Improved functional outcomes following exercise rehabilitation in patients with intermittent claudication

Physiological responses during walking in men and women with intermittent claudication

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Outcomes following supervised exercise and home-based exercise for patients with intermittent claudication

INTRODUCTION

Intermittent claudication (IC) is the most common symptom of peripheral arterial disease (PAD) which presents as a consequence of muscle ischaemia resulting from the atherosclerotic obstruction to arterial flow. High-quality evidence (Lane et al., 2017) shows that exercise programmes provide important benefits compared with usual care in improving pain-free and maximum walking distance in people with IC, but do not improve ankle-brachial pressure index (ABPI).

METHODS

Retrospective data were analysed to examine walking and ABPI outcomes for participants who completed a 12-week course of supervised or home-based exercise. All participants had a history of IC.

RESULTS

46 participants (mean age 69±11 years; 76% male; 29% current smokers) referred for exercise were assessed, completed a 12-week course of exercise (home-based or supervised) and subsequently attended for re-assessment. Claudication onset distance (COD) increased by 363% (mean improvement 344.7 ± 265.1m; p < .001) and peak walking distance (PWD) by 324.4% in the supervised exercise group; COD increased by 30.6% (mean improvement 32.8 ± 57.2 m; p = 0.026) and PWD by 31.5% in the home-based exercise group. Resting ABPI for the total cohort significantly improved from 0.82 ± 0.25 at A1 to 0.88 ± 0.25 at A2 (p = 0.027).

DISCUSSION

A 12-week course of supervised exercise results in significantly greater walking distance outcomes (COD and PWD) than unmonitored home-based exercise. In contrast with previous findings (Lane et al. 2017), this retrospective study demonstrated a significant improvement in resting ABPI with both supervised exercise as well as home-based exercise.

CONCLUSION

A 12-week programme of exercise favourably influenced walking and ABPI outcomes for patients with IC. Both home-based exercise and supervised individualised exercise increased walking distances, but the magnitude of the improvement in walking outcomes was greater in individuals who attended supervised exercise therapy.

Sarcopenia and peripheral arterial disease: a systematic review

BACKGROUND

Patients with lower extremity peripheral arterial disease (PAD) and sarcopenia are a population at risk requiring specific and targeted care. The aim of this review is to gather all relevant studies associating sarcopenia and PAD and to identify the underlying pathophysiological mechanisms as well as potential therapeutic strategies to improve skeletal muscle function.

METHODS

A systematic review was carried out following the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Data extraction allowed the evaluation of 140 publications; 87 met the inclusion criteria; of which 79 were included in the final review, reporting sufficient data for epidemiological and diagnostic criteria, mechanical analysis, and therapeutic approaches. Epidemiological analysis and diagnostic criteria were based on 18 studies following 2362 PAD patients [31.39% (SD 7.61) women], aged 72.42 (SD 2.84); sarcopenia was present in 34.63% (SD 12.86) of the patients. Mechanical and pathway analysis were based on five animal studies and 29 clinical reports, showing significantly altered muscle strength and function in 1352 PAD patients [26.49% (SD 17.32) women], aged 67.67 (SD 5.14) years; impaired muscle histology in 192 PAD patients (9.2% (SD 11.22) women), aged 64.3 (SD 0.99) years; +58.63% (SD 25.48) of oxidative stress in 69 PAD patients [16.96% (SD 8.10) women], aged 63.17 (SD 1.43) years; mitochondriopathy in 153 PAD patients [29.39% (SD 28.27) women], aged 63.50 (SD 1.83) years; +15.58% (SD 7.41) of inflammation in 900 PAD patients [40.77% (SD 3.71) women], aged 74.88 (SD 2.76) years; and altered signalling pathways in 51 PAD patients [34.45% (SD 32.23) women], aged 72.25 (SD 5.25) years. Therapeutic approaches analysis was based on seven animal studies and 21 clinical reports. In total, 884 patients followed an exercise therapy, and 18 received an angiogenesis treatment; 30.84% (SD 17.74) were women. Mean ages of patients studied were 66.85 (SD 3.96).

CONCLUSIONS

Sarcopenia and lower extremity PAD have musculoskeletal consequences that directly impair patients' quality of life and prognosis. Although PAD is primarily a vascular disease, all etiological factors of sarcopenia identified so far are present in PAD. Indeed, both sarcopenia and PAD are accompanied by oxidative stress, skeletal muscle mitochondrial impairments, inflammation, inhibition of specific pathways regulating muscle synthesis or protection (i.e. IGF-1, RISK, and SAFE), and activation of molecules associated with muscle degradation. To date, besides revascularization, the best therapeutic strategy includes exercise, but approaches targeting the underlying mechanisms still deserve further studies.

The exercise pressor reflex and active O2 transport in peripheral arterial disease

It is unclear if the exaggerated exercise pressor reflex observed in peripheral arterial disease (PAD) patients facilitates Oxygen (O2 ) transport during presymptomatic exercise. Accordingly, this study compared O2 transport between PAD patients and healthy controls during graded presymptomatic work. Seven PAD patients and seven healthy controls performed dynamic plantar flexion in the bore of a 3T MRI scanner. Perfusion, T2 * (an index of relative tissue oxygenation), and SvO2 (a measure of venous oxygen saturation) were collected from the medial gastrocnemius (MG) during the final 10 seconds of each stage. Blood pressure was also collected during the final minute of each stage. As expected, the pressor response to presymptomatic work (4 kg) was exaggerated in PAD patients compared to controls (+14 mmHg ± 4 and +7 mmHg ± 2, P ≤ 0.034). When normalized to changes in free water content (S0 ), T2 * was lower at 2 kg in PAD patients compared to controls (-0.91 Δms/ΔAU ± 0.3 and 0.57 Δms/ΔAU ± 0.3, P ≤ 0.008); followed by a greater increase in perfusion at 4 kg in the PAD group (+18.8 mL/min/100g ± 6.2 vs. -0.21 mL/min/100g ± 3.2 in PAD and controls, P ≤ 0.026). Lastly, SvO2 decreased at 4 kg in both groups (-13% ± 4 and -2% ± 4 in PAD and controls, P ≤ 0.049), suggesting an increase in O2 extraction in the PAD group. Based on these findings, O2 transport appears to be augmented during graded presymptomatic work in PAD patients, and this may be partially mediated by an exaggerated pressor response.

A systematic review and meta-analysis of the effects of supervised exercise therapy on modifiable cardiovascular risk factors in intermittent claudication

OBJECTIVE

Cardiovascular events, such as myocardial infarction and stroke, contribute significantly to the prognosis of patients with peripheral artery disease. Therefore cardiovascular risk reduction is a vital element of treatment in patients with intermittent claudication (IC). The cardiovascular risk is largely determined by modifiable risk factors, which can be treated with medical care and lifestyle adjustments, such as increasing physical activity. The objective of this study was to determine the effects of supervised exercise therapy (SET) on modifiable cardiovascular risk factors in IC patients.

METHODS

This is a systematic review and meta-analysis of prospective studies on the effects of SET on cardiovascular risk factors in symptomatic IC patients. Studies were eligible if they presented baseline and follow-up values for at least one of the following risk factors: blood pressure (systolic or diastolic), heart rate, lipid profile (total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol), glucose, glycated hemoglobin, body weight, body mass index, or cigarette smoking. Pooled mean differences between follow-up and baseline were analyzed using a random-effects model. Data were classified into short-term results (6 weeks-3 months) and midterm results (6-12 months). Statistical heterogeneity was presented as I² and Q statistic.

RESULTS

Twenty-seven studies with a total of 808 patients were included in this review. In the short term, SET resulted in significant improvements of systolic blood pressure (decrease of 4 mm Hg; 10 studies; 95% confidence interval [CI], -6.40 to -1.76; I², 0%) and diastolic blood pressure (decrease of 2 mm Hg; 8 studies; 95% CI, -3.64 to -0.22; I², 35%). In the midterm, SET contributed to significant lowering of levels of low-density lipoprotein cholesterol (decrease of 0.2 mmol/L; four studies; 95% CI, -0.30 to -0.12; I², 29%) and total cholesterol (decrease of 0.2 mmol/L, four studies; 95% CI, -0.38 to -0.10; I², 36%). No significant effects of SET were identified for heart rate, triglycerides, high-density lipoprotein cholesterol, glucose, glycated hemoglobin, body weight, body mass index, or cigarette smoking.

