The correlation between symptoms and non-invasive test results in patients referred for peripheral arterial disease testing

A high burden of diabetes and ankle brachial index abnormalities exists in Mexican Americans in South Texas

Ethnic differences exist in the United States in the interrelated problems of diabetes (DM), peripheral arterial disease (PAD), and leg amputations. The purpose of this study was to determine the prevalence and risk factor associations for subclinical PAD in a population sample of Mexican Americans using the ankle brachial (ABI) index. The ABI-High (higher of the two ankle pressures/highest brachial pressure) and ABI-Low (lower of the two ankle pressures/highest brachial pressure) were calculated to define PAD. Toe brachial index (TBI) was also calculated. 746 participants were included with an age of 53.4 ± 0.9 years, 28.3 % had diabetes mellitus (DM), 12.6 % were smokers, and 51.2 % had hypertension (HTN). Using ABI-High ≤ 0.9, the prevalence of PAD was 2.7 %. This rose to 12.7 % when an ABI-Low ≤ 0.9 was used; 4.0 % of the population had an ABI-High > 1.4. The prevalence of TBI < 0.7 was 3.9 %. DM was a significant risk factor for ABI-High ≤ 0.9 and ABI-High > 1.4, and TBI < 0.7. Increased age, HTN, smoking was associated with ABI-High ≤ 0.9, while being male was associated with ABI-High > 1.4. Increased age, smoking, and lower education were all associated with abnormal TBI. Despite relatively younger mean age than other studied Hispanic cohorts, the present population has a high burden of ABI abnormalities. DM was a consistent risk factor for PAD. These abnormalities indicate an important underlying substrate of vascular and metabolic disease that may predispose this population to the development of symptomatic PAD and incident amputations.

Psychosocial and socioeconomic factors are most predictive of health status in patients with claudication

BACKGROUND

As a key treatment goal for patients with symptomatic peripheral artery disease (PAD), improving health status has also become an important end point for clinical trials and performance-based care. An understanding of patient factors associated with 1-year PAD health status is lacking in patients with PAD.

METHODS

The health status of 1073 consecutive patients with symptomatic PAD in the international multicenter PORTRAIT (Patient-Centered Outcomes Related to Treatment Practices in Peripheral Arterial Disease: Investigating Trajectories) registry was measured at baseline and 1 year with the Peripheral Artery Questionnaire (PAQ). The association of 47 patient characteristics with 1-year PAQ scores was assessed using a random forest algorithm. Variables of clinical significance were retained and included in a hierarchical multivariable linear regression model predicting 1-year PAQ summary scores.

RESULTS

The mean age of patients was 67.7 ± 9.3 years, and 37% were female. Variables with the highest importance ranking in predicting 1-year PAQ summary score were baseline PAQ summary score, Patient Health Questionnaire-8 depression score, Generalized Anxiety Disorder-2 anxiety score, new onset symptom presentation, insurance status, current or prior diagnosis of depression, low social support, initial invasive treatment, duration of symptoms, and race. The addition of 19 clinical variables in an extended model marginally improved the explained variance in 1-year health status (from R2 0.312 to 0.335).

CONCLUSIONS

Patients' 1-year PAD-specific health status, as measured by the PAQ, can be predicted from 10 mostly psychosocial and socioeconomic patient characteristics including depression, anxiety, insurance status, social support, and symptoms. These characteristics should be validated and tested in other PAD cohorts so that this model can inform risk adjustment and prediction of PAD health status in comparative effectiveness research and performance-based care.

Physiological responses during walking in men and women with intermittent claudication

BACKGROUND

Miyasato et al. show that peak oxygen consumption, walking economy, anaerobic threshold, and cardiovascular responses (heart rate, blood pressure, and rate pressure product) during walking were similar between men and women with peripheral artery disease and intermittent claudication. There were no differences in the physiological responses to walking between men and women with intermittent claudication. Sex per se is not a factor that demands changes in walking prescription for patients with intermittent claudication.

OBJECTIVE

Peak oxygen consumption (VO2peak), anaerobic threshold, walking economy, and cardiovascular responses during walking are used to guide and monitor walking training in patients with peripheral artery disease and intermittent claudication. Women with peripheral artery disease and intermittent claudication present greater impairments than men, and evaluating training markers according to sex for decisions regarding walking prescription in this population is important. This study aimed to compare VO2peak, walking economy, anaerobic threshold, and cardiovascular responses during walking in men and women with peripheral artery disease and intermittent claudication.

METHODS

Forty patients (20 men and 20 women with similar baseline characteristics) underwent a cardiopulmonary treadmill test (3.2km/h and 2% increase in slope every 2 minutes until maximal leg pain). The VO2 and rate-pressure product were assessed. Data from men and women were compared using t-tests.

RESULTS

There were no significant differences between men and women (VO2peak: 15.0±4.8 versus 13.9±2.9mL∙kg-1∙min-1, p=0.38; walking economy: 9.6±2.7 versus 8.4±1.6mL∙kg-1∙min-1, p=0.09; anaerobic threshold: 10.5±3.2 versus 10.5±2.2mL∙kg-1∙min-1, p=0.98; rate pressure product at 1st stage: 13,465± 2,910 versus 14,445±4,379bpm∙mmHg, p=0.41; and rate pressure product at anaerobic threshold:13,673±3,100 versus 16,390±5,870bpm∙mmHg, p=0.08 and rate pressure product at peak exercise: 21,253±6,141 versus 21,923±7,414bpm∙mmHg, p=0.76, respectively).

CONCLUSION

Men and women with peripheral artery disease and similar baseline characteristics presented similar responses to walking, suggesting that decisions regarding walking prescription and monitoring can be made regardless of sex in this specific population.

Physician- and Patient-Elicited Barriers and Facilitators to Implementation of a Machine Learning-Based Screening Tool for Peripheral Arterial Disease: Preimplementation Study With Physician and Patient Stakeholders

BACKGROUND

Peripheral arterial disease (PAD) is underdiagnosed, partially due to a high prevalence of atypical symptoms and a lack of physician and patient awareness. Implementing clinical decision support tools powered by machine learning algorithms may help physicians identify high-risk patients for diagnostic workup.

OBJECTIVE

This study aims to evaluate barriers and facilitators to the implementation of a novel machine learning-based screening tool for PAD among physician and patient stakeholders using the Consolidated Framework for Implementation Research (CFIR).

METHODS

We performed semistructured interviews with physicians and patients from the Stanford University Department of Primary Care and Population Health, Division of Cardiology, and Division of Vascular Medicine. Participants answered questions regarding their perceptions toward machine learning and clinical decision support for PAD detection. Rapid thematic analysis was performed using templates incorporating codes from CFIR constructs.

RESULTS

A total of 12 physicians (6 primary care physicians and 6 cardiovascular specialists) and 14 patients were interviewed. Barriers to implementation arose from 6 CFIR constructs: complexity, evidence strength and quality, relative priority, external policies and incentives, knowledge and beliefs about intervention, and individual identification with the organization. Facilitators arose from 5 CFIR constructs: intervention source, relative advantage, learning climate, patient needs and resources, and knowledge and beliefs about intervention. Physicians felt that a machine learning-powered diagnostic tool for PAD would improve patient care but cited limited time and authority in asking patients to undergo additional screening procedures. Patients were interested in having their physicians use this tool but raised concerns about such technologies replacing human decision-making.

CONCLUSIONS

Patient- and physician-reported barriers toward the implementation of a machine learning-powered PAD diagnostic tool followed four interdependent themes: (1) low familiarity or urgency in detecting PAD; (2) concerns regarding the reliability of machine learning; (3) differential perceptions of responsibility for PAD care among primary care versus specialty physicians; and (4) patient preference for physicians to remain primary interpreters of health care data. Facilitators followed two interdependent themes: (1) enthusiasm for clinical use of the predictive model and (2) willingness to incorporate machine learning into clinical care. Implementation of machine learning-powered diagnostic tools for PAD should leverage provider support while simultaneously educating stakeholders on the importance of early PAD diagnosis. High predictive validity is necessary for machine learning models but not sufficient for implementation.

