Intermittent claudication. The effect of physical training on walking tolerance and venous lactate concentration

Exercise Oximetry Correlates Better With Exercise-Induced Lactate Increase, than Ankle Brachial Index or Walking Time, in Vascular Claudicants

In claudication, the correlation between walking-induced biomarkers and indices of clinical severity (e.g., walking distance or ankle brachial index (ABI)), is fair. We hypothesized that a correlation would be observed between the clinical estimation of ischemia severity with exercise transcutaneous oximetry (Ex-TcpO2) and lactate increase. A prospective study was performed among 377 patients with arterial claudication. We recorded age, sex, ABI, body mass index (BMI), systolic arterial blood pressure (SBP), and glycemia. Capillary blood lactate was measured at rest and 3 min after a constant load treadmill test. We recorded maximum walking time (MWT), heart rate (HRmax), the sum of minimal decrease from oxygen values for buttocks, thighs and calves Ex-TcpO2 (DROPmin), as well as the amplitude of chest-TcpO2 decrease. A multilinear regression model was used to assess the variables associated with lactate increase. BMI, SBP, HRmax, the amplitude of decrease in chest-TcpO2 and DROPmin, but not age, sex, ABI, MWT, diabetes mellitus nor glycemia, were significantly associated to lactate increase in the model. Because it accounts for the severity and diffusion of lower-limb exercise-induced ischemia and detects exercise induced hypoxemia, TcpO2 may be preferable to ABI or MWT to estimate the metabolic consequences of walking in claudicants.

Connecting the past to the present: A historical review of exercise training for peripheral artery disease

Peripheral artery disease (PAD), a prevalent manifestation of atherosclerosis, is associated with increased cardiovascular morbidity and mortality as well as decreased functional ability. Exercise training for PAD is acknowledged to be a highly effective treatment, which improves walking ability and cardiovascular risk. The historical development of this treatment has not been the focus of a report. Therefore, we present a historical review of research on exercise training for PAD. Overall, this body of knowledge has provided strong evidence of the efficacy of supervised exercise training (SET) to improve walking ability for patients with claudication due to PAD. SET, using intermittent bouts of walking exercise to moderate claudication pain on a treadmill, is considered the most efficacious mode of exercise to improve walking ability in patients with claudication. This compelling evidence published over the past 60 years was evaluated by the Centers for Medicare & Medicaid Services in 2017, which culminated in a national coverage determination for SET to improve symptomatic PAD. Future directions include determining optimal delivery strategies for SET and further elucidation of the mechanisms of improvement in walking ability resulting from SET. In addition, alternative forms of exercise should be evaluated and effective home- and community-based exercise interventions should be assessed. There is an enormous need to increase the inclusion of women and racial and ethnic minority groups in studies. It is to be hoped that researchers will continue with new innovative research and persistence in the treatment of claudication due to PAD.

Exercise for intermittent claudication

BACKGROUND

Exercise programmes are a relatively inexpensive, low-risk option compared with other, more invasive therapies for treatment of leg pain on walking (intermittent claudication (IC)). This is the fourth update of a review first published in 1998.

OBJECTIVES

Our goal was to determine whether an exercise programme was effective in alleviating symptoms and increasing walking treadmill distances and walking times in people with intermittent claudication. Secondary objectives were to determine whether exercise was effective in preventing deterioration of underlying disease, reducing cardiovascular events, and improving quality of life.

SEARCH METHODS

For this update, the Cochrane Vascular Information Specialist searched the Specialised Register (last searched 15 November 2016) and the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 10) via the Cochrane Register of Studies Online, along with trials registries.

SELECTION CRITERIA

Randomised controlled trials of an exercise regimen versus control or versus medical therapy for people with IC due to peripheral arterial disease (PAD). We included any exercise programme or regimen used for treatment of IC, such as walking, skipping, and running. Inclusion of trials was not affected by duration, frequency, or intensity of the exercise programme. Outcome measures collected included treadmill walking distance (time to onset of pain or pain-free walking distance and maximum walking time or maximum walking distance), ankle brachial index (ABI), quality of life, morbidity, or amputation; if none of these was reported, we did not include the trial in this review.

DATA COLLECTION AND ANALYSIS

For this update (2017), RAL and AH selected trials and extracted data independently. We assessed study quality by using the Cochrane 'Risk of bias' tool. We analysed continuous data by determining mean differences (MDs) and 95% confidence intervals (CIs), and dichotomous data by determining risk ratios (RRs) and 95% CIs. We pooled data using a fixed-effect model unless we identified significant heterogeneity, in which case we used a random-effects model. We used the GRADE approach to assess the overall quality of evidence supporting the outcomes assessed in this review.

