Minimal clinically important differences in treadmill, 6-minute walk, and patient-based outcomes following supervised and home-based exercise in peripheral artery disease

Effect of Low-Intensity vs High-Intensity Home-Based Walking Exercise on Walk Distance in Patients With Peripheral Artery Disease: The LITE Randomized Clinical Trial

IMPORTANCE

Supervised high-intensity walking exercise that induces ischemic leg symptoms is the first-line therapy for people with lower-extremity peripheral artery disease (PAD), but adherence is poor.

OBJECTIVE

To determine whether low-intensity home-based walking exercise at a comfortable pace significantly improves walking ability in people with PAD vs high-intensity home-based walking exercise that induces ischemic leg symptoms and vs a nonexercise control.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter randomized clinical trial conducted at 4 US centers and including 305 participants. Enrollment occurred between September 25, 2015, and December 11, 2019; final follow-up was October 7, 2020.

INTERVENTIONS

Participants with PAD were randomized to low-intensity walking exercise (n = 116), high-intensity walking exercise (n = 124), or nonexercise control (n = 65) for 12 months. Both exercise groups were asked to walk for exercise in an unsupervised setting 5 times per week for up to 50 minutes per session wearing an accelerometer to document exercise intensity and time. The low-intensity group walked at a pace without ischemic leg symptoms. The high-intensity group walked at a pace eliciting moderate to severe ischemic leg symptoms. Accelerometer data were viewable to a coach who telephoned participants weekly for 12 months and helped them adhere to their prescribed exercise. The nonexercise control group received weekly educational telephone calls for 12 months.

MAIN OUTCOMES AND MEASURES

The primary outcome was mean change in 6-minute walk distance at 12 months (minimum clinically important difference, 8-20 m).

RESULTS

Among 305 randomized patients (mean age, 69.3 [SD, 9.5] years, 146 [47.9%] women, 181 [59.3%] Black patients), 250 (82%) completed 12-month follow-up. The 6-minute walk distance changed from 332.1 m at baseline to 327.5 m at 12-month follow-up in the low-intensity exercise group (within-group mean change, -6.4 m [95% CI, -21.5 to 8.8 m]; P = .34) and from 338.1 m to 371.2 m in the high-intensity exercise group (within-group mean change, 34.5 m [95% CI, 20.1 to 48.9 m]; P < .001) and the mean change for the between-group comparison was -40.9 m (97.5% CI, -61.7 to -20.0 m; P < .001). The 6-minute walk distance changed from 328.1 m at baseline to 317.5 m at 12-month follow-up in the nonexercise control group (within-group mean change, -15.1 m [95% CI, -35.8 to 5.7 m]; P = .10), which was not significantly different from the change in the low-intensity exercise group (between-group mean change, 8.7 m [97.5% CI, -17.0 to 34.4 m]; P = .44). Of 184 serious adverse events, the event rate per participant was 0.64 in the low-intensity group, 0.65 in the high-intensity group, and 0.46 in the nonexercise control group. One serious adverse event in each exercise group was related to study participation.

CONCLUSIONS AND RELEVANCE

Among patients with PAD, low-intensity home-based exercise was significantly less effective than high-intensity home-based exercise and was not significantly different from the nonexercise control for improving 6-minute walk distance. These results do not support the use of low-intensity home-based walking exercise for improving objectively measured walking performance in patients with PAD.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02538900.

Satisfaction and Acceptability of Telemonitored Home-Based Exercise in Patients With Intermittent Claudication: Pragmatic Observational Pilot Study

BACKGROUND

Current guidelines recommend supervised exercise training (SET) as a first-line treatment in patients with intermittent claudication (IC). SET has been shown to be more effective than home-based exercise therapy (HBET). However, the lack of available SET programs hampers broad SET implementation in clinical practice.

OBJECTIVE

The aim of this study is to assess patient satisfaction and acceptability of a structured HBET program using wearable technology and elastic band resistance exercises.

METHODS

A total of 20 patients with IC (Rutherford 1-3) with internet access and currently not engaged in structured exercise training were recruited in a pragmatic observational pilot study. Participants were instructed to complete 3 walking sessions and 2 elastic band resistance exercise sessions per week in their home environment during a 4-week period. Patient satisfaction and acceptability were assessed using a 5-point Likert scale questionnaire (1-2=very unsatisfied, 3=neutral, and 4-5=very satisfied) evaluating the materials and intervention content. Secondary outcomes were evaluated at baseline and at completion of the 4-week intervention and included maximal walking distance (MWD) and pain-free walking distance (PFWD), physical fitness, and patient-reported outcomes on quality of life, walking capacity, levels of kinesiophobia, and self-efficacy. Statistically significant changes were tested using paired t tests or Wilcoxon signed-rank tests.

RESULTS

All patients (15 men, 5 women; mean age 64.6, SD 10.6 years; range 41-81 years) completed the 4-week intervention and were highly satisfied with the program (mean overall score 4.5, SD 0.5). Patients' questionnaire responses documented willingness to recommend the exercise program to other patients (mean 4.5, SD 0.5; median 4.5) and preference for continuing the intervention (mean 4.3, SD 0.5; median 4). Furthermore, participants endorsed the use of the sports watches to track walking sessions (mean 4.25, SD 0.6; median 4), felt safe (mean 4.4, SD 0.6; median 4), and appreciated personal feedback (mean 4.55, SD 0.5; median 5) and flexibility of training (mean 4.1, SD 0.7; median 4). Resistance training was not preferred over walking training (mean 2.65, SD 0.8; median 3). In addition, PFWD (+89 m; P=.001), MWD (+58 m; P=.03), Walking Impairment Questionnaire distance score (+0.18; P=.01), activity-related scores (+0.54; P<.001), and total quality of life (+0.36; P=.009) improved following the intervention. Other patient-related outcomes, physical fitness, and physical activity remained to be statistically unaltered.

