Attendance at Supervised Exercise Sessions and Walking Outcomes in Peripheral Artery Disease: Results From 2 Randomized Clinical Trials

Background Supervised exercise therapy (SET) is the first-line therapy for walking impairment in peripheral artery disease (PAD). This study evaluated the association between attendance at SET and improved walking performance, compared with a control group, in PAD. Methods and Results Data from 2 randomized clinical trials of SET for PAD were combined. In each trial, participants were randomized to 3 times weekly supervised treadmill exercise or an attention control group for 6 months (maximum, 77 exercise sessions). Participants randomized to SET were categorized into tertiles, according to the proportion of exercise sessions they attended. Results adjusted for age, sex, race, baseline walking performance, comorbidities, and other potential confounders. A total of 272 participants with PAD (mean age, 67.9±9.3 years; 44% women; 61% Black race) were included. For participants randomized to SET, tertiles of attendance rates at exercise sessions were as follows: 11% to 68% (N=45), 69% to <85% (N=46), and ≥85% (N=46). Compared with control, mean improvement in 6-minute walk was significantly greater in each SET tertile: mean (95% CI) for tertile 1, 27.9 m (1.3-54.4 m; P=0.04), tertile 2, 38.2 m (12.2-64.2 m; P=0.001), and tertile 3, 56.9 m (29.9-83.8 m; P<0.0001). Among participants randomized to SET, greater SET attendance was associated with greater improvement in 6-minute walk distance (overall P for trend=0.025). Compared with control, improvement in maximal treadmill walking time was greater in each SET attendance tertile: tertile 1 (3.3 minutes [95% CI, 1.7-4.8 minutes]; P<0.0001), tertile 2 (3.8 minutes [95% CI, 2.3-5.3 minutes]; P<0.0001), and tertile 3 (5.4 minutes [95% CI, 3.9-7.0 minutes]; P:<0.0001). Among participants randomized to SET, greater attendance at SET was not significantly associated with greater improvement in maximal treadmill walking time (overall P for trend=0.064). Conclusions Among people with PAD randomized to SET, better attendance at exercise sessions was associated with significantly greater 6-minute walk improvement. Among all participants with PAD, even relatively low SET attendance was associated with significantly greater improvement in walking performance, compared with a control group who did not exercise. Registration URL: https://clinicaltrials.gov/ct2/show/NCT01408901. URL: https://clinicaltrials.gov/ct2/show/NCT00106327.

Dysregulated Genes, MicroRNAs, Biological Pathways, and Gastrocnemius Muscle Fiber Types Associated With Progression of Peripheral Artery Disease: A Preliminary Analysis

Background Peripheral artery disease (PAD) is associated with gastrocnemius muscle abnormalities. However, the biological pathways associated with gastrocnemius muscle dysfunction and their associations with progression of PAD are largely unknown. This study characterized differential gene and microRNA (miRNA) expression in gastrocnemius biopsies from people without PAD compared with those with PAD. Participants with PAD included those with and without PAD progression. Methods and Results mRNA and miRNA sequencing were performed to identify differentially expressed genes, differentially expressed miRNAs, mRNA-miRNA interactions, and associated biological pathways for 3 sets of comparisons: (1) PAD progression (n=7) versus non-PAD (n=7); (2) PAD no progression (n=6) versus non-PAD; and (3) PAD progression versus PAD no progression. Immunohistochemistry was performed to determine gastrocnemius muscle fiber types and muscle fiber size. Differentially expressed genes and differentially expressed miRNAs were more abundant in the comparison of PAD progression versus non-PAD compared with PAD with versus without progression. Among the top significant cellular pathways in subjects with PAD progression were muscle contraction or development, transforming growth factor-beta, growth/differentiation factor, and activin signaling, inflammation, cellular senescence, and notch signaling. Subjects with PAD progression had increased frequency of smaller Type 2a gastrocnemius muscle fibers in exploratory analyses. Conclusions Humans with PAD progression exhibited greater differences in the number of gene and miRNA expression, biological pathways, and Type 2a muscle fiber size compared with those without PAD. Fewer differences were observed between people with PAD without progression and control patients without PAD. Further study is needed to confirm whether the identified transcripts may serve as potential biomarkers for diagnosis and progression of PAD.

