Exercise therapy for intermittent claudication: a review of the quality of randomised clinical trials and evaluation of predictive factors

All Patients Benefit Equally From a Supervised Exercise Program for Claudication

This study assessed the effect of gender, diabetic status, statin use, smoking, hypertension, cardiac status, and use of cilostazol on the outcome of a supervised exercise program for patients with claudication. Patient risk factors were prospectively recorded in a group of patients who had completed 1 year on a supervised exercise program. In 165 claudicant patients, maximum walking distance increased ( P < .0001) from 67 meters (range, 17-196) to 122 meters (range, 43-409). Quality of life as measured by the Medical Outcome Study Short Form 36 increased ( P < .0001) from a median of 78 (range, 55-110) to 99 (range, 71-154). The improvements in claudication distance, maximal walking distance, and quality of life after the exercise program were not dependent on any of the measured patient factors. Patients referred to exercise programs for claudication are a heterogenous group. Despite this, they benefit equally from such a program.

Bicycle exercise training improves ambulation in patients with peripheral artery disease

OBJECTIVE

Exercise training has multiple beneficial effects in patients with arteriosclerotic diseases; however, the exact underlying mechanisms of the effects are not completely understood. This study aimed to evaluate the effectiveness of a supervised exercise program in improving gait parameters, including the variability and walking performance of lower limb movements, in patients with peripheral artery disease (PAD) and intermittent claudication (IC).

METHODS

Sixteen patients with a history of PAD and IC were recruited for this study, and they completed a 3-month supervised bicycle exercise program. The ankle-brachial index and responses to quality of life (QOL) questionnaires were evaluated. Near-infrared spectroscopy was also performed to determine the hemoglobin oxygen saturation in the calf. Patients' kinematics and dynamics, including joint range of motion and muscle tension, were evaluated using an optical motion capture system. Computed tomography images of each muscle were assessed by manual outlining. Data were collected before and after the supervised bicycle exercise program, and differences were analyzed.

RESULTS

Significant differences were not found in step length, ankle-brachial index, and hemoglobin oxygen saturation before and after the supervised bicycle exercise program; however, IC distance (P = .034), maximum walking distance (P = .006), and all QOL questionnaire scores (P < .001) showed significant improvement. Hip range of motion (P = .035), maximum hip joint torque (right, P = .031; left, P = .044), maximum tension of the gluteus maximus muscle (right, P = .044; left, P = .042), and maximum hip joint work (right, P = .048; left, P = .043) also significantly decreased bilaterally. Computed tomography images showed a significant increase in the cross-sectional area of the abdominal, trunk, and thigh muscles but not in that of the lower leg muscles after the supervised exercise program intervention.

CONCLUSIONS

In this study, bicycle exercise training improved the QOL and walking distance and decreased hip movement. The results showed that bicycling might be as useful as walking in patients with PAD.

[Follow-up of patients with chronic obstructive arterial disease, some months after their rehabilitation: Assessment of a therapeutic education program]

Vascular rehabilitation (VR) is becoming increasingly important in the management of the arterial patient. Therapeutic Patient Education (TPE) is an integral part of rehabilitation programs and aims to transform patients' lifestyle habits. The effectiveness of patient management at short-term no longer needs to be demonstrated, but we can question the effectiveness of education over the long term, some months following a rehabilitation program.

OBJECTIVE

This study aims to assess, in the long term, the effects of TPE in VR, and to observe the transformation of certain lifestyle habits of patients.

METHOD

We convened 68 patients (51 men and 17 women) 6 months and 1 year after VR treatment during which these patients participated in an TPE program. We assessed: knowledge by questionnaire, walking range, weight and body composition by impedimetric techniques.

RESULTS

We found that patients improved their knowledge at the end of rehabilitation 45.8 (±7.6) of good responses on average, compared to 36.2 (±8.6) at the beginning of rehabilitation and these results are consolidated 6 months after 43.4 (±7.5) and 1 year after 44.1 (±8.1). We also found that walking distances during treadmill testing and outdoor walking improved at the end of rehabilitation and were maintained at six months and one year. Finally, weight, fat mass and lean mass decreased slightly compared to the end of rehabilitation. Only 7 patients out of 22 gave up smoking.