CONCLUSIONS

Patients with IC were satisfied and accepted technology to monitor and guide HBET, with observed short-term effectiveness regarding walking capacity and quality of life. However, elastic band resistance exercises as a part of HBET were not preferred over progressive walking.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04043546; https://clinicaltrials.gov/ct2/show/NCT04043546.

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.

A systematic review of the role of heat therapy for patients with intermittent claudication due to peripheral artery disease

Intermittent claudication (IC) is associated with impairments in quality of life and walking ability. Heat therapy is an emerging cardiovascular therapy, which may improve walking in patients with IC. We undertook a systematic review to establish current evidence for heat therapy for patients with IC. We searched five databases (Ovid Medline / PubMed, Embase, Scopus / Web of Science, Cochrane Library and Health Technology Assessment Databases). A total of 6751 records were screened with 76 full-text articles assessed for eligibility. We included three randomised control trials and three acute interventions. For chronic interventions, three different heat therapy interventions were used. The 6-minute walk distance significantly improved following whole-body immersion (p = 0.03; ES 0.94, 95% CI: 0.06-1.82), but not after Waon therapy or a water-perfused garment. Ankle-brachial pressure indices were significantly improved following whole-body immersion (p = 0.01; ES 1.10, 95% CI: 0.20-1.99) but not after other therapies. No form of heat therapy demonstrated statistical improvements in quality of life or brachial blood pressure. Acute interventions were characterised by large increases in limb blood flow and core temperature, and transient reductions in blood pressure post-heating. At present there are only three randomised controlled trials assessing heat therapy for patients with IC. Moreover, each of those randomised controlled trials utilised different heat therapies. There is also very limited study of the acute physiological responses to different heat therapy interventions in these populations. Future research should establish appropriate heat therapy protocols and implement more randomised trials to understand its effectiveness. PROSPERO: CRD42020187941.

Clinical characteristics and response to supervised exercise therapy of people with lower extremity peripheral artery disease

BACKGROUND

Among people with lower extremity peripheral artery disease (PAD), little is known about variation in response to supervised exercise therapy (SET). Clinical characteristics associated with greater responsiveness to SET have not been identified.

METHODS

Data from participants with PAD in two randomized clinical trials comparing SET vs nonexercising control were combined. The exercise intervention consisted of three times weekly supervised treadmill exercise. The control groups received lectures on health-related topics.

RESULTS

Of 309 unique participants randomized (mean age, 67.9 years [standard deviation, 9.3 years]; 132 [42.7%] women; 185 [59.9%] black), 285 (92%) completed 6-month follow-up. Compared with control, those randomized to SET improved 6-minute walk distance by 35.6 meters (95% confidence interval, 21.4-49.8; P < .001). In the 95 (62.1%) participants who attended at least 70% of SET sessions, change in 6-minute walk distance varied from -149.4 to +356.0 meters. Thirty-four (35.8%) had no 6-minute walk distance improvement. Among all participants, age, sex, race, body mass index, prior lower extremity revascularization, and other clinical characteristics did not affect the degree of improvement in 6-minute walk distance after SET relative to the control group. Participants with 6-minute walk distance less than the median of 334 meters at baseline had greater percentage improvement in 6-minute walk distance compared with those with baseline 6-minute walk distance above the median (+20.5% vs +5.3%; P for interaction = .0107).

CONCLUSIONS

Among people with PAD, substantial variability exists in walking improvement after SET. Shorter 6-minute walk distance at baseline was associated with greater improvement after SET, but other clinical characteristics, including age, sex, prior lower extremity revascularization, and disease severity, did not affect responsiveness to exercise therapy.

Acute effects of leg heat therapy on walking performance and cardiovascular and inflammatory responses to exercise in patients with peripheral artery disease

Lower-extremity peripheral artery disease (PAD) is associated with increased risk of cardiovascular events and impaired exercise tolerance. We have previously reported that leg heat therapy (HT) applied using liquid-circulating trousers perfused with warm water increases leg blood flow and reduces blood pressure (BP) and the circulating levels of endothelin-1 (ET-1) in patients with symptomatic PAD. In this sham-controlled, randomized, crossover study, sixteen patients with symptomatic PAD (age 65 ± 5.7 years and ankle-brachial index: 0.69 ± 0.1) underwent a single 90-min session of HT or a sham treatment prior to a symptom-limited, graded cardiopulmonary exercise test on the treadmill. The primary outcome was the peak walking time (PWT) during the exercise test. Secondary outcomes included the claudication onset time (COT), resting and exercise BP, calf muscle oxygenation, pulmonary oxygen uptake (V̇O2 ), and plasma levels of ET-1, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α). Systolic, but not diastolic BP, was significantly lower (~7 mmHg, p < .05) during HT when compared to the sham treatment. There was also a trend for lower SBP throughout the exercise and the recovery period following HT (p = .057). While COT did not differ between treatments (p = .77), PWT tended to increase following HT (CON: 911 ± 69 s, HT: 954 ± 77 s, p = .059). Post-exercise plasma levels of ET-1 were also lower in the HT session (CON: 2.0 ± 0.1, HT: 1.7 ± 0.1, p = .02). Calf muscle oxygenation, V̇O2 , COT, IL-6, and TNF-α did not differ between treatments. A single session of leg HT lowers BP and post-exercise circulating levels of ET-1 and may enhance treadmill walking performance in symptomatic PAD patients.

Individual Differences in Response to Supervised Exercise Therapy for Peripheral Artery Disease

Nonresponse to exercise has been extensively examined in young athletes but is seldom reported in studies of aerobic exercise interventions in older adults. This study examined the prevalence of nonresponse and poor response to exercise in functional and quality of life outcomes and response patterns between and among older adults undergoing 12-weeks of supervised exercise therapy for the management of peripheral artery disease (N = 44, mean age 72.3 years, 47.7% female). The prevalence of nonresponse (no change/decline in performance) in walking distance was 31.8%. The prevalence of poor response (lack of a clinically meaningful improvement) was 43.2%. Similar patterns of response were observed in both objective and patient-reported measures of physical function. All participants improved in at least one outcome; only two participants improved in all measured outcomes. Additional research should examine modifiable predictors of response to inform programming and maximize an individual's potential benefit from exercise therapy.