Effect of Telmisartan on Walking Performance in Patients With Lower Extremity Peripheral Artery Disease: The TELEX Randomized Clinical Trial

Importance

Patients with lower extremity peripheral artery disease (PAD) have reduced lower extremity perfusion, impaired lower extremity skeletal muscle function, and poor walking performance. Telmisartan (an angiotensin receptor blocker) has properties that reverse these abnormalities.

Objective

To determine whether telmisartan improves 6-minute walk distance, compared with placebo, in patients with lower extremity PAD at 6-month follow-up.

Design, Setting, and Participants

Double-blind, randomized clinical trial conducted at 2 US sites and involving 114 participants. Enrollment occurred between December 28, 2015, and November 9, 2021. Final follow-up occurred on May 6, 2022.

Interventions

The trial randomized patients using a 2 × 2 factorial design to compare the effects of telmisartan plus supervised exercise vs telmisartan alone and supervised exercise alone and to compare telmisartan alone vs placebo. Participants with PAD were randomized to 1 of 4 groups: telmisartan plus exercise (n = 30), telmisartan plus attention control (n = 29), placebo plus exercise (n = 28), or placebo plus attention control (n = 27) for 6 months. The originally planned sample size was 240 participants. Due to slower than anticipated enrollment, the primary comparison was changed to the 2 combined telmisartan groups vs the 2 combined placebo groups and the target sample size was changed to 112 participants.

Main Outcomes and Measures

The primary outcome was the 6-month change in 6-minute walk distance (minimum clinically important difference, 8-20 m). The secondary outcomes were maximal treadmill walking distance; Walking Impairment Questionnaire scores for distance, speed, and stair climbing; and the 36-Item Short-Form Health Survey physical functioning score. The results were adjusted for study site, baseline 6-minute walk distance, randomization to exercise vs attention control, sex, and history of heart failure at baseline.

Results

Of the 114 randomized patients (mean age, 67.3 [SD, 9.9] years; 46 were women [40.4%]; and 81 were Black individuals [71.1%]), 105 (92%) completed 6-month follow-up. At 6-month follow-up, telmisartan did not significantly improve 6-minute walk distance (from a mean of 341.6 m to 343.0 m; within-group change: 1.32 m) compared with placebo (from a mean of 352.3 m to 364.8 m; within-group change: 12.5 m) and the adjusted between-group difference was -16.8 m (95% CI, -35.9 m to 2.2 m; P = .08). Compared with placebo, telmisartan did not significantly improve any of the 5 secondary outcomes. The most common serious adverse event was hospitalization for PAD (ie, lower extremity revascularization, amputation, or gangrene). Three participants (5.1%) in the telmisartan group and 2 participants (3.6%) in the placebo group were hospitalized for PAD.

Conclusions and Relevance

Among patients with PAD, telmisartan did not improve 6-minute walk distance at 6-month follow-up compared with placebo. These results do not support telmisartan for improving walking performance in patients with PAD.

Trial Registration

ClinicalTrials.gov Identifier: NCT02593110.

Higher Arm Versus Lower Arm Systolic Blood Pressure and Cardiovascular Outcomes: a Meta-Analysis of Individual Participant Data From the INTERPRESS-IPD Collaboration

Guidelines recommend measuring blood pressure (BP) in both arms, adopting the higher arm readings for diagnosis and management. Data to support this recommendation are lacking. We evaluated associations of higher and lower arm systolic BPs with diagnostic and treatment thresholds, and prognosis in hypertension, using data from the Inter-arm Blood Pressure Difference—Individual Participant Data Collaboration.