CONCLUSIONS

This systematic review and meta-analysis shows favorable effects of SET on modifiable cardiovascular risk factors, specifically blood pressure and cholesterol levels. Despite the moderate quality, small trial sample sizes, and study heterogeneity, these findings support the prescription of SET programs not only to increase walking distances but also for risk factor modification. Future studies should address the potential effectiveness of SET to promote a healthier lifestyle and to improve cardiovascular outcomes in patients with claudication.

Changes in Function After a 6-Month Walking Intervention in Patients With Intermittent Claudication Who Are Obese or Nonobese

BACKGROUND AND PURPOSE

Both obesity and peripheral artery disease (PAD) limit function and may work additively to reduce mobility. The purpose of this study was to compare the effects of a 6-month, center-based walking program on mobility function between adults who are weight-stable obese and nonobese with PAD.

METHODS

This is a secondary data analysis of 2 combined studies taken from previous work. Fifty-three adults with PAD and intermittent claudication participated in 6 months of treadmill training or standard of care. Patients were divided into 4 groups for analyses: exercise nonobese (Ex), exercise obese (ExO), standard-of-care nonobese (SC), and standard-of-care obese (SCO). Mobility was assessed by a standardized treadmill test to measure claudication onset time (COT) and peak walking time (PWT) as well as the distance walked during a 6-minute walk distance (6MWD) test.

RESULTS

There was a significant (P < .001) interaction (intervention × obesity) effect on 6MWD, wherein both exercise groups improved (Ex = 7%, ExO = 16%; P < .02), the SC group did not change (0.9%; P > .05), and the SCO group tended to decline (-18%; P = .06). Both exercise intervention groups significantly improved COT (Ex = 92%, ExO = 102%; P < .01) and PWT (Ex = 54%, ExO = 103%; P < .001). There was no change (P > .05) in either standard-of-care group.

CONCLUSIONS

Individuals who are obese and nonobese with PAD made similar improvements after a 6-month, center-based walking program. However, patients who are obese with PAD and do not exercise may be susceptible to greater declines in mobility. Exercise may be particularly important in patients who are obese with PAD to avoid declines in mobility.

Sarcopenia in Peripheral Arterial Disease: Prevalence and Effect on Functional Status

OBJECTIVES

(1) To determine the prevalence of sarcopenia in older men with peripheral arterial disease (PAD); (2) to compare a subgroup of the group with age-, race-, sex-, and body mass index (BMI)-matched non-PAD control counterparts, and (3) to compare the functional status of those with PAD with and without sarcopenia.

DESIGN

Cohort study.

SETTING

Medical center.

PARTICIPANTS

Sedentary community-dwelling men (N=108; age, >50y) with a confirmed diagnosis of PAD (44% blacks; BMI, 27.8±0.4kg/m²; ankle-brachial index, .62±.01).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Dual-energy x-ray absorptiometry scans were used to assess appendicular lean mass and determine the prevalence of sarcopenia by/height². Treadmill tests were used to determine claudication onset time, peak walking time, and claudication recovery time. 6-Minute walk distance was also measured.

RESULTS

Sarcopenia prevalence in our PAD cohort was 25%. The PAD subgroup (n=42) matched with control counterparts in terms of race, sex, age, and BMI had higher prevalence rates than did their non-PAD counterparts (23.8% vs 2.4%; P<.05). Individuals with sarcopenia (n=28) had a shorter 6-minute walk distance (326±18.8m vs 380±9.7m; P<.05) and higher claudication recovery time (592±98s vs 395±29s; P<.05) than did individuals with PAD but without sarcopenia (n=80). There was no difference in claudication onset time or peak walking time between the PAD groups.

CONCLUSIONS

Men with PAD demonstrate a high prevalence of sarcopenia. Those with sarcopenia and PAD demonstrate decreased mobility function.

Supervised exercise training combined with ginkgo biloba treatment for patients with peripheral arterial disease

Objectives: To evaluate whether a combination of supervised exercise training and ginkgo biloba treatment is a better treatment than exercise training alone for patients with peripheral arterial disease.

Design: A 24-week double-blind, placebo-controlled ginkgo biloba trial with the first 12-week period as a non-exercise control stage and the second 12-week period as an exercise training stage.

Setting: Exercise physiology laboratory.

Subjects: Twenty-two subjects with peripheral arterial disease.

Interventions: The subjects were randomly allocated into a ginkgo or a placebo group. During the first stage, the ginkgo group ingested standardized ginkgo biloba tablets with a daily dosage of 240 mg, while the placebo group received placebo tablets. During the second stage, all subjects engaged in a supervised treadmill-walking programme while continuing to take the same dosage of ginkgo biloba or placebo tablets.

Main measures: Walking capacity on treadmill, oxygen consumption during exercise, peripheral haemodynamics and blood viscosity were measured at baseline, and after the first and the second stages of treatment.

Results: The ginkgo group did not show significant changes in most of the measured variables after each stage of treatment, except that the maximal walking time was significantly increased after the combined treatment (from 236 ± 112 seconds to 557 ± 130 seconds, P < 0.001). However, similar response was also found in the placebo group after exercise training (from 384 ± 125 seconds to 820 ± 146 seconds, P < 0.001).

Conclusion: Supervised exercise training combined with ginkgo biloba treatment did not produce greater beneficial effects than exercise training alone in patients with peripheral arterial disease.

Effects of 12-week supervised treadmill training on spatio-temporal gait parameters in patients with claudication

The purpose of the study was to evaluate selected temporal and spatial gait parameters in patients with intermittent claudication after completion of 12-week supervised treadmill walking training. The study included 36 patients (26 males and 10 females) aged: mean 64 (SD 7.7) with intermittent claudication. All patients were tested on treadmill (Gait Trainer, Biodex). Before the programme and after its completion, the following gait biomechanical parameters were tested: step length (cm), step cycle (cycle/s), leg support time (%), coefficient of step variation (%) as well as pain-free walking time (PFWT) and maximal walking time (MWT) were measured. Training was conducted in accordance with the current TASC II guidelines. After 12 weeks of training, patients showed significant change in gait biomechanics consisting in decreased frequency of step cycle (p < 0.05) and extended step length (p < 0.05). PFWT increased by 96% (p < 0.05). MWT increased by 100% (p < 0.05). After completing the training, patients' gait was more regular, which was expressed via statistically significant decrease of coefficient of variation (p < 0.05) for both legs. No statistically significant relation between the post-training improvement of PFWT and MWT and step length increase and decreased frequency of step cycle was observed (p > 0.05).

IMPLICATIONS FOR REHABILITATION

Twelve-week treadmill walking training programme may lead to significant improvement of temporal and spatial gait parameters in patients with intermittent claudication. Twelve-week treadmill walking training programme may lead to significant improvement of pain-free walking time and maximum walking time in patients with intermittent claudication.

Clinical Interest of Ambulatory Assessment of Physical Activity and Walking Capacity in Peripheral Artery Disease

The purpose of the present review was to provide, for the first time, a comprehensive analysis and synthesis of the available studies that highlighted the clinical interest of the ambulatory assessment of either physical activity (PA) or walking capacity in patients with lower extremity peripheral artery disease (PAD). We identified 96 related articles published up to March 2015 through a computer-assisted search of the MEDLINE, EMBASE, and Web of Science databases. Ambulatory-measured PA or related energy expenditure (EE) in PAD patients was performed in 87 of the 96 included studies. The main clinical interests of these measurements were (a) the assessment of PA/EE pattern; (b) the characterization of walking pattern; and (c) the control of training load during home-based walking programs. Ambulatory-measured walking capacity was performed in the remaining studies, using either Global Positioning System receivers or the Peripheral Arterial Disease Holter Control device. Highlighted clinical interests were (a) the assessment of community-based walking capacity; (b) the use of new outcomes to characterize walking capacity, besides the conventional absolute claudication distance; and (c) the association with the patient's self-perception of walking capacity. This review also provides for the clinicians step-by-step recommendations to specifically assess PA or walking capacity in PAD patients.

