients with clinically determined intermittent claudication. The supervised walking programme needed to be supervised at least twice a week for a consecutive six weeks of training.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, extracted data, and assessed the risk of bias for each study. As we included studies with different treadmill test protocols and different measuring units (metres, minutes, or seconds), the standardised mean difference (SMD) approach was used for summary statistics of mean walking distance (MWD) and pain-free walking distance (PFWD). Summary estimates were obtained for all outcome measures using a random-effects model. We used the GRADE approach to assess the certainty of the evidence.

MAIN RESULTS

For this update, five additional studies were included, making a total of 10 studies that randomised a total of 527 participants with intermittent claudication (IC). The alternative modes of exercise therapy included cycling, lower-extremity resistance training, upper-arm ergometry, Nordic walking, and combinations of exercise modes. Besides randomised controlled trials, two quasi-randomised trials were included. Overall risk of bias in included studies varied from high to low. According to GRADE criteria, the certainty of the evidence was downgraded to low, due to the relatively small sample sizes, clinical inconsistency, and inclusion of three studies with risk of bias concerns. Overall, comparing alternative exercise modes versus walking showed no clear differences for MWD at 12 weeks (standardised mean difference (SMD) -0.01, 95% confidence interval (CI) -0.29 to 0.27; P = 0.95; 6 studies; 274 participants; low-certainty evidence); or at the end of training (SMD -0.11, 95% CI -0.33 to 0.11; P = 0.32; 9 studies; 412 participants; low-certainty evidence). Similarly, no clear differences were detected in PFWD at 12 weeks (SMD -0.01, 95% CI -0.26 to 0.25; P = 0.97; 5 studies; 249 participants; low-certainty evidence); or at the end of training (SMD -0.06, 95% CI -0.30 to 0.17; P = 0.59; 8 studies, 382 participants; low-certainty evidence). Four studies reported on health-related quality of life (HR-QoL) and three studies reported on functional impairment. As the studies used different measurements, meta-analysis was only possible for the walking impairment questionnaire (WIQ) distance score, which demonstrated little or no difference between groups (MD -5.52, 95% CI -17.41 to 6.36; P = 0.36; 2 studies; 96 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

This review found no clear difference between alternative exercise modes and supervised walking exercise in improving the maximum and pain-free walking distance in patients with intermittent claudication. The certainty of this evidence was judged to be low, due to clinical inconsistency, small sample size and risk of bias concerns. The findings of this review indicate that alternative exercise modes may be useful when supervised walking exercise is not an option. More RCTs with adequate methodological quality and sufficient power are needed to provide solid evidence for comparisons between each alternative exercise mode and the current standard of supervised treadmill walking. Future RCTs should investigate outcome measures on walking behaviour, physical activity, cardiovascular risk, and HR-QoL, using standardised testing methods and reporting of outcomes to allow meaningful comparison across studies.

Discharge Prescription Patterns for Antiplatelet Therapy Following Lower Extremity Peripheral Vascular Intervention

BACKGROUND

Despite current guidelines suggesting a benefit for dual antiplatelet therapy (DAPT) following peripheral vascular intervention (PVI), there are limited data on antiplatelet prescribing patterns post-procedure. We attempted to determine variables associated with DAPT prescription following lower extremity PVI.

METHODS

Retrospective analysis of patients undergoing lower extremity PVI in the Vascular Quality Initiative (2017-2018) was performed. Participants not on anticoagulation or DAPT before the procedure were considered for the final analysis. Postdischarge antiplatelet therapy regimen rates were determined (none, aspirin only, P2Y12 inhibitor only, and DAPT). Multivariate logistic regression was performed to determine variables associated with DAPT initiation compared with those discharged on single-agent or no antiplatelet therapy.

RESULTS

A total of 16 597 procedures were included for analysis, with 49% initiated on DAPT post-PVI. Male sex (odds ratio [OR], 1.12 [95% CI, 1.05-1.20]), smoking (OR, 1.20 [95% CI, 1.09-1.32]), and coronary artery disease (OR, 1.19 [95% CI, 1.11-1.27]) were associated with an increased likelihood of post-PVI DAPT prescription. Procedures requiring multiple types of interventions (OR, 1.28 [95% CI, 1.15-1.42]), stent placement (OR, 1.16 [95% CI, 1.06-1.27]), and with complications (OR, 1.31 [95% CI, 1.14-1.52]) were also positively associated with DAPT prescription.

CONCLUSIONS

In patients not already receiving anticoagulation or on DAPT at the time of lower extremity PVI, prescription of DAPT following intervention is ≈50%. Multiple factors were associated with the decision for DAPT versus single antiplatelet therapy, and further study is required to understand how this affects postintervention adverse limb and cardiovascular events.

Predictors of Quitting Smoking in Cardiac Rehabilitation

Quitting smoking and participation in cardiac rehabilitation (CR) are effective strategies in reducing morbidity and mortality. However, little is known about the predictors of quitting smoking in those who attend CR. This study aimed to determine the sociodemographic and clinical factors associated with the likelihood of CR attendees who are quitting smoking. Data from the UK National Audit of Cardiac Rehabilitation (NACR) database, between April 2013 and March 2016, were used. Smoking status is categorized as smokers and quitters, assessed by patient self-report. The study used patient demographics, cardiovascular risk factors, comorbidities, and physical and psychosocial health measures. Binary logistic regression was performed to identify the predictors of quitting smoking among CR attendees. Of the 3290 patients who started CR and were entered into the NACR database, 2052 were continued smokers (mean age 58.59 ± 10.49 years, 73.6% men) and 1238 were quitters (mean age 57.63 ± 10.36 years, 75.8% men). The median duration of CR was 9 weeks. Compared to smokers, the quitters were younger, weighed more, were less anxious and depressed, and were more likely to be employed. Single patients had 0.60 times lower odds (95% CI 0.43 to 0.82) of quitting smoking than patients with partners, and low-risk patients had 1.71 times higher odds (95% CI 1.12 to 2.62) of quitting smoking than high-risk patients. Increasing number of comorbidities and depression scores were associated with decreasing likelihood of quitting. This study highlights the routine factors that determine smoking cessation outcomes, which could inform the delivery of CR to better help patients to quit smoking.

Rationale and Design of Therapeutic Angiogenesis by Cell Transplantation Using Adipose-Derived Regenerative Cells in Patients With Critical Limb Ischemia - TACT-ADRC Multicenter Trial

Background: Despite the growing knowledge regarding optimal treatments for critical limb ischemia (CLI), there are still a considerable number of patients who have to undergo major limb amputation. Intramuscular injection of autologous adipose-derived regenerative cells (ADRCs) in these patients has shown therapeutic potential in improving tissue ischemia, in both preclinical and initial pilot studies. Here, we present a clinical protocol for ADRCs use in a multicenter trial. Methods and Results: The TACT-ADRC multicenter trial is a prospective, interventional, single-arm, open-labeled study at 8 hospitals in Japan, investigating the safety and feasibility of intramuscular injections of ADRCs and testing the hypothesis that this treatment promotes neovascularization and improves major amputation-free survival rates in patients with CLI who have no other treatment option. 40 patients with CLI will be enrolled and followed up from November 2015 to November 2020. Freshly isolated autologous ADRCs will be injected into the target ischemic limbs. Survival rate, adverse events, major limb amputation, ulcer size, 6-min walking distance, numerical rating scale, ankle-brachial pressure index, skin perfusion pressure and digital subtraction angiography will be evaluated at baseline and during 6 months' follow-up. Conclusions: This trial will demonstrate whether implantation of autologous ADRCs is a safe and effective method for therapeutic angiogenesis, resulting in an improvement in major amputation-free survival rates in patients with CLI.