CONCLUSION

An education program concerning risk factor management during vascular rehabilitation enables patients to acquire knowledge that can be used to maintain new lifestyle habits and stabilize their health status.

Patient Characteristics and Comorbidities Influence Walking Distances in Symptomatic Peripheral Arterial Disease: A Large One-Year Physiotherapy Cohort Study

Objectives

The aim of this study is to investigate the association between age, gender, body-mass index, smoking behavior, orthopedic comorbidity, neurologic comorbidity, cardiac comorbidity, vascular comorbidity, pulmonic comorbidity, internal comorbidity and Initial Claudication Distance during and after Supervised Exercise Therapy at 1, 3, 6 and 12 months in a large sample of patients with Intermittent Claudication.

Methods

Data was prospectively collected in standard physiotherapy care. Patients received Supervised Exercise Therapy according to the guideline Intermittent Claudication of the Royal Dutch Society for Physiotherapy. Three-level mixed linear regression analysis was carried out to analyze the association between patient characteristics, comorbidities and Initial Claudication Distance at 1, 3, 6 and 12 months.

Results

Data from 2995 patients was analyzed. Results showed that being female, advanced age and a high body-mass index were associated with lower Initial Claudication Distance at all-time points (p = 0.000). Besides, a negative association between cardiac comorbidity and Initial Claudication Distance was revealed (p = 0.011). The interaction time by age, time by body-mass index and time by vascular comorbidity were significantly associated with Initial Claudication Distance (p≤ 0.05). Per year increase in age (range: 33–93 years), the reduction in Initial Claudication Distance was 8m after 12 months of Supervised Exercise Therapy. One unit increase in body-mass index (range: 16–44 kg/m²) led to 10m less improvement in Initial Claudication Distance after 12 months and for vascular comorbidity the reduction in improvement was 85m after 12 months.

Conclusions

This study reveals that females, patients at advanced age, patients with a high body-mass index and cardiac comorbidity are more likely to show less improvement in Initial Claudication Distances (ICD) after 1, 3, 6 and 12 months of Supervised Exercise Therapy. Further research should elucidate treatment adaptations that optimize treatment outcomes for these subgroups.

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.

Initial Results of a 12-week, Institution-based, Supervised Exercise Rehabilitation Program for the Management of Peripheral Arterial Disease

This study assessed the effectiveness of a 12-week, institution-based, supervised exercise rehabilitation program with atherogenic risk factor modification in improving cardiovascular profile, ambulatory function, and quality of life of patients with peripheral arterial disease (PAD) by comparing pre- and postprogram measurements. Participants were prospectively enrolled. Cardiovascular profile variables, ambulatory function tests, and quality of life questionnaires were evaluated. Of 101 institution-based program participants, 69 completed the 12-session minimum and 47 completed a postprogram evaluation. Mean postprogram results were significantly different from preprogram results, corresponding to improvement, for the following variables: triglyceride levels ( p = .036), both function tests ( p < .001 for both), four of five Walking Impairment Questionnaire measurements, and Intermittent Claudication Questionnaire score ( p = .001). This supervised exercise program improved the cardiovascular profiles, ambulatory function, and quality of life of PAD patients completing the program and is a viable adjunct to drug therapy and surgical intervention.

Increased perfusion and angiogenesis in a hindlimb ischemia model with plasmid FGF-2 delivered by noninvasive electroporation

Gene therapy approaches delivering fibroblast growth factor-2 (FGF-2) have shown promise as a potential treatment for increasing blood flow to ischemic limbs. Currently, effective noninvasive techniques to deliver plasmids encoding genes of therapeutic interest, such as FGF-2, are limited. We sought to determine if intradermal injection of plasmid DNA encoding FGF-2 (pFGF) followed by noninvasive cutaneous electroporation (pFGFE+) could increase blood flow and angiogenesis in a rat model of hindlimb ischemia. pFGFE+ or control treatments were administered on postoperative day 0. Compared to injection of pFGF alone (pFGFE-), delivery of pFGFE+ significantly increased FGF-2 expression for 10 days. Further, the increase in FGF-2 expression with pFGFE+ was sufficient to significantly increase ischemic limb blood flow, measured by laser Doppler perfusion imaging, beginning on postoperative day 3. Ischemic limb blood flow in the pFGFE+ treatment group remained significantly higher than all control groups through the end point of the study, postoperative day 14. Immunohistochemical staining of gastrocnemius cross sections determined there was a twofold increase in capillary density in the pFGFE+ treatment group. Our results suggest that pFGFE+ is a potential noninvasive, nonviral therapeutic approach to increase perfusion and angiogenesis for the treatment of limb ischemia.