Association of diabetic peripheral arterial disease and objectively-measured physical activity: NHANES 2003-2004

Background

Although much is known about the management of peripheral arterial disease among adults in the general population, the management of this disease among those with diabetes, and the effects of diabetic-induced peripheral arterial disease on objectively-measured physical activity, is unclear. Here, we examined the association between accelerometer-assessed physical activity and peripheral arterial disease among a national sample of U.S. adults with diabetes.

Methods

Data from the 2003–2004 National Health and Nutrition Examination Survey were used. Physical activity was measured using an accelerometer in 254 adults with diabetes. Peripheral arterial disease was assessed via ankle brachial index. Negative binomial regression analysis was used to examine the association between physical activity and peripheral arterial disease.

Results

Results were adjusted for age, gender, race-ethnicity, comorbidity index, smoking, HgbA1C, C-reactive protein, homocysteine, glomerular filtration rate, microalbuminuria, peripheral neuropathy, physical functioning, and medication use. After adjustments, participants with peripheral arterial disease engaged in 23% less physical activity (RR = 0.77, 95% CI: 0.62-0.96) than those without peripheral arterial disease.

Conclusions

These findings demonstrate an inverse association between accelerometer-assessed physical activity and peripheral arterial disease in a national sample of U.S adults with diabetes.

Exercise prescription using the heart of claudication pain onset in patients with intermittent claudication

OBJECTIVE

To assess the acute metabolic and cardiovascular responses to walking exercise at an intensity corresponding to the heart rate of claudication pain onset and to investigate the effects of a 12-week walking training program at this intensity on walking capacity.

METHODS

Twenty-nine patients with intermittent claudication were randomly allocated to the walking training (n=17) or control (CO, n=12) group. The walking training group performed an acute exercise session comprising 15×2-min bouts of walking at the heart rate of claudication pain onset, with 2-min interpolated rest intervals. The claudication symptoms and cardiovascular and metabolic responses were evaluated. Walking training was then performed at the same intensity twice each week for 12 weeks, while the control group engaged in twice weekly stretching classes. The claudication onset distance and total walking distance were evaluated before and after the interventions. Brazilian Registry Clinical Trials: RBR-7M3D8W.

RESULTS

During the acute exercise session, the heart rate was maintained within tight limits. The exercise intensity was above the anaerobic threshold and >80% of the heart rate peak and VO2peak. After the exercise training period, the walking exercise group (n=13) showed increased claudication onset distance (309±153 vs. 413±201m) and total walking distance (784±182 vs. 1,100±236m) compared to the control group (n=12) (p<0.05).

CONCLUSION

Walking exercise prescribed at the heart rate of claudication pain onset enables patients with intermittent claudication to exercise with tolerable levels of pain and improves walking performance.

Recruitment to clinical trials of exercise: challenges in the peripheral arterial disease population

OBJECTIVES

To describe recruitment to a randomised controlled trial of a 12-week (twice-weekly) supervised exercise programme for patients with peripheral arterial disease (PAD). PAD is a chronic, progressive disease with a significant cardiovascular and cerebrovascular risk burden, and exercise is an effective primary management approach.

METHOD

Potential patients were identified from the Non-Invasive Vascular Laboratory records and invited to participate in the study. On successful completion of an incremental treadmill exercise test, patients were allocated at random to a control (usual care) or an exercise group.

RESULTS

Between November 2006 and June 2009, 548 patients were identified. Of the 156 patients who met the inclusion criteria, 40 (26%) declined to participate. Of the 71 patients who underwent exercise testing, 23 (32%) did not complete the test. The final enrolment number was 44 (44/156; 28%). Eleven patients (11/28; 39%) subsequently withdrew from the exercise programme.

CONCLUSION

Recruitment to clinical trials of exercise presents significant challenges in the PAD population due to the presence of co-existing cardiovascular and cerebrovascular disease, a reluctance to exercise due to leg pain, and an acceptance of reduced mobility as part of ageing. Early identification in primary care before the onset of significant comorbidity may ameliorate some of these issues.

Exercise training and peripheral arterial disease

Peripheral arterial disease (PAD) is a common vascular disease that reduces blood flow capacity to the legs of patients. PAD leads to exercise intolerance that can progress in severity to greatly limit mobility, and in advanced cases leads to frank ischemia with pain at rest. It is estimated that 12 to 15 million people in the United States are diagnosed with PAD, with a much larger population that is undiagnosed. The presence of PAD predicts a 50% to 1500% increase in morbidity and mortality, depending on severity. Treatment of patients with PAD is limited to modification of cardiovascular disease risk factors, pharmacological intervention, surgery, and exercise therapy. Extended exercise programs that involve walking approximately five times per week, at a significant intensity that requires frequent rest periods, are most significant. Preclinical studies and virtually all clinical trials demonstrate the benefits of exercise therapy, including improved walking tolerance, modified inflammatory/hemostatic markers, enhanced vasoresponsiveness, adaptations within the limb (angiogenesis, arteriogenesis, and mitochondrial synthesis) that enhance oxygen delivery and metabolic responses, potentially delayed progression of the disease, enhanced quality of life indices, and extended longevity. A synthesis is provided as to how these adaptations can develop in the context of our current state of knowledge and events known to be orchestrated by exercise. The benefits are so compelling that exercise prescription should be an essential option presented to patients with PAD in the absence of contraindications. Obviously, selecting for a lifestyle pattern that includes enhanced physical activity prior to the advance of PAD limitations is the most desirable and beneficial.

Peripheral arterial disease of the lower extremities

Persons with peripheral arterial disease (PAD) are at increased risk for all-cause mortality, cardiovascular mortality, and mortality from coronary artery disease. Smoking should be stopped and hypertension, dyslipidemia, diabetes mellitus, and hypothyroidism treated. Statins reduce the incidence of intermittent claudication and improve exercise duration until the onset of intermittent claudication in persons with PAD and hypercholesterolemia. The serum low-density lipoprotein cholesterol should be reduced to < 70 mg/dl. Antiplatelet drugs such as aspirin or clopidogrel, angiotensin-converting enzyme inhibitors, and statins should be given to persons with PAD. β-Blockers should be given if coronary artery disease is present. Cilostazol improves exercise time until intermittent claudication. Exercise rehabilitation programs should be used. Revascularization should be performed if indicated.

Optimal exercise program length for patients with claudication

BACKGROUND

This prospective, randomized controlled clinical trial determined whether an optimal exercise program length exists to efficaciously change claudication onset time (COT) and peak walking time (PWT) in patients with peripheral artery disease and claudication.

METHODS

The study randomized 142 patients to supervised exercise (n = 106) or a usual care control group (n = 36), with 80 completing the exercise program and 27 completing the control intervention. The exercise program consisted of intermittent walking to nearly maximal claudication pain 3 days per week. COT and PWT were the primary outcomes obtained from a treadmill exercise test at baseline and bimonthly during the study.

RESULTS

After exercise, changes in COT (P < .001) and PWT (P < .001) were consistently greater than changes after the control intervention. In the exercise program, COT and PWT increased from baseline to month 2 (P < .05) and from months 2 to 4 (P < .05) but did not significantly change from months 4 to 6 (P > .05). When changes were expressed per mile walked during the first 2 months, middle 2 months, and final 2 months of exercise, COT and PWT only increased during the first 2 months (P < .05).

CONCLUSIONS

Exercise-mediated gains in COT and PWT occur rapidly within the first 2 months of exercise rehabilitation and are maintained with further training. The clinical significance is that a relatively short 2-month exercise program may be preferred to a longer program to treat claudication because adherence is higher, costs associated with personnel and use of facilities are lower per patient, and more patients can be trained for a given amount of personnel time and resource utilization.