Long term efficacy and safety of rivaroxaban plus cilostazol in the treatment of critical ischemia of the lower limbs in a frail, elderly patient with non valvular atrial fibrillation

Background

Many patients with critical lower limb ischemia are not eligible for revascularization procedures. Still, given the emerging role of both platelet and coagulation activation in the formation of arterial thrombi, they may benefit from the novel anticoagulant and antiplatelet drugs.

Case presentation

We describe the case of a male with critical lower limb ischemia complicated by older age, frailty, polymorbidity and non valvular atrial fibrillation, who was deemed as non eligible for surgery. The patient was successfully treated with the combination of rivaroxaban and cilostazol, and the clinical benefit was maintained throughout 32 months, with no occurrence of major or minor hemorrhagic or thrombotic events.

Conclusions

To our knowledge, this is the first report on the efficacy and safety of such a combination therapy in critical lower limb ischemia. In a clinical setting in which alternative pharmacological approaches are urgently needed, the association of rivaroxaban and cilostazol warrants further investigations.

Association of six-minute walk distance with subsequent lower extremity events in peripheral artery disease

The prognostic significance of the six-minute walk distance for lower extremity events in people with peripheral artery disease (PAD) is unknown. This longitudinal study assessed whether a poorer six-minute walk distance at baseline was associated with higher rates of subsequent lower extremity atherosclerotic disease events in PAD. A total of 369 patients (mean age 69.4 ± 10.0 years; mean ankle-brachial index (ABI) 0.67 ± 0.17; 31% women; 30% black individuals) from Chicago-area medical centers with PAD were enrolled. Participants underwent baseline six-minute walk testing and returned for annual study visits. Lower extremity events consisted of one or more of the following: ABI decline greater than 15% or medical record adjudicated lower extremity revascularization, critical limb ischemia, or amputation. At a mean follow-up of 33.3 months, lower extremity events occurred in 66/123 (53.7%) people in the first (worst) tertile of six-minute walk performance, 55/124 (44.4%) in the second tertile, and 56/122 (45.9%) in the third (best) tertile. After adjusting for age, sex, race, ABI, comorbidities, and other confounders, participants in the first (worst) tertile of six-minute walk distance at baseline had higher rates of lower extremity events during follow-up, compared to those in the best tertile at baseline (HR = 1.74, 95% CI 1.17-2.60, p = 0.0067). Among people with PAD, a poorer six-minute walk distance was associated with higher rates of subsequent lower extremity PAD-related events after adjusting for confounders. Further study is needed to determine whether interventions that improve six-minute walk distance can reduce lower extremity adverse events in people with PAD.

Combining diabetic foot and retinopathy screening: A step in the right direction? - a feasibility study

Objectives

Peripheral artery disease is a major cardiovascular disease affecting more than 200 million people globally and up to 4 times more frequent in the diabetic population. It can lead to lower extremity amputations or revascularisation and is associated with an increased risk of myocardial infarction, stroke and early mortality. This novel cross-sectional study aimed to explore the feasibility and acceptability of incorporating diabetic foot screening at routine diabetic retinopathy screening appointments.

Methods

Participants underwent foot screening during the interval between pupil dilatation and retinal photography as part of the eye screening procedure. Lower limb arterial assessment included ankle brachial index, pulse volume waveform and protective light touch sensation.

Results

Of 364 participants invited, 88% (n = 321) met the inclusion criteria. About 26.4% (n = 86) had asymptomatic peripheral artery disease and 3% (n = 10) had peripheral sensory neuropathy. Binary logistical regression analysis identified age (p < 0.005), existing coronary heart disease (p < 0.005) and gender (p = 0.03) as predictors of peripheral artery disease.

Conclusion

Incorporating foot examination during eye screening appointments is feasible and was well received by participants and staff alike. Undiagnosed early peripheral artery disease was evident in a third of the study population emphasising the benefit of introducing foot surveillance into eye screening appointments for the early identification of lower limb arterial disease and peripheral sensory neuropathy.

Differences in Intravascular Ultrasound Measurement Values Between Treatment Modalities for Restenosis in Femoropopliteal Lesions

BACKGROUND

The risk of restenosis after intervention is higher in femoropopliteal than in aortoiliac lesions. However, the appropriate endovascular therapy (EVT) for preventing restenosis after intervention for femoropopliteal lesions remains unknown. This study aimed to elucidate the relationship between lesion characteristics and patency after EVT using intravascular ultrasound (IVUS) measurement and to determine the predictors of restenosis on IVUS.

METHODS AND RESULTS

This prospective observational study was performed at 18 Japanese centers. We evaluated the lesion characteristics before and after EVT for femoropopliteal lesion using IVUS. Angiographic or duplex ultrasound follow-up was performed at 1 year after EVT. A total of 263 lesions underwent EVT between December 2016 and December 2017. In total, 20 lesions (8 cases of isolated common femoral artery lesion and 12 cases of restenosis lesion) were excluded, and 243 lesions were enrolled in this study. A total of 181 lesions were treated with stent placement, and 62 lesions were treated only with balloon angioplasty. In the case of stent use, a larger distal plaque burden was associated with restenosis, while a lower calcification angle was associated with higher patency in the case of balloon angioplasty alone.

CONCLUSIONS

The factors related to patency differed depending on the treating modality. The findings suggest that IVUS is a useful tool for predicting patency because it can provide a more accurate evaluation after EVT for femoropopliteal lesions.

Pathologic Disparities Between Peripheral Artery Disease and Coronary Artery Disease

Atherosclerosis is a systemic disease that involves multiple vascular beds. The pathological characteristics and clinical presentation, however, vary among the different vascular territories. Acute coronary syndrome is a relatively common manifestation of coronary atherosclerotic disease, wherein the thrombosis occurs secondary to disruption (65%-75%) and erosion (25%-35%) of the fibrous caps of atheromatous plaques. The plaques associated with plaque rupture have large necrotic cores and thin and inflamed fibrous caps. However, the pathological manifestations of peripheral artery disease result from thrombosis regardless of the extent of atherosclerosis. Approximately 75% of peripheral arteries with significant stenosis demonstrate presence of thrombi, of which two-thirds have thrombi associated with insignificant atherosclerosis. The presence of obliterative thrombi in peripheral arteries of patients with critical limb ischemia in the absence of coronary artery-like lesions suggests a locally thrombogenic or remotely embolic basis of disease. Extensive calcification of the medial vascular layer is commonly observed. In this review, we have described and compared the pathological basis of coronary and peripheral artery disease in patients with acute coronary syndrome and critical limb ischemia. It is expected that pathogenetic characterization would allow for definition of strategic targets for superior management of peripheral artery disease.

Systematic Literature Review of Randomized Trials Comparing Antithrombotic Therapy Following Revascularization Procedures in Patients With Peripheral Artery Disease

A systematic literature review was conducted to identify and summarize the clinical efficacy and safety of available antithrombotic therapies after peripheral endovascular or surgical revascularization in patients with peripheral artery disease (PAD). Five databases were searched using free-text and Emtree/Mesh terms for PAD, randomized controlled trials (RCTs), and antithrombotic therapies of interest (ie, single antiplatelet therapy, dual antiplatelet therapy, and vitamin K antagonists). Randomized controlled trials were eligible for inclusion if they assessed the risk of thrombotic events (ie, myocardial infarction, ischemic stroke, cardiovascular death, limb ischemia, or limb amputation) or safety profile (ie, minor, moderate, major, or fatal bleeding events) after revascularization. In total, 16 RCTs were identified. Only a few studies reported on treatment effects of the investigated therapies. Myocardial infarction, ischemic stroke, cardiovascular death, and amputation were reported in up to 2.3%, 2.3%, 5.6%, and 7.3% of patients, respectively. Bleeding events were observed in up to 8.4% (major) and 1.5% (fatal) of patients. Despite available treatments, patients with PAD undergoing revascularization remain at risk of thrombotic events. There is a need for new treatments that will help to optimize care for patients with symptomatic PAD undergoing revascularization.