Association between meeting daily step count goals with ambulatory function and quality of life in patients with claudication

OBJECTIVE

To determine (a) whether patients with peripheral artery disease (PAD) who walked at least 7000 and 10,000 steps/day had better ambulatory function and health-related quality of life (HRQoL) than patients who walked less than 7000 steps/day, and (b) whether differences in ambulatory function and HRQoL in patients grouped according to these daily step count criteria persisted after adjusting for covariates.

METHODS

Two hundred forty-eight patients were assessed on their daily ambulatory activity for 1 week with a step activity monitor, and were grouped according to daily step count targets. Patients who took fewer than 7000 steps/day were included in group 1 (n = 153), those who took 7000 to 9999 steps/day were included in group 2 (n = 57), and patients who took at least 10,000 steps/day were included in group 3 (n = 38). Primary outcomes were the 6-minute walk distance (6MWD) and Walking Impairment Questionnaire (WIQ) distance score, which is a disease-specific measurement of HRQoL. Patients were further characterized on demographic variables, comorbid conditions, and cardiovascular risk factors.

RESULTS

The groups were significantly different on ankle-brachial index (P = .02), and on the prevalence of hypertension (P = .04), diabetes (P < .01), abdominal obesity (P < .01), arthritis (P = .04), and chronic obstructive pulmonary disease (P < .01). Thus, these variables served as covariates in adjusted analyses, along with age, weight, and sex. The 6MWD (mean ± standard deviation) was significantly different among the groups in unadjusted (P < .01) and adjusted (P < .01) analyses (group 1, 313 ± 90 m; group 2, 378 ± 84 m; and group 3, 414 ± 77 m), with groups 2 and 3 having a higher 6MWD than group 1 (P < .01). The WIQ distance score was significantly different among the groups in unadjusted (P < .01) and adjusted (P < .01) analyses (group 1, 30 ± 30%; group 2, 45 ± 35%; and group 3, 47 ± 34%), with groups 2 and 3 having higher WIQ distance scores than group 1 (P < .01).

CONCLUSIONS

Patients with PAD who walked more than 7000 and 10,000 steps/day had greater ambulatory function and HRQoL than patients who walked fewer than 7000 steps/day. Second, the greater ambulatory function and HRQoL associated with walking 7000 and 10,000 steps/day persisted after adjusting for covariates. This study provides preliminary evidence that patients with PAD who walk more than 7000 steps/day have better ambulatory function and HRQoL than patients below this threshold.

Considering the Feasibility, Tolerability, and Safety of High-Intensity Interval Training as a Novel Treatment for Patients With Intermittent Claudication

PURPOSE

This study assessed the feasibility, tolerability, safety, and potential efficacy of a novel, 6-wk, high-intensity interval training (HIIT) program for patients with intermittent claudication (IC).

METHODS

Patients referred to a usual-care supervised exercise program were invited to undertake a HIIT program. All recruited patients performed a baseline cardiopulmonary exercise test (CPX) to inform their exercise prescription. HIIT involved 10, 1-min high-intensity cycling intervals interspersed with 1-min recovery intervals, performed 3 d/wk for 6 wk. Outcomes included feasibility, tolerability, safety, walking distance, and quality of life.

RESULTS

A total of 144 patients with IC were referred, 95 met initial eligibility criteria (66%) and 30 (32%) were recruited for HIIT, of which 15 (50%) completed. Of the recruited patients, 90% were on optimal medical therapy and 40% had concomitant cardiac, cerebrovascular, and/or respiratory disease. Patients who completed the program attended 100% of the sessions and one serious adverse event was recorded. Improvements in walking distances and quality of life were observed. Following recruitment of the first 20 patients, the inclusion criteria were refined on the basis of CPX, leading to improved completion rates.

CONCLUSIONS

This study provides preliminary findings indicating that patients with IC can complete a short-term HIIT program. We provide very early evidence that HIIT may be safe and well-tolerated. In addition, walking distances seem to improve following HIIT. After a small change in the exclusion criteria, the intervention and inclusion/exclusion criteria now seem appropriate for this population, meaning further research to evaluate HIIT in patients with IC is warranted.

Exercise training for intermittent claudication: a narrative review and summary of guidelines for practitioners

Peripheral artery disease (PAD) is caused by atherosclerotic narrowing of the arteries supplying the lower limbs often resulting in intermittent claudication, evident as pain or cramping while walking. Supervised exercise training elicits clinically meaningful benefits in walking ability and quality of life. Walking is the modality of exercise with the strongest evidence and is recommended in several national and international guidelines. Alternate forms of exercise such as upper- or lower-body cycling may be used, if required by certain patients, although there is less evidence for these types of programmes. The evidence for progressive resistance training is growing and patients can also engage in strength-based training alongside a walking programme. For those unable to attend a supervised class (strongest evidence), home-based or 'self-facilitated' exercise programmes are known to improve walking distance when compared to simple advice. All exercise programmes, independent of the mode of delivery, should be progressive and individually prescribed where possible, considering disease severity, comorbidities and initial exercise capacity. All patients should aim to accumulate at least 30 min of aerobic activity, at least three times a week, for at least 3 months, ideally in the form of walking exercise to near-maximal claudication pain.