Effects of a 6-month exercise program pilot study on walking economy, peak physiological characteristics, and walking performance in patients with peripheral arterial disease

The purpose of this study was to examine the effects of a 6-month exercise program on submaximal walking economy in individuals with peripheral arterial disease and intermittent claudication (PAD-IC). Participants (n = 16) were randomly allocated to either a control PAD-IC group (CPAD-IC, n = 6) which received standard medical therapy, or a treatment PAD-IC group (TPAD-IC; n = 10) which took part in a supervised exercise program. During a graded treadmill test, physiological responses, including oxygen consumption, were assessed to calculate walking economy during submaximal and maximal walking performance. Differences between groups at baseline and post-intervention were analyzed via Kruskal–Wallis tests. At baseline, CPAD-IC and TPAD-IC groups demonstrated similar walking performance and physiological responses. Postintervention, TPAD-IC patients demonstrated significantly lower oxygen consumption during the graded exercise test, and greater maximal walking performance compared to CPAD-IC. These preliminary results indicate that 6 months of regular exercise improves both submaximal walking economy and maximal walking performance, without significant changes in maximal walking economy. Enhanced walking economy may contribute to physiological efficiency, which in turn may improve walking performance as demonstrated by PAD-IC patients following regular exercise programs.

Associations of calf skeletal muscle characteristics and peripheral nerve function with self-perceived physical functioning and walking ability in persons with peripheral artery disease

We determined whether more adverse calf muscle characteristics and poorer peripheral nerve function were associated with impairments in self-perceived physical functioning and walking ability in persons with lower extremity peripheral artery disease (PAD). Participants included 462 persons with PAD; measures included the ankle-brachial index (ABI), medical history, electrophysiologic characteristics of nerves, and computed tomography of calf muscle. Self-perceived physical functioning and walking ability were assessed using the 36-Item Short Form Health Survey (SF-36) and the Walking Impairment Questionnaire (WIQ). Results were adjusted for age, sex, race, ABI, body mass index, comorbidities, and other confounders. Lower calf muscle area was associated with a poorer SF-36 physical function (PF) score (overall p-trend < 0.001, 33.76 PF score for the lowest quartile versus 59.74 for the highest, pairwise p < 0.001) and a poorer WIQ walking distance score (p-trend = 0.001, 29.71 WIQ score for the lowest quartile versus 48.43 for the highest, pairwise p < 0.001). Higher calf muscle percent fat was associated with a poorer SF-36 PF score (p-trend < 0.001, 53.76 PF score for the lowest quartile versus 40.28 for the highest, pairwise p = 0.009). Slower peroneal nerve conduction velocity was associated with a poorer WIQ speed score ( p-trend = 0.023, 30.49 WIQ score for the lowest quartile versus 40.48 for the highest, pairwise p = 0.031). In summary, adverse calf muscle characteristics and poorer peripheral nerve function are associated significantly and independently with impairments in self-perceived physical functioning and walking ability in PAD persons.

Optimizing supervised exercise therapy for patients with intermittent claudication

BACKGROUND

The first-line intervention for intermittent claudication is usually supervised exercise therapy (SET). The literature describes a range of exercise programs varying in setting, duration, and content. The purpose of the present study was to examine the exercise protocols offered and to identify the impact of the intensity of the SET programs (in terms of frequency, duration, and type of exercise) on improvements in walking distance (response) in the first 3 months. The present study is part of the Exercise Therapy in Peripheral Arterial Disease (EXITPAD) study, a multicenter randomized clinical trial comparing the effects of SET provided by regional physiotherapists, with or without daily feedback, on the level of activities with the effects of walking advice.

METHODS

The analysis included patients randomized to receive SET with or without feedback. The physical therapists administering the SET were asked to fill out therapy evaluation sheets stating frequency, duration, and type of exercises. The relationship between training volume and the impact on walking distance was explored by dividing training volume data into tertiles and relating them to the median change in maximum walking distance at 3 and 12 months.

RESULTS

Data of 169 patients were included in the analysis. A SET program consisting of at least two training sessions per week each lasting over 30 minutes, during the first 3 months of a 1-year program tailored to individual patients' needs led to better results in terms of walking distance after 3 and 12 months than the other variants. The results of our analysis dividing training volume into tertiles suggest that there is a relationship between training volume and improvement in walking distance and that at least 590 minutes of training should be offered in the first 3 months. No differences were found between program involving only walking and a combination of exercises, nor between individual and group training.

CONCLUSION

A SET programs consisting of at least two training sessions a week, each lasting over 30 minutes, should be offered during the first 3 months of the SET program to optimize improvement in terms of maximum walking distance.

Self-efficacy is associated with walking ability in persons with diabetes mellitus and peripheral arterial disease

Self-efficacy is a known predictor for behavior change. Little is known about the association of self-efficacy with walking ability in individuals with diabetes mellitus and peripheral arterial disease (PAD). The objective of this study was to determine the association of self-efficacy with walking ability in individuals with diabetes mellitus and PAD. In this cross-sectional study, baseline data were analyzed from individuals with diabetes mellitus type 1 or 2 and PAD who were enrolled in a walking intervention clinical trial. As part of the baseline assessment, individuals completed questionnaires to ascertain self-efficacy and co-existing illnesses. In addition, participants completed a treadmill walking test and a 6-minute walking test. A total of 145 individuals were enrolled (mean age 66.5 +/- 10.1 years) with diabetes mellitus and PAD; 45 (31%) were women. The mean ankle-bracial index was 0.70 (range - 0.18-2.20) and the mean glycosylated hemoglobin value was 7.1 (SD 1.2). The mean distance walked, as per the treadmill walking test, was 418 meters (SD 258) and the mean distance walked, as per the 6-minute walking test, was 272 meters (SD 74). As measured by the treadmill walking test and the 6-minute walking test, self-efficacy was associated with treadmill walking distance, coefficient 33.0 (95% CI 11.0, 55.1; p = 0.0036), and the 6-minute walking test, coefficient 10.4 (95% CI 3.0, 17.7; p = 0.0061), after adjusting for comorbidities, social habits, and disease severity. In conclusion, self-efficacy, a psychosocial mediator for behavior change, was significantly associated with walking ability in individuals with diabetes mellitus and PAD. Future studies should determine the benefits of targeting self-efficacy to improve adherence to walking therapy in patients with PAD.

The Roles of Physical Therapists in Wound Management: Part IV

Physical therapists are important members of the comprehensive wound management team. In addition to being able to provide standard wound care, they are well prepared to treat wounds with a variety of biophysical agents that introduce electromagnetic, acoustic, and mechanical energies that enhance healing. Physical therapists also address restoration of function that is frequently compromised in patients who suffer from chronically and acutely wounded tissues.

Strength training increases walking tolerance in intermittent claudication patients: randomized trial

OBJECTIVE

To analyze the effects of strength training (ST) in walking capacity in patients with intermittent claudication (IC) compared with walking training (WT) effects.

METHODS

Thirty patients with IC were randomized into ST and WT. Both groups trained twice a week for 12 weeks at the same rate of perceived exertion. ST consisted of three sets of 10 repetitions of whole body exercises. WT consisted of 15 bouts of 2-minute walking. Before and after the training program walking capacity, peak VO(2), VO(2) at the first stage of treadmill test, ankle brachial index, ischemic window, and knee extension strength were measured.

RESULTS

ST improved initial claudication distance (358 +/- 224 vs 504 +/- 276 meters; P < .01), total walking distance (618 +/- 282 to 775 +/- 334 meters; P < .01), VO(2) at the first stage of treadmill test (9.7 +/- 2.6 vs 8.1 +/- 1.7 mL.kg(-1).minute; P < .01), ischemic window (0.81 +/- 1.16 vs 0.43 +/- 0.47 mm Hg minute meters(-1); P = .04), and knee extension strength (19 +/- 9 vs 21 +/- 8 kg and 21 +/- 9 vs 23 +/- 9; P < .01). Strength increases correlated with the increase in initial claudication distance (r = 0.64; P = .01) and with the decrease in VO(2) measured at the first stage of the treadmill test (r = -0.52; P = .04 and r = -0.55; P = .03). Adaptations following ST were similar to the ones observed after WT; however, patients reported lower pain during ST than WT (P < .01).

CONCLUSION

ST improves functional limitation similarly to WT but it produces lower pain, suggesting that this type of exercise could be useful and should be considered in patients with IC.

Naftidrofuryl for intermittent claudication: meta-analysis based on individual patient data

OBJECTIVE

To assess the efficacy of naftidrofuryl compared with placebo in treating the symptoms of intermittent claudication.