Update on peripheral arterial disease and claudication rehabilitation

The prevalence of peripheral arterial disease is high and will continue to grow with our aging population. It is often under diagnosed and under treated due to a general lack of awareness on the part of the patient and the practitioner. The evidence-base is growing for the optimal medical management of the patient with peripheral arterial disease; in parallel, endovascular revascularization options continue to improve. Exercise training for claudication rehabilitation plays a critical role. Comprehensive care of the peripheral arterial disease patient focuses on the ultimate goals of improving quality of life and reducing cardiovascular morbidity and mortality.

Management of lower extremity peripheral arterial disease

Peripheral arterial disease (PAD), a manifestation of systemic atherosclerosis, is a significant health problem. It manifests in lower extremities as intermittent claudication, limb ischemia, or gangrene and other locations as stroke, renal failure, or mesenteric ischemia. Fontaine and Rutherford classifications are the 2 commonly used classifications to stage the severity of PAD. The diagnostic tools include ankle-brachial index, a valuable tool in diagnosing lower extremity PAD, and a treadmill test. Other useful diagnostic tools include the San Diego Claudication Questionnaire to screen patients for symptoms and imaging modalities such as duplex scan, angiogram, computer tomographic angiogram, and magnetic resonance angiogram. Medical management of PAD involves comprehensive care, including risk factor modification of etiologies predisposing to atherosclerosis. These involve using antiplatelet therapy with aspirin or clopidogrel, controlling hypertension, managing hypercholesterolemia, and using vasodilators such as cilostazol. Exercise rehabilitation is an efficacious approach to improve intermittent claudication and should be recommended to each patient. Revascularization therapy is indicated for those who have critical limb ischemia or severe claudication not improved by medical management. Revascularization consists of endovascular techniques to open up the vessel and traditional bypass surgery to bypass the diseased segment. Recent published guidelines detailing recommendations on different treatment modalities in patients with PAD are described.

Physiological and functional impact of an unsupervised but supported exercise programme for claudicants

OBJECTIVES

To evaluate an unsupervised home-based exercise programme for physiological, functional, and quality of life impact in patients with symptomatic peripheral arterial disease.

DESIGN

Prospective cohort with exercise intervention.

MATERIALS

Human performance laboratory with non-invasive haemodynamic assessment facilities.

METHODS

Forty-seven patients with symptomatic peripheral arterial disease (mean age 67.6+/-7 years, 33 males) participated in an unsupervised home-based exercise programme. Heart rate (HR), ankle brachial blood pressure index (ABPI), leg blood flow (BF), and blood lactate were measured before and after a graded treadmill walk at baseline and after the 12-week exercise programme. Maximum walking distance (MWD) during the treadmill walk was measured at baseline and 12 weeks. Exercise compliance, functional parameters, and quality of life (VascuQoL) were assessed by questionnaire.

RESULTS

MWD, leg BF, and VascuQoL scores increased significantly, while resting HR, exercise HR, and end of walk rate-pressure-product (RPP) decreased significantly after 12 weeks. Exercise compliance was significantly correlated with increase in MWD (r=0.89, p<0.001) and QOL score improvement (r=0.61, p<0.001).

CONCLUSIONS

This supported but unsupervised exercise programme generated improvements in walking distance and leg blood flow without detectable increases in cardiorespiratory work. Exercise compliance is related to MWD and VascuQoL score in a dose-response manner.

The role of exercise training in peripheral arterial disease

Peripheral arterial disease (PAD) is currently a major health problem affecting 8-12 million Americans, 15-40% of whom will have intermittent claudication that can lead to substantial impairment in their ability to carry out normal daily activities as well as perform the recommended cardiovascular exercise. Supervised exercise training is an effective tool in the treatment of claudication and is currently a recommended first-line therapy for patients with this condition. In addition to improving pain-free walking distance and quality of life, supervised exercise training can improve many cardiovascular risk factors, possibly reducing the risk for subsequent myocardial infarction, stroke, and death. This paper will review the benefits of supervised exercise training in patients with PAD.

