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

Rivaroxaban for Patients with Intermittent Claudication

BACKGROUND

The combination of rivaroxaban plus aspirin compared with aspirin alone reduces the risk of major adverse cardiovascular and limb events for high-risk patients with peripheral artery disease. It is unknown whether rivaroxaban plus aspirin improves intermittent claudication for adults with lower-risk peripheral arterial disease.

METHODS

In this randomized, open-label, multicenter, 24-week clinical trial, we randomly assigned patients with peripheral artery disease and intermittent claudication to receive either 2.5 mg of rivaroxaban twice daily plus 100 mg of aspirin once daily or 100 mg of aspirin once daily. The primary outcome was a 24-week change in total walking distance, measured by the 6-minute walking test. The primary safety outcome was the incidence of major bleeding or clinically relevant nonmajor bleeding.

RESULTS

Eighty-eight patients were randomly assigned to either rivaroxaban plus aspirin (n=46) or aspirin alone (n=42). The mean age was 67 years, and 54% were female. The total walking distance measured by 6-minute walk test improved by 89 ± 18 m (mean±standard error) in the rivaroxaban-plus-aspirin group versus 21 ± 16 m in the aspirin-alone group. This corresponded to an absolute difference of 68 ± 24 m (95% confidence interval [CI], 19 to 116 m; P=0.007) and a relative improvement over the aspirin-alone group of 327% (95% CI, 94 to 560%). No major bleeding events were observed in either group.

CONCLUSIONS

In patients with peripheral artery disease and intermittent claudication, 2.5 mg of rivaroxaban twice daily plus 100 mg of aspirin daily improved the total walking distance by a 6-minute walking test compared with 100 mg of aspirin daily alone. (Funded by Bayer S.A.; Clinicaltrials.gov number, NCT04853719.).

Effect of Arm-Ergometry Versus Treadmill Supervised Exercise on Cardiorespiratory Fitness and Walking Distances in Patients With Peripheral Artery Disease: The ARMEX Randomized Clinical Trial

PURPOSE

To compare arm-ergometry and treadmill supervised exercise training on cardiorespiratory fitness and walking distances in patients with peripheral artery disease (PAD).

METHODS

ARMEX was a single-center, single-blinded, parallel group, non-inferiority trial enrolling symptomatic patients with PAD. Patients were randomized (1:1 ratio) to a 12-wk arm-ergometry (AEx) or standard treadmill (TEx) supervised exercise training protocol. The powered primary end point was the change in peak oxygen uptake (VO 2 ) at 12 wk, measured on a treadmill cardiopulmonary exercise test (CPX). Secondary outcomes included changes in VO 2 at the first ventilatory threshold (VT-1), ventilatory efficiency (ratio of minute ventilation [VE] to carbon dioxide production [VCO 2 ], VE/VCO 2 ), walking distances by CPX and 6-min walking test (6MWT), and self-reported walking limitations.

RESULTS

Fifty-six patients (66 ± 8 yr; 88% male) were randomized (AEx, n = 28; TEx, n = 28). At 12 wk, VO 2peak change was not significantly different between groups (0.75 mL/kg/min; 95% CI, -0.94 to 2.44; P = .378), despite a significant increase only in AEx. VO 2 at VT-1 improved in both groups without between-group differences, and VE/VCO 2 slope improved more in AEx. The TEx attained greater improvements in walking distance by CPX (121.08 m; 95% CI, 24.49-217.66; P = .015) and 6MWT (25.08 m; 95% CI, 5.87-44.29; P = .012) and self-perceived walking distance.

CONCLUSIONS

Arm-ergometry was noninferior to standard treadmill training for VO 2peak , and treadmill training was associated with greater improvements in walking distance. Our data support the use of treadmill as a first-line choice in patients with PAD to enhance walking capacity, but arm-ergometry could be an option in selected patients.

Exercise Therapy for Peripheral Artery Disease

PURPOSE OF REVIEW

To summarize evidence regarding exercise treatments for lower extremity peripheral artery disease (PAD).