Prospective Assessment of the Diagnostic Accuracy of Multi-site Photoplethysmography Pulse Measurements for Diagnosis of Peripheral Artery Disease in Primary Care

Peripheral arterial disease (PAD) is associated with cerebral and coronary artery disease. Symptomatic PAD affects about 5% of people over 55 years; many more have asymptomatic PAD. Early detection enables modification of arterial disease risk factors. Diagnostically, assessment of symptoms or signs can be unreliable; ankle brachial pressure index (ABPI) testing is time-consuming and few healthcare professionals are properly trained. This study assessed the diagnostic accuracy of multi-site photoplethysmography (MPPG), an alternative non-invasive test for PAD, in primary care. PAD patients identified from general practice registers were age- and sex-matched with controls. Participants were assessed using MPPG, ABPI and duplex ultrasound (DUS). Outcome measures were sensitivity and specificity of MPPG and ABPI (relative to DUS) and concordance. MPPG test results were available in 249 of 298 eligible participants from 16 practices between May 2015 and November 2016. DUS detected PAD in 101/249 (40.6%). MPPG sensitivity was 79.8% (95% confidence interval [CI] 69.9-87.6%), with specificity 71.9% (95% CI 63.7-79.2%). ABPI sensitivity was 80.2% (95% CI 70.8-87.6%), with specificity 88.6% (95% CI 82-93.5%). With comparable sensitivity to ABPI, MPPG is quick, automated and simpler to do than ABPI; it offers the potential for rapid and accessible PAD assessments in primary care.

Study Design, Rationale, and Methodology for Promote Weight Loss in Patients With Peripheral Artery Disease Who Also Have Obesity: The PROVE Trial

Background Overweight and obesity are associated with adverse functional outcomes in people with peripheral artery disease (PAD). The effects of weight loss in people with overweight/obesity and PAD are unknown. Methods The PROVE (Promote Weight Loss in Obese PAD Patients to Prevent Mobility Loss) Trial is a multicentered randomized clinical trial with the primary aim of testing whether a behavioral intervention designed to help participants with PAD lose weight and walk for exercise improves 6-minute walk distance at 12-month follow-up, compared with walking exercise alone. A total of 212 participants with PAD and body mass index ≥25 kg/m2 will be randomized. Interventions are delivered using a Group Mediated Cognitive Behavioral intervention model, a smartphone application, and individual telephone coaching. The primary outcome is 12-month change in 6-minute walk distance. Secondary outcomes include total minutes of walking exercise/wk at 12-month follow-up and 12-month change in accelerometer-measured physical activity, the Walking Impairment Questionnaire distance score, and the Patient-Reported Outcomes Measurement Information System mobility questionnaire. Tertiary outcomes include 12-month changes in perceived exertional effort at the end of the 6-minute walk, diet quality, and the Short Physical Performance Battery. Exploratory outcomes include changes in gastrocnemius muscle biopsy measures of mitochondrial cytochrome C oxidase activity, mitochondrial biogenesis, capillary density, and inflammatory markers. Conclusions The PROVE randomized clinical trial will evaluate the effects of exercise with an intervention of coaching and a smartphone application designed to achieve weight loss, compared with exercise alone, on walking performance in people with PAD and overweight/obesity. Results will inform optimal treatment for the growing number of patients with PAD who have overweight/obesity. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT04228978.

Lower extremity symptoms and ankle-brachial index screening as predictors of cardiovascular outcomes in Black adults

BACKGROUND

The prevalence of peripheral artery disease (PAD) and leg symptoms are higher in Black than White adults. We studied the effects of self-reported lower extremity symptoms and ankle-brachial indices (ABI) groups on outcomes.

METHODS

Black participants in the Jackson Heart Study with baseline ABI and PAD symptom assessments (exertional leg pain by the San Diego Claudication questionnaire) were included. Abnormal ABI was < 0.90 or > 1.40. Participants were divided into (1) normal ABI, asymptomatic, (2) normal ABI, symptomatic, (3) abnormal ABI, asymptomatic, and (4) abnormal ABI, symptomatic to examine their associations with MACE (stroke, myocardial infarction, fatal coronary heart disease) and all-cause mortality, using Kaplan-Meier survival curves and stepwise Cox proportional hazard models adjusting for Framingham risk factors.

RESULTS

Of 4586 participants, mean age was 54.6 ± 12.6 years, with 63% women. Compared with participants with normal ABI who were asymptomatic, participants with abnormal ABI and leg symptoms had highest risk of MACE (adjusted HR 2.28; 95% CI 1.62, 3.22) and mortality (aHR 1.82; 95% CI 1.32, 2.56). Participants with abnormal ABI without leg symptoms had higher risk for MACE (aHR 1.49; 95% CI 1.06, 2.11) and mortality (aHR 1.44; 95% CI 1.12, 1.99). Participants with normal ABI and no leg symptoms did not have higher risks.

CONCLUSION

Among Black adults, the highest risk for adverse outcomes were in symptomatic participants with abnormal ABIs, followed by asymptomatic participants with abnormal ABIs. These findings underscore the need for further studies to screen for PAD and develop preventative approaches in Black adults with asymptomatic disease.

Subclinical atherosclerosis burden in non-diabetic hypertensives treated in primary care center: the IMTABI study

BACKGROUND

Identifying patients at high risk of cardiovascular disease in primary prevention is a challenging task. This study aimed at detecting subclinical atherosclerosis burden in non-diabetic hypertensive patients in a primary care centre.

METHODS

Clinical, anthropometric and analytical data were collected from patients with hypertension who were free from clinical vascular disease and diabetes. The cardiovascular risk was assessed using the SCORE system. Subclinical atherosclerosis burden was assessed by carotid ultrasonography (intima-medial thickness [IMT] and plaque) and measurement of the ankle-brachial index (ABI).

RESULTS

Out of 140 patients, 59 (42%) have carotid plaque, 32 (23%) have IMT higher than 75% and 12 (9%) have an ABI < 0.9. Total atherosclerosis burden was present in 91 (65%) of the subjects. Consequently, 59 (42%) patients were re-classified into the very high-risk category. In multivariate analyses, smoking, creatinine levels and duration of hypertension were associated with atherosclerosis burden. In contrast, only smoking and age were associated with the presence of carotid plaque. Almost 90% of patients were treated with hypotensive drugs, half of them combined several drugs and 60% were well-controlled. Only 30% received statins in monotherapy and only less than 20% had an LDL cholesterol < 100 mg/dL.

CONCLUSIONS

In non-diabetic hypertensive patients managed at a primary care centre, 4 out of 10 had subclinical atherosclerosis burden and were re-classified into the very high- risk category. There was clear undertreatment with lipid-lowering drugs of most LDL cholesterol inappropriate levels, according to current clinical guidelines.

The Edinburgh Claudication Questionnaire has poor diagnostic accuracy in people with intermittent claudication

BACKGROUND

The screening and diagnosis of intermittent claudication is a challenging process and often relies on the expertise of specialist vascular clinicians. We sought to investigate the diagnostic performance of the Edinburgh Claudication Questionnaire (ECQ) as a screening tool for referrals of suspected intermittent claudication from primary to secondary care.

METHOD

Prospectively, 100 referrals from primary care with a stated diagnosis or query regarding intermittent claudication were recruited. All participants who completed the ECQ, underwent an anklebrachial pressure index (ABPI) assessment and treadmill exercise testing. Outcomes of the ECQ were compared to clinical diagnoses of intermittent claudication.

RESULTS

The ECQ had a sensitivity of 46.8% (95% CI: 27-65%), specificity of 63.2% (95% CI: 43-82%) and accuracy of 53.0% (95% CI: 43-63%). The diagnostic performance was not changed by combining the ECQ with a positive ABPI or post-exercise ABPI outcome for PAD.

CONCLUSION

The ECQ had a poor diagnostic performance in this cohort. Considering the results found here and in other recent studies, the utility of the ECQ as a screening tool and epidemiological survey tool must be questioned. Novel, low-resource diagnostic tools are needed in this population.

Effect of a Home-Based, Walking Exercise Behavior Change Intervention vs Usual Care on Walking in Adults With Peripheral Artery Disease: The MOSAIC Randomized Clinical Trial

Importance

Home-based walking exercise interventions are recommended for people with peripheral artery disease (PAD), but evidence of their efficacy has been mixed.

Objective

To investigate the effect of a home-based, walking exercise behavior change intervention delivered by physical therapists in adults with PAD and intermittent claudication compared with usual care.

Design, Setting, and Participants

Multicenter randomized clinical trial including 190 adults with PAD and intermittent claudication in 6 hospitals in the United Kingdom between January 2018 and March 2020; final follow-up was September 8, 2020.

Interventions

Participants were randomized to receive a walking exercise behavior change intervention delivered by physical therapists trained to use a motivational approach (n = 95) or usual care (n = 95).