Incentivizing physical activity through activity monitoring interventions in PAD - a pilot study

Background: There is ample evidence to show that supervised exercise is efficacious and cost effective for improving claudication symptoms in patients with peripheral artery disease (PAD). Home based exercise therapy can be an effective alternative to supervised exercise however, the results of this is variable depending on the level of motivation and engagement of the patient. Patients and methods: We performed a pilot study in 41 patients to determine whether a home based exercise program with the use of an activity tracking device with personalized feedback and financial incentives can increase daily activity, improve walking and sustain engagement in the exercise regimen in patients with PAD. In this randomized pilot study, the patients in the study group were fitted with an activity monitoring device and given behavioral monitoring, motivational updates and feedback regarding their exercise program. This study group was further divided in to two groups. One half of these patients in the study group were also given financial incentives if they reached their set targets. The control group wore the device with no feedback or ability to see their number of steps walked. Results: Results showed that at the end of the 12 week period, patients in the study groups walked more compared to the controls and the financial incentive structure resulted in an additional 38-63% increase in average daily steps. Conclusions: This pilot study revealed that a home-based exercise program with activity monitoring, feedback and financial incentives resulted increased daily steps, 6-minute walking distance and overall compliance with the program in PAD patients with claudication.

A randomized controlled trial of treatment with intermittent negative pressure for intermittent claudication

OBJECTIVE

We investigated the effects of lower extremity intermittent negative pressure (INP) treatment for 1 hour two times daily for 12 weeks on the walking distance of patients with intermittent claudication (IC).

METHODS

Patients with IC were randomized to treatment with -40 mm Hg INP (treatment group) or -10 mm Hg INP (sham control group). Pain-free walking distance (PWD) and maximal walking distance (MWD) on a treadmill, resting and postexercise ankle-brachial index, resting and postischemic blood flow (plethysmography), and quality of life (EQ-5D-5L and Vascuqol-6) were measured at baseline and after 12 weeks of treatment.

RESULTS

A total of 72 patients were randomized, and 63 had data available for the intention-to-treat analyses. The between-group comparisons showed a significant change in the PWD, favoring the treatment group over the sham control group (estimated treatment effect, 50 m; 95% confidence interval [CI], 11-89; P = .014). The PWD had increased by 68 m (P < .001) in the treatment group and 18 m (P = .064) in the sham control group. No significant difference was found in the change in the MWD between the two groups (estimated treatment effect, 42 m; 95% CI, -14 to 97; P = .139). The MWD had increased by 62 m (P = .006) in the treatment group and 20 m (P = .265) in the sham control group. For patients with a baseline PWD of <200 m (n = 56), significant changes had occurred in both PWD and MWD between the two groups, favoring the treatment group (estimated treatment effect, 42 m; 95% CI, 2-83; P = .042; and estimated treatment effect, 62 m; 95% CI, 5-118; P = .032; respectively). Both overall and for the group of patients with a PWD <200 m, no significant differences were found in the changes in the resting and postexercise ankle-brachial index, resting and postischemic blood flow, or quality of life parameters between the two groups.

CONCLUSIONS

Treatment with -40 mm Hg INP increased the PWD compared with sham treatment in patients with IC. For the patients with a baseline PWD of <200 m, an increase was found in both PWD and MWD compared with sham treatment.

Leg heat therapy improves perceived physical function but does not enhance walking capacity or vascular function in patients with peripheral artery disease

A single session of leg heat therapy (HT) has been shown to elicit increases in leg blood flow and reduce blood pressure (BP) and the circulating levels of endothelin-1 (ET-1) in patients with symptomatic peripheral artery disease (PAD). We assessed whether 6 wk of supervised leg HT (3 times/wk) with water-circulating trousers perfused with water at 48°C improved 6-min walk distance in individuals with PAD compared with a sham treatment. Secondary outcomes included the assessment of leg vascular function, BP, quality of life, and serum ET-1 and nitrite plus nitrate (NOx) levels. Of 32 PAD patients randomized, 30 [age: 68 ± 8 yr; ankle-brachial index (ABI): 0.6 ± 0.1] completed the 3- and 6-wk follow-ups. Participants completed 98.7% of the treatment sessions. Compared with the sham treatment, exposure to HT did not improve 6-min walk distance, BP, popliteal artery reactive hyperemia, cutaneous microvascular reactivity, resting ABI, or serum NOx levels. The change from baseline to 6 wk in scores of the physical functioning subscale of the 36-item Short Form Health Survey was significantly higher in the HT group (control -6.9 ± 10 vs. HT 6.8 ± 15; 95% confidence interval: 2.5-24.3, P = 0.017). Similarly, the change in ET-1 levels after 6 wk was different between groups, with the HT group experiencing a 0.4 pg/mL decrease (95% confidence interval: -0.8-0.0, P = 0.03). These preliminary results indicate that leg HT may improve perceived physical function in symptomatic PAD patients. Additional, larger studies are needed to confirm these findings and determine the optimal treatment regimen for symptomatic PAD patients.NEW & NOTEWORTHY This is the first sham-controlled study to investigate the effects of leg heat therapy (HT) on walking performance, vascular function, and quality of life in patients with peripheral artery disease (PAD). Adherence to HT was high, and the treatment was well tolerated. Our findings revealed that HT applied with water-circulating trousers evokes a clinically meaningful increase in perceived physical function and reduces the serum concentration of the potent vasoconstrictor endothelin-1 in patients with PAD.

A Retrospective Comparison of Fitness and Exercise Progression in Patients With Coronary and Peripheral Artery Disease in Cardiac Rehabilitation

BACKGROUND

Cardiac rehabilitation (CR) is recommended for patients with coronary (CAD) and peripheral (PAD) artery disease. However, no study has compared changes in cardiorespiratory fitness (VO_2peak) or exercise prescription progression among PAD, CAD, and concomitant PAD and CAD (BOTH). The objectives of this study were to 1) compare change in VO_2peak among patients with PAD, CAD, and BOTH, and 2) examine progression in exercise prescription parameters in a comprehensive 6-month cardiac rehabilitation (CR) program.

