Asymptomatic peripheral arterial disease is associated with more adverse lower extremity characteristics than intermittent claudication

Neuromuscular Junction Damage in the Calf Muscles of Patients With Advanced Peripheral Artery Disease

AIMS

Peripheral artery disease (PAD) reduces blood flow to the legs and causes severe muscle and leg dysfunction for PAD patients. Skeletal muscle contractile function is dependent on the health of the muscle itself and that of the neuromuscular junction (NMJ) on the muscle membrane.

METHODS

To determine whether the NMJ, including the motor nerve terminals and nicotinic acetylcholine receptors (nAChR), is damaged in PAD, gastrocnemius muscles were collected from 3 controls and 13 PAD patients to capture images from 331 control NMJs and 512 PAD NMJs.

RESULTS

For the motor nerve terminals, there were more denervated nAChR clusters and fewer nerve terminal occupancies in NMJs in PAD patients, compared with controls. For the nAChR clusters in the NMJs, the area per nAChR cluster was 369.3 ± 6.7 versus 225.2 ± 5.3 μm2, the area per fragment was 195.9 ± 9.2 versus 107.1 ± 3.1 μm2, the number of fragments per nAChR cluster was 2.3 ± 0.1 versus 3.2 ± 0.1, the nAChR cluster area per endplate area was 75.7 ± 1.6 versus 55.7 ± 1.1%, total distance of fragments per nAChR cluster was 4.6 ± 0.4 versus 8.8 ± 0.8 μm, and the fragmented nAChR clusters were 7.6% versus 21.6% of total nAChR clusters in controls versus PAD patients, respectively (p < 0.05 in all parameters).

CONCLUSIONS

Our data demonstrate deterioration of the motor nerve terminals and nAChR clusters, which may compromise neuromuscular transmission, and contribute to the severe leg dysfunction observed in patients with PAD.

Single-centre, double-blinded, randomised placebo-controlled trial to determine the effect of a 12-week home-based programme of footplate neuromuscular electrical stimulation on walking capacity in people with peripheral artery disease: a protocol for the Foot-PAD trial

INTRODUCTION

Patients with peripheral artery disease (PAD) can experience intermittent claudication, which limits walking capacity and the ability to undertake daily activities. While exercise therapy is an established way to improve walking capacity in people with PAD, it is not feasible in all patients. Neuromuscular electrical stimulation (NMES) provides a way to passively induce repeated muscle contractions and has been widely used as a therapy for chronic conditions that limit functional capacity. Preliminary trials in patients with PAD demonstrate that stimulation of the leg muscles using a footplate-NMES device can be performed without pain and may lead to significant gains in walking capacity. Studies, to date, have been small and have not been adequately controlled to account for any potential placebo effect. Therefore, the current trial will compare the effect of a 12-week programme of footplate-NMES with a placebo-control on walking capacity (6 min walking distance) and other secondary outcomes in patients with PAD.

METHODS AND ANALYSIS

The Foot-PAD trial is a double-blinded, randomised placebo-controlled trial to determine the effect of a 12-week home-based programme of footplate NMES on walking capacity in people with PAD. This is a single-centre trial with numerous recruitment locations. A total of 180 participants with stable PAD and intermittent claudication will be randomly assigned (1:1 ratio) to receive either footplate-NMES (intervention condition) or footplate-placebo (control condition) for two 30 min periods each day for 12 weeks. The footplate-NMES device will deliver stimulation sufficient to induce contraction of the leg muscles and repeated plantar and dorsiflexion at the ankles. The footplate-placebo device will deliver a momentary low-intensity transient stimulation that is insufficient to induce contraction of the leg muscles. Outcomes will be assessed at baseline (week 0), mid-intervention (week 6), postintervention (week 12) and 6 weeks after the completion of the intervention (week 18). The primary outcome is walking capacity at week 12, measured as maximum walking distance during the 6 min walk test. Secondary outcomes will include pain-free walking distance during the 6 min walk test; pain-free and maximum walking time during a graded treadmill walking test; disease-specific quality of life (Intermittent Claudication Questionnaire), self-reported walking impairment (Walking Impairment Questionnaire) and accelerometer-derived physical activity levels. Exploratory outcomes will include the Ankle-Brachial Index; leg vascular function; perception of device-use experience and symptom monitoring throughout the trial using the Claudication Symptom Instrument and a pain Visual Analogue Scale.

ETHICS AND DISSEMINATION

The Foot-PAD trial has received ethics approval from the Human Research Ethics Committees of Queensland Health Metro North Hospital and Health Service (78962) and the University of the Sunshine Coast (A21659). Regardless of the study outcomes, the study findings will be published in peer-reviewed scientific journals and presented at scientific meetings.

TRIAL REGISTRATION NUMBER

ACTRN12621001383853.

Racial and Socioeconomic Health Disparities in Peripheral Artery Disease

Peripheral artery disease (PAD) is a progressive atherosclerotic disease that causes lower extremity arterial stenosis or occlusion. Patients with PAD are at increased risk of myocardial infarction, stroke, limitations in ambulation, and amputation. Despite the advances in medicine and technology, the outcomes from PAD, including critical limb-threatening ischemia, acute limb ischemia amputation, and mortality, remain increased among specific racial and ethnic groups that have been historically marginalized in America, including Black, Hispanic, and American Indian individuals in the United States when compared with White persons. The purpose of this review is to summarize PAD literature that incorporates racial and ethnic disparities in PAD. There are a rising number of studies focused on the interface of racial and ethnic disparities and PAD. The majority of these studies are specifically focused on Black race, whereas there are limited studies focused on other minoritized racial and ethnic groups in the United States. The application of race and ethnicity has also been shown to play a synergistic role with socioeconomic status on PAD outcomes. Effective strategies focused on implementing policies that support quality measures and focus on social determinants of health have been shown to promote health equity and reduce disparities. Current evidence suggests that biological differences are less likely to be the leading cause of disparities in PAD between racial and ethnic groups compared with White Americans and supports a renewed focus on social determinants of health to achieve health equity.

Peripheral arterial disease in women

Peripheral arterial disease (PAD) represents one of the most frequent manifestations of atherosclerosis in men and women. In both sexes, PAD is related to classical risk factors of atherosclerosis, which are similarly distributed, but some additional factors determine differences between men and women. More frequent asymptomatic disease in women than in men and less frequent screening in women may result in a false underestimation of the prevalence of PAD in women. All these factors may cause delayed diagnosis and treatment of PAD in women. Estrogen hormones have vasoprotective properties that lower the prevalence of atherosclerosis in women of younger age. However, estrogen probably does not have a protective role against the development of cardiovascular disease in women of an older age. Hormone replacement therapy (HRT) of less than one year does not appear to reduce the odds of developing PAD in postmenopausal women. It may even increase the risk of morbidity from vascular interventions. However, some studies indicated that HRT for more than one year significantly decreases the risk of PAD if administered early after the last menstruation. Also, treatment of PAD in women differs to some extent from men.

The link between impaired oxygen supply and cognitive decline in peripheral artery disease

Although peripheral artery disease (PAD) primarily affects large arteries outside the brain, PAD is also associated with elevated cerebral vulnerabilities, including greater risks for brain injury (such as stroke), cognitive decline and dementia. In the present review, we aim to evaluate recent literature and extract information on potential mechanisms linking PAD and consequences on the brain. Furthermore, we suggest novel therapeutic avenues to mitigate cognitive decline and reduce risk of brain injury in patients with PAD. Various interventions, notably exercise, directly or indirectly improve systemic blood flow and oxygen supply and are effective strategies in patients with PAD or cognitive decline. Moreover, triggering protective cellular and systemic mechanisms by modulating inspired oxygen concentrations are emerging as potential novel treatment strategies. While several genetic and pharmacological approaches to modulate adaptations to hypoxia showed promising results in preclinical models of PAD, no clear benefits have yet been clinically demonstrated. We argue that genetic/pharmacological regulation of the involved adaptive systems remains challenging but that therapeutic variation of inspired oxygen levels (e.g., hypoxia conditioning) are promising future interventions to mitigate associated cognitive decline in patients with PAD.

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia).

METHODS

A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate.

STRUCTURE

Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia).

METHODS

A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate.

STRUCTURE

Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

Evaluation of the relationship between adjusted ischemia-modified albumin and the presence and severity of peripheral artery disease

OBJECTIVES

Albumin undergoes structural changes under ischemia and oxidative stress, turning into ischemia-modified albumin (IMA). It has been proposed as an early biomarker for various diseases associated with ischemia. We aimed to investigate the relationship between serum IMA and peripheral artery disease (PAD) and whether it is a risk marker for the severity of PAD.