Main Outcomes and Measures

The primary outcome was 6-minute walking distance at 3-month follow-up (minimal clinically important difference, 8-20 m). There were 8 secondary outcomes, 3 of which were the Walking Estimated Limitation Calculated by History (WELCH) questionnaire (score range, 0 [best performance] to 100), the Brief Illness Perceptions Questionnaire (score range, 0 to 80 [80 indicates negative perception of illness]), and the Theory of Planned Behavior Questionnaire (score range, 3 to 21 [21 indicates best attitude, subjective norms, perceived behavioral control, or intentions]); a minimal clinically important difference was not defined for these instruments.

Results

Among 190 randomized participants (mean age 68 years, 30% women, 79% White race, mean baseline 6-minute walking distance, 361.0 m), 148 (78%) completed 3-month follow-up. The 6-minute walking distance changed from 352.9 m at baseline to 380.6 m at 3 months in the intervention group and from 369.8 m to 372.1 m in the usual care group (adjusted mean between-group difference, 16.7 m [95% CI, 4.2 m to 29.2 m]; P = .009). Of the 8 secondary outcomes, 5 were not statistically significant. At 6-month follow-up, baseline WELCH scores changed from 18.0 to 27.8 in the intervention group and from 20.7 to 20.7 in the usual care group (adjusted mean between-group difference, 7.4 [95% CI, 2.5 to 12.3]; P = .003), scores on the Brief Illness Perceptions Questionnaire changed from 45.7 to 38.9 in the intervention group and from 44.0 to 45.8 in the usual care group (adjusted mean between-group difference, -6.6 [95% CI, -9.9 to -3.4]; P < .001), and scores on the attitude component of the Theory of Planned Behavior Questionnaire changed from 14.7 to 15.4 in the intervention group and from 14.6 to 13.9 in the usual care group (adjusted mean between-group difference, 1.4 [95% CI, 0.3 to 2.5]; P = .02). Thirteen serious adverse events occurred in the intervention group, compared with 3 in the usual care group. All were determined to be unrelated or unlikely to be related to the study.

Conclusions and Relevance

Among adults with PAD and intermittent claudication, a home-based, walking exercise behavior change intervention, compared with usual care, resulted in improved walking distance at 3 months. Further research is needed to determine the durability of these findings.

Trial Registrations

ISRCTN Identifier: 14501418; ClinicalTrials.gov Identifier: NCT03238222.

Joint associations of peripheral artery disease and accelerometry-based physical activity with mortality: The Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

BACKGROUND AND AIMS

Peripheral artery disease (PAD) and lower levels of physical activity are both associated with higher mortality. Yet, their joint prognostic impact has not been systematically examined, especially in Hispanics/Latinos, and with objective measures. We aimed to examine the joint associations of PAD and physical activity with mortality in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

METHODS

We studied 7,620 Hispanic/Latino adults aged 45-74 years at baseline (2008-2011) who underwent assessment of PAD with ankle-brachial index (ABI) and physical activity with hip-worn accelerometry. We calculated four physical activity measures: sedentary time, light activity, moderate/vigorous activity, and total activity counts. We quantified the relationship between ABI and mortality overall, and by tertiles of activity measures in restricted cubic splines, using multivariable Cox models accounting for sampling weights. We also assessed cross-categories of ABI and activity measures with mortality.

RESULTS

During a median follow up of 7.1 years, 314 participants died. We observed a U-shaped association of ABI with mortality overall (e.g., hazard ratio 1.80 [95%CI 1.20-2.80] at ABI 0.7 vs 1.2). This U-shaped association was generally consistent after stratifying by activity measures, but an elevated mortality risk for higher ABI was not evident in the most active tertile based on sedentary time, time in light activity, and total activity counts. In the cross-category analysis of ABI and physical activity, the highest mortality risk was consistently seen in abnormal ABI (≤0.9 or >1.4) plus the least active tertile (e.g., HR 5.61 [3.31-9.51] for light activity), compared to referent ABI (0.9-1.4) plus the other more active two tertiles, with no interactions between ABI and activity measure.

CONCLUSIONS

Abnormal ABI and lower accelerometry-based physical activity were independently and jointly associated with mortality in Hispanics, suggesting the importance of simultaneously evaluating leg vascular condition and physical activity.

Related factors associated with exercise behavior in patients with peripheral arterial disease

[Purpose] This study aimed to identify the factors associated with exercise behavior in patients with peripheral arterial disease. [Participants and Methods] The study included 43 patients with peripheral arterial disease (mean age, 75.2 ± 5.6 years) who were admitted for endovascular treatment from January 2020 to June 2021. Participants were surveyed through questionnaires to assess their physical function for determining their exercise behavior and the presence of physical, personal, and environmental factors that might have affected their stage of change regarding exercise behavior. [Results] A comparison of physical, personal, and environmental factors between the two groups classified by the presence or absence of exercise behavior showed that subjective health and exercise self-efficacy were significantly lower in the group without exercise. Furthermore, a difference was noted in the presence or absence of work. The adjusted binomial logistic regression analysis results using each of the factors differing between the groups, plus the walking impairment questionnaire total score as explanatory variables, showed a significant relationship with exercise self-efficacy only. [Conclusion] The results of this study showed that exercise self-efficacy presented a useful predictive relationship with the presence of exercise behavior in patients with peripheral arterial disease.

Use of a Smartphone App Versus Motivational Interviewing to Increase Walking Distance and Weight Loss in Overweight/Obese Adults With Peripheral Artery Disease: Pilot Randomized Trial

BACKGROUND

Walking therapy improves functional outcomes in patients with peripheral artery disease (PAD). Less is known about the additive benefit of a dietary intervention.

OBJECTIVE

Our objectives were to develop a smartphone app and, as a pilot, explore its potential efficacy as compared to motivational interviewing (MI) to increase walking distance and promote weight loss in overweight/obese adults with PAD.

METHODS

We conducted a 3-month, 2-arm randomized pilot study at the University of Kansas. Inclusion criteria were BMI >27 kg/m² and symptomatic PAD, defined by an ankle-brachial index <0.9. Patients were randomized into 2 groups: MI, delivered through in-person and telephone counseling, and app, a mobile smartphone app. Both interventions encouraged walking for exercise and healthy dietary habits (increasing fruits and vegetables and whole grains while reducing fat and sugary drinks). We assessed medical history at baseline. At baseline and 3 months, participants completed an assessment of 6-minute walking distance, weight, quality of life, exercise behaviors, and dietary habits. The primary outcome was 3-month change in walking distance. Secondary outcomes were changes in weight, quality of life, exercise behaviors, and dietary habits. We used a Wilcoxon rank-sum test to analyze the primary and secondary outcomes at 3 months within the MI and app groups and to compare the changes between the groups with adjustment for baseline.

RESULTS

We randomized 29 participants with a mean age of 66.03 (SD 8.12) years; 25 participants completed the trial. At baseline, mean walking distance among completers was 260.40 (SD 94.32) meters and 326.15 (SD 69.28) meters for MI and app participants, respectively. At 3 months, the mean walking distance was 298.67 (SD 101.20) meters and 331.19 (SD 58.63) meters for MI and app participants, respectively (group difference P=.03, adjusting for baseline). Increase in walking distance at 3 months was 40.5 meters (95% CI 6.77 to 61.34; P=.02) in MI group. At baseline, mean body weight was 253.10 (SD 59.45) lbs and 225.13 (SD 58.93) lbs for MI and app participants, respectively. At 3 months, mean body weight was 242.14 (SD 58.54) lbs and 223.44 (SD 59.54) lbs for MI and app, respectively (group difference P=.006, adjusting for baseline). Pre-post study decrease in weight was 10.1 lbs (95% CI -17.9 to -3.0) and 2.3 lbs (95% CI -3.4 to -0.7) in MI and app group, respectively. Comparing baseline to 3 months, there were no statistically significant differences in quality of life, exercise behaviors, or dietary habits.

CONCLUSIONS

Our study demonstrates that MI can promote walking and weight loss in overweight/obese adults with PAD. The smartphone app showed a small weight loss but no statistically significant increase in walking distance. As this was a pilot study, future large-scale studies are needed to replicate the efficacy of MI to promote weight loss in overweight or obese adults with PAD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03694652; https://clinicaltrials.gov/ct2/show/NCT03694652.