DESIGN

Meta-analysis based on individual patient data.

DATA SOURCES

Medline, International Pharmaceutical Abstracts, Embase, Science Citation Index, and the Cochrane trial registers. Reference lists of retrieved articles were checked. Authors and companies were approached for additional information and individual patient data.

INCLUSION CRITERIA

Double blind, randomised controlled trials in patients with intermittent claudication receiving oral naftidrofuryl or placebo and with pain-free walking distance as primary outcome.

DATA COLLECTION

Individual patient data were collected from electronic data or from case report forms and checked for integrity.

ANALYSIS

All randomised patients were analysed following the intention to treat principle. Efficacy was assessed by the ratio of geometric mean of the relative improvement in pain-free walking distance after use of naftidrofuryl compared with placebo. In the analysis of responders, therapeutic success was defined as an improvement of walking distance at baseline by at least 50%.

RESULTS

In total, 1266 patients were randomised (1083 in the main analysis). The ratio of relative improvement in pain-free walking distance after use of naftidrofuryl compared with placebo was 1.37 (95% confidence interval 1.27 to 1.49). The difference in response rate was 22.3% (95% confidence interval 17.1% to 27.6%) and the number needed to treat for relief of symptoms during six months of treatment was 4.48 (95% confidence interval 3.62 to 5.85).

CONCLUSION

This meta-analysis of individual patient data provides evidence that naftidrofuryl has a clinically meaningful effect compared with placebo in improving walking distance in patients with intermittent claudication.

Alpha-adrenergic and neuropeptide Y Y1 receptor control of collateral circuit conductance: influence of exercise training

This study evaluated the role of alpha-adrenergic receptor- and neuropeptide Y (NPY) Y1 receptor-mediated vasoconstriction in the collateral circuit of the hind limb. Animals were evaluated either the same day (Acute) or 3 weeks following occlusion of the femoral artery; the 3-week animals were in turn limited to cage activity (Sed) or given daily exercise (Trained). Collateral-dependent blood flows (BFs) were measured during exercise with microspheres before and after alpha-receptor inhibition (phentolamine) and then NPY Y1 receptor inhibition (BIBP 3226) at the same running speed. Blood pressures (BPs) were measured above (caudal artery) and below (distal femoral artery) the collateral circuit. Arterial BPs were reduced by alpha-inhibition (50-60 mmHg) to approximately 75 mmHg, but not further by NPY Y1 receptor inhibition. Effective experimental sympatholysis was verified by 50-100% increases (P < 0.001) in conductance of active muscles not affected by femoral occlusion with receptor inhibition. In the absence of receptor inhibition, vascular conductance of the collateral circuit was minimal in the Acute group (0.13 +/- 0.02), increased over time in the Sed group (0.41 +/- 0.03; P < 0.001), and increased further in the Trained group (0.53 +/- 0.03; P < 0.02). Combined receptor inhibition increased collateral circuit conductances (P < 0.005), most in the Acute group (116 +/- 37%; P < 0.02), as compared to the Sed (41 +/- 6.6%; P < 0.001) and Trained (31 +/- 5.6%; P < 0.001) groups. Thus, while the sympathetic influence of the collateral circuit remained in the Sed and Trained animals, it became less influential with time post-occlusion. Collateral conductances were collectively greater (P < 0.01) in the Trained as compared to Sed group, irrespective of the presence or absence of receptor inhibition. Conductances of the active ischaemic calf muscle, with combined receptor inhibition, were suboptimal in the Acute group, but increased in Sed and Trained animals to exceptionally high values (e.g. red fibre section of the gastrocnemius: approximately 7 ml min(-1) (100 g)(-1) mmHg(-1)). Thus, occlusion of the femoral artery promulgated vascular adaptations, even in vessels that are not part of the collateral circuit. The presence of active sympathetic control of the collateral circuit, even with exercise training, raises the potential for reductions in collateral BF below that possible by the structure of the collateral circuit. However, even with release of this sympathetic vasoconstriction, conductance of the collateral circuit was significantly greater with exercise training, probably due to the network of structurally larger collateral vessels.

Supervised and home-based exercise training for patients with intermittent claudication

Home-based exercise training, applied as the primary treatment in patients with intermittent claudication, has produced inconsistent effects on walking capacity in previous published studies. The aim of the present study was to evaluate whether a home-based exercise training program could maintain improved walking capacity and other functional variables achieved through a supervised exercise training program. The present design was a 48-week self-controlled study. The first 12-week period was a control stage in which no prescribed exercise program was provided, the second 12-week period was a supervised treadmill-walking training program and the following 24-week period was a home-based exercise program. Twenty-two subjects with intermittent claudication were recruited initially; 15 of them (14 men and one woman) completed the whole program. Walking capacity, peak oxygen uptake, walking economy and ankle-brachial index were measured at baseline and at 12, 24 and 48 weeks. There was no significant change in the measured variables after the control stage. The 12-week supervised treadmill-walking training program significantly increased pain-free walking time, maximal walking time and peak oxygen uptake. Walking economy was also significantly improved. These improvements were successfully maintained after 24 weeks of home-based training. The results indicated that 12 weeks of supervised treadmill-walking training followed by a home-based training program is an effective model of exercise rehabilitation for patients with intermittent claudication.

Meta-analysis of interventions to increase physical activity among cardiac subjects

BACKGROUND

Extensive primary research has tested interventions to increase physical activity (PA) among adults with cardiovascular disease. This meta-analysis integrates the extant research about how to increase PA in cardiac samples.

METHODS

Extensive literature searching located published and unpublished intervention studies that measured PA outcomes. Results were coded from primary studies. Fixed- and random-effects meta-analytic procedures included moderator analyses.

RESULTS

Data were synthesized across 11,877 subjects from 79 eligible research reports. The overall mean PA effect size for 2-group comparisons was 0.35 (higher mean for treatment than control), which is consistent with a difference of 1984 kcal/week for treatment subjects versus 1615 for control subjects. The fitness effect size for 2-group comparisons was .17. Other statistically significantly positive 2-group effect sizes were .24 for quality of life and .23 for subsequent cardiac events. Effect sizes for anthropometric measures and blood pressure did not differ significantly from 0. Exploratory moderator analyses found large effect sizes for PA among studies that had (1) an exclusive focus on PA versus diverse health behaviors, (2) more contact between interventionists and subjects, (3) supervised exercise sessions, (4) fitness testing, (5) face-to-face encounters versus mediated intervention delivery, and (6) more minutes of activity per week. Effect sizes were unrelated to funding status, dissemination vehicle, gender distribution, or attrition rate.

CONCLUSIONS

These findings document that interventions can be effective in increasing PA among patients with cardiovascular diseases. Primary research should compare interventions in randomized trials to confirm causal relationships.

Estudo comparativo da evolução e sobrevida de pacientes com claudicação intermitente, com ou sem limitação para exercícios, acompanhados em ambulatório específico

CONTEXTO: Os fatores de risco para doença aterosclerótica, que influenciam na evolução natural dessa doença, estão bem estabelecidos, assim como o benefício do programa de exercícios para pacientes claudicantes. Entretanto, faltam informações sobre a relação entres limitações clínicas e fatores de risco, com desempenho do programa de caminhadas e suas implicações na evolução e mortalidade destes pacientes. OBJETIVO: Comparar, ao longo do tempo, a distância de claudicação e sobrevida de pacientes claudicantes em ambulatório específico, com ou sem limitação para exercícios. MÉTODOS: Foi feito um estudo tipo coorte retrospectivo de 185 pacientes e 469 retornos correspondentes, no período de 1999 a 2005, avaliando-se dados demográficos, distância média de claudicação (CI) e óbito. Os dados foram analisados nos programas Epi Info, versão 3.2, e SAS, versão 8.2. RESULTADOS: A idade média foi de 60,9±11,1 anos, sendo 61,1% do sexo masculino e 38,9% do sexo feminino. Oitenta e sete por cento eram brancos, e 13%, não-brancos. Os fatores de risco associados foram: hipertensão (69,7%), tabagismo (44,3%), dislipidemia (32,4%) e diabetes (28,6%). Nos claudicantes para menos de 500 m, a CI inicial em esteira foi de 154,0±107,6 m, e a CI final, de 199,8±120,5 m. Cerca de 45% dos pacientes tinham alguma limitação clínica para realizar o programa de exercícios preconizado, como: angina (26,0%), acidente vascular cerebral (4,3%), artropatia (3,8%), amputação menor ou maior com prótese (2,1%) ou doença pulmonar obstrutiva crônica (1,6%). Cerca de 11,4% dos pacientes tinham infarto do miocárdio prévio, e 5,4% deles usavam cardiotônico. O tempo de seguimento médio foi de 16,0±14,4 meses. A distância média de CI referida pelos pacientes aumentou 100% (de 418,47 m para 817,74 m) ao longo de 2 anos, nos grupos não-limitante (p < 0,001) e não-tabagista (p < 0,001). A sobrevida dos claudicantes foi significativamente menor no grupo com limitação. A análise de regressão logística mostrou que a limitação para realização de exercícios, isoladamente, influenciou significativamente na mortalidade (p < 0,001). CONCLUSÃO: A realização correta e regular dos exercícios e o abandono do fumo melhoram a distância de claudicação, além de reduzir a mortalidade nesses casos, seja por meio de efeitos positivos próprios do exercício, seja por meio de controle dos fatores de risco e de seus efeitos adversos.