The Nitric Oxide System in Peripheral Artery Disease: Connection with Oxidative Stress and Biopterins

Peripheral artery disease (PAD) pathophysiology extends beyond hemodynamics to include other operating mechanisms, including endothelial dysfunction. Oxidative stress may be linked to endothelial dysfunction by reducing nitric oxide (NO) bioavailability. We aimed to investigate whether the NO system and its regulators are altered in the setting of PAD and to assess the relationship between NO bioavailability and oxidative stress. Sera from 35 patients with intermittent claudication (IC), 26 patients with critical limb ischemia (CLI), and 35 non-PAD controls were analyzed to determine levels of tetrahydrobiopterin (BH4), dihydrobiopterin (BH2), nitrate/nitrite (nitric oxides, or NOx), arginine, citrulline, asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), and the oxidative stress markers 8-Oxo-2'-deoxyguanosine (8-OHdG), 4-hydroxynonenal (4-HNE), advanced glycation end products (AGEs), and protein carbonyls. NOx was significantly lower in IC and CLI patients compared to controls in association with elevated oxidative stress, with the greatest NOx reductions observed in CLI. Compared with controls, IC and CLI patients had reduced BH4, elevated BH2, and a reduced BH4/BH2 ratio. SDMA, the arginine/SDMA ratio, and the arginine/ADMA ratio were significantly higher in CLI patients. The NO system and its regulators are significantly compromised in PAD. This dysregulation appears to be driven by increased oxidative stress and worsens as the disease progresses from claudication to CLI.

Predictive Value of Abnormal and Borderline Ankle-Brachial Index for Coronary Re-Intervention and Mortality in Patients with Coronary Artery Disease: An Observational Cohort Study

Purpose

This study aimed to investigate the abnormal and borderline ABIs for predicting coronary re-intervention and mortality in patients with coronary artery disease (CAD).

Materials and Methods

Data from a previous study were obtained and used to investigate the prevalence of peripheral arterial disease among Korean patients with CAD (n=285) in 2010. All patients underwent follow-up coronary angiography as scheduled (asymptomatic: 2-, 5-, and 7-month intervals) or as clinically indicated (symptomatic).

Results

In total, 33 patients had an abnormal ABI (ab-ABI: <1.0 or >1.4), and 252 had a normal ABI (nl-ABI: 1.0≤ABI≤1.4). The mean follow-up was 47 months. The mortality was significantly higher in the ab-ABI group than in the nl-ABI group (18.2% vs. 6.7%, P=0.0233). MACEs were significantly more common in the ab-ABI group (60.6% vs. 34.5%, P=0. 0036). Moreover, the ab-ABI group had a greater CAD progression than the nl-ABI group (48.5% vs. 31.3%, P=0.0496). The incidence of clinically indicated coronary re-intervention was significantly higher in the ab-ABI group than in the nl-ABI group (33.3% vs. 13.1%, P=0.0025). After adjusting for age, diabetes, dyslipidemia, dialysis, smoking, and obesity, the incidence of clinically indicated re-intervention was significantly higher in the ab-ABI group than in the nl-ABI group (HR, 2.80; 95% CI, 1.24 to 6.34).

Conclusion

Abnormal and borderline ABI significantly increased the incidence of clinically indicated coronary revascularization and all-cause mortality during a 4-year follow-up among patients with CAD. Hence, ABI could be used to stratify extremely high-risk patients with CAD who may require aggressive surveillance or treatment.

Acute Lower Limb Ischemia-Etiology, Pathology, and Management

Acute limb ischemia (ALI) is a vascular emergency associated with a high risk for limb loss and death. Most cases result from in situ thrombosis in patients with preexisting peripheral arterial disease or those who have undergone vascular procedures including stenting and bypass grafts. The other common source is cardioembolic. The incidence has decreased in recent times due to better anticoagulation strategies. Patients with suspected ALI should be evaluated promptly by a vascular specialist and consideration should be given for transfer to a higher level of care if such expertise is not available locally. Initial assessment should focus on staging severity of ischemic injury and potential for limb salvage. Neurological deficits can occur early and are an important poor prognostic sign. Duplex ultrasound and computed tomography angiography help plan intervention in patients with a still-viable limb and prompt catheter-based angiography is mandated in patients with an immediately threatened limb. Further investigations need to be pursued to differentiate embolic from thrombotic cause for acute occlusion as this can change management. Options include intravascular interventions, surgical bypass, or a hybrid approach. In this article, the authors discuss the common etiologies, clinical evaluation, and management of patients presenting with acute limb ischemia.

A prospective community engagement initiative to improve clinical research participation in patients with peripheral artery disease

Objective:

Patients diagnosed with peripheral artery disease are difficult to recruit into clinical trials. However, there is currently no high-quality, patient-centered information explaining why peripheral artery disease patients choose to participate or not participate in clinical research studies.

Methods:

The current study was a prospective community engagement initiative that specifically asked patients with and without peripheral artery disease: (1) what motivates them to participate in clinical research studies, (2) their willingness to participate in different research procedures, (3) the barriers to participation, (4) preferences about study design, and (5) demographic and disease-related factors influencing participation. Data were gathered through focus groups (n = 19, participants aged 55–79 years) and mailed questionnaires (n = 438, respondents aged 18–85 years).

Results:

More than half of the respondents stated that they would be willing to participate in a study during evening or weekend time slots. Peripheral artery disease patients (n = 45) were more willing than those without peripheral artery disease (n = 360) to participate in drug infusion studies (48% versus 18%, p < 0.001) and trials of investigational drugs (44% versus 21%, p < 0.001). Motivating factors and barriers to participation were largely consistent with previous studies.

Conclusion:

Adults in our geographic region are interested in participating in clinical research studies related to their health; they would like their doctor to tell them what studies they qualify for and they prefer to receive a one-page advertisement that has color pictures of the research procedures. Peripheral artery disease patients are more willing than those without peripheral artery disease to participate in drug infusion studies, trials of investigational drugs, microneurography, and spinal/epidural infusions.

Impact of Kidney Disease on Peripheral Arterial Interventions: A Systematic Review and Meta-Analysis

BACKGROUND

There are limited data on outcomes of patients undergoing peripheral arterial disease (PAD) interventions who have comorbid CKD/ESRD versus those who do not have such comorbid condition. We performed a systematic review and meta-analysis to analyze outcomes in this patient population.

METHODS

Five databases were searched for studies comparing outcomes of lower extremity PAD interventions for claudication and critical limb ischemia (CLI) in patients with CKD/ESRD versus non-CKD/non-ESRD from January 2000 to June 2019.