Exercise Training Increases Resting Calf Muscle Oxygen Metabolism in Patients with Peripheral Artery Disease

Exercise training can mitigate symptoms of claudication (walking-induced muscle pain) in patients with peripheral artery disease (PAD). One adaptive response enabling this improvement is enhanced muscle oxygen metabolism. To explore this issue, we used arterial-occlusion diffuse optical spectroscopy (AO-DOS) to measure the effects of exercise training on the metabolic rate of oxygen (MRO₂) in resting calf muscle. Additionally, venous-occlusion DOS (VO-DOS) and frequency-domain DOS (FD-DOS) were used to measure muscle blood flow (F) and tissue oxygen saturation (StO₂), and resting calf muscle oxygen extraction fraction (OEF) was calculated from MRO₂, F, and blood hemoglobin. Lastly, the venous/arterial ratio (γ) of blood monitored by FD-DOS was calculated from OEF and StO₂. PAD patients who experience claudication (n = 28) were randomly assigned to exercise and control groups. Patients in the exercise group received 3 months of supervised exercise training. Optical measurements were obtained at baseline and at 3 months in both groups. Resting MRO₂, OEF, and F, respectively, increased by 30% (12%, 44%) (p < 0.001), 17% (6%, 45%) (p = 0.003), and 7% (0%, 16%) (p = 0.11), after exercise training (median (interquartile range)). The pre-exercise γ was 0.76 (0.61, 0.89); it decreased by 12% (35%, 6%) after exercise training (p = 0.011). Improvement in exercise performance was associated with a correlative increase in resting OEF (R = 0.45, p = 0.02).

Medical Management of Peripheral Arterial Disease: Deciphering the Intricacies of Therapeutic Options

Due to the pathophysiology of atherosclerosis, the management for coronary artery disease and peripheral arterial disease (PAD) were considered homogenous, with therapies focused on the use of lipid-lowering medications, antiplatelet therapy, glucose control, and blood pressure management. However, more recently, studies have supported the use of tailored therapeutics and medical targets for patients with PAD that sometimes differ from those for coronary artery disease. Moreover, we are now witnessing large randomized PAD-specific trials that have altered therapeutic regimens and targets. Given these updates, dissemination of knowledge is lacking, as evidenced by discordant guideline recommendations. This comprehensive review provides an overview of contemporary therapeutic options for secondary prevention for patients with PAD.

Central and peripheral arterial diseases in chronic kidney disease: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

Chronic kidney disease (CKD) affects about 10% of all populations worldwide, with about 2 million people requiring dialysis. Although patients with CKD are at high risk of cardiovascular disease and events, they are often underrepresented or excluded in clinical trials, leading to important knowledge gaps about how to treat these patients. KDIGO (Kidney Disease: Improving Global Outcomes) convened the fourth clinical Controversies Conference on the heart, kidney and vasculature in Dublin, Ireland, in February 2020, entitled Central and Peripheral Arterial Diseases in Chronic Kidney Disease. A global panel of multidisciplinary experts from the fields of nephrology, cardiology, neurology, surgery, radiology, vascular biology, epidemiology, and health economics attended. The objective was to identify key issues related to the optimal detection, management, and treatment of cerebrovascular diseases, central aortic disease, renovascular disease, and peripheral artery disease in the setting of CKD. This report outlines the common pathophysiology of these vascular processes in the setting of CKD, describes best practices for their diagnosis and management, summarizes areas of uncertainty, addresses ongoing controversial issues, and proposes a research agenda to address key gaps in knowledge that, when addressed, could improve patient care and outcomes.

Perceived Versus Objective Change in Walking Ability in Peripheral Artery Disease: Results from 3 Randomized Clinical Trials of Exercise Therapy

Background

In people with lower‐extremity peripheral artery disease, the effects of exercise on patient‐reported outcomes remain unclear.

Methods and Results

Four hundred four people with peripheral artery disease in 3 clinical trials were randomized to exercise (N=205) or a control group (N=199) and completed the 6‐minute walk and the Walking Impairment Questionnaire distance score (score 0–100, 100=best) at baseline and 6‐month follow‐up. Compared with the control group, exercise improved 6‐minute walk distance by +39.8 m (95% CI, 26.8–52.8, P<0.001) and the Walking Impairment Questionnaire distance score by +7.3 (95% CI, 2.4–12.1, P=0.003). In all, 2828 individual Walking Impairment Questionnaire distance score questions were completed at baseline and follow‐up. Among participants who perceived no change in ability to walk 1 or more distances between baseline and follow‐up, 6‐minute walk improved in the exercise group and declined in the control group (+26.8 versus −6.5 m, P<0.001). Among participants who perceived that their walking ability worsened for 1 or more distances between baseline and follow‐up, the 6‐minute walk improved in the exercise group and declined in the control group (+18.4 versus –27.3 m, P<0.001). Among participants who reported worsening calf symptoms at follow‐up, the exercise group improved and the control group declined (+28.9 versus −12.5 m, P<0.01).

Conclusions

In 3 randomized trials, exercise significantly improved the 6‐minute walk distance in people with peripheral artery disease, but many participants randomized to exercise reported no change or decline in walking ability. These findings suggest a significant discrepancy in objectively measured walking improvement relative to perceived walking improvement in people with peripheral artery disease.

Registration Information

clinicaltrials.gov. Identifiers: NCT 00106327, NCT 01408901.

Assessing health-related quality of life among patients with peripheral artery disease: A review of the literature and focus on patient-reported outcome measures

Peripheral artery disease (PAD) is a progressive atherosclerotic disease associated with high rates of morbidity and mortality. Symptomatic PAD typically presents with claudication, and symptom severity strongly associates with reduced health-related quality of life (HRQoL). Existing treatment strategies for PAD are aimed at reducing symptom severity and improving functional outcomes. However, there is a need to incorporate patient-reported outcome measures (PROMs) into PAD treatment and research in order to provide more patient-centered care. This review will discuss the impact of PAD on HRQoL, existing PROMs available to assess PAD-related HRQoL, utilization of PROMs in research studies and registries, and challenges and solutions related to the integration of PROMs into research and clinical settings.

"Should I stay or should I go now?" Recovery time effect on walking capacity in symptomatic peripheral artery disease

The objective of the study was to investigate the effect of recovery time on walking capacity (WC) throughout repeated maximal walking bouts in symptomatic lower-extremity peripheral artery disease (PAD). The effect of recovery time on WC (maximal walking time) was determined in 21 participants with PAD in three experimental conditions [recovery time from 0.5 to 9.5 min + a self-selected recovery time (SSRT)]: 1) 11 repeated sequences of two treadmill walking bouts (TW-ISO); 2) a single sequence of seven treadmill walking bouts (TW-CONS); 3) a single sequence of seven outdoor walking bouts (OW-CONS). Exercise transcutaneous oxygen pressure changes were continuously recorded as an indirect measure of ischemia. An individual recovery time (IRT) beyond which WC did not substantially increased was determined in participants with a logarithmic fit. At the group level, mixed models showed a significant effect (P < 0.001) of recovery time on WC restoration. At the participant level, strong logarithmic relationships were found (median significant R² ≥ 0.78). The median SSRT corresponded to a median work-to-rest ratio >1:1 (i.e., a lower recovery time in view of the corresponding previous walking time) and was related to unrecovered ischemia and a WC restoration level of <80%. A median work-to-rest ratio of ≤1:2 allowed full recovery of ischemia and full restoration of WC. The IRT ratio was between 1:1 and 1:2 and corresponded to the start of recovery from ischemia. Recovery time affects the restoration level of WC during repeated maximal walking bouts in symptomatic PAD. Meaningful variations in WC restoration were related to specific levels of work-to-rest ratios.NEW & NOTEWORTHY This study demonstrated that there is a significant and mostly logarithmic effect of recovery time on walking capacity in people with symptomatic PAD. This study revealed that a median work-to-rest ratio >1:1 leads to the resumption of walking with unrecovered ischemia and precludes the restoration of full walking capacity, whereas a work-to-rest ratio ≤1:2 allowed walking capacity to fully be restored.