METHODS

This prospective case-control study included 100 patients with lower extremity PAD and 50 volunteers without. Patients with resting pain, ulcer, and gangrene were excluded from the study. Patients with PAD included in the study were divided into two groups as mild claudication and moderate-severe claudication. Adjusted-IMA levels were calculated according to the median albumin values of the groups. The basic clinical features and laboratory findings of the participants were recorded and compared. Possible risk factors for presence and severity of PAD and IMA levels were examined by logistic regression and receiver-operating characteristic (ROC) curve analyses.

RESULTS

IMA and adjusted-IMA levels were significantly higher in the PAD group (p < 0.001, p < 0.001, respectively). IMA and adjusted-IMA levels were significantly higher in PAD group 2, which had moderate-to-severe claudication and more pronounced ischemic symptoms (p < 0.001, p < 0.001, respectively). Advanced age, presence of hypertension, smoking, low albumin levels, and high adjusted-IMA levels were independent predictors of PAD. There was a negative high correlation between adjusted-IMA levels and ABI (r: -0.666, p < 0.001, Spearman's correlation). ROC curve analysis demonstrated that adjusted-IMA cut-off values of 0.802 or above could predict presence and severity of peripheral artery disease with 70% sensitivity and 78% specificity (AUC: 0.825, 95% CI: 0.758-0.893, log rank p: 0.000).

CONCLUSION

We determinated that increased adjusted-IMA levels were a predictors of the presence and severity of PAD. In addition, adjusted-IMA values can be a valuable marker in the follow-up of clinical severity of PAD.

Discordance of patient-reported outcome measures with objectively assessed walking decline in peripheral artery disease

OBJECTIVE

Among people with peripheral artery disease (PAD), perceived change in walking difficulty over time, compared with people without PAD, is unclear. Among people reporting no change in walking difficulty over time, differences in objectively measured change in walking performance between people with and without PAD are unknown.

METHODS

A total of 1289 participants were included. Eight hundred seventy-four participants with PAD (aged 71.1 ± 9.1 years) were identified from noninvasive vascular laboratories and 415 without PAD (aged 69.9 ± 7.6 years) were identified from people with normal vascular laboratory testing or general medical practices in Chicago. The Walking Impairment Questionnaire and 6-minute walk were completed at baseline and 1-year follow-up. The Walking Impairment Questionnaire assessed perceived difficulty walking due to symptoms in the calves or buttocks on a Likert scale (range, 0-4). Symptom change was determined by comparing difficulty reported at 1-year follow-up to difficulty reported at baseline.

RESULTS

At 1-year follow-up, 31.9% of participants with and 20.6% of participants without PAD reported walking difficulty that was improved (P < .01), whereas 41.2% vs 55%, respectively, reported walking difficulty that was unchanged (P < .01). Among all reporting no change in walking difficulty, participants with PAD declined in 6-minute walk, whereas participants without PAD improved (-10 vs +15 meters; mean difference, -25; 95% confidence interval, -38 to -13; P < .01).

CONCLUSIONS

Most people with PAD reported improvement or no change in walking difficulty from calf or buttock symptoms at one-year follow-up. Among all participants who perceived stable walking ability, those with PAD had significant greater declines in objectively measured walking performance, compared with people without PAD.

Design and use of an ex vivo peripheral simulating bioreactor system for pharmacokinetic analysis of a drug coated stent

Currently, there are no ex vivo systems that can model the motion of peripheral arteries and allow for the evaluation of pharmacokinetics (PK) of endovascular devices. The objective of this study was to develop a novel peripheral simulating bioreactor system to evaluate drug pharmacokinetics of stents. We utilized 3D-printed and off-the-shelf components to construct a peripheral-simulating bioreactor system capable of mimicking the motion of peripheral arteries. Servo motors were primarily used to shorten/elongate, twist, and bend explanted porcine carotid arteries. To evaluate the pharmacokinetics in the bioreactor, drug-eluting stents were deployed within explanted arteries and subjected to vascular motion along with pulsatile flow conditions. Following 30 min and 24 h, the arteries were removed, and paclitaxel levels were measured. Scanning electron microscopy was also performed to evaluate the stent surface. Arterial paclitaxel levels of the stent-treated arteries were found to be higher at 30 min than at 24 h following pulsatile and no vascular motion and even higher at 24 h following pulsatile flow and vascular motion. The residual drug on the stent significantly decreased from 30 min to 24 h. Scanning electron microscopy confirmed the loss of paclitaxel coating at 24 h and greater disturbance in stents under peripheral motion versus pulsatile only. This system represents the first ex vivo system to determine the PK of drug-eluting stents under physiological flow and vascular motion conditions. This work provides a novel system for a quick and inexpensive preclinical tool to study acute drug tissue concentration kinetics of drug-releasing interventional vascular devices designed for peripheral applications.

Comparison of Postoperative Complications in Patients Undergoing Limb Salvage Reconstructive Surgery Based on Estimated Prevalence of Preexisting Peripheral Arterial Disease

BACKGROUND

Limb salvage after lower extremity (LE) trauma requires optimal blood flow for successful microsurgical reconstruction. Peripheral arterial disease (PAD) decreases LE perfusion, affecting wound healing. Patients who present with LE trauma may have undiagnosed PAD, particularly those with atherosclerotic risk factors. This study assesses outcomes after LE salvage in patients at risk for PAD.

METHODS

This retrospective review evaluated patients who underwent LE reconstruction at a level 1 trauma center between 2007 and 2022. Patients with a nontraumatic mechanism of injury, missing postoperative records, and unspecified race were excluded. Demographics, flap characteristics, and postoperative complications were abstracted. The prevalence of LE PAD was calculated using a validated risk assessment tool.

RESULTS

At our institution, 285 LE flaps performed on 254 patients were included in the study. Patients were categorized by prevalence of PAD, including 12 (4.7%) with high risk, 45 (17.7%) with intermediate risk, and 197 (77.6%) patients with low risk. The high-risk cohort had higher rates of partial flap necrosis ( P = 0.037), flap loss ( P = 0.006), and amputation ( P < 0.001) compared with the low-risk group. Fewer high-risk patients achieved full ambulation compared with the low-risk ( P = 0.005) cohort. Overall flap survival and limb salvage rates were 94.5% and 96.5%, respectively. Among the intermediate- and high-risk cohorts, only 50.9% of patients received a preoperative vascular assessment, and 3.8% received a vascular surgery consultation.

CONCLUSIONS

Peripheral arterial disease represents a reconstructive challenge to microvascular surgeons. Patients with high-risk for PAD had higher rates of partial flap necrosis, flap loss, and amputation. In the setting of trauma, emphasis should be placed on preoperative vascular assessment for patients at risk of having undiagnosed PAD. Prospective studies collecting ankle-brachial index assessments and/or angiography will help validate this study's findings.

Disparities in Diagnosis, Treatment, and Outcomes of Peripheral Artery Disease: JACC Scientific Statement

Disparities by sex, race, socioeconomic status, and geography exist in diagnosis, treatment, and outcomes for people with lower extremity peripheral artery disease (PAD). PAD prevalence is similar in men and women, but women have more atypical symptoms and undergo lower extremity revascularization at older ages compared to men. People who are Black have an approximately 2-fold higher prevalence of PAD, compared to people who are White and have more atypical symptoms, greater mobility loss, less optimal medical care, and higher amputation rates. Although fewer data are available for other races, people with PAD who are Hispanic have higher amputation rates than White people. Rates of amputation also vary by geography in the United States, with the highest rates of amputation in the southeastern United States. To improve PAD outcomes, intentional actions to eliminate disparities are necessary, including clinician education, patient education with culturally appropriate messaging, improved access to high-quality health care, science focused on disparity elimination, and health policy changes.

Lipoprotein(a) and Risks of Peripheral Artery Disease, Abdominal Aortic Aneurysm, and Major Adverse Limb Events

BACKGROUND

Lp(a) (lipoprotein[a])-lowering therapy to reduce cardiovascular disease is under investigation in phase 3 clinical trials. High Lp(a) may be implicated in peripheral artery disease (PAD), abdominal aortic aneurysms (AAAs), and major adverse limb events (MALE).

OBJECTIVES

The authors investigated the association of high Lp(a) levels and corresponding LPA genotypes with risk of PAD, AAA, and MALE.

METHODS

The authors included 108,146 individuals from the Copenhagen General Population Study. During follow-up, 2,450 developed PAD, and 1,251 AAAs. Risk of MALE was assessed in individuals with PAD at baseline and replicated in the Copenhagen City Heart Study.