METHODS

A retrospective analysis of patient data recorded from 2006 to 2017 from a large urban hospital was conducted. Patients with PAD (n = 63) and BOTH (n = 164) were included in the analyses. Patients with CAD (n = 63) were matched to PAD by sex (36.5% female), age (69 years), smoking status, diabetes, and year in program.

RESULTS

There were significant improvements in VO_2peak from baseline to 6 months in all groups (CAD +2.7 ± 3.4 mL⋅kg^-1⋅min^-1, PAD +2.4 ± 3.8 mL⋅kg^-1⋅min^-1, BOTH +1.8 ± 3.1 mL⋅kg^-1⋅min^-1; all P < 0.001). Between-group differences were significant between PAD and CAD as well as between CAD and BOTH (P = 0.001). Walking distance, duration, and pace increased for all groups over 6 months (P < 0.001), with a significant difference in pace between CAD and BOTH (P = 0.006).

CONCLUSIONS

Patients with PAD, CAD, and BOTH had significant improvements in VO_2peak following a 6-month CR program. However, despite similar prescribed walking distance and duration, improvements in VO_2peak were mitigated in PAD and BOTH compared with CAD. These results support benefits of CR for patients diagnosed with PAD, but alternate exercise strategies should be explored for patients with PAD.

Expanding the Use of Six-Minute Walking Test in Patients with Intermittent Claudication

BACKGROUND

Six-min walking test (6MWT) has been widely in patients with symptomatic peripheral artery disease (PAD) to quantify the walking impairment and the efficacy of different therapeutic interventions. Despite the aforementioned usefulness of 6MWT for PAD, the information provided by this test goes beyond the meters walked. The aim of this study was to describe the relative values of 6MWT and body weight-walking distance product (DW) in patients with symptomatic PAD.

METHODS

Two hundred twenty-seven patients with symptomatic PAD participated in the study. The 6MWT was performed and absolute and claudication distances were obtained. The results of 6MWT were then relativized and expressed as a percentage of a healthy subject. DW was obtained by the product of 6MWT distance by weight. In both sexes, the relative 6MWT ranged from 57% to 64%.

RESULTS

Absolute 6MWT total distance (P < 0.001) was lower in women than in men, whereas the relative 6MWT total distance was similar between sexes (P = 0.398). The absolute and relative 6MWT total distance were similar among age categories (P > 0.072). The DW was higher in men than in women (P < 0.05). In addition, in women, DW was higher in younger group than in other age groups (P < 0.05).

CONCLUSIONS

Patients with symptomatic PAD achieve less than 70% of the distance achieved by an age-matched healthy subject. In patients with symptomatic PAD, the relative values of 6MWT total distance are similar between sexes and among different age groups, whereas DW are influenced by age and sex.

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

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

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

INTRODUCTION

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

METHODS AND ANALYSIS

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

ETHICS AND DISSEMINATION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Diet is associated with ankle-brachial index, inflammation, and ambulation in patients with intermittent claudication

OBJECTIVE

The aims of this investigation were to determine whether the daily dietary intake of nutrients by patients with peripheral artery disease (PAD) and intermittent claudication (IC) met recommended levels for adults older than 50 years and to determine whether meeting recommended levels of nutrients was associated with ankle-brachial index (ABI), inflammation, and ambulation of patients with PAD and IC.

METHODS

A total of 48 patients were assessed on their dietary intake of 20 nutrients during a 3-day period. Patients were further characterized on demographic variables, comorbid conditions, cardiovascular risk factors, ABI, 6-minute walk distance (6MWD), and high-sensitivity C-reactive protein (hsCRP) concentration.

RESULTS

Few patients met the daily recommended intakes for calcium (4%), fiber (6%), vitamin E (6%), trans fatty acids (13%), vitamin A (15%), total sugars (19%), potassium (23%), sodium (29%), saturated fat (29%), and vitamin C (31%), and none of the patients met the daily recommended intake of vitamin D (0%). Overall, patients met few of the 20 dietary recommendations as the median score was seven recommendations. Only 17 of 48 patients met more than seven of the recommendations. For the ABI regression model adjusted for age, sex, race, smoking, hypertension, dyslipidemia, body mass index, and percentage body fat, the only significant predictor was total sugars (P < .001); patients who did not meet the recommendation had lower ABI values. For the hsCRP-adjusted regression model, the strongest significant predictor was omega-3 polyunsaturated fatty acids (P = .001), indicating that those who did not meet the recommendation had higher hsCRP values. Finally, for the 6MWD-adjusted regression model, folate (P = .011) and dietary score index (P = .014) were significant predictors; those who did not meet the recommendation for folate and those who met 5 or fewer of the 20 recommendations had shorter 6MWD.

CONCLUSIONS

Patients with PAD and IC consume a low-nutrient-dense diet that is deficient in many vitamins, calcium, fruits, and vegetables and contains too much added sugar, saturated and trans fats, and processed foods. In addition, more severe PAD, greater inflammation, and ambulatory dysfunction are independently associated with aspects of a low-nutrient-dense diet, such as too much intake of added sugars, low intake of omega-3 polyunsaturated fatty acids and folate, and meeting the recommended intakes of only five or fewer nutrients.

Association between calf muscle oxygen saturation with ambulatory function and quality of life in symptomatic patients with peripheral artery disease

OBJECTIVE

The objective of this study was to determine whether calf muscle hemoglobin oxygen saturation (Sto₂) obtained during a standardized treadmill test is associated with ambulatory function and health-related quality of life (HRQoL) in patients with symptomatic peripheral artery disease (PAD). We hypothesized that a rapid decline in calf muscle Sto₂ during walking is associated with impaired ambulatory function and HRQoL and that these associations are independent of ankle-brachial index (ABI).

METHODS

Calf muscle Sto₂, peak walking time, and claudication onset time were obtained during a treadmill test in 151 symptomatic men and women with PAD. Patients were further characterized by demographic variables, comorbid conditions, cardiovascular risk factors, ABI, 6-minute walk distance, daily ambulatory activity, Walking Impairment Questionnaire (WIQ) score, and Medical Outcomes Study 36-Item Short Form Health Survey physical function score to assess HRQoL.