RESULTS

Our study included 16 observational studies with 44,138 patients. Mean follow-up was 48.9 ± 27.4 months. Major amputation was higher with CKD/ESRD compared with non-CKD/non-ESRD (odds ratio [OR 1.97] [95% confidence interval [CI] 1.39-2.80], p = 0.001). Higher major amputations with CKD/ESRD versus non-CKD/non-ESRD were only observed when indication for procedure was CLI (OR 2.27 [95% CI 1.53-3.36], p < 0.0001) but were similar for claudication (OR 1.15 [95% CI 0.53-2.49], p = 0.72). The risk of early mortality was high with CKD/ESRD patients undergoing PAD interventions compared with non-CKD/non-ESRD (OR 2.55 [95% CI 1.65-3.96], p < 0.0001), which when stratified based on indication, remained higher with CLI (OR 3.14 [95% CI 1.80-5.48], p < 0.0001) but was similar with claudication (OR 1.83 [95% CI 0.90-3.72], p = 0.1). Funnel plot of included studies showed moderate bias.

CONCLUSIONS

Patients undergoing lower extremity PAD interventions for CLI who also have comorbid CKD/ESRD have an increased risk of experiencing major amputations and early mortality. Randomized trials to understand outcomes of PAD interventions in this at-risk population are essential.

Telephone health coaching with exercise monitoring using wearable activity trackers (TeGeCoach) for improving walking impairment in peripheral artery disease: study protocol for a randomised controlled trial and economic evaluation

INTRODUCTION

Peripheral artery disease (PAD) is the third most prevalent cardiovascular disease worldwide, with smoking and diabetes being the strongest risk factors. The most prominent symptom is leg pain while walking, known as intermittent claudication. To improve mobility, first-line treatment for intermittent claudication is supervised exercise programmes, but these remain largely unavailable and economically impractical, which has led to the development of structured home-based exercise programmes. This trial aims to determine the effectiveness and cost advantage of TeGeCoach, a 12-month long home-based exercise programme, compared with usual care of PAD. It is hypothesised that TeGeCoach improves walking impairment and lowers the need of health care resources that are spent on patients with PAD.

METHODS AND ANALYSIS

The investigators conduct a prospective, pragmatic randomised controlled clinical trial in a health insurance setting. 1760 patients diagnosed with PAD at Fontaine stage II are randomly assigned to either TeGeCoach or care-as-usual. TeGeCoach consists of telemonitored intermittent walking exercise with medical supervision by a physician and telephone health coaching. Participants allocated to the usual care group receive information leaflets and can access supervised exercise programmes, physical therapy and a variety of programmes for promoting a healthy lifestyle. The primary outcome is patient reported walking ability based on the Walking Impairment Questionnaire. Secondary outcome measures include quality of life, health literacy and health behaviour. Claims data are used to collect total health care costs, healthcare resource use and (severe) adverse events. Outcomes are measured at baseline, 12 and 24 months.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Medical Association Hamburg. Findings are disseminated through peer-reviewed journals, reports to the funding body, conference presentations and media press releases. Data from this trial are made available to the public and researchers upon reasonable request.NCT03496948 (www.clinicaltrials.gov), Pre-results.

Stromal Cell-Derived Factor-1 Plasmid Treatment for Patients With Peripheral Artery Disease (STOP-PAD) Trial: Six-Month Results

Purpose: To present the 6-month results of the Stromal Cell-Derived Factor-1 Plasmid Treatment for Patients with Peripheral Artery Disease (STOP-PAD) trial. The trial was an attempt to alter the course of chronic limb-threatening ischemia (CLTI) with a biological agent vs placebo after successful arterial revascularization at or below the knee. Materials and Methods: The multicenter, randomized, double-blinded, placebo-controlled, phase 2B STOP-PAD trial (ClinicalTrials.gov identifier NCT02544204) randomized 109 patients (mean age 71 years; 68 men) with Rutherford category 5 or 6 CLTI and evidence of persistent impaired forefoot perfusion following recent successful revascularization to 8- (n=34) or 16-mg (n=36) intramuscular injections of a non-viral DNA plasmid-based treatment vs placebo (n=34). The primary efficacy outcome was the 6-month wound healing score evaluated by an independent wound core laboratory; the primary safety endpoint was major adverse limb events (MALE), a composite of major amputation plus clinically-driven target lesion revascularization at 6 months. Results: Only one-third of the patients had complete wound healing at 6 months in the placebo (31%), 8-mg injection (33%), and 16-mg injection (33%) groups. In addition, the observed increase in the toe-brachial index from baseline to 6 months was statistically significant in each group; however, this did not result in lower rates of MALE at 6 months (24% in the placebo, 29% in the 8-mg injection, and 11% in the 16-mg injection groups). During the 6-month period, 6 patients (6%) died, and 24 patients (23%) had an amputation [only 4 (4%) major]. Conclusion: Combining revascularization and biological therapy failed to improve outcomes in CLTI at 6 months. STOP-PAD has provided insights for future trials to evaluate biological therapy.

Rationale and design of the granulocyte-macrophage colony stimulating factor in peripheral arterial disease (GPAD-3) study

BACKGROUND

Lower extremity peripheral arterial disease (PAD) is a public health problem and many patients with PAD experience claudication despite adequate medical and/or surgical management. Mobilization of endogenous progenitor cells using Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) is a novel therapeutic option that has shown promising results in experimental models and phase I/IIA clinical trials. The GPAD-3 trial will study the effect of two successive administrations of GM-CSF at 3-month interval for improving claudication among patients with lower extremity PAD.

METHODS

We plan to recruit 176 patients in this ongoing randomized, double-blind, placebo-controlled Phase IIB trial. After screening for inclusion and exclusion criteria, eligible subjects undergo a 4-week screening phase where they perform subcutaneous placebo injections thrice weekly and walk at least three times a day until they develop claudication. After the screening phase, eligible subjects undergo baseline testing and are randomized 2:1 to receive 500 μg/day of GM-CSF subcutaneously thrice weekly for three weeks or placebo injections. After 3 months, follow-up endpoint testing is performed and subjects in the GM-CSF group receive the second administration of the drug for three weeks while subjects in placebo group receive matching placebo injections. All participants undergo endpoint testing at six-month and nine-month follow-up. The primary endpoint is change in 6-min walk distance between baseline and 6-month follow-up.

CONCLUSION

GPAD-3 explores a novel approach to address the need for alternative therapies that can alleviate symptoms among patients with lower extremity PAD. If successful, this study will pave the way for a pivotal Phase III trial.

Low skeletal muscle mass is associated with arterial stiffness in community-dwelling Chinese aged 45 years and older

Background

Evidence suggests that body composition has impact on arterial stiffness. However, evidence in Chinese are limited, and results remain controversial. The aim of our study is to investigate whether skeletal muscle mass is associated with arterial stiffness in Chinese community-dwelling men and women aged 45 years and older.

Methods

In this cross-sectional study, 20,477 participants (age range: 45–80 years, 68.8% women) were included in the analysis. Brachial-ankle pulse wave velocity (baPWV), an indicator of arterial stiffness was measured using a waveform device. Total muscle mass and muscle mass of arm, leg and trunk were measured by bioelectrical impedance analysis. Height and weight were measured and appendicular skeletal muscle mass index (ASMI) was calculated as appendicular skeletal muscle mass (sum of arm and leg muscle mass) divided by height square.

Results

After adjustment for age, body fat percentage, systolic blood pressure and diastolic blood pressure, ASMI was negatively associated with baPWV [β (SE) for men: − 0.208 (0.016), p < 0.0001; for women: − 0.245 (0.012), p < 0.0001]. High ASMI was a protective factor for the presence of arterial stiffness (defined as baPWV) [OR (95%CI) for men: 0.730 (0.682, 0.782), p < 0.0001; women: 0.634 (0.593, 0.677), p < 0.0001]. Similar associations were found between quantity of muscle mass (total and appendicular muscle mass, muscle mass of arm, leg and trunk) and arterial stiffness in men and women after further adjustment for height (all p < 0.0001).