RESULTS

Higher Lp(a) was associated with a stepwise increase in risk of PAD and AAA (P for trend <0.001). For individuals with Lp(a) levels ≥99th (≥143 mg/dL, ≥307 nmol/L) vs <50th percentile (≤9 mg/dL, ≤17 nmol/L), multivariable-adjusted HRs were 2.99 (95% CI: 2.09-4.30) for PAD and 2.22 (95% CI: 1.21-4.07) for AAA. For individuals with PAD, the corresponding incidence rate ratio for MALE was 3.04 (95% CI: 1.55-5.98). Per 50 mg/dL (105 nmol/L) genetically higher Lp(a) risk ratios were 1.39 (95% CI: 1.24-1.56) for PAD and 1.21 (95% CI: 1.01-1.44) for AAA, consistent with observational risk ratios of 1.33 (95% CI: 1.24-1.43) and 1.27 (95% CI: 1.15-1.41), respectively. In women smokers aged 70 to 79 years with Lp(a) <50th and ≥99th percentile, absolute 10-year risks of PAD were 8% and 21%, and equivalent risks in men 11% and 29%, respectively. For AAA, corresponding risks were 2% and 4% in women, and 5% and 12% in men.

CONCLUSIONS

High Lp(a) levels increased risk of PAD, AAA, and MALE by 2- to 3-fold in the general population, opening opportunities for prevention given future Lp(a)-lowering therapies.

Outcomes of lower extremity revascularization in octogenarians and nonagenarians for intermittent claudication

OBJECTIVE

Revascularization for intermittent claudication (IC) due to infrainguinal peripheral arterial disease (PAD) is dependent on durability and expected benefit. We aimed to assess outcomes for IC interventions in octogenarians and nonagenarians (age ≥80 years) and those younger than 80 years (age <80 years).

METHODS

The Vascular Quality Initiative was queried (2010-2020) for peripheral vascular interventions (PVIs) and infrainguinal bypasses (IIBs) performed to treat IC. Baseline characteristics, procedural details, and outcomes were analyzed (comparing age ≥80 years and age <80 years).

RESULTS

There were 84,210 PVIs (12.1% age ≥80 years and 87.9% age <80 years) and 10,980 IIBs (7.4% age ≥80 years and 92.6% age <80 years) for IC. For PVI, patients aged ≥80 years more often underwent femoropopliteal (70.7% vs 58.1%) and infrapopliteal (19% vs 9.3%) interventions, and less often iliac interventions (32.1% vs 48%) (P < .001 for all). Patients aged ≥80 years had more perioperative hematomas (3.5% vs 2.4%) and 30-day mortality (0.9% vs 0.4%) (P < .001). At 1-year post-intervention, the age ≥80 years cohort had fewer independently ambulatory patients (80% vs 91.5%; P < .001). Kaplan-Meier analysis showed patients aged ≥80 years had lower reintervention/amputation-free survival (81.4% vs 86.8%), amputation-free survival (87.1% vs 94.1%), and survival (92.3% vs 96.8%) (P < .001) at 1-year after PVI. Risk adjusted analysis showed that age ≥80 years was associated with higher reintervention/amputation/death (hazard ratio [HR], 1.22; 95% confidence interval [CI], 1.1-1.35), amputation/death (HR, 1.85; 95% CI, 1.61-2.13), and mortality (HR, 1.92; 95% CI, 1.66-2.23) (P < .001 for all) for PVI. For IIB, patients aged ≥80 years more often had an infrapopliteal target (28.4% vs 19.4%) and had higher 30-day mortality (1.3% vs 0.5%), renal failure (4.1% vs 2.2%), and cardiac complications (5.4% vs 3.1%) (P < .001). At 1 year, the age ≥80 years group had fewer independently ambulatory patients (81.7% vs 88.8%; P = .02). Kaplan-Meier analysis showed that the age ≥80 years cohort had lower reintervention/amputation-free survival (75.7% vs 81.5%), amputation-free survival (86.9% vs 93.9%), and survival (90.4% vs 96.5%) (P < .001 for all). Risk-adjusted analysis showed age ≥80 years was associated with higher amputation/death (HR, 1.68; 95% CI, 1.1-2.54; P = .015) and mortality (HR, 1.85; 95% CI, 1.16-2.93; P = .009), but not reintervention/amputation/death (HR, 1.1; 95% CI, 0.85-1.44; P = .47) after IIB.

CONCLUSIONS

Octogenarians and nonagenarians have greater perioperative morbidity and long-term ambulatory impairment, limb loss, and mortality after PVI and IIB for claudication. Risks of intervention on elderly patients with claudication should be carefully weighed against the perceived benefits of revascularization. Medical and exercise therapy efforts should be maximized in this population.

Assessing Automatic Plethysmographic Ankle-Brachial Index Devices in Peripheral Artery Disease Detection: A Comparative Study with Doppler Ankle-Brachial Index Measurements

BACKGROUND The ankle-brachial index (ABI) is a critical diagnostic test for peripheral artery disease (PAD), albeit requiring technical expertise and dedicated resources. The advent of automatic ABI devices proposes a more accessible approach, necessitating fewer resources and less expertise. This study was conducted to gather data on PAD prevalence and to evaluate the correlation and efficacy of automatic ABI measurements vs traditional Doppler ABI measurements to understand their potential role in primary care settings. MATERIAL AND METHODS ABI measurements were obtained using both the Doppler method and an automatic plethysmographic device (Dopplex ABility, Huntleigh Healthcare). RESULTS Of the 290 participants (mean age 67.6±7.4 years), Doppler ABI method identified 16.8% with abnormal results (<0.9), while the automatic method identified only 5.9%. The mean Doppler ABI was 1.05±0.15, and the mean automatic ABI was 1.12±0.13. The sensitivity of the automatic ABI measurements was 22.2%, and the specificity was 96.8%, with a positive predictive value of 57.1%, and a negative predictive value of 86.9%. Adjustments in the automatic assessment and inclusion of pulse wave velocity enhanced the diagnostic capabilities of the automatic ABI device. CONCLUSIONS While the automatic plethysmographic ABI device may lack the necessary diagnostic capabilities to replace the traditional Doppler ABI device as a standalone test in PAD diagnosis, it could still offer significant value in primary care settings if integrated with adjusted cut-off points and pulse wave velocity analysis.

Relationship Between Physical Performance and Peripheral Arterial Diseases in Different Age Groups of Chinese Community-Dwelling Older Adults

Aims: This study aimed to examine the relationship between physical performance and peripheral artery disease (PAD) in different age groups of Chinese older adults.

Methods: We enrolled 1357 relatively healthy ≥ 65 years old participants of Chinese ethnicity. We classified the participants into two age categories, the pre-old group (65–74 years,n =968) and the old group (≥ 75 years,n =389). We assessed the cross-sectional association of the ankle–brachial index (ABI), which is used for the classification of patients with PAD (ABI ≤ 0.9). Physical performance mainly focused on muscle strength, mobility, and balance, which were measured via hand grip, 4 m walking speed, and the Timed Up and Go Test.

Results: A total of 125 (9.2%) patients met the diagnostic criteria and were defined as having PAD. After multivariate adjustment, we found that grip strength and 4 m walking speed were correlated negatively with PAD (odds ratio (OR)=0.953, 95% confidence interval (CI)=0.919–0.989; OR=0.296, 95% CI=0.093–0.945) in pre-old participants, whereas balance (OR=1.058, 95% CI=1.007–1.112) was correlated positively with PAD only in older participants.

Conclusion: Our study further confirmed the association between physical performance and PAD in community-dwelling older Chinese adults. Muscle strength and mobility correlated negatively with PAD, and balance was positively associated with PAD in older participants. These findings might help with better early screening and management of PAD.

The association between peripheral arterial disease and risk for hip fractures in elderly men is not explained by low hip bone mineral density. Results from the MrOS Sweden study

In this prospective study in Swedish elderly men, PAD based on an ABI < 0.9 was associated with an increased risk of hip fracture, independent of age and hip BMD. However, after further adjustments for comorbidity, medications, physical function, and socioeconomic factors, the association diminished and was no longer statistically significant.

INTRODUCTION

To examine if peripheral arterial disease (PAD) is associated with an increased risk for hip fracture in men independent of hip BMD.

METHODS

Ankle-brachial index (ABI) was assessed in the Swedish MrOS (Osteoporotic Fractures in Men) study, a prospective observational study including 3014 men aged 69-81 years at baseline. PAD was defined as ABI < 0.90. Incident fractures were assessed in computerized X-ray archives. The risk for hip fractures was calculated using Cox proportional hazard models. At baseline, BMD was assessed using DXA (Lunar Prodigy and Hologic QDR 4500) and functional measurements and blood samples were collected. Standardized questionnaires were used to collect information about medical history, falls, and medication.