RESULTS

The median calf muscle Sto₂ value at rest was 52%, which declined to 22% after only 1 minute of walking during the treadmill test and reached a minimum value of 9% after a median time of 87 seconds of walking. Of the various calf muscle Sto₂ measurements obtained during the treadmill test, the exercise time to the minimum calf muscle Sto₂ value (log transformed) had the strongest univariate associations with peak walking time (r = 0.56; P < .001), claudication onset time (r = 0.49; P < .001), 6-minute walk distance (r = 0.31; P < .001), WIQ distance score (r = 0.33; P < .001), WIQ speed score (r = 0.39; P < .001), WIQ stair-climbing score (r = 0.37; P < .001), and Medical Outcomes Study 36-Item Short Form Health Survey physical function score (r = 0.32; P < .001). In adjusted multiple regression models, these associations persisted (P < .001) after adjustment for demographic measures, cardiovascular risk factors, comorbid conditions, and ABI.

CONCLUSIONS

More rapid decline in oxygen saturation of the calf musculature during walking, indicative of impaired microcirculation, is predictive of impaired ambulatory function and HRQoL in patients with symptomatic PAD. Of particular importance, these associations are independent of ABI and other common health burdens, highlighting the clinical relevance that the microcirculation has on ambulatory function and HRQoL in patients with symptomatic PAD.

Cocoa to Improve Walking Performance in Older People With Peripheral Artery Disease: The COCOA-PAD Pilot Randomized Clinical Trial

RATIONALE

Cocoa and its major flavanol component, epicatechin, have therapeutic properties that may improve limb perfusion and increase calf muscle mitochondrial activity in people with lower extremity peripheral artery disease (PAD).

OBJECTIVE

In a phase II randomized clinical trial, to assess whether 6 months of cocoa improved walking performance in people with PAD, compared with placebo.

METHODS AND RESULTS

Six-month double-blind, randomized clinical trial in which participants with PAD were randomized to either cocoa beverage versus placebo beverage. The cocoa beverage contained 15 g of cocoa and 75 mg of epicatechin daily. The identical appearing placebo contained neither cocoa nor epicatechin. The 2 primary outcomes were 6-month change in 6-minute walk distance measured 2.5 hours after a study beverage at 6-month follow-up and 24 hours after a study beverage at 6-month follow-up, respectively. A 1-sided P<0.10 was considered statistically significant. Of 44 PAD participants randomized (mean age, 72.3 years [±7.1]; mean ankle brachial index, 0.66 [±0.15]), 40 (91%) completed follow-up. Adjusting for smoking, race, and body mass index, cocoa improved 6-minute walk distance at 6-month follow-up by 42.6 m ([90% CI, +22.2 to +∞] P=0.005) at 2.5 hours after a final study beverage and by 18.0 m ([90% CI, -1.7 to +∞] P=0.12) at 24 hours after a study beverage, compared with placebo. In calf muscle biopsies, cocoa improved mitochondrial COX (cytochrome c oxidase) activity (P=0.013), increased capillary density (P=0.014), improved calf muscle perfusion (P=0.098), and reduced central nuclei (P=0.033), compared with placebo.

CONCLUSIONS

These preliminary results suggest a therapeutic effect of cocoa on walking performance in people with PAD. Further study is needed to definitively determine whether cocoa significantly improves walking performance in people with PAD.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02876887. Visual Overview: An online visual overview is available for this article.

Effects of heated water-based versus land-based exercise training on vascular function in individuals with peripheral artery disease

Peripheral artery disease (PAD) is an atherosclerotic disease that is associated with poor vascular function, walking impairment, and reduced quality of life. Land-based exercise therapy (LBET) is frequently recommended to improve walking and reduce symptoms. Recently, evidence has suggested that heated-water exercise therapy (HWET) is an effective intervention for PAD. However, the efficacy of LBET versus HWET in PAD patients had not been elucidated. Therefore, we sought to compare effects of LBET with HWET on cardiovascular function, exercise tolerance, physical function, and body composition in PAD patients. PAD patients (n = 53) were recruited and randomly assigned to a LBET group (n = 25) or HWET group (n = 28). The LBET group performed treadmill walking, whereas the HWET group performed walking in heated water for 12 wk. Leg (legPWV) and brachial-to-ankle arterial stiffness (baPWV), blood pressure (BP), ankle-brachial index (ABI), 6-min walking distance (6MWD), claudication onset time (COT), physical function, and body composition were assessed before and after 12 wk. There were significant group-by-time interactions (P < 0.05) for legPWV, BP, 6MWD, COT, body composition, and resting metabolic rate (RMR). Both groups significantly reduced (P < 0.05) legPWV, BP, and body fat percentage, and HWET measures were significantly lower than LBET measures. Both groups significantly increased 6MWD, COT, and RMR, and HWET group measures were significantly greater than LBET measures. A time effect was noted for baPWV reduction in both groups (P < 0.05). These results suggest that both LBET and HWET improve cardiovascular function, exercise tolerance, and body composition, and HWET showed considerably greater improvements compared with LBET in patients with PAD.NEW & NOTEWORTHY The results of this study reveal for the first time that although land-based exercise therapy is effective for reducing arterial stiffness and blood pressure in patients with peripheral artery disease (PAD), heated-water exercise therapy demonstrates greater benefits on vascular function. The greater improvements in muscular strength, time to onset of claudication, and exercise tolerance after heated-water exercise therapy may have clinical implications for improving quality of life in patients with PAD. The heated-water exercise therapy intervention demonstrated relatively higher exercise training adherence (∼88%) compared with the land-based exercise intervention (∼81%).

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.