Sustained physical activity in peripheral artery disease: Associations with disease severity, functional performance, health-related quality of life, and subsequent serious adverse events in the LITE randomized clinical trial

This study investigated cross-sectional associations of peripheral artery disease (PAD) severity (defined by the ankle-brachial index (ABI)) and amounts of daily sustained physical activity (PA) (defined as > 100 activity counts per minute lasting 5 consecutive minutes or more). This study also investigated associations of amounts of daily sustained PA with 6-minute walk (6MW) distance and the Short Form-36 physical functioning domain (SF-36 PF) score in cross-sectional analyses and with serious adverse events (SAEs) in longitudinal analyses of people with PAD. PA was measured continuously for 10 days using a tri-axial accelerometer at baseline in 277 participants with PAD randomized to the LITE clinical trial. In regression analyses, each 0.15 lower ABI value was associated with a 5.67% decrease in the number of daily bouts of sustained PA (95% CI: 3.85-6.54; p < 0.001). Every additional bout of sustained PA per day was associated with a 4.56-meter greater 6MW distance (95% CI: 2.67-6.46; p < 0.0001), and a 0.81-point improvement in SF-36 PF score (95% CI: 0.34-1.28; p < 0.001). Participants with values of daily bouts of sustained PA below the median had higher rates of SAEs during follow-up, compared to participants above the median (41% vs 24%; p = 0.002). In conclusion, among participants with PAD, lower ABI values were associated with fewer bouts of daily sustained PA. A greater number of bouts of daily sustained PA were associated with better 6MW performance and SF-36 PF score, and, in longitudinal analyses, lower rates of SAEs. Clinicaltrials.gov ID: NCT02538900.

Reallocating Time From Sedentary Behavior to Physical Activity in Patients With Peripheral Artery Disease: Analyzing the Effects on Walking Capacity Using Compositional Data Analysis

BACKGROUND

To examine the associations between physical activity (PA) and sedentary behavior (SB) with walking capacity and the effects of reallocating time from SB to PA in patients with symptomatic peripheral artery disease (PAD) using compositional data analysis.

METHODS

This cross-sectional study included 178 patients (34% females, mean age = 66 [9] y, body mass index = 27.8 [5.0] kg/m2, and ankle-brachial index = 0.60 [0.18]). Walking capacity was assessed as the total walking distance (TWD) achieved in a 6-minute walk test, while SB, light-intensity PA, and moderate to vigorous-intensity PA (MVPA) were measured by a triaxial accelerometer and conceptualized as a time-use composition. Associations between time reallocation among wake-time behaviors and TWD were determined using compositional isotemporal substitution models.

RESULTS

A positive association of MVPA with TWD (relative to remaining behaviors) was found in men (βilr = 66.9, SE = 21.4, P = .003) and women (βilr = 56.5, SE = 19.8; P = .005). Reallocating 30 minutes per week from SB to MVPA was associated with higher TWD in men (6.7 m; 95% confidence interval, 2.6-10.9 m) and women (4.5 m; 95% confidence interval, 1.5-7.5 m).

CONCLUSIONS

The findings highlight, using a compositional approach, the beneficial and independent association of MVPA with walking capacity in patients with symptomatic PAD, whereas SB and light-intensity PA were not associated.

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.

Calf and non-calf hemodynamic recovery in patients with arterial claudication: Implication for exercise training

BACKGROUND

Previous studies in patients with arterial claudication have focused on calf hemodynamic recovery. We hypothesized that the duration of hemodynamic recovery with TcpO2 at calf and non-calf levels would be shorter than 10 min. We analyzed the factors that influence the recovery time.

METHODS

We monitored limb changes minus chest changes from rest (DROP) of transcutaneous oximetry on buttocks, thighs and calves, during and following a treadmill test (3.2 km/h; 10% grade). We calculated the time required to reach 50% (50%RT) and 10% (90%RT) of minimal DROP value (DROPm) from walking cessation. Regression analyses were used to determine the factors associated to 50%RT and 90%RT.

RESULTS

Of the 132 patients studied, 18.2% reported isolated non-calf pain by history. Of the 792 recovery time values, only 3 (0.4%) and 23 (2.9%) were in excess of 10 min for 50%RT and for 90%RT, respectively. A weak correlation was found between each of the 792 DROPm and 50%RT (r = -0.270, p < 0.001) as well as for 90%RT (r = -0.311 p < 0.001). Lowest DROPm and BMI (but not age, sex, the use of beta-blockers, the duration of the walking period) were associated to both 50%RT and 90%RT.

CONCLUSION

Although recovery duration correlates significantly with the severity of ischemia of the same location, a wide discrepancy exists and the longest recovery time does not always correlate to the localization of the most severe ischemia. Non-calf ischemia should be measured when one aims at objectifying the biological effects of exercise or the effects of treatments on recovery from exercise.

Reliability of the Edinburgh Claudication Questionnaire for Identifying Symptomatic PAD in General Practice

The Edinburgh Claudication Questionnaire (ECQ) was developed to help identify peripheral arterial disease (PAD) in the general population but has not been validated against diagnostic arterial imaging methods such as Duplex Vascular Ultrasound Scanning (DUS). In the present study, we assessed the accuracy of the ECQ for diagnosis using DUS. As part of a National Institute of Health Research funded project looking at novel diagnostic methods, 250 patients were studied from 15 general practices across North East England from May 2015 and November 2016. Practices identified those with a PAD diagnosis from their registers as well as age- and sex-matched controls. All the ECQs were recorded by a vascular specialist nurse. Duplex vascular ultrasound scanning was used as a reference standard for the diagnosis of occlusive PAD. The ECQ had a sensitivity of 52.5% (95% CI: 42.3%-62.5%), specificity of 87.1% (95% CI: 80.6%-92.0%), positive likelihood ratio of 4.06 (95% CI: 2.57-6.42), and negative likelihood ratio of 0.55 (95% CI: 0.44-0.68) compared with reference standard DUS. The ECQ has relatively poor overall diagnostic test accuracy in isolation. It may be helpful in ruling out PAD or as a supplementary test to improve diagnosis of symptomatic disease in General Practice.

Higher habitual flavonoid intakes are associated with a lower risk of peripheral artery disease hospitalizations

BACKGROUND

The role of nutrition in the primary prevention of peripheral artery disease (PAD), the third leading cause of atherosclerotic cardiovascular disease, is undetermined. Flavonoids may attenuate atherosclerosis and therefore persons who consume flavonoid-rich foods may have a lower risk of developing PAD.

OBJECTIVES

We aimed to examine the association between flavonoid intake and PAD hospitalizations and investigate if the association differs according to established risk factors for PAD.

METHODS

Baseline data from 55,647 participants of the Danish Diet, Cancer, and Health Study without PAD, recruited from 1993 to 1997, were cross-linked with Danish nationwide registries. Flavonoid intake was calculated from FFQs using the Phenol-Explorer database. Associations were examined using multivariable-adjusted restricted cubic splines based on Cox proportional hazards models.

RESULTS

After a median [IQR] follow-up time of 21 [20-22] y, 2131 participants had been hospitalized for any PAD. The association between total flavonoid intake and total PAD hospitalizations was nonlinear, reaching a plateau at ∼750-1000 mg/d. Compared with the median flavonoid intake in quintile 1 (174 mg/d), an intake of 1000 mg/d was associated with a 32% lower risk of any PAD hospitalization (HR: 0.68; 95% CI: 0.60, 0.77), a 26% lower risk of atherosclerosis (HR: 0.74; 95% CI: 0.62, 0.88), a 28% lower risk of an aneurysm (HR: 0.72; 95% CI: 0.59, 0.88), and a 47% lower risk of a hospitalization for other peripheral vascular disease (HR: 0.53; 95% CI: 0.42, 0.67). A higher total flavonoid intake was also significantly associated with a lower incidence of revascularization or endovascular surgery and lower extremity amputation. The association between total flavonoid intake and PAD hospitalizations differed according to baseline smoking status, alcohol intake, BMI, and diabetes status.

CONCLUSIONS

Ensuring the adequate consumption of flavonoid-rich foods, particularly in subpopulations prone to the development of atherosclerosis, may be a key strategy to lower the risk of PAD.

Assessment of all-cause and cardiovascular death risk in Russian men with leg pain

Aim. To study the prevalence of intermittent claudication (IC) and assess the risk of cardiovascular and all-cause death In Russian men with IC according to 30-year follow-up.

Material and methods. The study used data obtained from representative samples of men examined inMoscow andSt. Petersburg (formerly known  as Leningrad) from 1975 to 1986. Response rate was 75%. The examination of men (n=10953) aged 35-70 years (mean age 48,8±6,6 years) was carried out according to a single protocol, which included a standard survey, biochemical profile test, measurement of blood pressure (BP) and heart rate, anthropometry and 12-lead electrocardiography. To determine IC, the original Rose questionnaire was used, according to which four categories of pain were identified. The first is the absence of pain (P0); the second — mixed pain, including not associated with exercise (P1); the third — atypical pain in calf muscles lasting >10 minutes of rest (P2); the fourth — typical IC (P3). The median follow-up was 21,9 years. In total, 7,893 people died, including 4220 people due to cardiovascular diseases (CVD). The KaplanMeier curves was used to assess the associations between IC categories and survival. The risk of death, including due to CVD, was assessed using Cox proportional hazard models.