Conclusion

Low skeletal muscle mass is associated with increased risk of arterial stiffness in Chinese community-dwelling adults aged 45 years and older.

Association of Circulating Osteopontin Levels With Lower Extremity Arterial Disease in Subjects With Type 2 Diabetes Mellitus: A Cross-Sectional Observational Study

Osteopontin (OPN) is involved in the atherosclerotic and inflammatory process. In this article, we examined the relationship between circulating OPN levels with lower extremity arterial disease (LEAD) in individuals with type 2 diabetes mellitus (T2DM). Seventy individuals with T2DM and 66 individuals without T2DM were recruited. Diagnosis of LEAD was based on the absence of triphasic waveform on the pedal arteries. Plasma OPN levels were determined by Luminex Multiplex immunoassay. LEAD was present in 34 (48.6%) patients with T2DM. In the diabetes cohort, individuals with LEAD had higher plasma OPN concentrations than those without LEAD (geometric mean [95% confidence intervals]; 43.4 [37.5-50.4] vs 26.1 [22.9-29.8] ng/mL, respectively, P < .001). Multivariable analysis showed that presence of LEAD independently associated with higher OPN levels in subjects with T2DM, with marginal statistical significance ( P = .049). In both cohorts, plasma OPN concentrations were negatively associated with ankle-brachial index values ( P < .05). In the total sample, there was a gradual increase of OPN levels across subgroups with triphasic, biphasic, and monophasic/blunted waveforms ( P < .001). In conclusion, plasma OPN levels are associated with the presence and severity of LEAD in subjects with T2DM. Further studies are needed to investigate the role of OPN in the pathogenesis and progression of LEAD.

Mortality After Paclitaxel Coated Balloon Angioplasty and Stenting of Superficial Femoral and Popliteal Artery in the Vascular Quality Initiative

BACKGROUND

To compare mortality after treatment of superficial femoral-popliteal artery disease with paclitaxel and nonpaclitaxel devices using a multicenter vascular registry.

METHODS

Patients (N=8376) undergoing endovascular treatment of superficial femoral-popliteal artery disease in the Society for Vascular Surgery Vascular Quality Initiative were studied from October 2016 to December 2017. One-year mortality was compared between 3 groups; plain balloon angioplasty (N=2104) versus paclitaxel-coated balloon angioplasty (N=3543), bare-metal stenting (N= 2045) versus paclitaxel-eluting stents (N=684), and combined paclitaxel versus nonpaclitaxel devices. Mortality rates with hazard ratios (HR) and 95% CI were compared in unadjusted and propensity-matched cohorts and illustrated by Kaplan-Meier analysis with subgroup analysis for intermittent claudication, chronic limb-threatening ischemia, and secondary interventions.

RESULTS

In propensity-matched analyses, mortality was similar after plain balloon angioplasty (12.6%) and paclitaxel-coated balloon angioplasty (9.6%; HR=0.84 [95% CI, 0.66-1.06], P=0.14). In propensity-matched groups, mortality was similar after bare-metal stenting (9.8%) and paclitaxel-eluting stenting (8.8%; HR=0.93 [95% CI, 0.62-1.41], P=0.75). In the combined, matched analysis mortality was significantly lower in the paclitaxel device group (8.5%) compared with the nonpaclitaxel device group (11.5%; HR=0.82 [95% CI, 0.68-0.98], P=0.03). Secondary interventions were similar after nonpaclitaxel (N=1113/4149, 26.8%) and paclitaxel device use (N=1113/4227, 26.3%). For intermittent claudication, mortality was lower after paclitaxel device use (1.6%) compared with nonpaclitaxel devices (4.4%; adjusted HR=0.59 [95% CI, 0.39-0.89], P=0.01). For chronic limb-threatening ischemia, the mortality difference was not significant; paclitaxel (12.8%) versus nonpaclitaxel devices (15.5%; adjusted HR=0.85 [95% CI, 0.72-1.00], P=0.05).

CONCLUSIONS

At 1 year, mortality was similar if not lower after treatment of femoral-popliteal occlusive disease with paclitaxel versus nonpaclitaxel devices. This work highlights the potential use of the Society for Vascular Surgery Vascular Quality Initiative for surveillance of the safety of new peripheral arterial devices.

Incidence, Characteristics, and Outcomes of Myocardial Infarction in Patients With Peripheral Artery Disease: Insights From the EUCLID Trial

Importance

Patients with peripheral artery disease (PAD) are at high risk for myocardial infarction (MI).

Objective

To characterize the incidence and types of MI in a PAD population, identify factors associated with MI, and determine the association of MI with cardiovascular mortality and acute limb ischemia.

Design, Setting, and Participants

The Study Comparing Cardiovascular Effects of Ticagrelor and Clopidogrel in Patients With Peripheral Artery Disease (EUCLID) was a double-blind randomized clinical trial conducted at 811 sites in 28 countries that randomized 13 885 patients with symptomatic PAD to monotherapy with ticagrelor or clopidogrel. Participants had an ankle-brachial index (ABI) of 0.80 or less or previous lower extremity revascularization. Median follow-up was 30 months. For these analyses, patients were evaluated for MI occurrence during follow-up irrespective of treatment. Data were analyzed from June 2017 to September 2018.

Main Outcomes and Measures

An adjudication clinical events committee classified MI as type 1 (spontaneous), type 2 (secondary), type 3 (sudden cardiac death), type 4a (less than 48 hours after percutaneous coronary intervention), type 4b (definite stent thrombosis), or type 5 (less than 72 hours after coronary artery bypass graft). A multivariate regression model was developed by stepwise selection to identify factors associated with MI, and a time-dependent multivariate Cox regression analysis was performed to determine the association of MI with cardiovascular death and acute limb ischemia requiring hospitalization.

Results

Of the 13 885 patients included in this analysis, 9997 (72.0%) were male, and the median (interquartile range) age was 66 (60-73) years. Myocardial infarction occurred in 683 patients (4.9%; 2.4 events per 100 patient-years) during a median follow-up of 30 months. Patients experiencing MI were older (median [interquartile range] age, 69 [62-75] vs 66 [60-72] years), more likely to have diabetes (349 of 683 [51.1%] vs 4996 of 13 202 [37.8%]) or a previous lower extremity revascularization (466 of 683 [68.2%] vs 7409 of 13 202 [56.1%]), and had a lower ABI (if included by ABI) compared with censored patients. Of the 683 patients with MI during follow-up, the most common MI type was type 1 (405 [59.3%]), followed by type 2 (236 [34.6%]), type 4a (14 [2.0%]), type 3 (12 [1.8%]), type 4b (11 [1.6%]), and type 5 (5 [0.7%]). Postrandomization MI was independently associated with cardiovascular death (adjusted hazard ratio, 9.0; 95% CI, 7.3-11.2; P < .001) and acute limb ischemia requiring hospitalization (adjusted hazard ratio, 2.5; 95% CI, 1.3-5.0; P = .008).

Conclusions and Relevance

Approximately 5% of patients with symptomatic PAD had an MI during a median follow-up of 30 months. Type 1 MI (spontaneous) was the most common MI type; however, one-third of MIs were type 2 MI (secondary). More research is needed to identify therapies to reduce the risk of MI in patients with PAD and to improve management of type 2 MI.

Trial Registration

ClinicalTrials.gov Identifier: NCT01732822.