National assessment of availability, awareness, and utilization of supervised exercise therapy for peripheral artery disease patients with intermittent claudication

BACKGROUND

Supervised exercise therapy (SET) is an inexpensive, low-risk, and effective option when compared with invasive therapies for the treatment of patients with peripheral artery disease (PAD) and intermittent claudication. Randomized, controlled trials have demonstrated the benefits of SET in improving maximum walking distance in intermittent claudication patients, and society guidelines recommend SET as first-line therapy. In 2017, the Centers for Medicare & Medicaid Services (CMS) added coverage of SET. We aimed to evaluate the availability and use of SET programs, determine the awareness of SET CMS coverage in the United States, and gauge the academic interest in SET in the vascular community.

METHODS

An eight-question online survey regarding SET coverage, reimbursement, barriers to prescription, and SET use was sent to 900 vascular surgeons, cardiologists, and vascular medicine physicians across the United States. The most recent 2-year programs for the Vascular Annual Meeting, Midwestern Vascular Society, Eastern Vascular Society, and Western Vascular Society were reviewed to identify SET-related abstracts and gauge academic interest and awareness for SET within the vascular surgery community.

RESULTS

We received 135 physician responses (15%) to the survey. All 50 states were represented. The majority of responders (54%) stated that there was no SET program at their facility, and 5% did not know if there was a SET program available. Of those who did have a SET program available, 81% were associated with cardiac rehabilitation and 19% had a PAD-specific program. A significant number of physicians (49%) had never referred a patient for SET. Twenty-six percent were not aware that CMS covered SET sessions. Of the physicians who were aware of CMS reimbursement, 36% had never referred a patient to a SET program. Of all surveyed, 98% indicated they would refer patients to a SET program if one was available. Top barriers to use of a SET program included (1) no SET center availability and (2) significant cost or travel expense to the patient. A review of major vascular surgery meeting programs for the last 2 years yielded no identification of a SET-related abstract.

CONCLUSIONS

There is a lack of both availability and use of SET for patients with PAD with claudication, despite guideline recommendations and CMS reimbursement for SET sessions in the United States. When SET is offered, it is typically through cardiac rehabilitation programs which is not focused on PAD. Travel distance, lack of SET program availability, and low reimbursement rates are primary areas that could be addressed to improve use.

Heat therapy vs. supervised exercise therapy for peripheral arterial disease: a 12-wk randomized, controlled trial

Peripheral arterial disease (PAD) is characterized by lower limb atherosclerosis impairing blood supply and causing walking-induced leg pain or claudication. Adherence to traditional exercise training programs is poor due to these symptoms despite exercise being a mainstay of conservative treatment. Heat therapy improves many cardiovascular health outcomes, so this study tested if this was a viable alternative cardiovascular therapy for PAD patients. Volunteers with PAD were randomized to 12 wk of heat ( n = 11; mean age 76 ± 8 yr, BMI 28.7 ± 3.5 kg/m2, 4 females) or exercise ( n = 11; 74 ± 10 yr, 28.5 ± 6.8 kg/m2, 3 females). Heat involved spa bathing at ∼39°C, 3–5 days/wk for ≤30 min, followed by ≤30 min of callisthenics. Exercise involved ≤90 min of supervised walking and gym-based exercise, 1–2 days/wk. Following the interventions, total walking distance during a 6-min walk test increased (from ∼350 m) by 41 m (95% CI: [13, 69], P = 0.006) regardless of group, and pain-free walking distance increased (from ∼170 m) by 43 m ([22, 63], P < 0.001). Systolic blood pressure was reduced more following heat (−7 mmHg, [−4, −10], P < 0.001) than following exercise (−3 mmHg, [0, −6], P = 0.078), and diastolic and mean arterial pressure decreased by 4 mmHg in both groups ( P = 0.002). There were no significant changes in blood volume, ankle-brachial index, or measures of vascular health. There were no differences in the improvement in functional or blood pressure outcomes between heat and exercise in individuals with PAD.

NEW & NOTEWORTHY Heat therapy via hot-water immersion and supervised exercise both improved walking distance and resting blood pressure in peripheral arterial disease (PAD) patients over 12 wk. Adherence to heat therapy was excellent, and the heat intervention was well tolerated. The results of the current study indicate that heat therapy can improve functional ability and has potential as an effective cardiovascular conditioning tool for individuals with PAD.

Listen to this article's corresponding podcast at https://ajpheart.podbean.com/e/heat-therapy-vs-exercise-in-peripheral-arterial-disease/ .

Test-retest reliability, agreement, and minimal detectable change in the 6-minute walk test in patients with intermittent claudication

OBJECTIVE

Standardized walk tests are important for objective assessment of walking distance in patients with intermittent claudication (IC). The 6-minute walk test (6MWT) has been suggested to correlate more closely than testing on a treadmill with everyday ambulatory function, but its measurement properties have hardly been studied in IC. The aim of this study was to determine the test-retest reliability, agreement, standard error of measurement (SEM), and minimal detectable change of the 6MWT in patients with IC.

METHODS

This reliability and agreement study recruited 102 patients with stable IC (mean age, 72 ± 7.4 years; 43 women) from the vascular surgery outpatient clinic at Sahlgrenska University Hospital in Sweden. The patients performed the 6MWT twice, with at least 30 minutes of rest between tests. To determine test-retest reliability, the intraclass correlation coefficient was calculated. Bland-Altman plots were used to measure agreement.

RESULTS

The mean walking distance in both test and retest was 397.8 m (standard deviation, 81.2 m; N = 100), and the individual walking distance varied from 175 to 600 m. Excellent test-retest reliability for the 6MWT (intraclass correlation coefficient, 0.95; 95% confidence interval, 0.9-0.97) was observed. The SEM was 16.6 m (95% confidence interval, 14.6-19.3), the SEM percentage was 4.2%, and the minimal detectable change was 46 m. Five observations (5%) were positioned outside the limits of agreement; there was a small proportional bias, and the scatter of values for differences decreased as the average values increased.