RECENT FINDINGS

Supervised walking exercise is recommended by practice guidelines for PAD. Supervised treadmill exercise improves treadmill walking distance by approximately 180 m and 6-min walk distance by 30-35 m, compared to control. The Centers for Medicaid and Medicare Services covers 12 weeks of supervised exercise, but most people with PAD do not participate. Home-based walking exercise may be more convenient and accessible than supervised exercise. In randomized clinical trials, home-based walking exercise interventions incorporating behavioral methods, such as accountability to a coach, goal-setting, and self-monitoring, improved 6-min walk distance by 40-54 m, compared to control. Arm and leg ergometry also improved walking endurance for people with PAD, but efficacy compared to walking exercise remains unclear. Walking exercise is first-line therapy for PAD-related walking impairment and can be effective in either a supervised or a structured home-based setting.

Winners do what they fear: exercise and peripheral arterial disease-an umbrella review

AIMS

This systematic review aims to evaluate and summarize findings from published meta-analyses on the effects of regular exercise in patients with peripheral arterial disease (PAD). The review will assess the impact of exercise on functional parameters, health-related quality of life, haemodynamic parameters, physical activity levels, adverse events, and mortality.

METHODS AND RESULTS

A systematic search was performed in PubMed, Web of Science, Scopus, and Cochrane Library databases (up to May 2023) to identify meta-analyses including randomized controlled trials that examined the effects of regular exercise in patients with PAD. Sixteen studies, with a total of 198 meta-analyses, were identified. Results revealed with strong evidence that patients with PAD who exercised improved functional and health-related quality of life parameters. Specifically, supervised aerobic exercise (i.e. walking to moderate-maximum claudication pain) improves maximum walking distance [mean difference (MD): 177.94 m, 95% confidence interval (CI) 142.29-213.60; P < 0.00001; I2: 65%], pain-free walking distance (fixed MD: 68.78 m, 95% CI 54.35-83.21; P < 0.00001; I2: 67%), self-reported walking ability [i.e. distance score (MD: 9.22 points, 95% CI 5.74-12.70; P < 0.00001; I2: 0%), speed score (MD: 8.71 points, 95% CI 5.64-11.77; P < 0.00001, I2: 0%), stair-climbing score (MD: 8.02 points, 95% CI 4.84-11.21; P < 0.00001, I2: 0%), and combined score (MD: 8.76 points, 95% CI 2.78-14.74; P < 0.0001, I2: 0%)], aerobic capacity (fixed MD: 0.62 mL/kg/min, 95% CI 0.47-0.77, P < 0.00001, I2: 64%), and pain score (MD: 7.65, 95% CI 3.15-12.15; P = 0.0009; I2: 0%), while resistance exercise improves lower limb strength (standardized mean difference: 0.71, 95% CI 0.29-1.13, P = 0.0009; I2: 0%]. Regarding other outcomes, such as haemodynamic parameters, no significant evidence was found, while physical activity levels, adverse events, and mortality require further investigation.

CONCLUSION

Synthesis of the currently available meta-analyses suggests that regular exercise may be beneficial for a broad range of functional tasks improving health-related quality of life in patients with PAD. Supervised aerobic exercise is the best type of exercise to improve walking-related outcomes and pain, while resistance exercise is more effective to improve lower limb strength.

Predictors of walking capacity in patients with peripheral arterial disease

BACKGROUND

Walking capacity is severely impaired in patients with peripheral arterial disease (PAD). Given the prognostic importance of walking capacity, the level of evidence on possible predictors of walking capacity in patients with PAD is insufficient.

AIMS

To investigate the predictors of walking capacity in patients with PAD.

METHODS

A total of 51 patients with PAD were included in this cross-sectional study. Walking capacity was determined with 6‑minute walk test (6MWT) and walking impairment questionnaire (WIQ). Functional mobility was assessed with repeated sit-to-stand test (RSS) and timed up and go test (TUG). Hand-held dynamometer was used to measurement lower extremity muscle strength. Balance was assessed with Biodex Balance System-limit of stability (BBS-LOS). Fatigue was evaluated with fatigue impact scale (FIS).