Evidence-Based Medical Management of Peripheral Artery Disease

Peripheral artery disease is an atherosclerotic disease of the lower extremities associated with high cardiovascular mortality. Management of this condition may include lifestyle modifications, medical management, endovascular repair, or surgery. The medical approach to peripheral artery disease is multifaceted and includes cholesterol reduction, antiplatelet therapy, anticoagulation, peripheral vasodilators, blood pressure management, exercise therapy, and smoking cessation. Adherence to this regimen can reduce limb-related complications like critical limb ischemia and amputation, as well as systemic complications of atherosclerosis like stroke and myocardial infarction. Relative to coronary artery disease, peripheral artery disease is an undertreated condition. In this article, we explore the evidence behind medical therapies for the management of peripheral artery disease.

Tackling Elevated Risk in PAD: Focus on Antithrombotic and Lipid Therapy for PAD

The PAD population is at increased risk of major adverse cardiovascular events (MACE) and major adverse limb events (MALE). Risk factor modification, symptom control, antithrombotic, and lipid therapies are the mainstays of PAD medical therapy. Recent data has challenged prior recommendations regarding the optimal secondary prevention strategies in PAD. PURPOSE OF REVIEW: To review clinical evidence from large randomized controlled trials showing the benefit of antithrombotic and lipid therapy in the PAD population. RECENT FINDINGS: The COMPASS trial challenged prior recommendations regarding anticoagulation in PAD. Among the PAD subgroup, rivaroxaban 2.5 mg plus aspirin reduced MACE (HR 0.72, 95% CI 0.57-0.90, p = 0.0047), MALE (HR 0.54, 95% CI 0.35-0.82, p = 0.0037), and major amputation (HR 0.30, 95% CI 0.11-0.80, p = 0.011) compared with aspirin monotherapy. The THEMIS trial showed a 55% risk reduction for MALE with ticagrelor DAPT compared with aspirin monotherapy (HR 0.45, 95% CI 0.23-0.86). The FOURIER trial revealed that lowering LDL cholesterol below current targets with a PCSK9 inhibitor reduced MACE (HR 0.73, 95% CI 0.59-0.91, p = 0.0040) and MALE (HR 0.43, 95% CI 0.19-0.99, p = 0.042) in subjects with symptomatic PAD. Recent high-quality evidence shows the benefit of antiplatelet therapy, anticoagulation therapy, and lipid therapy in reducing MACE and MALE in PAD. Despite these findings, implementation remains a challenge and focus should now shift towards adopting evidence-based recommendations in clinical practice.

Ultrasonographic measurement of the renal resistive index in the cynomolgus monkey (Macaca fascicularis) under conscious and ketamine-immobilized conditions

Measurement of the renal resistive index (RRI) is one of the standard diagnostic procedures for assessing kidney disability clinically. This method is expected to be used for the same purpose in many kinds of animals, including monkeys utilized in conventional toxicology studies. To establish a practical RRI measurement procedure in cynomolgus monkeys (Macaca fascicularis), RRI was measured by ultrasonography in the spine position in conscious and ketamine-immobilized monkeys. The RRI of conscious monkeys and ketamine-immobilized monkeys could be measured consistently without excessive abdominal or thoracic movement. Consequently, the variability of the RRI in conscious monkeys was comparable to that in ketamine-anesthetized monkeys. No sex difference in RRI was noted between the two conditions. The mean values and SD of the RRI of 48 healthy monkeys (n=24/sex) were 0.55 ± 0.07 and 0.50 ± 0.05, under conscious and ketamine-immobilized conditions, respectively. The RRI of ketamine-immobilized monkeys was significantly lower than that of conscious monkeys, correlating with the decreased blood pressure and heart rate. In a monkey model of cisplatin-induced acute renal injury, which was characterized histopathologically by minimal to mild renal tubular necrosis and regeneration, the RRI was increased beyond the cut off value (mean + 2SD, 0.68) associated with the progression of renal pathogenesis. The present results suggest that ultrasonographic measurement of the RRI in conscious monkeys would be a useful tool in conventional toxicology studies evaluating drug-induced renal injury.

Adherence to Guideline-Recommended Therapy-Including Supervised Exercise Therapy Referral-Across Peripheral Artery Disease Specialty Clinics: Insights From the International PORTRAIT Registry

Background

Underuse of guideline‐recommended therapy in peripheral artery disease (PAD) in administrative and procedural databases has been described, but reports on medically managed patients and referral to supervised exercise therapy (SET) in PAD are lacking. We aimed to document the use of PAD guideline‐recommended therapy, including SET in patients with PAD symptoms consulting a specialty clinic across 3 countries.

Methods and Results

The 16‐center PORTRAIT (Patient‐Centered Outcomes Related to Treatment Practices in Peripheral Arterial Disease: Investigating Trajectories) registry enrolled 1275 patients with new or an exacerbation of PAD symptoms (2011–2015). We prospectively documented antiplatelet medications, statins, smoking cessation counseling and/or therapy, and referral to SET: “2 quality measures” referred to the use of both statin and antiplatelet medications; “4 quality measures” to receiving all 4 measures. Median odds ratios were calculated to quantify treatment variation across sites. A total of 89% patients were on antiplatelets, 83% on statins, and 23% had been referred to SET. Of 455 current smokers, 342 (72%) patients received smoking cessation therapy/counseling. Overall, 77.2% of patients received “2 quality measures” and 19.7% “4 quality measures.” The median odds ratio for 2 quality measures was 2.13 (95% CI, 1.61–3.56; P<0.001) and for 4 quality measures was 5.43 (95% CI, 2.84–17.91; P<0.001). Variability in adherence was not explained by country, except for referral to SET. The odds for SET referral in The Netherlands (70% referral rate) was nearly 100 times greater than in US sites (2% referral rate).

Conclusions

Not all patients who have undergone a PAD workup at a specialty care facility are treated with evidence‐based care, especially so for SET.

Combined Aerobic and Resistance Exercise in Walking Performance of Patients With Intermittent Claudication: Systematic Review

Background: The short-term benefits of aerobic and resistance exercise in subjects affected by Peripheral Arterial Disease (PAD) are scarcely examined in interaction. This study aimed to identify the effects of combined aerobic and resistance exercise programs on walking performance compared with isolated aerobic exercise or with the usual care in patients with intermittent claudication.

Methods: A systematic review was conducted following the PRISMA statement. A total of five electronic databases were searched (until October 2019) for randomized and non-randomized controlled trials. The focus comprised PAD patients with intermittent claudication who performed a combined aerobic and resistance exercise program that assessed the walking performance.

Results: Seven studies include combined aerobic and resistance exercise vs. isolated aerobic or vs. usual care. The studies represented a sample size of 337 participants. The follow-up ranged from 4 to 12 weeks, 2 to 5 times-per-week. The risk of bias in the trials was a deemed moderate-to-high risk. After the interventions, the percent change in walking performance outcomes had a large variation. In the combined and isolated aerobic programs, the walking performance always improved, while in the usual care group oscillates between the deterioration and the improvement in all outcomes. Combined exercise and isolated aerobic exercise improved the claudication onset distance from 11 to 396%, and 30 to 422%, the absolute claudication distance from 81 to 197%, and 53 to 121%, and the maximal walking distance around 23 and 10%, respectively.

Conclusions: Currently, there is insufficient evidence about the effects of combined aerobic and resistance exercise compared to isolated aerobic exercise or usual care on walking performance. However, despite the low quality of evidence, the combined aerobic and resistance exercise seems to be an effective strategy to improve walking performance in patients with intermittent claudication. These combined exercise modes or isolated aerobic exercise produce positive and significant results on walking performance. The usual care approach has a trend to deteriorate the walking performance. Thus, given the scarcity of data, new randomized controlled trial studies that include assessments of cardiovascular risk factors are urgently required to better determine the effect of this exercise combination.