Effects of Walking Exercise at a Pace With Versus Without Ischemic Leg Symptoms on Functional Performance Measures in People With Lower Extremity Peripheral Artery Disease: The LITE Randomized Clinical Trial

Background In people with peripheral artery disease, post hoc analyses of the LITE (Low Intensity Exercise Intervention in Peripheral Artery Disease) randomized trial were conducted to evaluate the effects of walking exercise at a pace inducing ischemic leg symptoms on walking velocity and the Short Physical Performance Battery, compared with walking exercise without ischemic leg symptoms and compared with a nonexercising control group. Methods and Results Participants with peripheral artery disease were randomized to: home-based walking exercise that induced ischemic leg symptoms; home-based walking exercise conducted without ischemic leg symptoms; or a nonexercising control group for 12 months. Outcomes were change of walking velocity over 4 m and change of the Short Physical Performance Battery (0-12, with 12=best) at 6- and 12-month follow-up. A total of 264 participants (48% women, 61% Black race) were included. Compared with walking exercise without ischemic symptoms, walking exercise that induced ischemic symptoms improved change in usual-paced walking velocity over 4 m at 6-month (0.056 m/s [95% CI, 0.019-0.094 m/s]; P<0.01) and 12-month follow-up (0.084 m/s [95% CI, 0.049-0.120 m/s]; P<0.01), change in fast-paced of walking velocity over 4 m at 6-month follow-up (P=0.03), and change in the Short Physical Performance Battery at 12-month follow-up (0.821 [95% CI, 0.309-1.334]; P<0.01). Compared with control, walking exercise at a pace inducing ischemic symptoms improved change in usual-paced walking velocity over 4 m at 6-month follow-up (0.066 m/s [95% CI, 0.021-0.111 m/s]; P<0.01). Conclusions In people with peripheral artery disease, those who walked for exercise at a comfortable pace without ischemic leg symptoms slowed their walking speed during daily life and worsened the Short Physical Performance Battery score, a potentially harmful effect, compared with people who walked for exercise at a pace inducing ischemic leg symptoms. Compared with a control group who did not exercise, home-based walking exercise at a pace inducing ischemic leg symptoms significantly improved change of walking velocity over 4 m at 6-month follow-up, but this benefit did not persist at 12-month follow-up. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02538900.

The Global Epidemiological Transition in Cardiovascular Diseases: Unrecognised Impact of Endemic Infections on Peripheral Artery Disease

An epidemiological transition in the prevalence of peripheral artery disease (PAD) is taking place especially in low- and middle-income countries (LMICs) where an ageing population and adoption of western lifestyles are associated with an increase in PAD. We discuss the limited evidence which suggests that infection, potentially mediated by inflammation, may be a risk factor for PAD, and show by means of an ecological analysis that country-level prevalence of the major endemic infections of HIV, tuberculosis and malaria are associated with the prevalence of PAD. While further research is required, we propose that scientists and health authorities pay more attention to the interplay between communicable and non-communicable diseases, and we suggest that limiting the occurrence of endemic infections might have some effect on slowing the epidemiological transition in PAD.

Ankle-Brachial Index and Energy Production in People Without Peripheral Artery Disease: The BLSA

Background Lower ankle-brachial index (ABI) values within the 0.90 to 1.40 range are associated with poorer mitochondrial oxidative capacity of thigh muscles in cross-sectional analyses. Whether ABI decline is associated with greater declines in thigh muscle oxidative capacity with aging is unknown. Method and Results We analyzed data from 228 participants (100 men) of the BLSA (Baltimore Longitudinal Study of Aging), aged 39 to 97 years, with an ABI between 0.9 and 1.40 at baseline and at follow-up (mean follow-up period of 2.8 years). We examined mitochondrial oxidative capacity of the left thigh muscle, by measuring the postexercise phosphocreatine recovery rate constant (kPCr) from phosphorus-31 magnetic resonance spectroscopy. Greater kPCr indicated higher mitochondrial oxidative capacity. Although kPCr was available on the left leg only, ABI was measured in both legs. Longitudinal rates of change (Change) of left and right ABI and kPCr of the left thigh muscle were estimated using linear mixed effects models, and their association was analyzed by standardized multiple linear regressions. In multivariate analysis including sex, age, baseline kPCr, both left and right baseline ABI, and ABI change in both legs, (kPCr)Change was directly associated with ipsilateral (left) (ABI)Change (standardized [STD]-β=0.14; P=0.0168) but not with contralateral (right) (ABI)Change (P=0.22). Adjusting for traditional cardiovascular risk factors, this association remained significant (STD-β=0.18; P=0.0051). (kPCr)Change was steeper in White race participants (STD-β=0.16; P=0.0122) and body mass index (STD-β=0.13; P=0.0479). There was no significant association with current smoking status (P=0.63), fasting glucose (P=0.28), heart rate (P=0.67), mean blood pressure (P=0.78), and low-density lipoprotein (P=0.75), high-density lipoprotein (P=0.82), or triglycerides (P=0.15). Conclusions In people without peripheral arterial disease, greater decline in ABI over time, but not baseline ABI, was associated with faster decline in thigh mitochondrial oxidative capacity in the ipsilateral leg. Further studies are needed to examine whether early interventions that improve lower extremity muscle perfusion can improve and prevent the decline of muscle energetics.