RESULTS

There was a strong correlation between 6MWT walking distance and WIQ, two methods of assessing walking capacity (r = 0.835 p < 0.001). The 6MWT was correlated with RSS, TUG, lower extremity muscle strength, BBS-LOS and FIS. The WIQ was correlated with RSS, TUG, BBS-LOS and FIS. The RSS and FIS were independent determinants of the 6MWT and WIQ, accounting for 68% and 57% of the variance, respectively.

CONCLUSION

This study demonstrated that functional mobility and fatigue were independent predictors of walking capacity in patients with PAD. Both subjective and objective measurement methods can be used for determining the level of walking capacity in the patients with PAD.

Supervised exercise training improves cardiorespiratory fitness and reduces perioperative risk in peripheral artery disease patients with intermittent claudication

INTRODUCTION

This study examined to what extent supervised aerobic and resistance exercise combined with continued unsupervised exercise training improves cardiorespiratory fitness and corresponding perioperative risk in peripheral artery disease (PAD) patients with intermittent claudication.

METHODS

A total of 106 patients (77% male) were enrolled into the study, alongside 155 healthy non-PAD control participants. Patients completed supervised exercise therapy (aerobic and resistance exercises of the upper and lower limbs) twice a week for 10 weeks. Thereafter, 52 patients completed 12 weeks of an unsupervised tailored home-based exercise. Pain-free walking distance (PWD), maximum walking distance (MWD), peak oxygen uptake ([Formula: see text]) and perioperative risk were assessed before and after both exercise interventions.

RESULTS

Patients were highly unconditioned relative to healthy controls ([Formula: see text]=11.9 vs 24.2ml/kg/min, p=<0.001) with 91% classified as high perioperative risk (peak oxygen uptake <15ml/kg/min). Supervised exercise increased PWD (+44±81m, p=<0.001), MWD (+44±71m, p=<0.001) and [Formula: see text] (+1.01±1.63ml/kg/min, p=<0.001) and lowered perioperative risk (91% to 85%, p=<0.001). When compared with supervised exercise, the improvements in PWD were maintained following unsupervised exercise (+11±91m vs supervised exercise, p=0.572); however, MWD and [Formula: see text] decreased (-15±48m, p=0.030 and -0.34±1.11ml/kg/min, p=0.030, respectively) and perioperative risk increased (+3%, p=<0.001) although still below baseline (p=<0.001).

CONCLUSIONS

Supervised aerobic and resistance exercise training and, to a lesser extent, unsupervised tailored exercise improves walking capacity and cardiorespiratory fitness and reduces perioperative risk in PAD patients with intermittent claudication.

Use of the speed achieved on the 6MWT for programming aerobic training in patients recovering from severe COVID-19: an observational study

INTRODUCTION

Patients who suffered severe COVID-19 need pulmonary rehabilitation. Training may be prescribed objectively based on the maximum speed in the six-minute walk test. The objective of this study was to determine the effects of a personalized pulmonary rehabilitation program based on the six-minute walk test speed for post-COVID-19 patients.

METHODS

Observational quasi-experimental study. The pulmonary rehabilitation program consisted of 8 weeks of training, twice a week for 60 minutes per session of supervised exercise. Additionally, the patients carried out home respiratory training. Patients were evaluated by exercise test, spirometry and the Fatigue Assessment Scale before and after the eight-week pulmonary rehabilitation program.

RESULTS

After the pulmonary rehabilitation program, forced vital capacity increased from 2.47 ± 0.60 to 3.06 ± 0.77 L (p < .001) and the six-minute walk test result increased from 363.50 ± 88.87 to 480.9 ± 59.25 m (p < .001). In fatigue perception, a significant decrease was observed, from 24.92 ± 7.01 to 19.10 ± 7.07 points (p < .01). Isotime evaluation of the Incremental Test and the Continuous Test showed a significant reduction in heart rate, dyspnoea and fatigue.