RESULTS

During 10 years of follow-up, 186 men had an incident hip fracture. The hazard ratio (HR) for hip fracture in men with PAD was 1.70 (95% CI 1.14-2.54), adjusted for age and study site. Additional adjustment for total hip BMD marginally affected this association (HR 1.64; 95% CI 1.10-2.45). In a final multivariate model, the HR attenuated to a non-significant HR 1.38 (95% CI 0.91-2.11) adjusted for age, site, hip BMD, BMI, falls, smoking, eGFR, handgrip strength, walking speed, former hip fracture, antihypertensive treatment, diabetes, education, and history of cardiovascular disease.

CONCLUSION

This study suggests that PAD is associated with an increased risk for hip fracture independently of hip BMD in elderly Swedish men. However, the high frequency of comorbidity and lower physical performance among men with PAD might partly explain this association.

Therapeutic angiogenesis-based strategy for peripheral artery disease

Peripheral artery disease (PAD) poses a great challenge to society, with a growing prevalence in the upcoming years. Patients in the severe stages of PAD are prone to amputation and death, leading to poor quality of life and a great socioeconomic burden. Furthermore, PAD is one of the major complications of diabetic patients, who have higher risk to develop critical limb ischemia, the most severe manifestation of PAD, and thus have a poor prognosis. Hence, there is an urgent need to develop an effective therapeutic strategy to treat this disease. Therapeutic angiogenesis has raised concerns for more than two decades as a potential strategy for treating PAD, especially in patients without option for surgery-based therapies. Since the discovery of gene-based therapy for therapeutic angiogenesis, several approaches have been developed, including cell-, protein-, and small molecule drug-based therapeutic strategies, some of which have progressed into the clinical trial phase. Despite its promising potential, efforts are still needed to improve the efficacy of this strategy, reduce its cost, and promote its worldwide application. In this review, we highlight the current progress of therapeutic angiogenesis and the issues that need to be overcome prior to its clinical application.

Presence of asymptomatic Peripheral Arterial Disease in combination with common risk factors elevates the cardiovascular risk Substantially

Background and aims

This study evaluates the risks for adverse cardiovascular (CV) events in Asymptomatic Peripheral Arterial Disease (APAD) combined with different traditional CV risk factors.

Methods

A population-based observational study of 8000 subjects, identified 559 subjects as having APAD through ankle-brachial index (ABI) measurements and questionnaires regarding limb symptoms. This cohort and subgroups classified by presence of different traditional CV risk factors at baseline were assessed for 10 years on CV outcome. The recorded endpoints were all-cause mortality, CV mortality and non-fatal CV events.

Results

Before subdividing the APAD subjects, the CV mortality incidence was 28.5 deaths per 1000 person-years as compared to 8.7 deaths for references without APAD. For subjects with hypertension at baseline the CV mortality incidence was 35.4 when combined with APAD and 11.7 without. In women with hypertension but without other risk factors, presence of APAD increased the age-adjusted Hazard Ratio (HR) for fatal and non-fatal CV events by 1.86 [CI 1.54,2.24, p < 0.001].

Conclusions

ABI measurements should be considered an important indication for aggressive multifactorial risk factor reduction in populations with any other prevalent CV risk factor. In hypertension, diabetes mellitus and a smoking history, coexisting APAD contributes significantly to the increased age-adjusted CV risk.

Long-Term Exposures to Air Pollutants and Risk of Peripheral Arterial Occlusive Disease: A Nationwide Cohort Study in Taiwan

Air pollution is one of the most alarming environmental issues which causes multiple health hazards. An association between air pollution and cardiovascular diseases has been established through many prior studies. In this study, we aimed to evaluate the risk of long-term exposure to air pollution (PM2.5, CO, and NO2) and its association with the risk of developing peripheral arterial occlusive disease (PAOD). PAOD is a condition involving impairment of perfusion of blood in the distal parts of the aorta due to narrowing of the arteries (arterial stenosis) and has been reported as a risk factor for developing cardiovascular diseases. Furthermore, the risk of PAOD increases with age, and hence is a serious public health issue and a cause for concern, especially for an aging society such as Taiwan. Two national-scale databases from Taiwan, the national health insurance database (NHIRD) and the Taiwan air quality-monitoring database (TAQMD), were linked to conduct this cohort study between 2003 and 2013. Cox proportional hazards regression with time-dependent modeling was used to evaluate the hazard ratio (HR) for PAOD with respect to daily exposure to air pollutants. The concentrations of each of the pollutants of interest (PM2.5, NO2, and CO) were categorized into four categories according to the daily average concentration of air pollutants for every quarter of the year, Q1 to Q4 (Q4 = highest). The cumulative incidence of PAOD was examined by Kaplan-Meier analysis with two-tailed log-rank test. A total of 1,598 PAOD cases were identified during the 10-year follow-up period, along with 98,540 non-PAOD controls. In the multivariate analysis, after adjusting for age, gender, urbanization level, residential area, baseline comorbidities, and medications, the adjusted HRs were PM2.5 = 1.14 (95% CI 1.13-1.16), NO2 = 1.03 (95% CI 1.02-1.04), and CO = 2.35 (95% CI 1.95-2.84). Kaplan-Meier analysis showed that CO (P < 0.0001) and PM2.5 (P < 0.0001) concentrations were strongly and positively associated with the cumulative incidence of PAOD during the follow-up period. Findings from this study established that prolonged exposure to air pollutants CO and PM2.5 are significant factors that, among other well-known causes, may also play a potential role in PAOD pathogenesis.

Urinary neutrophil gelatinase-associated lipocalin (NGAL) can potentially predict vascular complications and reliably risk stratify patients with peripheral arterial disease

Neutrophil gelatinase-associated lipocalin (NGAL) is expressed in atherosclerotic plaques and implicated in the development of cardiovascular diseases. Peripheral arterial disease (PAD) is an atherosclerotic disease that often results in major cardiovascular events. This study aimed to prospectively examine the potential of urine NGAL (uNGAL) in predicting worsening PAD status and major adverse limb events (MALE). Baseline urine NGAL (uNGAL) and urine creatinine (uCr) concentrations were measured in PAD (n = 121) and non-PAD (n = 77) patients. Levels of uNGAL were normalized for urine creatinine (uNGAL/uCr). Outcomes included worsening PAD status, which was defined as a drop in ankle brachial index (ABI) > 0.15, and major adverse limb events (MALE), which was defined as a need for surgical revascularization or amputations. PAD patients had 2.30-fold higher levels of uNGAL/uCr [median (IQR) 31.8 (17.0–62.5) μg/g] in comparison to non-PAD patients [median (IQR) 73.3 (37.5–154.7) μg/g] (P = 0.011). Multivariate cox analysis showed that uNGAL/uCr levels were independently associated with predicting worsening PAD status and MALE outcomes. Cumulative survival analysis, over follow up period, demonstrated a direct correlation between elevated uNGAL/uCr levels and PAD disease progression and MALE outcomes. These data demonstrate an association between elevated uNGAL/uCr levels and worsening PAD disease status and MALE outcomes, indicating its potential for risk-stratification of PAD patients.

Peripheral artery disease and physical function in women with and without HIV

OBJECTIVES

Peripheral artery disease (PAD) is associated with decreased physical function and increased mortality in the general population. We previously found that PAD is common in middle-aged women with and without HIV infection, but its association with functional decline is unclear. We examine the contribution of PAD to functional decline in the Women's Interagency HIV Study, controlling for traditional cardiovascular risk factors and HIV-related factors.

METHODS

Analysis included 1839 participants (72% with HIV) with measured ankle-brachial index (ABI) and 4 m gait speed. ABI values categorized PAD severity. Linear models with repeated measures estimated the association of PAD severity with log-transformed gait speed after controlling for demographic, behavioral, and metabolic risk factors, and HIV/hepatitis C virus status.

RESULTS

Median age was 50 years and more than 70% were Black. Compared with normal ABI, there was a dose-response relationship between increasing PAD severity and slower gait speed in univariable analyses: 6% slower gait speed for low-normal ABI [95% confidence interval (CI): 4-9%], 10% for borderline PAD (95% CI: 6-13%), 14% for mild PAD (95% CI: 9-18%), and 16% for moderate-severe PAD (95% CI: 5-25%). PAD severity remained associated with slower gait speed in multivariable analyses. HIV/hepatitis C virus co-infection was independently associated with 9% (95% CI: 4-14%) slower gait speed compared with those with neither infection. Among women with HIV, neither CD4+ cell count nor HIV-RNA level was associated with gait speed.