Patient-Reported Outcome Measures in Symptomatic, Non-Limb-Threatening Peripheral Artery Disease: A State-of-the-Art Review

Patient-reported outcome measures (PROMs) are health outcomes directly reported by the patient that can be used to measure the effect of disease and treatments on patient perceived well-being. This review summarizes current evidence regarding the validation of PROMs in people with symptomatic, nonlimb-threatening peripheral artery disease. A literature search was conducted to identify studies of symptomatic peripheral artery disease without limb-threatening ischemia that included PROMs and had sample sizes ≥25. PROMs were summarized along a continuum of validation using classical test theory framework and according to whether they fulfilled defined criteria for (1) content validity; (2) psychometric validation; and (3) further validation evidence base expansion. Of 2198 articles identified, 157 (7.1%) met inclusion criteria. Twenty-four PROMs in patients with symptomatic peripheral artery disease were reviewed. Among disease-specific PROMs, 8 of 15 had excellent reliability as measured by a Cronbach alpha ≥0.80. Based on established criteria for PROM responsiveness, 6 of 15 disease-specific PROMs demonstrated excellent sensitivity to change. Of these, the disease-specific peripheral artery questionnaire, vascular quality of life questionnaire, and walking impairment questionnaire met criteria for validation at each stage of the continuum. For generic (nondisease specific) PROMs, the European Quality of Life 5-Dimension and SF-36 had the most extensive evidence of validation. Evidence from this review can inform selection of PROMs aligned with scientific and clinical goals, given the variable degree of validation and potential complementary nature of the measures.

One-Year Change in Walking Performance and Subsequent Mobility Loss and Mortality Rates in Peripheral Artery Disease: Longitudinal Data From the WALCS

Background

Associations of 1‐year change in functional performance measures with subsequent mobility loss and mortality in people with lower extremity peripheral artery disease are unknown.

Methods and Results

Six‐minute walk and 4‐meter walking velocity (usual and fastest pace) were measured at baseline and 1 year later in 612 people with peripheral artery disease (mean age 71±9 years, 37% women). Participants were categorized into tertiles, based on 1‐year changes in walking measures. Cox proportional hazards models were used to examine associations between 1‐year change in each walking measure and subsequent mobility loss and mortality, respectively, adjusting for potential confounders. Compared with the best tertile, the worst tertile (ie, greatest decline) in 1‐year change in each performance measure was associated with higher rates of mobility loss: 6‐minute walk (Tertile 1 [T1] cumulative incidence rate [IR], 72/160; Tertile 3 [T3] IR, 47/160; hazard ratio [HR], 2.35; 95% CI, 1.47–3.74), usual‐paced 4‐meter walking velocity (T1 IR, 54/162; T3 IR, 57/162; HR, 2.21; 95% CI, 1.41–3.47), and fast‐paced 4‐meter walking velocity (T1 IR, 61/162; T3 IR, 58/162; HR, 1.81; 95% CI, 1.16–2.84). Compared with the best tertile, the worst tertiles in 1‐year change in 6‐minute walk (T1 IR, 66/163; T3 IR, 54/163; HR, 1.61; 95% CI, 1.07–2.43) and fast‐paced 4‐meter walking velocity (T1 IR, 63/166; T3 IR, 44/166; HR, 1.75; 95% CI, 1.16, 2.64) were associated with higher mortality.

Conclusions

In people with peripheral artery disease, greater 1‐year decline in 6‐minute walk or 4‐meter walking velocity may help identify people with peripheral artery disease at highest risk for mobility loss and mortality.