Effects of Supervised Treadmill Walking Training on Calf Muscle Capillarization in Patients with Intermittent Claudication

The aim of this study was to evaluate the effects of supervised treadmill walking training on the calf muscle capillarization in patients with intermittent claudication. The first 12-week period was a nonexercise, within-subject control stage, and the second 12-week period was an exercise training stage. Calf muscle biopsy and functional capacity measurement were performed at baseline, preexercise and postexercise training. In all, 11 subjects completed all procedures. Their average age was (mean ± standard deviation) 73.9 ± 5.5 years and resting ankle-to-brachial systolic blood presure index was 0.57 ± 0.11. After exercise training, the difference between the pretraining and posttraining capillaries in contact with type IIx and IIa muscle fibers for each subject was significantly correlated with an improved pain-free walking time, r = 0.69 and r = 0.62 (both P < .05), respectively. This finding suggests that the change in calf muscle capillarization might contribute to the improved walking capacity following supervised treadmill walking training in patients with intermittent claudication.

Incident physical disability in people with lower extremity peripheral arterial disease: the role of cardiovascular disease

OBJECTIVES

To evaluate the risk of incident physical disability and the decline in gait speed over a 6-year follow-up associated with a low ankle-arm index (AAI) in older adults.

DESIGN

Observational cohort study.

SETTING

Forsyth County, North Carolina; Sacramento County, California; Washington County, Maryland; and Allegheny County, Pennsylvania.

PARTICIPANTS

Four thousand seven hundred five older adults, 58% women and 17.6% black, participating in the Cardiovascular Health Study.

MEASUREMENTS

AAI was measured in 1992/93 (baseline). Self-reported mobility, activity of daily living (ADL), and instrumental activity of daily living (IADL) disability and gait speed were recorded at baseline and at 1-year intervals over 6 years of follow-up. Mobility disability was defined as any difficulty walking half a mile and ADL and IADL disability was defined as any difficulty with 11 specific ADL and IADL tasks. Individuals with mobility, ADL, or IADL disability at baseline were excluded from the respective incident disability analyses.

RESULTS

Lower baseline AAI values were associated with increased risk of mobility disability and ADL/IADL disability. Clinical cardiovascular disease (CVD), diabetes mellitus, and interim CVD events partially explained these associations for mobility disability and clinical CVD and diabetes mellitus partially explained these associations for ADL and IADL disability. Individuals with an AAI less than 0.9 had on average a mean decrease in gait speed of 0.02 m/s per year, or a decline of 0.12 m/s over the 6-year follow-up. Prevalent CVD partly explained this decrease but interim CVD events did not further attenuate it.

CONCLUSION

Low AAI serves as marker of future disability risk. Reduction of disability risk in patients with a low AAI should consider cardiovascular comorbidity and the prevention of additional disabling CVD events.

Effects of a long-term exercise program on lower limb mobility, physiological responses, walking performance, and physical activity levels in patients with peripheral arterial disease

OBJECTIVE

The purpose of the study was to examine the effects of a 12-month exercise program on lower limb mobility (temporal-spatial gait parameters and gait kinematics), walking performance, peak physiological responses, and physical activity levels in individuals with symptoms of intermittent claudication due to peripheral arterial disease (PAD-IC).

METHODS

Participants (n = 21) with an appropriate history of PAD-IC, ankle-brachial pressure index (ABI) <0.9 in at least one leg and a positive Edinburgh claudication questionnaire response were prospectively recruited. Participants were randomly allocated to either a control PAD-IC group (CPAD-IC) (n = 11) that received standard medical therapy and a treatment PAD-IC group (TPAD-IC) (n = 10), which also took part in a 12-month supervised exercise program. A further group of participants (n = 11) free of PAD (ABI >0.9) and who were non-regular exercisers were recruited from the community to act as age and mass matched controls (CON). Lower limb mobility was determined via two-dimensional video motion analysis. A graded treadmill test was used to assess walking performance and peak physiological responses to exercise. Physical activity levels were measured via a 7-day pedometer recording. Differences between groups were analyzed via repeated measures analysis of variance (ANOVA).

RESULTS

The 12-month supervised exercise program had no significant effect on lower limb mobility, peak physiological responses, or physical activity levels in TPAD-IC compared with CPAD-IC participants. However, the TPAD-IC participants demonstrated significantly greater walking performance (171% improvement in pain free walking time and 120% improvement in maximal walking time compared with baseline).

CONCLUSION

The results of this study confirm that a 12-month supervised exercise program will result in improved walking performance, but does not have an impact on lower limb mobility, peak physiological responses, or physical activity levels of PAD-IC patients.

Meta-analysis of patient education interventions to increase physical activity among chronically ill adults

OBJECTIVE

This meta-analysis integrates primary research testing the effect of patient education to increase physical activity (PA) on behavior outcomes among adults with diverse chronic illnesses.

METHODS

Extensive literature searching strategies located published and unpublished intervention studies that measured PA behavior outcomes. Primary study results were coded. Fixed- and random-effects meta-analytic procedures included moderator analyses.

RESULTS

Data were synthesized across 22,527 subjects from 213 samples in 163 reports. The overall mean weighted effect size for two-group comparisons was 0.45 (higher mean for treatment than control). This effect size is consistent with a difference of 48 min of PA per week or 945 steps per day. Preliminary moderator analyses suggest interventions were most effective when they targeted only PA behavior, used behavioral strategies (versus cognitive strategies), and encouraged PA self-monitoring. Differences among chronic illnesses were documented. Individual strategies unrelated to PA outcomes included supervised exercise sessions, exercise prescription, fitness testing, goal setting, contracting, problem solving, barriers management, and stimulus/cues. PA outcomes were unrelated to gender, age, ethnicity, or socioeconomic distribution among samples.

CONCLUSION

These findings suggest that some patient education interventions to increase PA are effective, despite considerable heterogeneity in the magnitude of intervention effect.

PRACTICE IMPLICATIONS

Moderator analyses are preliminary and provide suggestive evidence for further testing of interventions to inform practice.

Exercise training for claudication

Exercise advice is a well established component of the conservative management of intermittent claudication. Supervised programmes of exercise remain relatively uncommon and are provided mainly in secondary care. This review outlines the evidence for the effectiveness of different exercise regimens and the relative benefits of exercise therapy, where comparisons have been made with medical therapy, angioplasty and surgery.