CONCLUSION

The eight-week personalized pulmonary rehabilitation program prescribed on the basis of the six-minute walk test speed improved respiratory function, fatigue perception and the six-minute walk test result in post-COVID-19 patients.KEY MESSAGESCOVID-19 is a multisystem disease with common complications affecting the respiratory, cardiac and musculoskeletal systems.The 6MWT speed-based training plan allowed for increased speed and incline during the eight-week RP program.Aerobic, strength and flexibility training reduced HR, dyspnoea and fatigue in severe post-COVID-19 patients.

A Multicenter, Investigator-Blinded, Randomized Controlled Trial to Assess the Efficacy of Calf Neuromuscular Electrical Stimulation Program on Walking Performance in Peripheral Artery Disease: The ELECTRO-PAD Study Protocol

This paper describes a currently on-going multicenter, randomized controlled trial designed to assess the efficacy of calf neuromuscular electrical stimulation (NMES) on changes in maximal walking distance in people with lower extremity peripheral artery disease (PAD), compared with a non-intervention control-group. This study (NCT03795103) encompasses five participating centers in France. PAD participants with a predominant claudication at the calf level and a maximal treadmill walking distance ≤300 m are randomized into one of the two groups: NMES group or Control group. The NMES program consists of a 12-week program of electrical stimulations at the calf-muscle level. The primary outcome of the study is the change in maximal treadmill walking distance at 12 weeks. Main secondary outcomes include changes in the pain-free treadmill walking distance; 6 min total walking distance; global positioning system (GPS)-measured outdoor walking capacity; daily physical activity level by accelerometry; self-reported walking impairment; self-reported quality of life; ankle-brachial index; and skin microvascular function, both at the forearm and calf levels. Recruitment started in September 2019 and data collection is expected to end in November 2022.

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.

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.

Effectiveness of supervised exercise, home-based exercise or walk advice strategies on walking performance and muscle endurance in patients with intermittent claudication (SUNFIT trial)-a randomized clinical trial

BACKGROUND

Supervised exercise is a guideline-recommended treatment in intermittent claudication (IC). Hospital-based supervised exercise-programmes (SEP) are underutilized while home-based structured exerciseprogrammes (HSEP) have attracted interest. The results from HSEP in IC are inconsistent and may confer no benefit over walk advice (WA) and be less effective than SEP.

AIMS

To compare the effectiveness of best medical treatment, including Nordic pole WA alone, or WA + SEP or WA + HSEP for patients with IC.

METHODS

This three-armed, multicentre randomized clinical trial enrolled patients with IC, all patients received best medical treatment including walking poles and the advice of regular Nordic pole walking (WA). For HSEP and SEP, additional exercise programmes were provided. The primarily investigated hypothesis was a non-inferiority analysis of SEP vs HSEP regarding the six-minute walk test (6MWT) maximum distance, with a pre-defined non-inferiority margin of 50 m. Supporting outcomes included muscle endurance tests and the Walking Impairment Questionnaire. Outcomes were assessed at baseline, 3, 6 and 12 months by a blinded evaluator.

RESULTS

Altogether 166 patients (mean age 72 years; 59% males) were randomized. In HSEP were 24% and SEP 26% fully exercise adherent. All three groups improved pain-free walking distance over time, but there were no significant intergroup differences. The intergroup 6MWT difference between SEP and HSEP from 0-12 months was -11.6  m, 95% CI: -36.4 to 13.0  m (i.e., within the pre-specified non-inferiority margin).

CONCLUSION

HSEP was non-inferior to SEP in patients with IC. There were no significant differences observed between the three groups at one year.

CLINICAL TRIAL DATABASE ID

Registration: ClinicialTrials.gov (NCT02341716). Trial registry name: Hospital- and Home-based Supervised Exercise Versus Unsupervised Walk Advice For Patients With InTermittent Claudication (SUNFIT).