Presentation Pattern of Lower Extremity Endovascular Intervention versus Percutaneous Coronary Intervention

AIM

The aim of the current study is to describe the presentation pattern of symptomatic peripheral artery disease undergoing endovascular therapy (EVT) in comparison to symptomatic coronary artery disease undergoing percutaneous coronary intervention (PCI) based on data from nationwide databases.

METHODS

Data were extracted from the nationwide procedural databases of EVT and PCI in Japan (J-EVT and J-PCI) between 2012 and 2017. The presentation pattern was investigated using a Poisson regression model, including the month, seasonality, and weekend (versus weekday) as the explanatory variables. Seasonality was expressed as a cosine function of a 12-month period, and its significance was evaluated using the Fisher-Yates shuffle method.

RESULTS

A total of 41,906 and 62,585 cases underwent EVT for critical limb ischemia (CLI) and intermittent claudication (IC), respectively, whereas 518,858 and 504,139 cases underwent PCI for acute coronary syndrome (ACS) and stable angina (SA). The procedural volume increased by 21.6%, 12.3%, 4.5%, and 3.6% per year in CLI, IC, ACS, and SA. CLI and ACS, but not IC or SA, showed a significant volume seasonality. Compared with ACS, CLI demonstrated a larger peak-to-trough ratio of seasonality (1.75 versus 1.21; P＜0.001), and a later peak appearance (February-March versus January-February by 1.37 months; P＜0.001). The procedural volume on weekends relative to weekdays was smaller for SA, IC, and CLI than for ACS. These distinct features were observed in a diabetic population and a non-diabetic population.

CONCLUSIONS

The current study analyzed nationwide procedural databases and demonstrated the presentation pattern of symptomatic PAD and CAD warranting revascularization.

How To Assess a Claudication and When To Intervene

PURPOSE OF THE REVIEW

Peripheral artery disease (PAD) affects close to 200 million people worldwide. Claudication is the most common presenting symptom for patients with PAD. This review summarizes the current diagnostic and treatment options for patients with claudication. Comprehensive history and physical examination in order to differentiate between claudication secondary to vascular disease vs. neurogenic causes is paramount for initial diagnosis. Ankle-brachial index is the most commonly used test for screening and diagnostic purposes. Treatment consists of four different approaches, which are best utilized in combination: non-pharmacological treatment for claudication improvement, pharmacological treatment for claudication improvement, pharmacological treatment for secondary risk reduction, and interventional treatment for claudication improvement.

RECENT FINDINGS

Cilostazol is the only Food and Drug Administration (FDA)-approved agent for symptomatic treatment of claudication. Supervised exercise programs provide the maximum benefit for claudication improvement, but home-based exercise programs are an alternative. High-intensity statins and an antiplatelet agent should be prescribed to all patients with PAD. Angiotensin-converting-enzyme inhibitors can provide additional risk reduction, especially in patients with diabetes or hypertension. Rivaroxaban of low dosage (2.5 mg twice daily) in combination with aspirin further decreases cardiovascular risk, but this reduction comes at the cost of higher bleeding risk. Peripheral artery disease (PAD) is a form of atherosclerotic disease that affects hundreds of millions of people worldwide-one of its most common manifestations is intermittent claudication (IC), which results from insufficient blood flow to meet the metabolic demands of an affected extremity. This paper reviews the current literature regarding the workup, diagnosis, diagnostic modalities, treatment options, and management of intermittent claudication.

Clinical Outcome and Diverse Risk Factors for Different Therapeutic Target Locations of Peripheral Artery Disease

Aim: Previous studies on peripheral artery disease (PAD) only enrolled patients with atherosclerotic lesion limited to any one of isolated locations (aortoiliac [AI], femoropopliteal [FP], and below the knee [BTK]). However, the interventions for PAD in a real-world clinical setting are often simultaneously performed for several different locations.

Methods: We conducted a prospective multicenter study that included 2,230 patients with PAD who received intervention for lower extremity lesions in each area and across different areas. Patients were divided into 7 groups according to the combination of treatment locations. Overall survival (OS), major adverse limb events (MALEs), and risk factors for OS and MALEs were statistically analyzed.

Results: After adjustment for confounding factors, the attributable risk for OS was similar among isolated AI, FP, and BTK treatments. MALEs increased in correlation with the number of treatment locations. Dialysis and critical limb ischemia were the common risk factors for OS and MALEs. However, the contribution of other factors such as type of drug usage was different according to treatment locations.

Conclusions: In patients with PAD, OS was largely defined by comorbidities but not by lesion location. The background risk factors, underlying comorbidities, and event rates were different according to PAD location, suggesting that stratified treatment should be established for different patient populations.

Underutilization of Evidence-Based Smoking Cessation Support Strategies Despite High Smoking Addiction Burden in Peripheral Artery Disease Specialty Care: Insights from the International PORTRAIT Registry

Background

Smoking is the most important risk factor for peripheral artery disease (PAD). Smoking cessation is key in PAD management. We aimed to examine smoking rates and smoking cessation interventions offered to patients with PAD consulting a vascular specialty clinic; and assess changes in smoking behavior over the year following initial visit.

Methods and Results

A total of 1272 patients with PAD and new or worsening claudication were enrolled at 16 vascular specialty clinics (2011–2015, PORTRAIT (Patient‐Centered Outcomes Related to Treatment Practices in Peripheral Arterial Disease: Investigating Trajectories) registry). Interviews collected smoking status and cessation interventions at baseline, 3, 6, and 12 months. Among smokers, transition state models analyzed smoking transitions at each time point and identified factors associated with quitting and relapse. On presentation, 474 (37.3%) patients were active, 660 (51.9%) former, and 138 (10.8%) never smokers. Among active smokers, only 16% were referred to cessation counseling and 11% were prescribed pharmacologic treatment. At 3 months, the probability of quitting smoking was 21%; among those continuing to smoke at 3 months, the probability of quitting during the next 9 months varied between 11% and 12% (P<0.001). The probability of relapse among initial quitters was 36%. At 12 months, 72% of all smokers continued to smoke.

Conclusions

More than one third of patients with claudication consulting a PAD provider are active smokers and few received evidence‐based cessation interventions. Patients appear to be most likely to quit early in their treatment course, but many quickly relapse and 72% of all patients smoking at baseline are still smoking at 12 months. Better strategies are needed to provide continuous cessation support.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01419080.

Practice patterns of dual antiplatelet therapy after lower extremity endovascular interventions

Antiplatelet therapy is commonly prescribed following endovascular interventions. However, there is limited data regarding the regimen and duration of antiplatelet therapy following lower extremity endovascular interventions. The aim of this study was to investigate the practice patterns of dual antiplatelet therapy (DAPT) after lower extremity endovascular interventions. We identified all patients who received an endovascular intervention in the Vascular Study Group of New England (VSGNE) registry from 2010 through 2018. The antiplatelet regimen was examined at the time of discharge and follow-up. Variables predicting discharge antiplatelet therapy and duration of antiplatelet therapy were investigated. There were 13,510 (57.69%) patients discharged on DAPT, 8618 (36.80%) patients discharged on single antiplatelet therapy, and 1292 (5.51%) patients discharged without antiplatelet therapy. Patients with coronary artery disease (CAD), prior vascular bypass and endovascular intervention, preoperative statin use, stent placement compared with angioplasty, and femoropopliteal and tibial treatment were associated with higher odds of being discharged with DAPT compared with no antiplatelet therapy and single antiplatelet therapy. Of the patients discharged on DAPT who were followed up at 9–12 months and 21–24 months, 56.49% and 49.63% remained on DAPT, respectively. Only a narrow margin of the patient majority undergoing endovascular interventions was discharged with DAPT, suggesting that only a small proportion of patients undergoing endovascular intervention remain on DAPT long-term. As the number of peripheral vascular interventions continues to grow, further studies are crucial to identify the optimal duration of DAPT.