CONCLUSION

In middle-aged women with and without HIV infection, greater PAD severity is associated with progressively slower gait speed. Early detection of subclinical PAD may decrease the risk of lower extremity functional impairment and its long-term health consequences.

Automated Measurements of Ankle-Brachial Index: A Narrative Review

Peripheral artery disease (PAD) is an atherosclerotic disease that causes obstruction in lower limb arteries. It increases cardiovascular risk even in asymptomatic patients. Accurate diagnostic tools for identification of affected individuals are needed. Recently, there have been attempts to establish a reliable method of automated ankle-brachial index (ABI) identification. A search of PubMed database to identify studies assessing automatic ABI measurements in agreement with standard PAD diagnosis methods was conducted in December 2020. A total of 57 studies were analyzed in the review. The majority of analyzed studies found ABI measured by automatic oscillometric devices to be potentially feasible for use. Some note that, even though the Doppler and oscillometric methods are not fully interchangeable, the oscillometric devices could be used in screening. Significantly fewer publications are available on automatic plethysmographic devices. For photoplethysmography, most studies reported either good or moderate agreement with reference standards. For air plethysmography, poorer agreement with Doppler ABI is suggested. It is noted that pulse volume recording (PVR) function may improve the diagnostic accuracy of the devices.

Long-Term (7-Year) Clinical Implications of Newly Unveiled Asymptomatic Abnormal Ankle-Brachial Index in Patients With Coronary Artery Disease

Background The long-term impact of newly discovered, asymptomatic abnormal ankle-brachial index (ABI) in patients with significant coronary artery disease is limited. Methods and Results Between January 2006 and December 2009, ABI was evaluated in 2424 consecutive patients with no history of claudication or peripheral artery disease who had significant coronary artery disease. We previously reported a 3-year result; therefore, the follow-up period was extended. The primary end point was a composite of all-cause death, myocardial infarction (MI), and stroke over 7 years. Of the 2424 patients with significant coronary artery disease, 385 had an abnormal ABI (ABI ≤0.9 or ≥1.4). During the follow-up period, the rate of the primary outcome was significantly higher in the abnormal ABI group than in the normal ABI group (P<0.001). The abnormal ABI group had a significantly higher risk of composite of all-cause death/MI/stroke than the normal ABI group, after adjustment with multivariable Cox proportional hazards regression analysis (hazard ratio [HR], 2.07; 95% CI, 1.67-2.57; P<0.001) and propensity score-matched analysis (HR, 1.97; 95% CI, 1.49-2.60; P<0.001). In addition, an abnormal ABI was associated with a higher risk of all-cause death, MI, and stroke, but not repeat revascularization. Conclusions Among patients with significant coronary artery disease, asymptomatic abnormal ABI was associated with sustained and increased incidence of composite of all-cause death/MI/stroke, all-cause death, MI, and stroke during extended follow-up over 7 years.

Lower Extremity Peripheral Artery Disease: Contemporary Epidemiology, Management Gaps, and Future Directions: A Scientific Statement From the American Heart Association

Lower extremity peripheral artery disease (PAD) affects >230 million adults worldwide and is associated with increased risk of various adverse clinical outcomes (other cardiovascular diseases such as coronary heart disease and stroke and leg outcomes such as amputation). Despite its prevalence and clinical importance, PAD has been historically underappreciated by health care professionals and patients. This underappreciation seems multifactorial (eg, limited availability of the first-line diagnostic test, the ankle-brachial index, in clinics; incorrect perceptions that a leg vascular disease is not fatal and that the diagnosis of PAD would not necessarily change clinical practice). In the past several years, a body of evidence has indicated that these perceptions are incorrect. Several studies have consistently demonstrated that many patients with PAD are not receiving evidence-based therapies. Thus, this scientific statement provides an update for health care professionals regarding contemporary epidemiology (eg, prevalence, temporal trends, risk factors, and complications) of PAD, the present status of diagnosis (physiological tests and imaging modalities), and the major gaps in the management of PAD (eg, medications, exercise therapy, and revascularization). The statement also lists key gaps in research, clinical practice, and implementation related to PAD. Orchestrated efforts among different parties (eg, health care providers, researchers, expert organizations, and health care organizations) will be needed to increase the awareness and understanding of PAD and improve the diagnostic approaches, management, and prognosis of PAD.

Intelligent Oscillometric System for Automatic Detection of Peripheral Arterial Disease

Peripheral arterial disease (PAD) is a progressing arterial disorder that is associated with significant morbidity and mortality. The conventional PAD detection methods are invasive, cumbersome, or require expensive equipment and highly trained technicians. Here, we propose a new automated, noninvasive, and easy-to-use method for the detection of PAD based on characterizing the arterial system by applying an external varying pressure using a cuff. The superposition of the internal arterial pressure and the externally applied pressure were measured and mathematically modeled as a function of cuff pressure. A feature-based learning algorithm was then designed to identify PAD patterns by analyzing the parameters of the derived mathematical models. Genetic algorithm and principal component analysis were employed to select the best predictive features distinguishing PAD patterns from normal. A RUSBoost ensemble model using neural network as the base learner was designed to diagnose PAD from genetic algorithm selected features. The proposed method was validated on data collected from 14 PAD patients and 19 healthy individuals. It achieved a high accuracy, sensitivity, and specificity of 91.4%, 90.0%, and 92.1%, respectively, in detecting PAD. The effect of age, a confounding factor that may have impacted our analyzes, was not considered in this study. The proposed method shows promise toward noninvasive and accurate detection of PAD and can be integrated into routine oscillometric blood pressure measurements.

Advances in Revascularization for Peripheral Artery Disease: Revascularization in PAD

Effective revascularization of the patient with peripheral artery disease is about more than the procedure. The approach to the patient with symptom-limiting intermittent claudication or limb-threatening ischemia begins with understanding the population at risk and variation in clinical presentation. The urgency of revascularization varies significantly by presentation; from patients with intermittent claudication who should undergo structured exercise rehabilitation before revascularization (if needed) to those with acute limb ischemia, a medical emergency, who require revascularization within hours. Recent years have seen the rapid development of new tools including wires, catheters, drug-eluting technology, specialized balloons, and biomimetic stents. Open surgical bypass remains an important option for those with advanced disease. The strategy and techniques employed vary by clinical presentation, lesion location, and lesion severity. There is limited level 1 evidence to guide practice, but factors that determine technical success and anatomic durability are largely understood and incorporated into decision-making. Following revascularization, medical therapy to reduce adverse limb outcomes and a surveillance plan should be put in place. There are many hurdles to overcome to improve the efficacy of lower extremity revascularization, such as restenosis, calcification, microvascular disease, silent embolization, and tools for perfusion assessment. This review highlights the current state of revascularization in peripheral artery disease with an eye toward technologies at the cusp, which may significantly impact current practice.

Lower Extremity Peripheral Artery Disease Without Chronic Limb-Threatening Ischemia: A Review

IMPORTANCE

Lower extremity peripheral artery disease (PAD) affects approximately 8.5 million people in the US and approximately 230 million worldwide.

OBSERVATIONS

Peripheral artery disease is uncommon before aged 50 years but affects up to 20% of people aged 80 years and older. It can be noninvasively diagnosed with the ankle-brachial index (ABI), a ratio of Doppler-recorded pressures in the dorsalis pedis and/or posterior tibial artery in each leg to brachial artery pressures. An ABI value less than 0.90 is 57% to 79% sensitive and 83% to 99% specific for arterial stenosis of at least 50%. Intermittent claudication, consisting of exertional calf pain that does not begin at rest and that resolves within 10 minutes of rest, is considered the classic symptom of PAD. However, 70% to 90% of people with an ABI value less than 0.90 either report no exertional leg symptoms (ie, asymptomatic) or report leg symptoms with walking that are not consistent with classic claudication. Over time, people with PAD restrict walking activity or slow walking speed to avoid leg symptoms. Thus, although approximately 75% of people with PAD report no change in leg symptoms over time, those with PAD have significantly greater annual declines in 6-minute walk performance compared with those without it. Approximately 11% of people with PAD develop chronic limb-threatening ischemia, the most severe form of PAD. Compared with people without PAD, those with the disease have approximately twice the rate of all-cause mortality, cardiovascular mortality, and major coronary events at 10-year follow-up. High-dose statins and antiplatelet therapy with or without antithrombotic therapy reduced rates of coronary events and stroke in people with PAD. Supervised treadmill exercise improved 6-minute walk distance by 30 to 35 m, consistent with a clinically meaningful change, whereas effective home-based walking exercise interventions improved 6-minute walk by 42 to 53 m. Effective home-based exercise programs require behavioral methods, including monitoring by a coach.