Supervised Exercise Training Improves 6 min Walking Distance and Modifies Gait Pattern during Pain-Free Walking Condition in Patients with Symptomatic Lower Extremity Peripheral Artery Disease

This study aimed to investigate the effects of supervised exercise training (SET) on spatiotemporal gait and foot kinematics parameters in patients with symptomatic lower extremity peripheral artery disease (PAD) during a 6 min walk test. Symptomatic patients with chronic PAD (Fontaine stage II) following a 3 month SET program were included. Prior to and following SET, a 6 min walk test was performed to assess the 6 min walking distance (6MWD) of each patient. During this test, spatiotemporal gait and foot kinematics parameters were assessed during pain-free and painful walking conditions. Twenty-nine patients with PAD (65.4 ± 9.9 years.) were included. The 6MWD was significantly increased following SET (+10%; p ≤ 0.001). The walking speed (+8%) and stride frequency (+5%) were significantly increased after SET (p ≤ 0.026). The stride length was only significantly increased during the pain-free walking condition (+4%, p = 0.001), whereas no significant differences were observed during the condition of painful walking. Similarly, following SET, the relative duration of the loading response increased (+12%), the relative duration of the foot-flat phase decreased (−3%), and the toe-off pitch angle significantly increased (+3%) during the pain-free walking condition alone (p ≤ 0.05). A significant positive correlation was found between changes in the stride length (r = 0.497, p = 0.007) and stride frequency (r = 0.786, p ≤ 0.001) during pain-free walking condition and changes in the 6MWD. A significant negative correlation was found between changes in the foot-flat phase during pain-free walking condition and changes in the 6MWD (r = −0.567, p = 0.002). SET was found to modify the gait pattern of patients with symptomatic PAD, and many of these changes were found to occur during pain-free walking. The improvement in individuals’ functional 6 min walk test was related to changes in their gait pattern.

A look to the future: Pandemic-induced digital technologies in vascular surgery

Like many areas of medicine, vascular surgery has been transformed by the COVID-19 (coronavirus disease 2019) pandemic. Public health precautions to minimize disease transmission have led to reduced attendance at hospitals and clinics in elective and emergency settings; fewer face-to-face and hands-on clinical interactions; and increased reliance on telemedicine, virtual attendance, investigations, and digital therapeutics. However, a “silver lining” to the COVID-19 pandemic may be the mainstream acceptance and acceleration of telemedicine, remote monitoring, digital health technology, and three-dimensional technologies, such as three-dimensional printing and virtual reality, by connecting health care providers to patients in a safe, reliable, and timely manner, and supplanting face-to-face surgical simulation and training. This review explores the impact of these changes in the delivery of vascular surgical care.

Improvement in 6-Minute Walking Distance after Supervised Exercise Training Is Related to Changes in Quality of Life in Patients with Lower Extremity Peripheral Artery Disease

This study aimed to investigate the relationship between supervised exercise training (SET)-induced changes in treadmill performance and 6 min walking distance, and changes in general (physical and mental) self-perceived health-related quality of life (HRQoL) in symptomatic patients with lower extremity peripheral artery disease (PAD). This is an observational study investigating Fontaine stage II PAD patients participating in 3-month SET. Before and following SET, treadmill performance (pain-free (PFWD) and maximal (MWD)), and 6 min walking distance (6MWD) were assessed. Self-perceived HRQoL was assessed with the Medical Outcomes Study Short-Form 36 (SF-36). Ankle- and toe-brachial indexes were also measured. One-hundred forty-seven patients with PAD were included (64.9 ± 9.6 y, 70% men). After SET, PFWD (+102%, p ≤ 0.001), MWD (+87%, p ≤ 0.001), and 6MWD (+14%, p ≤ 0.001) significantly increased. All eight SF-36 subscale scores significantly improved following SET (p ≤ 0.04). SET significantly improved physical and mental component summaries of the SF-36 (p ≤ 0.001). Larger increases in 6MWD were associated with greater improvements in physical (β = 0.19; p = 0.02) and mental (β = 0.24; p = 0.005) component summaries of the SF-36. No significant relationship was observed between changes in treadmill performance and changes in physical and mental component summaries of the SF-36. These results show that improvements in 6MWD following SET are related to improvements in general self-perceived HRQoL in patients with symptomatic lower extremity PAD. On the contrary, changes in treadmill performance were not related to improvements in HRQoL. These results suggest that the 6 min walking test is an essential outcome measure to assess overall patient functional status following interventions in patients with PAD.