MAIN RESULTS

We included two new studies in this update and identified additional publications for previously included studies, bringing the total number of studies meeting the inclusion criteria to 32, and involving a total of 1835 participants with stable leg pain. The follow-up period ranged from two weeks to two years. Types of exercise varied from strength training to polestriding and upper or lower limb exercises; supervised sessions were generally held at least twice a week. Most trials used a treadmill walking test for one of the primary outcome measures. The methodological quality of included trials was moderate, mainly owing to absence of relevant information. Most trials were small and included 20 to 49 participants. Twenty-seven trials compared exercise versus usual care or placebo, and the five remaining trials compared exercise versus medication (pentoxifylline, iloprost, antiplatelet agents, and vitamin E) or pneumatic calf compression; we generally excluded people with various medical conditions or other pre-existing limitations to their exercise capacity.Meta-analysis from nine studies with 391 participants showed overall improvement in pain-free walking distance in the exercise group compared with the no exercise group (MD 82.11 m, 95% CI 71.73 to 92.48, P < 0.00001, high-quality evidence). Data also showed benefit from exercise in improved maximum walking distance (MD 120.36 m, 95% CI 50.79 to 189.92, P < 0.0007, high-quality evidence), as revealed by pooling data from 10 studies with 500 participants. Improvements were seen for up to two years.Exercise did not improve the ABI (MD 0.04, 95% CI 0.00 to 0.08, 13 trials, 570 participants, moderate-quality evidence). Limited data were available for the outcomes of mortality and amputation; trials provided no evidence of an effect of exercise, when compared with placebo or usual care, on mortality (RR 0.92, 95% CI 0.39 to 2.17, 5 trials, 540 participants, moderate-quality evidence) or amputation (RR 0.20, 95% CI 0.01 to 4.15, 1 trial, 177 participants, low-quality evidence).Researchers measured quality of life using Short Form (SF)-36 at three and six months. At three months, the domains 'physical function', 'vitality', and 'role physical' improved with exercise; however this was a limited finding, as it was reported by only two trials. At six months, meta-analysis showed improvement in 'physical summary score' (MD 2.15, 95% CI 1.26 to 3.04, P = 0.02, 5 trials, 429 participants, moderate-quality evidence) and in 'mental summary score' (MD 3.76, 95% CI 2.70 to 4.82, P < 0.01, 4 trials, 343 participants, moderate-quality evidence) secondary to exercise. Two trials reported the remaining domains of the SF-36. Data showed improvements secondary to exercise in 'physical function' and 'general health'. The other domains - 'role physical', 'bodily pain', 'vitality', 'social', 'role emotional', and 'mental health' - did not show improvement at six months.Evidence was generally limited in trials comparing exercise versus antiplatelet therapy, pentoxifylline, iloprost, vitamin E, and pneumatic foot and calf compression owing to small numbers of trials and participants.Review authors used GRADE to assess the evidence presented in this review and determined that quality was moderate to high. Although results showed significant heterogeneity between trials, populations and outcomes were comparable overall, with findings relevant to the claudicant population. Results were pooled for large sample sizes - over 300 participants for most outcomes - using reproducible methods.

AUTHORS' CONCLUSIONS

High-quality evidence shows that exercise programmes provided important benefit compared with placebo or usual care in improving both pain-free and maximum walking distance in people with leg pain from IC who were considered to be fit for exercise intervention. Exercise did not improve ABI, and we found no evidence of an effect of exercise on amputation or mortality. Exercise may improve quality of life when compared with placebo or usual care. As time has progressed, the trials undertaken have begun to include exercise versus exercise or other modalities; therefore we can include fewer of the new trials in this update.

Exercise for intermittent claudication

BACKGROUND

Exercise programmes are a relatively inexpensive, low-risk option compared with other more invasive therapies for leg pain on walking (intermittent claudication (IC)). This is an update of a review first published in 1998.

OBJECTIVES

The prime objective of this review was to determine whether an exercise programme in people with intermittent claudication was effective in alleviating symptoms and increasing walking treadmill distances and walking times. Secondary objectives were to determine whether exercise was effective in preventing deterioration of underlying disease, reducing cardiovascular events and improving quality of life.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched September 2013) and CENTRAL (2013, Issue 8).

SELECTION CRITERIA

Randomised controlled trials of an exercise regimen versus control or versus medical therapy in people with IC due to peripheral arterial disease. Any exercise programme or regimen used in the treatment of intermittent claudication was included, such as walking, skipping and running. Inclusion of trials was not affected by the duration, frequency or intensity of the exercise programme. Outcome measures collected included treadmill walking distance (time to onset of pain or pain-free walking distance and maximum walking time or maximal walking distance), ankle brachial index (ABI), quality of life, morbidity or amputation; if none of these were reported the trial was not included in this review.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality.