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.

Exercise therapy and the additional effect of supervision on exercise therapy in patients with intermittent claudication. Systematic review of randomised controlled trials

OBJECTIVE

To review the evidence for the effectiveness of exercise therapy and to estimate the additional effect of supervision on exercise therapy in patients with intermittent claudication.

MATERIALS AND METHODS

A systematic review was performed of all randomised controlled trials (RCTs) comparing supervised exercise therapy to unsupervised exercise regimens or observation in patients with intermittent claudication. Main endpoints were pain free walking distance (PWD) and absolute walking distance (AWD). Quality assessment and data extraction were performed independently by two observers.

RESULTS

Fifteen manuscripts, published between 1990 and May 2006, were eligible for analysis, evaluating 761 patients. In the studies comparing supervised exercise to standard care the weighted mean difference in pain free walking distance (PWD) and absolute walking distance (AWD) was 81.3meters (95% CI; 35.5-127.1) and 155.8meters (95% CI; 80.8-230.7), respectively. In the studies comparing supervised to unsupervised exercise therapy, the weighted mean difference in PWD and AWD was 143.8meters (95% CI; 5.8-281.8) and 250.4meters (95% CI; 192.4-308.5).

CONCLUSION

Exercise therapy increases the PWD and AWD in patients with intermittent claudication. Supervised exercise therapy increases the PWD and AWD more than standard care. However, the additional value of supervision over unsupervised exercise regimens needs further clarification.

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.

Evidence for prescribing exercise as therapy in chronic disease

Considerable knowledge has accumulated in recent decades concerning the significance of physical activity in the treatment of a number of diseases, including diseases that do not primarily manifest as disorders of the locomotive apparatus. In this review we present the evidence for prescribing exercise therapy in the treatment of metabolic syndrome-related disorders (insulin resistance, type 2 diabetes, dyslipidemia, hypertension, obesity), heart and pulmonary diseases (chronic obstructive pulmonary disease, coronary heart disease, chronic heart failure, intermittent claudication), muscle, bone and joint diseases (osteoarthritis, rheumatoid arthritis, osteoporosis, fibromyalgia, chronic fatigue syndrome) and cancer, depression, asthma and type 1 diabetes. For each disease, we review the effect of exercise therapy on disease pathogenesis, on symptoms specific to the diagnosis, on physical fitness or strength and on quality of life. The possible mechanisms of action are briefly examined and the principles for prescribing exercise therapy are discussed, focusing on the type and amount of exercise and possible contraindications.

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.

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.

Effectiveness of exercise therapy: a best-evidence summary of systematic reviews

The purpose of this project was to summarise the available evidence on the effectiveness of exercise therapy for patients with disorders of the musculoskeletal, nervous, respiratory, and cardiovascular systems. Systematic reviews were identified by means of a comprehensive search strategy in 11 bibliographic databases (08/2002), in combination with reference tracking. Reviews that included (i) at least one randomised controlled trial investigating the effectiveness of exercise therapy, (ii) clinically relevant outcome measures, and (iii) full text written in English, German or Dutch, were selected by two reviewers. Thirteen independent and blinded reviewers participated in the selection, quality assessment and data-extraction of the systematic reviews. Conclusions about the effectiveness of exercise therapy were based on the results presented in reasonable or good quality systematic reviews (quality score > or = 60 out of 100 points). A total of 104 systematic reviews were selected, 45 of which were of reasonable or good quality. Exercise therapy is effective for patients with knee osteoarthritis, sub-acute (6 to 12 weeks) and chronic (> or = 12 weeks) low back pain, cystic fibrosis, chronic obstructive pulmonary disease, and intermittent claudication. Furthermore, there are indications that exercise therapy is effective for patients with ankylosing spondylitis, hip osteoarthritis, Parkinson's disease, and for patients who have suffered a stroke. There is insufficient evidence to support or refute the effectiveness of exercise therapy for patients with neck pain, shoulder pain, repetitive strain injury, rheumatoid arthritis, asthma, and bronchiectasis. Exercise therapy is not effective for patients with acute low back pain. It is concluded that exercise therapy is effective for a wide range of chronic disorders.