Impact of chronic kidney disease on hemoglobin among patients with peripheral artery disease treated with P2Y12 inhibitors: Insights from the EUCLID trial

Patients with chronic kidney disease may develop new or more severe anemia when treated with antiplatelet agents due to blood loss in conjunction with impaired erythropoiesis. Because anemia independently predicts limb amputation and mortality among patients with peripheral artery disease (PAD), we evaluated the relationship between estimated glomerular filtration rate (eGFR) and hemoglobin (Hb) levels in the EUCLID trial in which patients with symptomatic PAD were randomized to ticagrelor or clopidogrel. At baseline, 9025, 1870, and 1000 patients had eGFR ⩾ 60, 45-59, and < 45 mL/min/1.73 m², respectively. The mean fall in Hb during the trial was 0.46 ± 1.68 g/dL and did not differ by baseline eGFR category, although Hb fall ⩾ 10% was more frequent among patients with lower eGFR (p for trend < 0.0001). On-study treatment with iron, erythropoiesis-stimulating agents, and/or red blood cell transfusion was reported for 479 (5.3%), 165 (8.8%), and 129 (12.9%) patients in the three eGFR categories, respectively (p for trend < 0.0001). After adjustment for baseline and post-randomization effects, those not receiving anemia treatment had a smaller reduction in Hb from baseline than those receiving anemia treatment (p < 0.0001). Other determinants of Hb reduction included absence of on-study myocardial infarction, coronary or peripheral revascularization, residence outside North America, male sex, and baseline eGFR. We conclude that among patients with PAD treated with P2Y₁₂ inhibitors, lower baseline eGFR was associated with a greater reduction in Hb. ClinicalTrials.gov Identifier: NCT01732822.

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.

Multimodal Supervised Exercise Training Is Effective in Improving Long Term Walking Performance in Patients with Symptomatic Lower Extremity Peripheral Artery Disease

This study aimed to evaluate the effect of a multimodal supervised exercise training (SET) program on walking performance for 12 months in patients with symptomatic lower extremity peripheral artery disease (PAD). Consecutive patients with Fontaine stage II PAD participating in the SET program of our hospital were retrospectively investigated. Walking performance, assessed using a treadmill with measures of the pain-free and maximal walking distance (PFWD, MWD, respectively), and 6 min walking distance (6MWD), were tested before and following SET, as well as at 6 and 12 months after SET completion. Ninety-three symptomatic patients with PAD (65.0 ± 1.1 y) were included in the study. Following SET, the walking performance significantly improved (PFWD: +145%, p ≤ 0.001; MWD: +97%, p ≤ 0.001; 6MWD: +15%, p ≤ 0.001). At 6 months, PFWD (+257%, p ≤ 0.001), MWD (+132%, p ≤ 0.001), and 6MWD (+11%, p ≤ 0.001) remained significantly improved compared with the pre-SET condition. At 12 months, PFWD (+272%, p ≤ 0.001), MWD (+130%, p ≤ 0.001), and 6MWD (+11%, p ≤ 0.001) remained significantly improved compared with the pre-training condition. The walking performance remained significantly improved in both women and men for up to 12 months (p ≤ 0.001). Multimodal SET is effective at improving walking performance in symptomatic patients with PAD, with improvements lasting up to 12 months.

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

AIM

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Network Meta-Analysis Comparing the Outcomes of Treatments for Intermittent Claudication Tested in Randomized Controlled Trials