CONCLUSIONS AND RELEVANCE

Peripheral artery disease affects approximately 230 million people worldwide and is associated with increased rates of cardiovascular events, lower extremity events, and functional decline compared with that of people without PAD. People with PAD should be treated with the highest dose of statin tolerated, antithrombotic and/or antiplatelet therapy, and exercise.

Urinary fatty acid binding protein 3 (uFABP3) is a potential biomarker for peripheral arterial disease

Plasma levels of fatty acid binding protein 3 (pFABP3) are elevated in patients with peripheral artery disease (PAD). Since the kidney filters FABP3 from circulation, we investigated whether urinary fatty acid binding protein 3 (uFABP3) is associated with PAD, and also explored its potential as a diagnostic biomarker for this disease state. A total of 130 patients were recruited from outpatient clinics at St. Michael's Hospital, comprising of 65 patients with PAD and 65 patients without PAD (non-PAD). Levels of uFABP3 normalized for urine creatinine (uFABP3/uCr) were 1.7-folds higher in patients with PAD [median (IQR) 4.41 (2.79-8.08)] compared with non-PAD controls [median (IQR) 2.49 (1.78-3.12), p-value = 0.001]. Subgroup analysis demonstrated no significant effect of cardiovascular risk factors (age, sex, hypertension, hypercholesteremia, diabetes and smoking) on uFABP3/uCr in both PAD and non-PAD patients. Spearmen correlation studies demonstrated a significant negative correlation between uFABP3/uCr and ABI (ρ = - 0.436; p-value = 0.001). Regression analysis demonstrated that uFABP3/Cr levels were associated with PAD independently of age, sex, hypercholesterolemia, smoking, prior history of coronary arterial disease and Estimated Glomerular Filtration rate (eGFR) [odds ratio: 2.34 (95% confidence interval: 1.47-3.75) p-value < 0.001]. Lastly, receiver operator curve (ROC) analysis demonstrated unadjusted area under the curve (AUC) for uFABP3/Cr of 0.79, which improved to 0.86 after adjusting for eGFR, age, hypercholesteremia, smoking and diabetes. In conclusion, our results demonstrate a strong association between uFABP3/Cr and PAD and suggest the potential of uFABP3/Cr in identifying patients with PAD.

Establishing Thresholds for Minimal Clinically Important Differences for the Peripheral Artery Disease Questionnaire

BACKGROUND

Understanding minimum clinically important differences (MCID) in patient-reported outcomes is essential in interpreting the magnitude of changes in these measures. No MCID from patients' perspectives has ever been published for peripheral artery disease-specific health status assessment tools. The Peripheral Artery Questionnaire (PAQ) is a commonly used, validated peripheral artery disease-specific health status instrument for which we sought to prospectively establish its MCID from patients' perspectives.

METHODS AND RESULTS

Patients presenting to vascular clinics with new or worsened claudication in the US cohort of the PORTRAIT (Patient-Centered Outcomes Related to Treatment Practices in Peripheral Arterial Disease: Investigating Trajectories) registry who completed baseline and follow-up PAQ assessments along with the Global Assessment of Functioning scale were included. Mean change in PAQ summary scores from 3- to 6-month follow-up was calculated according to Global Assessment of Functioning category. MCID was defined as the mean difference in scores between those with small improvement or deterioration and those with no change. Multivariable linear regression was used to provide an MCID estimate after adjusting for patients' 3-month PAQ score. Of the 483 patients who completed the Global Assessment of Functioning score at 6 months and who had available 3- and 6-month PAQ assessments, the mean age was 69 years, 42% were female, and 71% were White. The MCIDs for PAQ summary scale improvement and worsening were 8.7 (2.9-14.5) and -11.0 (-18.6 to -3.3), respectively. After multivariable adjustment, these were 8.9 (3.0-14.8) and -11.2 (-18.2 to -4.2), respectively. There was no significant interaction between treatment (invasive versus noninvasive) and Global Assessment of Functioning response (P=0.75).

CONCLUSIONS

In patients with new or worsened claudication, a 10-point change in PAQ summary score represents an MCID. This estimate needs external validation and may inform the interpretation of PAQ scores when used as outcomes in clinical trials or in routine clinical care. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01419080.

Relationship between requirement to stop during a six-minute walk test and health-related quality of life, physical activity and physical performance amongst people with intermittent claudication

AIM

A simple objective test is required to identify people with impaired physical aspects of health-related quality of life (QOL) due to intermittent claudication. This study assessed the relationship of QOL, function and physical activity to the need to stop during a six-minute walking test (6MWT) amongst people with intermittent claudication.

METHOD

This was a prospective case-control study conducted at two centers in Australia. 173 participants with a history of intermittent claudication and peripheral artery disease diagnosed by ankle brachial pressure index <0.9, completed two 6MWTs one week apart. QOL was assessed with the short form (SF)-36. Physical activity was assessed by an accelerometer to record step count, stepping time and energy expenditure over 7 days. Physical performance was assessed by the Short Physical Performance Battery (SPPB) test. The associations of the need to stop at least once during the 6MWT with QOL, function and activity were assessed using Mann Whitney U test and analysis of covariates.

RESULTS

Participants that had to stop at least once during the two 6MWTs (46; 26.6%) had significantly lower scores for three of the domains (physical functioning, role-physical and bodily pain) and the physical component summary (PCS) measure of the SF-36 compared to those who did not need to stop (n = 127; 73.4%). After adjusting for the risk factor co-variates (diabetes, hypertension and ankle brachial pressure index) which were significantly unequally distributed, needing to stop during the 6MWTs was significantly associated with a lower PCS score (adjusted mean 36.5, standard error 0.8 vs. 30.5, standard error 1.3; F = 14.0; P < 0.001; partial eta squared 0.077). Participants that had to stop at least once during the two 6MWTs had significantly lower 7-day step count, time stepping and energy expenditure, but not total SPPB score, compared to those who did not need to stop.

CONCLUSIONS

Needing to stop during a 6MWT identified participants with intermittent claudication with poorer QOL and less physical activity compared to those that do not need to stop.

Asymptomatic peripheral artery disease: Silent but deadly

Peripheral Artery Disease (PAD) is a manifestation of atherosclerosis characterized by diminished perfusion of the limb and a state of dysmetabolism. The asymptomatic PAD phenotype is a relatively recent classification. It is unknown how many people currently live with asymptomatic PAD because there are no universal screening recommendations for patients at risk for PAD. Patients with asymptomatic PAD suffer from a similar risk profile of morbidity and mortality as their counterparts with claudication. Despite this increased risk, there is a dearth of clinical investigations into therapies that specifically benefit the asymptomatic PAD population. At present, current pharmacotherapies that have been studied in PAD patient populations do not stratify by symptom status. We believe that further investigation of the impact of existing therapies in this unique population presents an opportunity to reduce morbidity and mortality due to PAD. This can only be achieved in combination with wide-spread adoption of screening for asymptomatic PAD.

Cardiovascular long-term outcome and prophylactic treatment patterns in peripheral arterial disease in a population-based cohort

AIMS

This study evaluates 10-year follow-up data on associated comorbidity, mortality, and pharmacological treatment patterns for men and women with different stages of peripheral arterial disease (PAD) in a population-based setting.

METHODS AND RESULTS

This was a prospective observational population-based cohort study, based on physical examinations and questionnaires at baseline supplemented with national register data between 2005 and 2015. Subjects were placed in subgroups defined by ankle-brachial index levels and reported symptoms; asymptomatic PAD (APAD), intermittent claudication (IC), severe limb ischaemia (SLI), or references (Ref). Cox proportional hazards regression models were used for analysis with adjustments for sex and baseline age and comorbidity. The cohort consisted of 5080 subjects (45% males). At baseline, APAD, IC, and SLI were prevalent in 559 (11%), 320 (6.3%), and 78 (1.5%) subjects, respectively. A significant increased risk for cardiovascular (CV) death, even when adjusted for age and baseline morbidity, were noted in all PAD stages as compared with reference group with a small difference between APAD and IC, an adjusted hazard ratio 1.80 (confidence interval 1.45-2.22) and 1.95 (1.50-2.53), respectively. Only about 60% of PAD subjects received medical prophylactic treatment as recommended in guidelines.