Management options for patients with intermittent claudication

Peripheral arterial disease is a chronic condition, affecting a significant proportion of the adult population. Intermittent claudication is the earliest clinical manifestation of peripheral arterial disease and the patient's walking distance can be significantly reduced. This restriction can profoundly disrupt activities of living. Treatment options vary according to the level of the disease and co-morbidity of the patient. Current evidence to support risk factor assessment highlights the role of the nurse in encouraging lifestyle modification.

Metabolic inertia in contracting skeletal muscle: a novel approach for pharmacological intervention in peripheral vascular disease

Peripheral vascular disease (PVD) is generally accepted to result in the failure of skeletal muscle blood flow to increase adequately at the onset of muscular work. There are currently no routine pharmacological interventions towards the treatment of PVD, however, recent Phase III trials in the USA have demonstrated the clinical potential of the phosphodiesterase III inhibitor Cilostazol for pain-free and maximal walking distances in patients with intermittent claudication. PVD is characterized by a marked reliance on oxygen-independent routes of ATP regeneration (phosphocreatine hydrolysis and glycolysis) in skeletal muscle during contraction and the rapid onset of muscular pain and fatigue. The accumulation of metabolic by-products of oxygen-independent ATP production (hydrogen and lactate ions and inorganic phosphate) has long been associated with an inhibition in contractile function in both healthy volunteers and PVD patients. Therefore, any strategy that could reduce the reliance upon ATP re-synthesis from oxygen-independent routes, and increase the contribution of oxygen-dependent (mitochondrial) ATP re-synthesis, particularly at the onset of exercise, might be expected to improve functional capacity and be of considerable therapeutic value. Historically, the increased contribution of oxygen-independent ATP re-synthesis to total ATP generation at the onset of exercise has been attributed to a lag in muscle blood flow limiting oxygen delivery during this period. However, recent evidence suggests that limited inertia is present at the level of oxygen delivery, whilst considerable inertia exists at the level of mitochondrial enzyme activation and substrate supply. In support of this latter hypothesis, we have reported on a number of occasions that activation of the pyruvate dehydrogenase complex, using pharmacological interventions, can markedly reduce the dependence on ATP re-synthesis from oxygen-independent routes at the onset of muscle contraction. This review will focus on these findings and will highlight the pyruvate dehydrogenase complex as a novel therapeutic target towards the treatment of peripheral vascular disease, or any other disease state where premature muscular fatigue is prevalent due to metabolite accumulation.

Response to exercise rehabilitation in smoking and nonsmoking patients with intermittent claudication

BACKGROUND

The purpose was to compare the changes in claudication pain, ambulatory function, daily physical activity, peripheral circulation, and health-related quality of life following a program of exercise rehabilitation in smoking and nonsmoking patients with peripheral arterial disease (PAD) limited by intermittent claudication. Methods and results Thirty-nine smokers (63 +/- 4 pack-year smoking history; mean +/- SE) and 46 nonsmokers (former smokers who had a 51 +/- 7 pack-year smoking history who quit 14 +/- 2 years prior to investigation) completed the study. The 6-month exercise rehabilitation program consisted of intermittent treadmill walking to near maximal claudication pain 3 days per week, with progressive increases in walking duration and intensity during the program. Measurements were obtained on each patient before and after rehabilitation. Following exercise rehabilitation the smokers and nonsmokers had similar improvements in these measures, as initial claudication distance increased by 119% in the smokers (P <.001) and by 97% in the nonsmokers (P <.001), and absolute claudication distance increased by 82% (P <.001) and 59% (P <.001) in the smokers and nonsmokers, respectively. Furthermore, exercise rehabilitation improved (P <.05) ambulatory function, daily physical activity, peripheral circulation, and health-related quality of life in the smokers and nonsmokers.

CONCLUSION

Exercise rehabilitation is an effective therapy to improve functional independence in both smoking and nonsmoking patients with PAD limited by intermittent claudication. Therefore, smokers with intermittent claudication are prime candidates for exercise rehabilitation because their relatively low baseline physical function does not impair their ability to regain lost functional independence to levels similar to nonsmoking patients with PAD.

Outcome of Conservative Therapy of Patients with Severe Intermittent Claudication

BACKGROUND

Intermittent claudication due to peripheral artery disease (PAD) can be treated conservatively, or by revascularization.