Background No network meta-analysis has considered the relative efficacy of cilostazol, home exercise therapy, supervised exercise therapy (SET), endovascular revascularization (ER), and ER plus SET (ER+SET) in improving maximum walking distance (MWD) over short- (<1 year), moderate- (1 to <2 years), and long-term (≥2 years) follow-up in people with intermittent claudication. Methods and Results A systematic literature search was performed to identify randomized controlled trials testing 1 or more of these 5 treatments according to Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. The primary outcome was improvement in MWD assessed by a standardized treadmill test. Secondary outcomes were adverse events and health-related quality of life. Network meta-analysis was performed using the gemtc R statistical package. The Cochrane collaborative tool was used to assess risk of bias. Forty-six trials involving 4256 patients were included. At short-term follow-up, home exercise therapy (mean difference [MD], 89.4 m; 95% credible interval [CrI], 20.9-157.7), SET (MD, 186.8 m; 95% CrI, 136.4-237.6), and ER+SET (MD, 326.3 m; 95% CrI, 222.6-430.6), but not ER (MD, 82.5 m; 95% CrI, -2.4 to 168.2) and cilostazol (MD, 71.1 m; 95% CrI, -24.6 to 167.9), significantly improved MWD (in meters) compared with controls. At moderate-term follow-up, SET (MD, 201.1; 95% CrI, 89.8-318.3) and ER+SET (MD, 368.5; 95% CrI, 195.3-546.9), but not home exercise therapy (MD, 99.4; 95% CrI, -174.0 to 374.9) or ER (MD, 84.2; 95% CrI, -35.3 to 206.4), significantly improved MWD (in meters) compared to controls. At long-term follow-up, none of the tested treatments significantly improved MWD compared to controls. Adverse events and quality of life were reported inconsistently and could not be meta-analyzed. Risk of bias was low, moderate, and high in 4, 24, and 18 trials respectively. Conclusions This network meta-analysis suggested that SET and ER+SET are effective at improving MWD over the moderate term (<2 year) but not beyond this. Durable treatments for intermittent claudication are needed.

Exercise Training and Revascularization in the Management of Symptomatic Peripheral Artery Disease

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In the management of symptomatic peripheral artery disease, aerobic exercise therapy and lower extremity revascularization are the mainstays of therapy.

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In this structured review, the most effective therapies, with 6 to 18 months of follow-up, indicated that exercise therapy and lower extremity revascularization each independently improve peak walking performance.

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The combination of therapies was superior to either therapy alone and may decrease the need for subsequent revascularization.

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Further research is needed to evaluate the long-term durability of these interventions, their impacts on subsequent invasive procedures, and predictors of response.

Exercise therapy and lower extremity revascularization both improve walking performance in symptomatic patients with peripheral artery disease. The combination of therapies provides greater benefit than either alone and may reduce the need for subsequent revascularization procedures, but further trials with longer follow-up are needed for the outcome of subsequent revascularization.

Wearable Activity Monitors in Home Based Exercise Therapy for Patients with Intermittent Claudication: A Systematic Review

OBJECTIVE

Intermittent claudication (IC) can severely limit functional capacity and quality of life. Supervised exercise therapy is the recommended first line management; however, this is often limited by accessibility, compliance and cost. As such, there has been an increased interest in the use of wearable activity monitors (WAMs) in home based telemonitoring exercise programmes for claudicants. This review aims to evaluate the efficacy of WAM as a feedback and monitoring tool in home based exercise programmes for patients with IC.

DATA SOURCES

A search strategy was devised. The databases MEDLINE, EMBASE, and Web of Science were searched through to April 2020.

REVIEW METHODS

Randomised trials and prospective trials were included. Eligible trials had to incorporate WAMs as a feedback tool to target walking/exercise behaviour. The primary outcome was the change in walking ability. Study quality was assessed with risk of bias tool.

RESULTS

A total of 1148 records were retrieved. Of these, eight randomised controlled trials and one prospective cohort study, all of which compared a WAM intervention against standard care and/or supervised exercise, met the inclusion criteria. Owing to heterogeneity between studies, no meta-analysis was conducted. WAM interventions improved measures of walking ability (heterogeneous outcomes such as maximum walking distance, claudication distance and six minute walk distance), increased daily walking activity (steps/day), cardiovascular metrics (maximum oxygen consumption), and quality of life.

CONCLUSION

There is some evidence that home based WAM interventions are beneficial for improving walking ability and quality of life in patients with IC. However, existing studies are limited by inadequate sample size, duration, and appropriate power. Achieving consensus on outcome reporting and study methods, as well as maximising device adherence, is needed.