Effect of training on the response of plasma vascular endothelial growth factor to exercise in patients with peripheral arterial disease

Expansion of the capillary network, or angiogenesis, occurs following endurance training. This process, which is reliant on the presence of VEGF (vascular endothelial growth factor), is an adaptation to a chronic mismatch between oxygen demand and supply. Patients with IC (intermittent claudication) experience pain during exercise associated with an inadequate oxygen delivery to the muscles. Therefore the aims of the present study were to examine the plasma VEGF response to acute exercise, and to establish whether exercise training alters this response in patients with IC. In Part A, blood was collected from patients with IC (n=18) before and after (+20 and +60 min post-exercise) a maximal walking test to determine the plasma VEGF response to acute exercise. VEGF was present in the plasma of patients (45.11+/-29.96 pg/ml) and was unchanged in response to acute exercise. Part B was a training study to determine whether exercise training altered the VEGF response to acute exercise. Patients were randomly assigned to a treatment group (TMT; n=7) that completed 6 weeks of high-intensity treadmill training, or to a control group (CON; n=6). All patients completed a maximal walking test before and after the intervention, with blood samples drawn as for Part A. Training had no effect on plasma VEGF at rest or in response to acute exercise, despite a significant increase in maximal walking time in the TMT group (915+/-533 to 1206+/-500 s; P=0.009) following the intervention. The absence of a change in plasma VEGF may reflect altered VEGF binding at the endothelium, although this cannot be confirmed by the present data.

Determinants of Walking Exercise Among Individuals With Intermittent Claudication

PURPOSE

This study examined psychosocial determinants of walking exercise among individuals with intermittent claudication and explored perceived pain intensity as a moderator of the intention-behavior relationship.

METHODS

Ninety-four participants (n = 61 m/33 f, 70.05 +/- 9.02 years) were recruited from a medical facility and completed baseline measures of attitudes (ie, positive or negative evaluation of walking exercise), subjective norms (ie, perceived social pressure regarding walking exercise), perceived behavioral control (ie, ease or difficulty for engaging in walking exercise), and intentions regarding walking exercise in the upcoming 4 weeks. Participants were contacted weekly by telephone for 4 weeks and asked to recall their walking exercise and associated perceived pain intensity for the preceding 7-day period. Outcome measures were participants' baseline intentions to walk and their reported walking exercise for 4 weeks.

RESULTS

Attitudes, subjective norms, and perceived behavioral control contributed to a multiple regression model predicting 67% of the variance in walking intentions. Intentions and perceived behavioral control explained 34% of the variance in walking exercise. Perceived pain intensity was not associated with walking exercise and failed to moderate the intention-behavior relationship.

CONCLUSION

Findings support the theory of planned behavior for predicting walking intentions and exercise among individuals with intermittent claudication and suggest that pain cognitions as measured in this study do not play a role in determining walking.

Peripheral arterial disease in the elderly

Smoking should be stopped and hypertension, diabetes mellitus, dyslipidemia, and hypothyroidism treated in elderly patients with peripheral arterial disease (PAD) of the lower extremities. Statins reduce the incidence of intermittent claudication and improve exercise duration until the onset of intermittent claudication in patients with PAD and hypercholesterolemia. Antiplatelet drugs such as aspirin or clopidogrel, especially clopidogrel, angiotensin-converting enzyme inhibitors, and statins should be given to all elderly patients with PAD without contraindications to these drugs. Beta blockers should be given if coronary artery disease is present. Exercise rehabilitation programs and cilostazol increase exercise time until intermittent claudication develops. Chelation therapy should be avoided. Indications for lower extremity percutaneous transluminal angioplasty or bypass surgery are (1) incapacitating claudication in patients interfering with work or lifestyle; (2) limb salvage in patients with limb-threatening ischemia as manifested by rest pain, nonhealing ulcers, and/or infection or gangrene; and (3) vasculogenic impotence.

Established and evolving medical therapies for claudication in patients with peripheral arterial disease

Claudication resulting from peripheral arterial disease causes substantial impairment in the ability to carry out normal daily activities. The medical treatments for claudication that are currently available are exercise rehabilitation and one drug, cilostazol. Pentoxifylline, which improves red cell deformability, lowers fibrinogen levels and decreases platelet aggregation, has been used historically, but frequency of use has declined because of limited effectiveness. Exercise rehabilitation, while efficacious, has been underused in the past. This therapy is, however, currently the subject of several large research projects. These studies are investigating mechanisms by which exercise therapy could benefit people with claudication and are also directly comparing it with other therapies. Concurrently, several new drug therapies for claudication are in the process of being evaluated. These research efforts might increase the available armamentarium and thereby help to alleviate the impairments associated with this symptom. The aim of this article is to discuss the current medical treatments being developed for use in patients with claudication resulting from peripheral arterial disease.

Effects of supervised treadmill-walking training on strength and endurance of the calf muscles of individuals with peripheral arterial disease

OBJECTIVE

Supervised treadmill-walking training is an effective treatment to improve walking capacity for individuals with peripheral arterial disease (PAD). The primary aim of this study was to examine whether a supervised treadmill-walking program would improve calf-muscle strength and endurance in individuals with PAD.

DESIGN

The study included two stages. The first 12-week period was a nonexercise, within-subject control stage and the second 12-week period was an exercise training stage.

SETTING

Southern Cross University, Australia.

SUBJECTS

Twenty-two subjects with stable intermittent claudication were recruited. Their resting and postexercise ankle-to-brachial systolic blood pressure index (ABI) was 0.61 +/- 0.13 and 0.41 +/- 0.22, respectively.

INTERVENTIONS

Subjects trained in the laboratory, 3 sessions per week for 12 weeks.

OUTCOME MEASUREMENTS

Walking capacity, calf-muscle strength (peak torques in isokinetic plantar flexion at velocities of 30 degrees per second, 60 degrees per second, and 90 degree per second) and endurance (mean peak force, total work, and mean power in repeated maximal plantar flexions at 60 degrees per second), ABI, and peak oxygen uptake were measured at the baseline and the end of each stage.

RESULTS

Analysis of variance (ANOVA) with repeated measures indicated that the supervised treadmill-walking program significantly increased calf-muscle strength and endurance. Walking capacity and peak oxygen uptake also showed significant improvements following the training program. Significant correlation was found between the improved calf-muscle endurance and walking capacity.

CONCLUSION

Supervised treadmill exercise is highly effective in improving walking capacity. The improved walking capacity is accompanied by improved calf-muscle strength and endurance in individuals with PAD.

Red blood cell deformability in patients with claudication after pain-free treadmill training

OBJECTIVES

To assess the effect of pain-free treadmill training on red blood cell deformability and walking distance in patients with claudication.

DESIGN

Randomized-controlled trial of exercise training.

SETTING

Patients were recruited from the primary care, vascular outpatient clinic.

PATIENTS

A total of 60 patients with peripheral arterial occlusive disease (stage II according to Leriche-Fontaine) were randomized into the treadmill program or a control group. Fifty-five patients completed the study (27 in the exercising group and 28 in the control group).

INTERVENTIONS

Patients in the exercising group were walking on the treadmill 3 times a week for 3 months. Each session consisted of 1 hour repetitive walking [performed to 85% of the pain-free walking time (PFWT)] was supervised by a qualified physiotherapist.

MAIN OUTCOME MEASUREMENTS

Changes in erythrocyte deformability and treadmill walking performance (PFWT, maximal walking time) were assessed in both groups before the study and after 3 months.

RESULTS

After 3 months of treadmill training, red blood cell deformability in the exercising group significantly increased (P<0.01). No significant changes were seen in the erythrocyte deformability in the control group. PFWT was prolonged by 102% from 191+/-34 to 386+/-60 seconds (P<0.01), and maximal walking time increased by 49% from 438+/-62 to 656+/-79 seconds (P<0.01) in the exercising group, whereas these changes were insignificant in the control group.

CONCLUSIONS

A significant improvement of walking ability over 3 months of pain-free treadmill training is associated with a significant increase in red cell deformability in patients with claudication.

Upper- vs lower-limb aerobic exercise rehabilitation in patients with symptomatic peripheral arterial disease: A randomized controlled trial

OBJECTIVES

To investigate the effects of a 24-week program of upper- and lower-limb aerobic exercise training on walking performance in patients with symptomatic peripheral arterial disease (PAD) and to study the mechanisms that could influence symptomatic improvement.