OBJECTIVES

To assess the short-term outcome of conservatively-treated claudicants, and determine predictors for clinical improvement. Design. A retrospective cohort study.

METHODS

We evaluated Fontaine stage, walking distance and ankle brachial index (ABI) at baseline and after median 9 months (interquartile range (IQR) 6-24) in 181 patients with severe claudication.

RESULTS

We found clinical improvement by at least one Fontaine stage in 38 patients (21%) with an increased walking distance from baseline median 100 m (IQR 50-150) to follow-up median 650 m (IQR 300 to unlimited; p<0.001), but without changes in ABI (median 0.57, IQR 0.48-0.73 vs. median 0.54, IQR 0.45-0.81; p=0.10). One hundred and thirty-eight patients (76%) remained clinically and hemodynamically stable. A worsening of the clinical stage but without amputation was recorded in five patients (3%). Female gender (hazard ratio (HR) 0.51, p=0.052), diabetes (HR 0.35, p=0.020), and baseline ABI below 0.44 (HR 0.31, p=0.019) were associated with a reduced probability of clinical improvement.

CONCLUSION

Certain patients with intermittent claudication show substantial clinical improvement with conservative medical therapy, despite any lack of hemodynamic improvement. Given the low number of patients with clinical deterioration in the short term, primarily conservative therapy should be the preferred initial option for most claudicants.

Predictors of treatment outcome in intermittent claudication

OBJECTIVE

To derive formulae to predict the likely 12-month health-related quality of life outcome following different treatments for intermittent claudication (IC).

DESIGN

A prospective, randomized, controlled study.

MATERIALS

One hundred and seventy-one unselected patients with stable IC were sequentially randomized to invasive therapy, supervised physical training or observation. Hierarchical analysis was used to identify significant predictors of outcome.

RESULTS

The strongest outcome predictors were baseline values of the respective outcome variables in all groups. No more than two significant secondary predictors were identified for each outcome variable and no outcome variable was a predictor of any other outcome variable. Resulting prediction equations achieved between 61 and 90% concordance with improvement (75% considered adequate), with best prediction for invasive therapy and poorest for observation. Suggested cutpoints for the various endpoints in the three groups had sensitivities ranging between 65 and 100% and false positive rates between 5 and 50%.

CONCLUSIONS

The derived equations adequately predicted improvement on the various outcome variables in invasive therapy and supervised physical training, and may serve as aids in selecting patients likely to benefit most from a particular treatment strategy. The uniqueness of the outcome variables underscores the importance of implementing a comprehensive set of endpoints relevant to the impacts of the condition.

Improving maximum walking distance in early peripheral arterial disease: randomised controlled trial

The purpose of this study was to determine the impact of increased physical activity and cessation of smoking on the natural history of early peripheral arterial disease. We conducted a randomised controlled trial in Perth, Western Australia, involving 882 men with early peripheral arterial disease identified via population-based screening using the Edinburgh Claudication Questionnaire and the ankle:brachial index. Members of the control group (n = 441) received "usual care" from their general practitioner while members of the intervention group (n = 441) were allocated to a "stop smoking and keep walking" regime - a combined community-based intervention of cessation of smoking (where applicable) and increased physical activity. Postal follow-up occurred at two and 12 months post-entry into the trial. The main outcome of interest was maximum walking distance. There were no statistically significant differences in the characteristics of the "intervention" and "usual care" groups at recruitment. Follow-up information at two and 12 months was available for 85% and 84% of participants, respectively. At 12 months, more men allocated to the intervention group had improved their maximum walking distance (23% vs 15%; chi2 = 9.74, df = 2, p = 0.008). In addition, more men in the intervention group reported walking more than three times per week for recreation (34% vs 25%, p = 0.01). Although not statistically significant, more men in the intervention group who were smokers when enrolled in the trial had stopped smoking (12% vs 8%, p = 0.43). It is concluded that referral of older patients with intermittent claudication to established physiotherapy programs in the community can increase levels of physical activity and reduce disability related to peripheral arterial disease. A combination of simple and safe interventions that are readily available in the community through physiotherapists and general practitioners has the potential to improve early peripheral arterial disease.