Skeletal Muscle Pathology in Peripheral Artery Disease: A Brief Review

This brief review summarizes current evidence regarding lower extremity peripheral artery disease (PAD) and lower extremity skeletal muscle pathology. Lower extremity ischemia is associated with reduced calf skeletal muscle area and increased calf muscle fat infiltration and fibrosis on computed tomography or magnetic resonance imaging. Even within the same individual, the leg with more severe ischemia has more adverse calf muscle characteristics than the leg with less severe ischemia. More adverse computed tomography-measured calf muscle characteristics, such as reduced calf muscle density, are associated with higher rates of mobility loss in people with PAD. Calf muscle in people with PAD may also have reduced mitochondrial activity compared with those without PAD, although evidence is inconsistent. Muscle biopsy document increased oxidative stress in PAD. Reduced calf muscle perfusion, impaired mitochondrial activity, and smaller myofibers are associated with greater walking impairment in PAD. Preliminary evidence suggests that calf muscle pathology in PAD may be reversible. In a small uncontrolled trial, revascularization improved both the ankle-brachial index and mitochondrial activity, measured by calf muscle phosphocreatine recovery time. A pilot clinical trial showed that cocoa flavanols increased measures of myofiber health, mitochondrial activity, and capillary density while simultaneously improving 6-minute walk distance in PAD. Calf muscle pathological changes are associated with impaired walking performance in people with PAD, and interventions that both increase calf perfusion and improve calf muscle health are promising therapies to improve walking performance in PAD.

Meaningful change in 6-minute walk in people with peripheral artery disease

OBJECTIVE

The 6-minute walk test is a common outcome measure in clinical trials of people with lower extremity peripheral artery disease (PAD). However, what constitutes a meaningful change in the 6-minute walk distance has not been well defined for people with PAD. The present study related the change in the 6-minute walk distance to the degree of participant-reported improvement or decline in the 6-minute walk distance to define a meaningful change in the 6-minute walk distance for those with PAD.

METHODS

Participants with PAD from three observational longitudinal studies completed the walking impairment questionnaire (WIQ) distance score and 6-minute walk at baseline and 1 year later. The WIQ distance score measures participants' perceived difficulty walking seven different distances without stopping (ranging from walking around the home to walking 5 blocks) on a 0 to 4 Likert scale, with 0 representing an inability to walk the distance and 4 representing no difficulty. The mean changes in the 6-minute walk distance corresponding to the participants' report of no change, 1-unit change, or 2-unit change, respectively, in the Likert scale score between the baseline and 1-year follow-up measures were calculated for each WIQ distance.

RESULTS

A total of 777 participants with PAD (mean age, 71.2 ± 8.8 years; mean baseline 6-minute walk distance, 350.1 ± 118.1 meters) completed 5439 questions about their difficulty walking each WIQ distance at baseline and follow-up. Participants with PAD who reported no change in their difficulty in walking each WIQ distance between baseline and follow-up had a decline of 7.2 meters (95% confidence interval [CI], -11.6 to -2.8 meters) in the 6-minute walk test. Relative to those reporting no change in difficulty walking, the participants reporting 1- and 2-point improvements in walking ability showed 6-minute walk distance improvements of 7.8 meters (95% CI, -0.3 to 15.9 meters) and 20.1 meters (95% CI, 1.1-39.2 meters), respectively. Relative to those reporting no change in walking difficulty, those reporting 1- and 2-point declines in perceived walking difficulty showed declines of -11.2 meters (95% CI, -19.0 to -3.4 meters) and -23.8 meters (95% CI, -37.4 to -10.3 meters) in the 6-minute walk distance.

CONCLUSIONS

Among people with PAD, ∼8- and ∼20-meter improvements in the 6-minute walk distance represent small and large improvements in walking ability, respectively. People with PAD who reported no change in their ability to walk distances over 1 year simultaneously declined by a mean of 7 meters in the 6-minute walk test. These findings will be useful for interpreting the results from randomized trials of interventions to improve the walking performance of people with PAD.