METHODS

After approval from the North Sheffield Local Research Ethics Committee, 104 patients (median age, 69 years; range, 50 to 85 years) with stable PAD were randomized into an upper- or lower-limb aerobic exercise training group (UL-Ex or LL-Ex), or to a nonexercise training control group. Training was performed twice weekly for 24 weeks at equivalent relative exercise intensities. An incremental arm- and leg-crank test (ACT and LCT) to maximum exercise tolerance was performed before and at 6, 12, 18, and 24 weeks of the intervention to determine peak oxygen consumption (VO(2)). Walking performance, defined as the claudicating distance (CD) and maximum walking distance (MWD) achieved before intolerable claudication pain, was assessed at the same time points by using a shuttle-walk protocol. Peak blood lactate concentration, Borg ratings of perceived exertion (RPE) and pain category ratio (CR-10) were recorded during all assessments.

RESULTS

CD and MWD increased over time (P < .001) in both training groups. At 24 weeks, CD had improved by 51% and 57%, and MWD had improved by 29% and 31% (all P < .001) in the UL-Ex and LL-Ex groups, respectively. An increase in peak heart rate at MWD in the UL-Ex group (109 +/- 4 vs 115 +/- 4 beats/min; P < .01) and LL-Ex group (107 +/- 3 vs 118 +/- 3 beats/min; P = .01) was accompanied by an increase in the amount of pain experienced in both groups (P < .05), suggesting that exercising patients could tolerate a higher level of cardiovascular stress and an increased intensity of claudication pain before test termination after training. Patients assigned to exercise training also showed an increase in LCT peak VO2 at the 24-week time point in relation to baseline (P < .01) and control patients (P < .01), whereas ACT peak VO2 was only improved in the UL-Ex group (P < .05).

CONCLUSIONS

Our results suggest that a combination of physiologic adaptations and improved exercise pain tolerance account for the improvement in walking performance achieved through upper-limb aerobic exercise training in patients with PAD. Furthermore, that both arm- and leg-crank training could be useful exercise training modalities for improving cardiovascular function, walking performance, and exercise pain tolerance in patients with symptomatic PAD.

Abnormal cardiovascular response to exercise in patients with peripheral arterial disease: Implications for management

Exercise is beneficial in improving claudication and functional capacity in patients with peripheral arterial disease (PAD). However, the physiologic response during and after exercise testing in this patient population has not been fully described. This study examined the cardiovascular response to exercise and explored the potential contribution of vascular noncompliance to exercise-induced hypertension in 124 patients with PAD and claudication and 31 comparison (C) patients with PAD with no walking limitations. Maximal walking distance was determined by an exercise treadmill test. Heart rate and blood pressure were monitored before, during, and immediately after an exercise test. Vascular compliance of the small and large vessels was measured using pulse waveform analysis. Individuals with low supine resting heart rate had longer pain-free walking distance (r = -0.195, P = .019) and maximal walking versus the C group (62 beats/min, standard deviation [SD] = 10, P = .02). Systolic blood pressure during supine rest was significantly lower for the PAD group (mean = 141 mm Hg, +/- SD = 22) versus the C group (mean = 153 mm Hg, +/- SD = 20, P = .003). Vascular compliance of large vessels was higher in the C group (mean = 4.13 +/- 4.13 mL/mm Hg x 100) compared with the PAD group (mean = 2.95 +/- 1.6 mL/mm Hg x 100). This study describes the exaggerated exercise cardiovascular response and impaired vascular compliance in patients with PAD. These results provide further evidence supporting the importance of a monitored treadmill exercise test before initiation of an exercise program to ensure safe and accurate exercise recommendations, and to identify individuals that require more intensive pharmacotherapy to prevent exercise-induced hypertension and tachycardia.

Experimental Model of Pain-Free Treadmill Training in Patients with Claudication

OBJECTIVE

Treadmill training in claudication is often based on walking exercise to a pain threshold or longer to the maximum muscle pain of the lower limbs. This kind of exercise may cause an inflammatory response. The purpose of this study was to determine whether pain-free treadmill training using walking exercise to 85% of the distance to onset of claudication pain can significantly improve pain-free walking distance in patients with intermittent claudication and to evaluate whether this kind of program may induce an inflammatory response leading to the progression of atherosclerosis.

DESIGN

A total of 98 patients aged 50-70 yrs with stable intermittent claudication were randomized into a supervised treadmill training program or a comparison group. Patients in the treatment group participated in 12 wks of supervised treadmill training. We examined the effects of 12 wks of pain-free treadmill training on pain-free walking distance, total leukocyte count, neutrophil count, and microalbuminuria in patients with claudication.

RESULTS

A total of 80 participants completed the program. Exercise rehabilitation increased the time to onset of claudication pain by 119.2%, from 87.4 +/- 38 m to 191.6 +/- 94.8 m (P < 0.001). There was no increase in total leukocyte count, neutrophil count, or microalbuminuria after 12 wks of treadmill exercise (P > 0.05)

CONCLUSION

A pain-free training program can be used in the treatment of claudication as a low-risk program, increasing walking ability without potential harmful effects of ischemia-reperfusion injury.

The effect of exercise intensity on the response to exercise rehabilitation in patients with intermittent claudication

PURPOSE

The purpose of this randomized trial was to compare the efficacy of a low-intensity exercise rehabilitation program vs a high-intensity program in changing physical function, peripheral circulation, and health-related quality of life in peripheral arterial disease (PAD) patients limited by intermittent claudication.

METHODS

Thirty-one patients randomized to low-intensity exercise rehabilitation and 33 patients randomized to high-intensity exercise rehabilitation completed the study. The 6-month exercise rehabilitation programs consisted of intermittent treadmill walking to near maximal claudication pain 3 days per week at either 40% (low-intensity group) or 80% (high-intensity group) of maximal exercise capacity. Total work performed in the two training regimens was similar by having the patients in the low-intensity group exercise for a longer duration than patients in the high-intensity group. Measurements of physical function, peripheral circulation, and health-related quality of life were obtained on each patient before and after the rehabilitation programs.

RESULTS

After the exercise rehabilitation programs, patients in the two groups had similar improvements in these measures. Initial claudication distance increased by 109% in the low-intensity group (P < .01) and by 109% in the high-intensity group (P < .01), and absolute claudication distance increased by 61% (P < 0.01) and 63% (P < .01) in the low-intensity and high-intensity groups, respectively. Furthermore, both exercise programs elicited improvements (P < .05) in peak oxygen uptake, ischemic window, and health-related quality of life.

CONCLUSION

The efficacy of low-intensity exercise rehabilitation is similar to high-intensity rehabilitation in improving markers of functional independence in PAD patients limited by intermittent claudication, provided that a few additional minutes of walking is accomplished to elicit a similar volume of exercise.

Quality of life and exercise performance after aortoiliac stent placement for claudication

PURPOSE

To determine the effect of aortoiliac stent placement on walking ability and health-related quality of life (QOL) for elderly individuals with moderate to severe intermittent claudication.

MATERIALS AND METHODS

A prospective single-center study was performed in 35 consecutive patients (46 symptomatic limbs) with intermittent claudication and aortoiliac insufficiency (mean age+/-SD, 61.1 years+/-9.5). Baseline and follow-up data to 12 months included clinical status, ankle-brachial index (ABI), exercise performance according to a standardized treadmill exercise protocol, and self-reported health-related QOL according to the Walking Impairment Questionnaire (WIQ) and the Short Form 36 (SF-36).

RESULTS

Comparing baseline with 12-month data, mean ABI significantly improved from 0.64+/-0.15 to 0.89+/-0.19 (P<.01). Similarly, mean initial claudication duration improved from 1.7 minutes+/-1.0 to 4.7 minutes+/-3.3 and maximum walking duration on the treadmill test improved from a mean of 3.3 minutes+/-1.8 to 8.7 minutes+/-4.4. All WIQ subscales showed significant improvement, and the SF-36 physical component scale as well as subscales of physical functioning, bodily pain, role physical, and vitality showed significant improvement. There was no 30-day mortality. Complications in the perioperative period that required treatment were observed in three patients (9%), but surgery was not required for any complications. Importantly, urgent or emergent surgery was not required for any complication and no permanent disability related to complications occurred.

CONCLUSIONS

A high technical success rate (97%) and low complication rate were observed. Exercise performance and health-related QOL results improved significantly after stent placement. Revascularization with stent placement should be strongly considered in addition to conservative management for moderate to severe claudication with aortoiliac obstruction. A randomized clinical trial would be needed to gauge the relative effectiveness of stent implantation and conservative therapy.