Exercise training reduces the acute inflammatory response associated with claudication

BACKGROUND

recent research has shown that episodes of claudication may be associated with a systemic inflammatory response that causes injury to the vascular endothelium. As claudicants are often directed to undertake regular walking exercises there has been a concern that this may accelerate endothelial injury.

AIMS

the aim of our study was to assess the baseline markers of ischaemia-reperfusion injury (IRI) in claudicants and controls after acute treadmill exercise and to then examine the effect of a 3 month supervised exercise-training programme, on these markers, in the claudicant group.

METHODS

forty-six claudicants and 22 age-matched controls undertook acute treadmill exercise. Neutrophil activation, degranulation, free radical damage and antioxidants were measured (by flow cytometry, ELISA, and chemiluminescence) at rest and at 5, 30 and 60 min post-exercise. Claudicants were then recruited into an intensive 3 month supervised exercise programme (SEP) after which the same parameters of IRI were reassessed at different time points, at 3 and 6 months.

RESULTS

resting markers of IRI were similar in both groups. Exercise had no effect on the control group. Immediately after exercise, claudicants developed significant neutrophil activation and degranulation with free radical damage. This effect decreased sequentially after 3 months of exercise training.

CONCLUSION

this study for the first time demonstrates that the exercise training of claudicants is beneficial, not only in terms of improving their walking distance, but also by decreasing the injurious effects of IRI that occur during claudication. Exercise training should be an essential part of the medical management of the majority of claudicants.

A primary care walking exercise program for patients with intermittent claudication

PURPOSE

In a pilot study, the hypothesis was tested that a home-based walking exercise program with structured coaching would improve walking performance and adherence in patients with intermittent claudication (IC).

METHODS

Thirty-one IC patients with a rest ankle-brachial pressure index < 0.90 started a 24-wk walking program in the home environment. They were coached according to the Health Counseling Model (HCM). Patients were instructed to walk at least 9 bouts.wk-1 and to walk through the pain. The main effect measures were pain-free (initial claudication distance (ICD)) and maximum walking distance (absolute claudication distance (ACD)) measured with a graded treadmill test, a corridor exercise test, a walking-diary, and the score on the Walking Impairment Questionnaire (WIQ).

RESULTS

Twenty-four participants completed the program. The reported walking frequency was 7.4 times.wk-1. The average ICD improved from 289 m (95% CI, 209-369) to 347 m (95% CI, 244-449) (P < 0.05) and from 241 m (95% CI, 171-310) to 373 m (95% CI, 273-472) on the treadmill and the corridor test, respectively. The average ACD improved from 490 m (95% CI, 397-583) to 544 m (95% CI, 438-650) and from 564 m (95% CI, 412-717) to 726 m (95% CI, 546-906) (P < 0.01) on the treadmill and the corridor test, respectively. The average maximum distance reported in the walking-diary improved from 957 m (95% CI, 291-1623) to 1294 m (95% CI, 646-1941). The score of the walking distance on the WIQ improved from 57% (95% CI, 42-71%) to 60% (95% CI, 46-74%).

CONCLUSION

IC patients improved their average ICD and ACD. The walking exercise program in the home environment with coaching according to the HCM seems a promising intervention to be tested in a randomized controlled trial.

Gene therapy for therapeutic angiogenesis in critically ischaemic lower limb - on the way to the clinic

Currently, no effective pharmacological treatment is available for vascularisation defects in lower limbs. Many patients presenting with persistent pain and ischaemic ulcers are not suitable candidates for surgical or endovascular approaches. Further refinement of the available methods will undoubtedly lead to a more active approach towards treatment of peripheral arterial occlusive disease (PAOD). Recently, therapeutic angiogenesis, in the form of recombinant growth factor administration or gene therapy, has emerged as a novel tool to treat these patients. However, improved gene transfer methods and better understanding of blood vessel formation are required to bring therapeutic angiogenesis to clinical practice. Here we review the clinical problem (PAOD), mechanisms of blood vessel formation (angiogenesis, vasculogenesis and arteriogenesis), experimental evidence and clinical trials for therapeutic angiogenesis in critically ischaemic lower limbs. Also, angiogenic growth factors, including vascular endothelial growth factors (VEGFs) and fibroblast growth factors (FGFs), delivery methods, and vectors for gene transfer in skeletal muscle, are discussed. In addition to vascular growth, gene transfer of growth factors may enhance regeneration, survival, and innervation of ischaemic skeletal muscle. Nitric oxide (NO) appears to be a key mediator in vascular homeostasis and growth, and a reduction in its production by age, hypercholesterolemia or diabetes leads to the impairment of ischaemic disorders.