Results. There were 38,8% of men with leg pain. The prevalence of IC in the studied sample was 1,0%, increasing with age from 0,4 to 2,3% in the older age group. As expected, individuals without leg pain live the longest. The years of life lost in persons with IC was 12. This parameter for cardiovascular deaths was 22,4 years. The contribution to survival not only of IC (P3), but also of atypical pain (P2) remains significant regardless of age. Moreover, the results of multivariate analysis showed that the contribution to mortality of P3 and P2 does not depend on increased blood pressure, smoking, ischemic and other electrocardiographic abnormalities, a history of myocardial infarction, which indicates the common etiology of lower limb and heart artery diseases. Similar data were obtained regarding cardiovascular mortality, however, the contribution of CI is more significant.

Conclusion. IC In Russian men aged 35-70 years is an independent predictor of all-cause and cardiovascular death.

Burden of Peripheral Artery Disease on Mortality and Incident Cardiovascular Events

Using data from the Multi-Ethnic Study of Atherosclerosis (United States, 2000-2015), 6,527 racially/ethnically diverse adults (mean age, 62 (standard deviation, 10) years) free of known cardiovascular (CVD) had ankle brachial index (ABI) assessment of their bilateral dorsalis pedis/posterior tibial arteries (4 vessels total) and were followed for total mortality and incident CVD events/mortality. Individuals were classified into categories of 0-, 1-, 2-, 3- or 4-vessel peripheral artery disease (PAD) (ABI of ≤0.9). There were 1,202 deaths (18%), 656 incident CVD events (10%), and 282 CVD deaths (4.3%). Of the 6,527 individuals, 5,711 (87.5%) had 0-, 460 (7.0%) had 1-, 218 (3.3%) had 2-, 69 (1.1%) had 3-, and 69 (1.1%) had 4-vessel PAD, respectively. In multivariable Cox models, higher number of vessels with PAD was associated with higher risk of mortality (P for trend <0.001), CVD events (P for trend = 0.002), and CVD mortality (P for trend = 0.001). Compared with individuals who had 0-vessel disease, hazard ratios for mortality were 1.29 (95% confidence interval (CI): 1.06, 1.59) for 1-, 1.45 (95% CI: 1.14, 1.86) for 2-, 1.58 (95% CI: 1.13, 2.21) for 3-, and 2.15 (95% CI: 1.58, 2.94) for 4-vessel disease. A similar pattern was seen for CVD events/mortality. These results suggest the importance of accounting for ABI values of all 4 leg arteries in clinical practice and research.

Cardiovascular Responses during and after Maximal Walking in Men and Women with Symptomatic Peripheral Artery Disease

BACKGROUND

Walking is recommended for patients with peripheral arterial disease (PAD). It has been shown that patients with PAD present sharper increases in blood pressure (BP) and heart rate (HR) during maximal walking when compared with healthy subjects. Additionally, women with PAD present a worse physiological profile, and it is possible that they may present higher cardiovascular load during and after a bout of maximal walking than men. Thus, the objective of this study was to compare cardiovascular and autonomic responses during and after maximal walking between men and women with PAD and intermittent claudication (IC).

METHODS

Forty patients with PAD and IC (20 men and 20 women) underwent, in random order, 2 sessions: control (standing on treadmill) and exercise (maximal treadmill walking test with Gardner's protocol). During the exercise, HR and BP were measured. Before and after the sessions, cardiovascular variables (BP HR, cardiac output, peripheral vascular resistance, and stroke volume) and autonomic modulation (HR and BP variabilities and baroreflex sensitivity) were assessed. In addition, an ambulatory BP monitoring was recorded after each session.

RESULTS

Men and women presented similar maximal walking capacity. During the walking test, HR and systolic BP increased similarly in men and women. After the maximal walking, cardiovascular and autonomic responses did not differ between the genders. In addition, postintervention ambulatory BP parameters were also similar in men and women. Therefore, in men and women, maximal walking similarly reduced clinic systolic BP and stroke volume, and increased HR and total power of HR variability during the recovery period.

CONCLUSIONS

Men and women with PAD and IC present similar cardiovascular and autonomic responses during and after maximal walking.

Underuse of Cardiovascular Medications in Individuals With Known Lower Extremity Peripheral Artery Disease: HCHS/SOL

Background

Underuse of cardiovascular medications for secondary prevention among individuals with peripheral artery disease (PAD) has been reported. Little is known about PAD treatment status in the Hispanic/Latino population in the United States, who may have limited access to health care and who have worse clinical outcomes than non‐Hispanic individuals.

Methods and Results

We studied the use of cardiovascular therapies in 1244 Hispanic/Latino individuals recruited from 4 sites in the United States, including 826 individuals who reported diagnosis of PAD by physician and 418 individuals with coronary artery disease alone, in the Hispanic Community Health Study/Study of Latinos. We compared the prevalence of using antiplatelet therapy, lipid‐lowering therapy and antihypertensive therapy by PAD and coronary artery disease status. Among those with PAD, we studied factors associated with taking cardiovascular medications, including demographic and socioeconomic factors, acculturation, access to health care and comorbidities, using multivariable regression models. The overall prevalence for individuals with PAD taking antiplatelet therapy, lipid‐lowering therapy and, among hypertensive individuals, antihypertensive therapy was 31%, 26% and 57%, respectively. Individuals of Mexican background had the lowest use for all classes of cardiovascular medications. Older age, number of doctor visits and existing hypertension and diabetes mellitus were significantly associated with taking cardiovascular therapies in adjusted models. Compared with those with PAD alone, individuals with PAD and concurrent coronary artery disease were 1.52 (95% CI, 1.20–1.93) and 1.74 (1.30–2.32) times more likely to use antiplatelet agents and statins according to multivariable analysis. No significant difference of antihypertensive medication use was found among PAD patients with or without coronary artery disease.

Conclusions

Hispanic/Latino individuals with known PAD underuse cardiovascular medications recommended in clinical guidelines. More efforts should be directed to improve treatment in this important group.

Correlations of Calf Muscle Macrophage Content With Muscle Properties and Walking Performance in Peripheral Artery Disease

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

Vascular Assessment of the Foot Surgery Patient

Foot surgery is common. Orthopaedic nurses charged with evaluating and treating patients who have undergone foot surgery are required to evaluate the vascular status of the patient's foot (or feet). As a result, these nurses are often the first to identify vascular issues. This article provides orthopaedic nurses with the background to understand how the patient's history, the procedure(s) performed, and a thorough assessment of the foot's circulation will allow them to promptly identify circulatory problems and potentially save a patient from having a serious complication.

Are cardiovascular function and habitual physical activity levels similar in patients with classic and atypical claudication symptoms? A cross-sectional study

Objective

To analyze the impact of the different types of exertional leg pain on cardiovascular function, functional capacity, and habitual physical activity levels in patients with peripheral arterial disease.

Methods

In this cross-sectional study, 124 patients with symptomatic peripheral arterial disease were included. Exertional leg pain was evaluated using the San Diego Claudication Questionnaire. Subsequently, patients were categorized into two groups according to their exertional leg pain: atypical leg pain (non-calf pain and atypical calf pain, n = 31) and intermittent claudication (classic intermittent claudication symptoms, n = 93). Cardiovascular function (blood pressure, heart rate, arterial stiffness, and heart rate variability), functional capacity (6-min walk distance, handgrip strength, and short physical performance battery), and habitual physical activity levels were measured.

Results

Functional capacity and physical activity levels were similar between patients with atypical leg pain and symptoms of intermittent claudication. However, patients with classic intermittent claudication symptoms presented higher central systolic blood pressure ( P = 0.028) and arterial stiffness (augmentation index and pulse pressure; P ≤ 0.001 and 0.019, respectively) compared to patients with atypical leg pain.

Conclusion

The type of exertional leg pain does not influence functional capacity and habitual physical activity levels in patients with peripheral arterial disease. However, patients with classic intermittent claudication symptoms present impaired cardiovascular function compared to patients with atypical leg pain.