CONCLUSION

Peripheral arterial disease subjects had significantly increased CV morbidity and mortality risks, especially males. Asymptomatic PAD subjects confer similar risk for CV events as symptomatic patients. Our findings motivate enhanced preventive efforts of all PAD stages, including in asymptomatic disease.

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.

Rationale and design of a smartphone-enabled, home-based exercise program in patients with symptomatic peripheral arterial disease: The smart step randomized trial

BACKGROUND

Supervised exercise therapy (SET) is recommended in patients with symptomatic peripheral arterial disease (PAD) as first-line therapy, although patient adoption remains low. Home-based exercise therapy (HBET) delivered through smartphones may expand access. The feasibility of such programs, especially in low-resource settings, remains unknown.

METHODS

Smart Step is a pilot randomized trial of smartphone-enabled HBET vs walking advice in patients with symptomatic PAD in an inner-city hospital. Participants receive a smartphone app with daily exercise reminders and educational content. A trained coach performs weekly phone-based coaching sessions. All participants receive a Fitbit Charge HR 2 to measure physical activity. The primary outcome changes in 6-minute walking test (6MWT) distance at 12 weeks over baseline. Secondary outcomes are the degree of engagement with the smartphone app and changes in health behaviors and quality of life scores after 12 weeks and 1 year.

RESULTS

A total of 15 patients are randomized as of December 15, 2019 with a mean (SD) age of 66.1 (5.8) years. The majority are female (60%) and black (87%). At baseline, the mean (SD) ABI and 6MWT were 0.86 (0.29) and 363.5 m, respectively. Enrollment is expected to continue until December 2020 to achieve a target size of 50 participants.

CONCLUSIONS

The potential significance of this trial will be to provide preliminary evidence of a home-based, "mobile-first" approach for delivering a structured exercise rehabilitation program. Smartphone-enabled HBET can be potentially more accessible than center-based programs, and if proven effective, may have a potential widespread public health benefit.

Pilot screening program for lower extremities atherosclerotic disease in a population of central Greece

BACKGROUND

Screening program in lower extremity atherosclerotic disease (LEAD) has not been widely implemented from health systems. The aim of this study was to assess the incidence of LEAD in Greece though a pilot LEAD screening program.

METHODS

Males >60 years old without known diagnosis of LEAD or chronic renal disease were invited through public primary health care institutions to participate in a pilot screening program in Central Greece. Demographics, atherosclerotic risk factors and other comorbidities were recorded. LEAD was defined as ankle-brachial pressure index (ABPI) of <0.9 or >1.4.

RESULTS

Among a total of 1152 individuals (invitation acceptance 70%; 1152/1638) LEAD was detected in 13% (148); including 7% with ABPI<0.9 and 6% with ABPI>1.4. Comparing the groups with ABPI<0.9 vs. normal ABPI, abnormal ABPI was associated with older age (P=0.001), hypertension (HT) (P=0.037), smoking (P=0.002), duration of smoking (P=0.01), packs/year (P=0.002), coronary artery disease (P=0.02), chronic obstructive pulmonary disease (P=0.028) and cerebrovascular disease (P=0.001). After multivariate analysis, increased age (0.94, CI: 0.026-5.2; P=0.022), history of HT (2.4, CI: 0.44- 3.7; P=0.05) and longer duration of smoking (0.9, CI: 0.01-6.1; 0.013) were associated with ABPI <0.9. Abnormally higher ABPI (>1.4) was not associated with any factor. Among those without known CAD or CVD (96/148), 37.5% (36/96) were on statins and 21% (20/96) on antiplatelets.

CONCLUSIONS

Incidence of LEAD was 13% in a male >60 years-old population of central Greece; these individuals maybe undertreated. ABPI<0.9 was diagnosed in 7% and was associated with older age, HT and duration of smoking.

Association of peripheral artery disease with life-space mobility restriction and mortality in community-dwelling older adults

OBJECTIVE

Symptomatic peripheral artery disease (PAD) impairs walking, but data on the impact of PAD on community mobility is limited. Life-space mobility measures the distance, frequency, and assistance needed as older adults move through geographic areas extending from their bedroom (life-space mobility score: 0) to beyond their town (life-space mobility score: 120). We evaluated the association of PAD with longitudinal life-space mobility trajectory.

METHODS

Participants were part of the University of Alabama at Birmingham Study of Aging, a longitudinal study of community-dwelling older adults who were observed from 2001 to 2009. We limited our analysis to those who survived at least 6 months (N = 981). PAD was based on self-report with verification by physician report and hospital records. Our primary outcome was life-space mobility score assessed every 6 months. A multilevel change model (mixed model) was used to determine the association between PAD and life-space mobility trajectory during a median 7.9 years of follow-up.

RESULTS

Participants had a mean age of 75.7 (standard deviation, 6.7) years; 50.5% were female, and 50.4% were African American. PAD prevalence was 10.1%, and 57.1% of participants with PAD died. In participants with both PAD and life-space restriction, defined as life-space mobility score <60, we observed the highest mortality (73.1%). In a multivariable adjusted mixed effects model, participants with PAD had a more rapid decline in life-space mobility by -1.1 (95% confidence interval [CI], -1.9 to -0.24) points per year compared with those without PAD. At 5-year follow-up, model-adjusted mean life-space mobility was 48.1 (95% CI, 43.5-52.7) and 52.4 (95% CI, 50.9-53.8) among those with and without PAD, respectively, corresponding to a restriction in independent life-space mobility at the level of one's neighborhood.

CONCLUSIONS

Life-space mobility is a novel patient-centered measure of community mobility, and PAD is associated with significant life-space mobility decline among community-dwelling older adults. Further study is needed to mechanistically confirm these findings and to determine whether better recognition and treatment of PAD alter the trajectory of life-space mobility.

Effects of Intermittent Calf Muscle Electrical Stimulation on Walking Capacity in Claudicants Living with Type 2 Diabetes

BACKGROUND

First-line therapy for diabetic patients presenting with intermittent claudication includes supervised exercise programs to improve walking distance. However, exercise comes with a variety of barriers and may be contraindicated in certain conditions. The aim of this study was to evaluate whether calf muscle electrostimulation improves claudication distance.

METHODS

A prospective, one-group, pretest-posttest study design was used on 40 participants living with type 2 diabetes mellitus, peripheral artery disease (ankle brachial pressure index, <0.90), and calf muscle claudication. Calf muscle electrostimulation of varying frequencies (1-250 Hz) was prescribed on both limbs for 1-hour daily sessions for 12 consecutive weeks. The absolute claudication distance (ACD) was measured at baseline and after the intervention.

RESULTS

The recruited cohort (30 men and ten women; mean age, 71 years; mean ankle brachial pressure index, 0.70) registered a mean ± SD baseline ACD of 333.71 ± 208 m. After a mean ± SD of 91.68 ± 6.23 days of electrical stimulation, a significant mean ± SD increase of 137 ± 136 m in the ACD (P = .001, Wilcoxon signed rank test) was registered. Improvement was found to be sex independent, but age was negatively correlated with proportion of improvement (r = -0.361; P = .011, Pearson correlation test).

CONCLUSIONS

Electrical stimulation of varying frequencies on ischemic calf muscles significantly increased the maximal walking capacity in claudicants with type 2 diabetes. This therapeutic approach should be considered in patients with impaired exercise tolerance or as an adjunct treatment modality.

High prevalence of exercise-induced ischemia in the asymptomatic limb of patients with apparently strictly unilateral symptoms and unilateral peripheral artery disease

BACKGROUND:

The prevalence of exercise-induced ischemia in the asymptomatic limb of patients with unilateral claudication based on history and treadmill evaluation, and with unilateral ipsilateral peripheral artery disease (i.e ankle-to-brachial systolic pressure index <0.90) is unknown.

METHODS:

We detected exercise-induced ischemia in the asymptomatic limb of patients with apparently unilateral claudication. Among 6059 exercise-oximetry tests performed in 3407 nondiabetic and 961 diabetic patients. We estimated the intensity of ischemia in the both limb (buttocks and calves) using the lowest minimum value of the decrease from rest of oxygen pressure (DROP; limb changes minus chest changes from rest), with significant ischemia defined as DROP lower than -15 mmHg.

RESULTS:

We found 152 tests performed in 142 nondiabetic patients and 40 tests performed in 38 diabetic patients. The asymptomatic limb showed significant ischemia in 46.7% and 37.5% of the tests. Strictly unilateral exercise-induced claudication with apparently unilateral peripheral artery disease was rare (<4% of all tests). However, among these highly selected tests, significant ischemia was found in the asymptomatic limb in more than one-third of cases.