Treatment efficacy of intermittent claudication by surgical intervention, supervised physical exercise training compared to no treatment in unselected randomised patients I: one year results of functional and physiological improvements

OBJECTIVES

to compare the effect of surgery, exercise and simple observation on maximum exercise power in claudicants.

DESIGN

prospective, randomised study.

METHODS

a total of 264 unselected claudicants were randomised to supervised exercise training, invasive treatment (open surgical or endovascular procedures) or observation. One year treatment outcomes were analysed on an intention to-treat basis.

RESULTS

invasively treated patients showed a significant improvement in maximum walking power, stopping distance, post-ischaemic blood flow and big toe pressure at one year. Patients randomised to physical exercise training or to the control group did not improve in any outcome measure.

CONCLUSION

invasive treatment increased walking capacity, leg blood pressure and flow. Supervised physical exercise training offered no therapeutic advantage compared to untreated controls.

Exercise training and smoking cessation as the cornerstones of managing claudication

Based on research, the classic recommendation to prevent progression of lower extremity peripheral arterial disease (PAD) is "start exercising and stop smoking." Unfortunately, a paramount problem for clinicians is motivating targeted individuals to begin and adhere to an exercise regimen and quit smoking. The purpose of this review is to provide the most current information regarding exercise training and smoking cessation. It is hoped that this article will help health care professionals present accurate information to their patients with PAD, address the difficulties in lifestyle change, and intervene effectively.

Exercise training for claudicants: changes in blood flow, cardiorespiratory status, metabolic functions, blood rheology and lipid profile

OBJECTIVE

Exercise training improves the walking distance of claudicants. The aim of this study was to investigate factors associated with the improvement in the maximum walking distance (MWD) in respect to cardiovascular, respiratory and metabolic adaptations.

METHODS

Forty claudicants were studied. Common femoral artery blood flow (BF), heart rate (HR), oxygen consumption (VO(2)), respiratory exchange ratio (RER), lactate levels, blood rheology and lipid profiles were measured. Tests were repeated after 3 months of exercise training.

RESULTS

Fifteen patients did not complete the exercise program. For patients who did complete the program, MWD improved by 82%. A significant reduction in HR and VO(2)during exercise was demonstrated. No significant changes occurred in BF or RER. Although MWD increased significantly, there was no increase in recovery VO(2)(oxygen debt). A significant reduction in post-exercise lactate levels occurred. Blood rheology was unchanged, but an improvement in HDL levels was noted.

CONCLUSIONS

Many claudicants could not complete an exercise program, mainly due to osteoarthritis. Exercise training improved exercise tolerance significantly without any increase in BF. The HR and oxygen cost of similar exercise was reduced. An improved MWD did not correlate with a higher oxygen debt or lactate load. Favourable changes in lipid profiles occurred.

Exercise training and peripheral vascular disease

BACKGROUND

Conservative management is advocated as a treatment of choice for patients with intermittent claudication. This is a review of the mechanisms behind the improvement following an exercise rehabilitation programme.

METHODS

All Medline articles from the National Library of Medicine, USA containing the text words 'claudication' or 'peripheral vascular disease' and 'exercise' were reviewed. Cross-referencing from relevant articles was carried out.

RESULTS AND CONCLUSION

The poor physical status of a patient with intermittent claudication is not solely due to a reduction in blood flow to the lower limbs; associated factors, such as metabolic inefficiency, poor cardiorespiratory reserve and exercise-induced inflammation contribute. An exercise programme frequently improves both the physical aspect and quality of life, and the success of such exercise is multifactorial. An increase in the blood flow to the lower extremity is uncommon. Other factors, such as a redistribution of blood flow, changes in oxidative capacity of the skeletal muscles and greater utilization of oxygen, occur and the associated metabolic dysfunction of the skeletal muscles is rectified. Following exercise training, blood rheology improves and exercise-induced inflammation is ameliorated; cardiorespiratory status also benefits and the oxygen cost of exercise decreases.