Investigation of arterial claudication with transcutaneous oxygen pressure at exercise: Interests and limits

Transcutaneous oxygen pressure (TcpO2) measurement has been used for years at rest in patients with lower extremity artery disease. It was proposed for exercise testing (Ex-TcpO2) in the 80ies to evaluate regional blood flow impairment (RBFI) at the proximal and distal levels simultaneously and on both sides, in case of claudication. It was suggested that the use of a chest electrode was mandatory to show that decreases in TcpO2 at the limb level result from limb RBFI and not from a systemic pO2 decrease of cardiopulmonary origin (exercise-induced hypoxemia). Unfortunately, a major pitfall of Ex-TcpO2 was the low absolute reliability of the regional perfusion index (RPI: ratio of limb to chest values) and the technique was almost abandoned until 2003, when the DROP index (Decrease from rest of oxygen pressure: limb changes minus chest changes from rest) was proposed. The DROP mathematical formula makes Tcpo2 results independent from the absolute pO₂ starting values, improving reliability of Ex-TcpO2 as compared to the RPI. Since then, Ex-TcpO2 has been of renewed interest. The present paper addresses the physiology of Ex-TcpO2, interpretation of its results, and common misunderstandings about its use.

Durability of Benefits From Supervised Treadmill Exercise in People With Peripheral Artery Disease

Background It is currently unknown whether 6 months of supervised treadmill exercise has a durable benefit on 6-minute walk performance, even after exercise is completed, in people with peripheral artery disease. Methods and Results A total of 156 participants with peripheral artery disease were randomized to 1 of 3 groups: supervised treadmill exercise, supervised resistance training, or attention control. Participants received supervised sessions during months 1 to 6 and telephone contact during months 6 to 12. Primary outcomes were change in 6-minute walk distance and short physical performance battery at 6-month follow-up and have been reported previously. Secondary outcomes were change in 6-minute walk and short physical performance battery at 12-month follow-up and are reported here. A group of 134 participants (86%) completed the 12-month follow-up. At 6-month follow-up, compared with control, 6-minute walk distance improved in the treadmill exercise group (+36.1 m, 95% CI =13.9-58.3, P=0.001). Between 6- and 12-month follow-up, 6-minute walk distance significantly declined (-28.6 m, 95% CI=-52.6 to -4.5, P=0.020) and physical activity declined -272 activity units (95% CI =-546 to +2, P=0.052) in the treadmill exercise group compared with controls. At 12-month follow-up, 6 months after completing supervised treadmill exercise, change in 6-minute walk distance was not different between the treadmill exercise and control groups (+7.5, 95% CI =-17.5 to +32.6, P=0.56). There were no differences in short physical performance battery change between either exercise group and control at 6-month or 12-month follow-up. Conclusions A 6-month supervised treadmill exercise intervention that improved 6-minute walk distance at 6-month follow-up did not have persistent benefit at 12-month follow-up. These results do not support a durable benefit of supervised treadmill exercise in peripheral artery disease. Clinical Trial Registration URL : https://www.clinicaltrials.gov . Identifier: NCT 00106327.

Comparing 6-minute walk versus treadmill walking distance as outcomes in randomized trials of peripheral artery disease

BACKGROUND

Randomized trials of people with peripheral artery disease (PAD) and intermittent claudication have traditionally used maximal treadmill walking distance as the primary outcome, but the 6-minute walk test is increasingly used as a primary outcome in randomized trials of PAD. This study compared relative changes in maximal treadmill walking distance versus 6-minute walk distance in response to a therapeutic intervention or control in randomized trials of participants with PAD.

METHODS

Data from four randomized trials of therapeutic interventions in participants with PAD that measured both 6-minute walk and treadmill walking performance at baseline and the 6-month follow-up were combined. Two trials studied supervised treadmill exercise, one studied home-based walking exercise, and one studied resveratrol.

RESULTS

Of 467 participants (mean age, 69.8; standard deviation, 9.7), the mean ankle-brachial index was 0.66 (standard deviation, 0.17). At the 6-month follow-up, participants with PAD randomized to control or placebo significantly declined in 6-minute walk distance (-10.2 m; 95% confidence interval, -18.2 to -2.2; P = .013), but improved maximal treadmill walking distance (+25.7 m; 95% CI, +6.0 to +45.3 m; P = .010; difference between change in 6-minute walk versus maximal treadmill walking distance: -37.3 m; 95% CI, -56.4 to -18.2; P < .001). Home-based exercise improved the 6-minute walk distance by 43.2 m (95% CI, +28.4 to +57.9), and supervised treadmill exercise improved the 6-minute walk distance by 25.0 m (95% CI, +14.7 to +35.2; mean difference, +18.2 m favoring home-based exercise [95% CI, +0.2 to +36.2 m; P = .048]). Among all participants, the presence (vs absence) of treadmill exercise training was associated with a 141.3-m greater improvement in maximal treadmill walking distance compared to 6-minute walk distance (95% CI, 88.2-194.4; P < .001), suggesting a benefit from treadmill training on the treadmill outcome.

CONCLUSIONS

Maximal treadmill walking distance and the 6-minute walk distance are not interchangeable outcomes in participants with PAD. Participants with PAD randomized to control groups improved treadmill walking distance but simultaneously meaningfully declined in 6-minute walk distance. Supervised treadmill exercise training amplified improvement in treadmill walking distance because of a training to the outcome measure phenomenon.

Motivating Structured walking Activity in people with Intermittent Claudication (MOSAIC): protocol for a randomised controlled trial of a physiotherapist-led, behavioural change intervention versus usual care in adults with intermittent claudication

INTRODUCTION

Walking exercise is a recommended but underused treatment for intermittent claudication caused by peripheral arterial disease (PAD). Addressing the factors that influence walking exercise may increase patient uptake of and adherence to recommended walking. The primary aim of this randomised controlled trial (RCT) is to evaluate the efficacy of a physiotherapist-led behavioural change intervention on walking ability in adults with intermittent claudication (MOtivating Structured walking Activity in people with Intermittent Claudication (MOSAIC)) in comparison with usual care.

METHODS AND ANALYSIS

The MOSAIC trial is a two-arm, parallel-group, single-blind RCT. 192 adults will be recruited from six National Health Service Hospital Trusts. Inclusion criteria are: aged ≥50 years, PAD (Ankle Brachial Pressure Index ≤0.90, radiographic evidence or clinician report) and intermittent claudication (San Diego Claudication Questionnaire), being able and willing to participate and provide informed consent. The primary outcome is walking ability (6 min walking distance) at 3 months. Outcomes will be obtained at baseline, 3 and 6 months by an assessor blind to group allocation. Participants will be individually randomised (n=96/group, stratified by centre) to receive either MOSAIC or usual care by an independent randomisation service. Estimates of treatment effects will use an intention-to-treat framework implemented using multiple regression adjusted for baseline values and centre.

ETHICS AND DISSEMINATION

This trial has full ethical approval (London-Bloomsbury Research Ethics Committee (17/LO/0568)). It will be disseminated via patient forums, peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

ISRCTN14501418.

Are Walking Treatment Beliefs and Illness Perceptions Associated With Walking Intention and 6-Min Walk Distance in People With Intermittent Claudication? A Cross-Sectional Study

Intermittent claudication is debilitating leg pain affecting older people with peripheral arterial disease, which is improved by regular walking. This study evaluated associations between psychosocial variables and 6-min walk distance (6MWD) to identify factors that motivate walking. A total of 142 individuals with intermittent claudication (116 males; M_age = 66.9 years [SD = 10.2]) completed cross-sectional assessments of sociodemographics, walking treatment beliefs and intention (Theory of Planned Behaviour), illness perceptions (Revised Illness Perceptions Questionnaire), and 6MWD. Multiple linear regression was used to evaluate relationships among psychosocial variables (treatment beliefs and illness perceptions) and outcomes (walking intention and 6MWD). Theory of planned behavior constructs were associated with intention (R = .72, p < .001) and 6MWD (R = .08, p < .001). Illness perceptions were associated with 6MWD only (R = .27, p < .001). Intention (β = 0.26), treatment control (β = -0.27), personal control (β = 0.32), coherence (β = 0.18), and risk factor attributions (β = 0.22; all ps < .05) were independently associated with 6MWD. Treatment beliefs and illness perceptions associated with intention and 6MWD in people with intermittent claudication are potential intervention targets.

Using wearable monitors to assess daily walking limitations induced by ischemic pain in peripheral artery disease

PURPOSE

To develop, assess the feasibility of, and determine the clinical validity of an event-based analysis method using wearable monitors to quantify walking pain manifestations (WPMs) and stops induced by walking pain (SIWPs) during daily life walking in people with peripheral artery disease (PAD).