CONCLUSION:

The asymptomatic limb of patients with peripheral artery disease should not be considered a normal limb.

Design and rationale of a randomized noninferiority trial to evaluate the SurVeil drug-coated balloon in subjects with stenotic lesions of the femoropopliteal artery - the TRANSCEND study

BACKGROUND

Drug-coated balloons (DCBs), developed to reduce restenosis after percutaneous intervention in peripheral arterial disease (PAD), have been shown to be safe and efficacious, particularly in treating PAD affecting the femoropopliteal segment. The SurVeil DCB uses an excipient intended to optimize both the uniformity and transfer of paclitaxel to the vessel wall, allowing for efficient drug loading and lower systemic exposure than currently available DCBs, Heretofore, clinical outcomes have not previously been compared to other DCBs.

STUDY DESIGN AND OBJECTIVES

This prospective, multicenter, international, randomized, single-blind, trial will compare 1:1 the SurVeil DCB with the IN.PACT Admiral DCB for treatment of patients with Rutherford classification 2 to 4 due to femoral and/or popliteal arterial disease. The trial will randomize 446 subjects (with reference vessel diameter 4-7 mm and total lesion length ≤180 mm). Subjects will be followed for 60 months. The primary efficacy endpoint is 1 year primary patency, defined as composite freedom from clinically-driven target-lesion revascularization (TLR) and binary restenosis (core lab-adjudicated duplex ultrasound peak systolic velocity ratio ≥2.4, or ≥50% stenosis via angiography). The primary safety endpoint is composite freedom from device- and procedure-related death through 30 days and freedom from target limb major amputation and clinically-driven target vessel revascularization through 12 months. The primary analysis is a test of noninferiority of the SurVeil vs. IN.PACT Admiral on the primary efficacy and safety endpoints according to absolute deltas of 15.0% and 10.0%, respectively.

CONCLUSION

The Randomized And Controlled Noninferiority Trial to Evaluate Safety and Clinical Efficacy of the SurVeil DCB in the Treatment of Subjects with Stenotic Lesions of the Femoropopliteal Artery Compared to the Medtronic IN.PACT Admiral (TRANSCEND) study will assess safety and efficacy of the SurVeil DCB relative to a commonly used DCB.

Life's Simple 7 and Peripheral Artery Disease: The Multi-Ethnic Study of Atherosclerosis

INTRODUCTION

In 2010, the American Heart Association initiated Life's Simple 7 with the goal of significantly improving cardiovascular health by the year 2020. The association of Life's Simple 7 with risk of peripheral artery disease has not been thoroughly explored.

METHODS

Racially diverse individuals from the Multi-Ethnic Study of Atherosclerosis (2000-2012) were followed for incident peripheral artery disease (ankle brachial index ≤0.90) and decline in ankle brachial index (≥0.15) over approximately 10 years of follow-up. Cox and logistic regression were used to assess associations of individual Life's Simple 7 components (score 0-2) and overall Life's Simple 7 score (score 0-14) with incident peripheral artery disease and ankle brachial index decline, respectively, adjusted for age, sex, race/ethnicity, education, and income. Analyses were performed in 2016-2018.

RESULTS

Of 5,529 participants, 251 (4.5%) developed incident peripheral artery disease; 419 (9.8%) of 4,267 participants experienced a decline in ankle brachial index. Each point higher for the overall Life's Simple 7 score was associated with a 17% lower rate of incident peripheral artery disease (hazard ratio=0.83, 95% CI=0.78, 0.88, p<0.001). Additionally, each point higher in overall Life's Simple 7 was associated with a 0.94-fold lower odds of decline in ankle brachial index (OR=0.94, 95% CI=0.87, 0.97, p=0.003). Four components (smoking, physical activity, glucose, and blood pressure) were associated with incident peripheral artery disease and two (smoking and glucose) with decline in ankle brachial index.

CONCLUSIONS

Better cardiovascular health as measured by Life's Simple 7 is associated with lower incidence of peripheral artery disease and less decline in ankle brachial index. Use of the Life's Simple 7 to target modifiable health behaviors may aid in decreasing the population burden of peripheral artery disease-related morbidity and mortality.

Pulse Oximetry as a Screening Test for Hemodynamically Significant Lower Extremity Peripheral Artery Disease in Adults with Type 2 Diabetes Mellitus

Objective

The main objective is to determine if digital pulse oximetry is an acceptable screening tool to detect hemodynamically significant lower extremity peripheral artery disease (PAD) in patients 50 years old and above with type 2 diabetes mellitus (T2DM) seen at the University of Santo Tomas Hospital (USTH).

Methodology

A total of 78 subjects (155 limbs) were included. Using duplex ultrasonography as the reference standard for the presence of hemodynamically significant lower extremity PAD, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were obtained for abnormal percent oxygen saturation (SpO₂) gradients and for ankle-brachial index (ABI).

Results

Of the 155 limbs, 38.7% had hemodynamically significant stenosis. Pulse oximetry had 76.7% sensitivity (95% CI, 65.2% to 88.1%), 85.3% specificity (95% CI, 78.0% to 92.6%), 76.7% PPV (95% CI, 66.5% to 84.4%) and 85.3% NPV (95% CI, 78.4% to 90.2%). ABI had 40.7% sensitivity (95% CI, 30.1% to 51.3%), 88.2% specificity (95% CI, 80.0% to 96.3%), 68.6% PPV (95% CI, 53.6% to 80.4%) and 70.1% NPV (95% CI, 65.1% to 74.5%). Combining both produces 88.1% sensitivity (95% CI, 78.5% to 97.8%), 74.2% specificity (95% CI, 65-83.4%), 68.4 PPV (95% CI, 60.3% to 75.6%) and 90.8% NPV (95% CI, 83.0% to 95.2%).

Conclusion

The results of this study suggest that pulse oximetry has a higher sensitivity than ABI as a screening tool for hemodynamically significant lower extremity PAD in T2DM patients 50 years old and above. Combining these two tests may be done to achieve a higher sensitivity.

Screening for Peripheral Artery Disease Using the Ankle-Brachial Index: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Peripheral artery disease (PAD) is associated with a high risk for cardiovascular events and poor ambulatory function, even in the absence of symptoms. Screening for PAD with the ankle-brachial index (ABI) may identify patients in need of treatment to improve health outcomes.

OBJECTIVE

To systematically review evidence for the US Preventive Services Task Force on PAD screening with the ABI, the diagnostic accuracy of the test, and the benefits and harms of treatment of screen-detected PAD.

DATA SOURCES

MEDLINE, PubMed, and the Cochrane Central Register of Controlled Trials for relevant English-language studies published between January 2012 and May 2, 2017. Surveillance continued through February 7, 2018.

STUDY SELECTION

Studies of unselected or generally asymptomatic adults with no known cardiovascular disease.

DATA EXTRACTION AND SYNTHESIS

Independent critical appraisal and data abstraction by 2 reviewers.

MAIN OUTCOMES AND MEASURES

Cardiovascular morbidity; PAD morbidity; mortality; health-related quality of life; diagnostic accuracy; and serious adverse events.

RESULTS

Five studies (N = 5864 participants) were included that examined the indirect evidence for the benefits and harms of screening and treatment of screen-detected PAD. No population-based screening trials evaluated the direct benefits or harms of PAD screening with the ABI alone. A single diagnostic accuracy study of the ABI compared with magnetic resonance angiography gold-standard imaging (n = 306) found low sensitivity (7%-34%) and high specificity (96%-100%) in a screening population. Two adequately powered trials (n = 4626) in asymptomatic populations with and without diabetes with a variably defined low ABI (≤0.95 or ≤0.99) showed no statistically significant effect of aspirin (100 mg daily) for composite CVD outcomes (adjusted hazard ratio [HR], 1.00 [95% CI, 0.81-1.23] and HR, 0.98 [95% CI, 0.76-1.26]). One trial (n = 3350) demonstrated no statistically significant increase in major bleeding events with the use of aspirin (adjusted HR, 1.71 [95% CI, 0.99- 2.97]) and no statistically significant increase in major gastrointestinal bleeding (relative risk, 1.13 [95% CI, 0.44-2.91]). Two exercise trials (n = 932) in screen-relevant populations reported no differences in quality of life, Walking Impairment Questionnaire walking distance, or symptoms at 12 and 52 weeks; no harms were reported.

CONCLUSIONS AND RELEVANCE

There was no direct evidence and limited indirect evidence on the benefits of PAD screening with the ABI in unselected or asymptomatic populations. Available studies suggest low sensitivity and lack of beneficial effect on health outcomes, but these studies have important limitations.