Platelets as Modulators of Cerebral Ischemia/Reperfusion Injury

Ischemic stroke is among the leading causes of disability and death worldwide. In acute ischemic stroke, the rapid recanalization of occluded cranial vessels is the primary therapeutic aim. However, experimental data (obtained using mostly the transient middle cerebral artery occlusion model) indicates that progressive stroke can still develop despite successful recanalization, a process termed "reperfusion injury." Mounting experimental evidence suggests that platelets and T cells contribute to cerebral ischemia/reperfusion injury, and ischemic stroke is increasingly considered a thrombo-inflammatory disease. The interaction of von Willebrand factor and its receptor on the platelet surface, glycoprotein Ib, as well as many activatory platelet receptors and platelet degranulation contribute to secondary infarct growth in this setting. In contrast, interference with GPIIb/IIIa-dependent platelet aggregation and thrombus formation does not improve the outcome of acute brain ischemia but dramatically increases the susceptibility to intracranial hemorrhage. Here, we summarize the current understanding of the mechanisms and the potential translational impact of platelet contributions to cerebral ischemia/reperfusion injury.

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.

The acute effects of different levels of intermittent negative pressure on peripheral circulation in patients with peripheral artery disease

Intermittent negative pressure (INP) applied to the lower leg induces acute increase in arterial and skin blood flow. The aim of this study was to identify the optimal level of INP to increase blood flow in patients with lower extremity peripheral artery disease (PAD). We investigated the acute effects of different levels of INP in 16 subjects (7 women and 9 men, mean (SD) age 71(8) years) diagnosed with PAD. During application of INP in a pressure chamber sealed below the knee, arterial blood flow was continuously recorded in the dorsalis pedis artery or tibialis posterior artery (ultrasound Doppler), and skin blood flow was continuously recorded at the pulp of the first toe (laser Doppler). Different pressure levels (0, -10, -20, -40, and -60 mmHg) were tested in randomized order. Maximal arterial blood flow relative to baseline (median [25th, 75th percentiles]) was: 0 mmHg; 1.08 (1.02, 1.13), -10 mmHg; 1.11 (1.07, 1.17), -20 mmHg; 1.18 (1.11, 1.32), -40 mmHg; 1.39 (1.27, 1.91) and -60 mmHg; 1.48 (1.37, 1.78). Maximal laser Doppler flux (LDF) relative to baseline was: 0 mmHg; 1.06 (1.02, 1.12), -10 mmHg; 1.08 (1.05, 1.16) -20 mmHg; 1.12 (1.06, 1.27), -40 mmHg; 1.24 (1.14, 1.50) and -60 mmHg; 1.35 (1.10, 1.70). There were significantly higher maximal arterial blood flow and maximal LDF at -40 mmHg compared with -10 mmHg (P = 0.001 and P = 0.025, respectively). There were no significant differences in maximal arterial blood flow and maximal LDF between 0 and -10 mmHg (both P = 1.0), or between -40 and -60 mmHg (both P = 1.0). INP of -40 mmHg was the lowest negative pressure level that increased blood flow.

Diabetic Foot Infection Presenting Systemic Inflammatory Response Syndrome: A Unique Disorder of Systemic Reaction from Infection of the Most Distal Body

Diabetic foot infection (DFI) is a major complication of diabetic foot that lead to nontraumatic lower-extremity amputation (LEA). Such distal infection of the body having systemic inflammatory response syndrome (SIRS) is rarely reported. Consecutive patients treated for limb-threatening DFI in a major diabetic foot center in Taiwan were analyzed between the years 2014 to 2017. Clinical factors, laboratory data, perfusion, extent, depth, infection and sensation (PEDIS) wound score in 519 subjects with grade 3 DFI and 203 presenting SIRS (28.1%) were compared. Major LEA and in-hospital mortality were defined as poor prognosis. Patients presenting SIRS had poor prognosis compared with those with grade 3 DFI (14.3% versus 6.6% for major LEA and 6.4% versus 3.5% for in-hospital mortality). Age, wound size, and HbA1c were independent risk factors favoring SIRS presentation. Perfusion grade 3 (odds ratio 3.37, p = 0.044) and history of major adverse cardiac events (OR 2.41, p = 0.036) were the independent factors for poor prognosis in treating patients with DFI presenting SIRS. SIRS when presented in patients with DFI is not only limb- but life-threatening as well. Clinicians should be aware of the clinical factors that are prone to develop and those affecting the prognosis in treating patients with limb-threatening foot infections.

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.

Altered Metabolomic Profile in Patients with Peripheral Artery Disease

Peripheral artery disease (PAD) is a common atherosclerotic disease characterized by narrowed or blocked arteries in the lower extremities. Circulating serum biomarkers can provide significant insight regarding the disease progression. Here, we explore the metabolomics signatures associated with different stages of PAD and investigate potential mechanisms of the disease. We compared the serum metabolites of a cohort of 26 PAD patients presenting with claudication and 26 PAD patients presenting with critical limb ischemia (CLI) to those of 26 non-PAD controls. A difference between the metabolite profiles of PAD patients from non-PAD controls was observed for several amino acids, acylcarnitines, ceramides, and cholesteryl esters. Furthermore, our data demonstrate that patients with CLI possess an altered metabolomic signature different from that of both claudicants and non-PAD controls. These findings provide new insight into the pathophysiology of PAD and may help develop future diagnostic procedures and therapies for PAD patients.

Paclitaxel-Based Devices for the Treatment of PAD: Balancing Clinical Efficacy with Possible Risk

PURPOSE OF REVIEW

Paclitaxel-based endovascular devices have become the standard of care in symptomatic, medication-refractory peripheral artery disease (PAD) and in critical limb ischemia (CLI). This review examines the data on the efficacy and safety of these devices relative to standard balloon angioplasty (PTA) and bare metal stents (BMS).

RECENT FINDINGS

Randomized controlled trials (RCTs) have found that peripheral devices coated with paclitaxel result in superior patency rates and decreased target lesion revascularization (TLR) compared with non-drug-coated devices. Recently, a meta-analysis of randomized controlled trials unexpectedly reported an increase in mortality in patients treated with paclitaxel-coated devices (PCDs), resulting in the pausing of ongoing trials and a warning of safety from the FDA. Observational data that has been published since this time has not supported this safety concern. PAD is a common disease that severely impacts quality and length of life. PCDs are a promising therapy for patients with PAD, offering a more effective and durable intervention when compared with traditional PTA/BMS. A meta-analysis of RCTs identified a signal of harm with these devices which has now been replicated by the FDA. However, there is significant missing data from the trials analyzed by the meta-analysis and FDA, no plausible mechanism linking paclitaxel to death, and no correlation between paclitaxel dose and mortality. Analyses in observational data have found no safety signal. An FDA panel evaluating the validity of this late-mortality signal recently adjourned, emphasizing that the available data is incomplete. PCDs will remain on the market, and an active discussion is underway for developing an approach for improved post-market surveillance, device-labeling, and cause of death adjudication.

The Ever-Humbling Challenge of Peripheral Artery Disease Treatment Seen Across the Sexes

See Article Ramkumar et al