METHODS

The following two conditions were studied: a standardized outdoor walking session (OWS) and a seven-day free-living measurement (FLM) period. The PAD participants (n = 23) wore an accelerometer and a watch. They were asked to press the event marker button on the watch to indicate events related to WPMs and SIWPs. To assess the clinical validity of the method, the computed pain-free walking time (PFWT) and maximal walking time (MWT) were compared with the PFWT and MWT assessed using standard treadmill walking protocols, respectively.

RESULTS

Following OWSs, the PFWT^[OWS] and MWT^[OWS] were significantly correlated with the PFWT^[Strandness] (r = .955, P < .001) and MWT^[Strandness] (r = .821, P < .001), respectively. During the FLM, PAD participants experienced only 2 WPMs/day and 1 SIWP/day, although severely limited on the treadmill and during the OWS. The average WPMs/day were moderately correlated with the PFWT^[Strandness] (r = -.54, P = .016). The PFWT^[FLM] was on average 12 times longer than the PFWT^[Strandness] . Interestingly, the intensity of the walking bouts as assessed by the accelerometer counts during the FLM was significantly lower than that during the OWS (45 ± 15 vs 66 ± 20 counts/s, P < .001).

CONCLUSION

This new method offers opportunities for studies investigating the experience of living with PAD and the assessment of daily life walking capacity for both diagnostic and therapeutic purposes.

Evaluation of the atherosclerotic burden in hypertensive patients with prediabetes

AIM

To assess the atherosclerotic burden in hypertensive patients with prediabetes without cardiovascular disease.

PATIENTS AND METHODS

We included patients with hypertension and prediabetes (fasting blood glucose: 100-125mg/dL and/or glycohemoglobin A1c: 5.7-6.4%), excluding those with established cardiovascular disease or those at very high risk. We recorded major vascular risk factors. Subclinical arteriosclerosis was measured by the ankle/brachial index (ABI) and carotid intima-medial thickness (IMT). Subclinical arteriosclerosis was mild if IMT was >75p adjusted by age and sex and/or ABI was 0.7-0.9 and was considered moderate-severe when there was plaque and/or ABI<0.7.

RESULTS

We included 53 patients, 63±7 years-old; women: 50,9% (95%CI: 36.8-64.9). Atherosclerotic burden was detected in 66.0% (95%CI: 51.7-78.5) of subjects. 24,5% (95%CI: 13.8-38.3) of patients had mild arteriosclerosis disease and 41.5% (95%CI: 28.1-55.9) had moderate-severe. This allowed us to re-stratified as very high vascular risk the 41.5% (95%CI: 28.1-55.9) of patients. 45.4% (95%CI: 16-74.8) of subjects with moderate initial risk were considered high or very high risk. In multivariate analyses, only smoking was associated with atherosclerotic burden (P=.07).

CONCLUSIONS

Two thirds of hypertensive patients with prediabetes had subclinical arteriosclerotic disease when they were evaluated by the ankle/brachial index and carotid ultrasonography. Approximately forty percent of patients were re-stratified as very high vascular risk. Nearly half of the prediabetic hypertensive patients initially classified as moderate risk were considered high or very high risk.

Clinical Assessment of Peripheral Arterial Disease in the Office: What Do the Guidelines Say?

Lower extremity peripheral arterial disease (PAD) is the manifestation of atherosclerotic disease within the lower extremities. The presentation of PAD is diverse ranging from asymptomatic disease to claudication or to debilitating rest pain, nonhealing ulcers, and gangrene. PAD is associated with significant morbidity, mortality, and healthcare costs. Proper diagnosis and management of PAD is important so as to maintain quality of life and reduce the risk of cardiovascular disease and adverse limb events such as amputation. This document provides a comprehensive outpatient approach to the clinical assessment of PAD that includes risk factors, diagnosis, treatment, and follow-up options.

Racial Differences in the Effect of Granulocyte Macrophage Colony-Stimulating Factor on Improved Walking Distance in Peripheral Artery Disease: The PROPEL Randomized Clinical Trial

Background The effects of race on response to medical therapy in people with peripheral artery disease ( PAD ) are unknown. Methods and Results In the PROPEL (Progenitor Cell Release Plus Exercise to Improve Functional Performance in PAD) Trial, PAD participants were randomized to 1 of 4 groups for 6 months: supervised treadmill exercise+granulocyte-macrophage colony-stimulating factor ( GM - CSF ) (Group 1), exercise+placebo (Group 2), attention control+ GM - CSF (Group 3), or attention control+placebo (Group 4). Change in 6-minute walk distance was measured at 12- and 26-week follow-up. In these exploratory analyses, groups receiving GM - CSF (Groups 1 and 3), placebo (Groups 2 and 4), exercise (Groups 1 and 2), and attention control (Groups 2 and 4) were combined, maximizing statistical power for studying the effects of race on response to interventions. Of 210 PAD participants, 141 (67%) were black and 64 (30%) were white. Among whites, GM - CSF improved 6-minute walk distance by +22.0 m (95% CI : -4.5, +48.5, P=0.103) at 12 weeks and +44.4 m (95% CI : +6.9, +82.0, P=0.020) at 26 weeks, compared with placebo. Among black participants, there was no effect of GM - CSF on 6-minute walk distance at 12-week ( P=0.26) or 26-week (-5.0 m [-27.5, +17.5, P=0.66]) follow-up, compared with placebo. There was an interaction of race on the effect of GM - CSF on 6-minute walk change at 26-week follow-up ( P=0.018). Exercise improved 6-minute walk distance in black ( P=0.006) and white ( P=0.034) participants without interaction. Conclusions GM - CSF improved 6-minute walk distance in whites with PAD but had no effect in black participants. Further study is needed to confirm racial differences in GM - CSF efficacy in PAD . Clinical Trial Registration URL : http://www.clinicaltrials.gov . Unique identifier: NCT 01408901.

Endovascular treatment of femoro-popliteal lesions

Peripheral artery disease (PAD) is a major health concern affecting more than 200 million people worldwide and studies have shown PAD to be a strong predictor of mortality, morbidity, and disability. The management of PAD is multi-tiered and advancements in technology have given physicians more options for endovascular revascularization if medical therapy does not result in substantial improvement. Many randomized controlled trials have reported efficacy of various therapies including laser atherectomy, stent technology, and drug-coated balloons over standard percutaneous transluminal angioplasty; however, uncertainty regarding the best standard of care remains unclear because of a lack of head to head comparisons between novel therapies. Furthermore, variability in the reported clinical outcomes exists and makes it difficult to evaluate the superiority of any specific treatment modality, especially for functional capacity and quality of life. Recently established consensus definitions for clinical outcomes coupled with investigators incorporating direct comparisons within clinical trials will be crucial to establish consistent care and meaningful gain in treatment for these patients. This review will highlight the treatment modalities, literature supporting each treatment modality, and insight into why they are being used and why variation exists around the United States.

Living a burdensome and demanding life: A qualitative systematic review of the patients experiences of peripheral arterial disease

Background

Peripheral arterial disease (PAD) has a significant negative impact on the quality of life of individuals. Understanding the experiences of people living with PAD will be useful in developing comprehensive patient-centred secondary prevention therapies for this population.

Aim

The aim of this study is to identify first-hand accounts of patients’ experiences of living with PAD.

Methods

Six databases (CINALH, PsyclNFO, MEDLINE, AMED, EMBASE, Social citation index/Science citation index via Web of Science (WOS)) and reference lists of identified studies were searched until September 2017 (updated February 2018). Qualitative studies reporting patients’ account of living with PAD were eligible for inclusion. A framework thematic synthesis was implemented.

Results

Fourteen studies with 360 participants were included. Pain and walking limitation were recurrent among the varied symptom descriptions. Patients’ ignorance and trivialisation of symptoms contributed to delays in diagnosis. Inadequate engagement in disease understanding and treatment decisions meant patients had poor attitudes towards walking treatments and unrealistic expectations about surgery. Depending on symptom progression, patients battle with walking impairment, powerlessness, and loss of independence which were a source of burden to them. Lack of disease understanding is central through patients’ journey with PAD and, although they subsequently began adaptation to long term living with PAD, many worried about their future.

Conclusions

Disease understanding is vital across the illness trajectory in patients with PAD. Although certain experiences are common throughout patient journey, some might be unique to a particular stage (e.g. unrealistic expectation about surgery, or rationale of walking in spite of pain in a supervised exercise program). Given that PAD is an overarching construct ranging from the mildest form of intermittent claudication to severe critical limb ischemia with ulceration and gangrene, consideration of important patient constructs specific to each stage of the disease may enhance treatment success. Systematic review registration CRD42017070417.