CONCLUSIONS

The excellent test-retest reliability implies that it is sufficient for a patient with IC to perform the 6MWT once, at every test occasion. For the individual, an improvement or deterioration in maximum walking distance of >46 m after an intervention would be required to be 95% confident that the change is significant. Being a simple and clinically useful test, the 6MWT can be widely used to evaluate the effects of different interventions in patients with IC.

Efficacy of ankle-foot orthoses on walking ability in peripheral artery disease

Calf claudication is a significant cause of walking limitation for patients with peripheral artery disease (PAD). Ankle-foot orthoses (AFO) are leg devices that can reduce the physical demands on the calf muscles during ambulation. The purpose of this study was to determine the efficacy of AFO on walking ability in patients with PAD. This was an open-label, interventional trial including 15 patients with calf claudication who were fit with AFO. Patients completed graded treadmill testing, followed by 12 weeks of unstructured community-based walking using the AFO ad libitum. Comparison of peak walking time (PWT) at baseline versus 12 weeks was the primary outcome. A secondary outcome was claudication onset time (COT) assessed during graded treadmill tests. Change in walking ability of AFO group patients was also compared to outcomes from a historical PAD control group (n = 10) who received upfront advice to walk at home. Patients in the AFO group significantly improved their walking ability from baseline to 12 weeks (mean ± SD) (PWT: 7.8 ± 5.1 to 9.3 ± 5.4 min, p = 0.049; COT: 3.0 ± 2.3 to 4.8 ± 2.7 min, p = 0.01). Change in PWT for AFO group patients when tested without using the devices was not significantly greater compared to historical controls (+1.4 ± 2.4 vs +0.1 ± 2.6 min, p = 0.16) but it was for COT (+1.8 ± 2.5 vs -0.6 ± 2.2 min, p = 0.02). This study found that AFO used during community-based walking improved the primary outcome of PWT in patients with PAD. Further, using AFO delayed claudication onset, indicating patients may be able to increase their walking activity. Large-scale, randomized controlled trials are needed to further explore the use of AFO for PAD. ClinicalTrials.gov identifier: NCT02280200.

Responsiveness and minimal clinically important difference of Modified Ashworth Scale in patients with stroke

BACKGROUND

Spasticity is a major problem in patients with stroke and influences their activities of daily living, participation, and quality of life. The Modified Ashworth Scale is widely used to assess spasticity. However, the responsiveness and minimal clinically important differences of the Modified Ashworth Scale in patients with stroke have not been explored.

AIM

This study aims to examine the responsiveness and minimal clinically important differences of the Modified Ashworth Scale in patients with stroke.

DESIGN

Longitudinal six-month follow-up study.

SETTING

Rehabilitation wards of a tertiary hospital.

POPULATION

One-hundred and fifteen patients with stroke were recruited.

METHODS

All patients underwent the assessment of Modified Ashworth Scale for the upper extremity (flexors of the elbow, wrist, and fingers) and the lower extremity (hip adductor, knee flexor, and ankle plantar flexor) at baseline and 6-month follow-up. The average Modified Ashworth Scale scores of the upper and lower extremity muscles were obtained for analysis. Responsiveness of the Modified Ashworth Scale was determined using standardized mean response, and the minimal clinically important differences were determined using a distribution-based approach with Effect Sizes of 0.5 and 0.8 standard deviations.

RESULTS

The responsiveness of the Modified Ashworth Scale in the upper and lower extremity muscles was marked (standardized response mean = 0.89-1.09). The minimal clinically important differences of the average Modified Ashworth Scale of Effect Sizes 0.5 and 0.8 standard deviations for the upper extremity muscles were 0.48 and 0.76, respectively, while those for the lower extremity muscles were 0.45 and 0.73, respectively.

CONCLUSIONS

The Modified Ashworth Scale was markedly responsive in detecting the changes in muscle tone in patients with stroke. The minimal clinically important differences of the Modified Ashworth Scale reported in this study can be used by researchers and clinicians in determining whether the observed changes are clinically meaningful post-treatment or at follow-up.

CLINICAL REHABILITATION IMPACT

The minimal clinically important differences of the Modified Ashworth Scale reported in this study will enable clinicians and researchers in determining whether changes in the muscle tone are true and clinically meaningful, and can be used as a reference for clinical decision-making.

Meta-analysis of clinical trials examining the benefit of structured home exercise in patients with peripheral artery disease

Background

Supervised exercise is recommended for the management of peripheral artery disease (PAD); however, the uptake is limited. Structured home exercise programmes may be more feasible, but their effectiveness is unclear. This systematic review and meta-analysis examined the benefit of structured home exercise programmes for treating PAD in comparison to controls not receiving an exercise programme.

Methods

A literature search was conducted to identify RCTs comparing structured home exercise with controls not receiving an exercise programme among patients with PAD. To be included, studies had to report outcomes from treadmill or corridor walking tests, or objective assessment of physical activity. Inverse variance-weighted meta-analysis was performed to compare changes in maximum walking distance and intermittent claudication onset distance in treadmill tests, walking distance during a 6-min walking test, and physical activity measured using a pedometer or accelerometer. Summarized results are presented in terms of standard deviation differences.

Results

Eleven randomized trials involving 807 patients were included. Follow-up ranged from 2 to 24 months; only one trial included follow-up beyond 12 months. Meta-analyses showed that structured home exercise programmes led to significant improvements in maximum walking distance (mean difference (MD) 0·32, 95 per cent c.i. 0·15 to 0·50; P &lt; 0·001), intermittent claudication onset distance (MD 0·45, 0·27 to 0·62; P &lt; 0·001), walking distance in a 6-min walking test (MD 0·28, 0·09 to 0·47; P = 0·004) and physical activity (MD 0·27, 0·11 to 0·43; P = 0·001).

Conclusion

This meta-analysis suggests that structured home exercise programmes are effective at improving walking performance and physical activity in the short term for patients with PAD.