Midlife Cardiorespiratory Fitness and the Development of Peripheral Artery Disease in Later Life

Background Data are sparse on the prospective associations between physical activity and incidence of lower extremity peripheral artery disease (PAD). Methods and Results Linking participant data from the CCLS (Cooper Center Longitudinal Study) to Medicare claims files, we studied 19 023 participants with objectively measured midlife cardiorespiratory fitness through maximal effort on the Balke protocol who survived to receive Medicare coverage between 1999 and 2009. The study aimed to determine the association between midlife cardiorespiratory fitness and incident PAD with proportional hazards intensity models, adjusted for age, sex, body mass index, and other covariates, to PAD failure time data. During 121 288 person-years of Medicare follow-up, we observed 805 PAD-related hospitalizations/procedures among 19 023 participants (21% women, median age 50 years). Lower midlife fitness was associated with a higher rate of incident PAD in patients aged 65 years and older (low fit [quintile 1]: 11.4, moderate fit [quintile 2 to 3]: 7.8, and high fit [quintile 4 to 5]: 5.7 per 1000 person years). After multivariable adjustment for common predictors of incident PAD such as age, body mass index, hypertension, and diabetes, these findings persisted. Lower risk for PAD per greater metabolic equivalent task of fitness was observed (hazard ratio [HR], 0.93 [95% CI, 0.90-0.97]; P<0.001). Among a subset of patients with an additional fitness assessment, each 1 metabolic equivalent task increase from baseline fitness was associated with decreased risk of incident PAD (HR, 0.90 [95% CI, 0.82-0.99]; P=0.03). Conclusions Cardiorespiratory fitness in healthy, middle-aged adults is associated with lower risk of incident PAD in later life, independent of other predictors of incident PAD.

Identifying Gaps in Disease Knowledge among Patients with Peripheral Artery Disease

INTRODUCTION

An individual's understanding of disease risk factors and outcomes is important for the ability to make healthy lifestyle choices and decisions about disease treatment. Peripheral artery disease (PAD) is a condition with increasing global prevalence and high risk of adverse patient outcomes. This study seeks to understand the adequacy of disease understanding in patients with PAD.

METHODS

This was an observational study of patients with PAD recruited from vascular surgery outpatient clinic and PAD clinical studies at a single academic medical center over an 8-month period. A 44-item paper survey assessed demographic and socioeconomic information, knowledge of personal medical history, PAD risk factors, consequences of PAD, and health education preferences. Patients with documented presence of PAD were offered the survey. Patients unable to complete the survey or provide informed consent were not considered eligible. Disease "awareness" was defined as correct acknowledgement of the presence or absence of a disease, including PAD, in the personal medical history. "PAD knowledge score" was the percentage of correct responses to questions on general PAD risk factors and consequences. Of 126 eligible patients, 109 participated. Bivariate analysis was used to study factors associated with awareness of PAD diagnosis. Factors associated with the PAD knowledge score were studied using the Pearson correlation coefficient, two-sample T-test, or one-way ANOVA. P value < .05 was considered statistically significant.

RESULTS

Mean participant age was 69.4 ± 11.0 years and 39.4% (N=43) were female. Most participants (78.9%; N=86) had critical limb-threatening ischemia. Only 65.4% (N=70) of participants were aware of a diagnosis of PAD, which was less than their awareness of related comorbidities. Factors positively associated with PAD diagnosis awareness were female sex (81.4% vs. 54.7%; P=.004) and history of percutaneous leg revascularization (78.6% vs. 47.9%; p=.001). Among 17 patients who had undergone major leg amputation, 35% (N=6) were unaware of a diagnosis of PAD. PAD knowledge scores correlated positively with an awareness of PAD diagnosis (59.1% vs. 48.7%; P=.02) and negatively with a history of hypertension (53.4% vs. 68.1%; P=.001). Most participants (86.5%; N=90) expressed a desire to be further educated on PAD. The most popular education topics were dietary recommendations, causes, and treatment for PAD.

CONCLUSION

Patients with PAD have deficits in their awareness of this diagnosis and general knowledge about PAD. Future research priorities should further define these deficits and their causes in order to inform new strategies that foster information-seeking behavior and effective educational programs for PAD.

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.

Walking Exercise Therapy Effects on Lower Extremity Skeletal Muscle in Peripheral Artery Disease

Walking exercise is the most effective noninvasive therapy that improves walking ability in peripheral artery disease (PAD). Biologic mechanisms by which exercise improves walking in PAD are unclear. This review summarizes evidence regarding effects of walking exercise on lower extremity skeletal muscle in PAD. In older people without PAD, aerobic exercise improves mitochondrial activity, muscle mass, capillary density, and insulin sensitivity in skeletal muscle. However, walking exercise increases lower extremity ischemia in people with PAD, and therefore, mechanisms by which this exercise improves walking may differ between people with and without PAD. Compared with people without PAD, gastrocnemius muscle in people with PAD has greater mitochondrial impairment, increased reactive oxygen species, and increased fibrosis. In multiple small trials, walking exercise therapy did not consistently improve mitochondrial activity in people with PAD. In one 12-week randomized trial of people with PAD randomized to supervised exercise or control, supervised treadmill exercise increased treadmill walking time from 9.3 to 15.1 minutes, but simultaneously increased the proportion of angular muscle fibers, consistent with muscle denervation (from 7.6% to 15.6%), while angular myofibers did not change in the control group (from 9.1% to 9.1%). These findings suggest an adaptive response to exercise in PAD that includes denervation and reinnervation, an adaptive process observed in skeletal muscle of people without PAD during aging. Small studies have not shown significant effects of exercise on increased capillary density in lower extremity skeletal muscle of participants with PAD, and there are no data showing that exercise improves microcirculatory delivery of oxygen and nutrients in patients with PAD. However, the effects of supervised exercise on increased plasma nitrite abundance after a treadmill walking test in people with PAD may be associated with improved lower extremity skeletal muscle perfusion and may contribute to improved walking performance in response to exercise in people with PAD. Randomized trials with serial, comprehensive measures of muscle biology, and physiology are needed to clarify mechanisms by which walking exercise interventions improve mobility in PAD.

Effects of supervised exercise therapy on blood pressure and heart rate during exercise, and associations with improved walking performance in peripheral artery disease: Results of a randomized clinical trial

OBJECTIVE

Supervised exercise therapy (SET) improves walking ability in people with peripheral artery disease (PAD). However, the effects of SET on cardiovascular health in PAD remain unclear. Using data from a randomized clinical trial, this post hoc analyses investigated the effects of a 6-month SET intervention, compared with a control group, on changes in blood pressure (BP) and heart rate (HR) during a graded treadmill exercise test in people with PAD.

METHODS

We randomized 210 participants with PAD to either SET (3× weekly) or control (1× weekly health lectures) for 6 months. A graded treadmill exercise test, 6-minute walk test, and Walking Impairment Questionnaire were completed at baseline and the 6-month follow-up. BP and HR were measured at the end of each 2-minute stage of the graded treadmill exercise test. Mixed effects regression models compared the overall mean 6-month change in systolic BP, diastolic BP, pulse pressure (PP), and HR during the first 5 stages of the graded treadmill exercise test between groups.

RESULTS

Of the 210 randomized participants with PAD, 176 (67 ± 9 years; 72 [41%] female, 115 [65%] Black) completed the graded treadmill exercise test at baseline and the 6-month follow-up. Compared with the control group at the 6-month follow-up, SET significantly decreased overall mean systolic BP (-12 mm Hg; P < .001), PP (-9 mm Hg; P < .001), and HR (-7 b/min; P < .01) during a graded treadmill exercise test but not diastolic BP. Among participants randomized to SET, a greater decrease in systolic BP, PP, and HR during a graded treadmill exercise test was significantly associated with a greater improvement in 6-minute walk distance (systolic BP, r = -0.19 [P = .03] and PP, r = -0.23 [P < .01]; and HR, r = -0.21 [P < .01]) and with maximal treadmill walking distance (systolic BP, r = -0.21 [P < .01] and PP, r = -0.17 [P = .03]) at the 6-month follow-up. A greater decrease in the HR during a graded treadmill exercise test was significantly associated with a better WIQ distance score (r = -0.27; P = .03) at the 6-month follow-up.

CONCLUSIONS

In people with PAD, compared with a control group, SET improved cardiovascular health, measured by changes in BP and HR during exercise. The degree of improvement in cardiovascular health correlated with the degree of improvement in walking performance in people with PAD. NCT: 01408901.

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.

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.

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.