MAIN RESULTS

Eleven additional studies were included in this update making a total of 30 trials which met the inclusion criteria, involving a total of 1816 participants with stable leg pain. The follow-up period ranged from two weeks to two years. The types of exercise varied from strength training to polestriding and upper or lower limb exercises; generally supervised sessions were at least twice a week. Most trials used a treadmill walking test for one of the outcome measures. Quality of the included trials was moderate, mainly due to an absence of relevant information. The majority of trials were small with 20 to 49 participants. Twenty trials compared exercise with usual care or placebo, the remainder of the trials compared exercise to medication (pentoxifylline, iloprost, antiplatelet agents and vitamin E) or pneumatic calf compression; people with various medical conditions or other pre-existing limitations to their exercise capacity were generally excluded.Overall, when taking the first time point reported in each of the studies, exercise significantly improved maximal walking time when compared with usual care or placebo: mean difference (MD) 4.51 minutes (95% confidence interval (CI) 3.11 to 5.92) with an overall improvement in walking ability of approximately 50% to 200%. Walking distances were also significantly improved: pain-free walking distance MD 82.29 metres (95% CI 71.86 to 92.72) and maximum walking distance MD 108.99 metres (95% CI 38.20 to 179.78). Improvements were seen for up to two years, and subgroup analyses were performed at three, six and 12 months where possible. Exercise did not improve the ABI (MD 0.05, 95% CI 0.00 to 0.09). The effect of exercise, when compared with placebo or usual care, was inconclusive on mortality, amputation and peak exercise calf blood flow due to limited data. No data were given on non-fatal cardiovascular events.Quality of life measured using the Short Form (SF)-36 was reported at three and six months. At three months, physical function, vitality and role physical all significantly improved with exercise, however this was a limited finding as this measure was only reported in two trials. At six months five trials reported outcomes of a significantly improved physical summary score and mental summary score secondary to exercise. Only two trials reported improvements in other domains, physical function and general health.Evidence was generally limited for exercise compared with antiplatelet therapy, pentoxifylline, iloprost, vitamin E and pneumatic foot and calf compression due to small numbers of trials and participants.

AUTHORS' CONCLUSIONS

Exercise programmes are of significant benefit compared with placebo or usual care in improving walking time and distance in people with leg pain from IC who were considered to be fit for exercise intervention.

Exercise interventions for patients with peripheral arterial disease: a review of the literature

Peripheral arterial disease (PAD) is a common chronic cardiovascular condition that affects the lower extremities and can substantially limit daily activities and quality of life. Lifestyle interventions, including smoking cessation, diet modification, regular physical activity, and pharmacotherapy, are often prescribed to treat patients with PAD. Exercise interventions can be effective in increasing claudication onset time and maximal walking distance. Of the various types of exercise interventions available for patients with PAD, little is known about the differences that may exist between men and women in patient response to such interventions. The purpose of this literature review is to examine the current knowledge of exercise interventions for individuals with mild (Fontaine stages I-II) PAD and to consider any differences that may exist between men and women. Women with PAD present with a different clinical profile compared with men, but respond similarly to an acute bout of exercise and a training program. Patients with PAD should be encouraged to walk regularly; however, more research is needed to determine differences between men and women in their response to various exercise interventions.

Pharmacologic therapy for intermittent claudication

Peripheral artery disease, defined as atherosclerosis in the lower extremities, affects nearly 8.5 million people in the United States. Due to the frequent asymptomatic manifestation of peripheral artery disease, diagnosis may be delayed and its true incidence underestimated. However, some patients may experience aching pain, numbness, weakness, or fatigue, a condition termed intermittent claudication. Peripheral atherosclerosis is associated with cardiovascular risk and physical impairment; therefore, treatment goals are aimed at decreasing cardiovascular risk, as well as improving quality of life. Little debate exists regarding the management of cardiovascular risk reduction, which consists of both antiplatelet therapy and risk factor modification. Despite recently published guidelines, the treatment of intermittent claudication is less well established and the management remains controversial and uncertain. Exercise remains the first-line therapy for intermittent claudication; however, pharmacologic treatment is often necessary. Although only two prescription drugs have been approved by the U.S. Food and Drug Administration for the treatment of intermittent claudication, several supplements and investigational agents have been evaluated. Therapeutic optimization should balance the anticipated improvements in quality of life with the potential safety risks.

Exercise for intermittent claudication

BACKGROUND

Exercise programmes are a relatively inexpensive, low-risk option compared with other more invasive therapies for leg pain on walking (intermittent claudication (IC)).

OBJECTIVES

To determine the effects of exercise programmes on IC, particularly in respect of reduction of symptoms on walking and improvement in quality of life.

SEARCH STRATEGY

The Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last search February 2008) and the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library 2008, Issue 1.

SELECTION CRITERIA

Randomised controlled trials of exercise regimens in people with IC due to peripheral arterial disease.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed trial quality.

MAIN RESULTS

Twenty-two trials met the inclusion criteria involving a total of 1200 participants with stable leg pain. Follow-up period was from two weeks to two years. There was some variation in the exercise regimens used, all recommended at least two sessions weekly of mostly supervised exercise. All trials used a treadmill walking test for one of the outcome measures. Quality of the included trials was good, though the majority of trials were small with 20 to 49 participants. Fourteen trials compared exercise with usual care or placebo; patients with various medical conditions or other pre-existing limitations to their exercise capacity were generally excluded.Compared with usual care or placebo, exercise significantly improved maximal walking time: mean difference (MD) 5.12 minutes (95% confidence interval (CI) 4.51 to 5.72;) with an overall improvement in walking ability of approximately 50% to 200%; exercise did not affect the ankle brachial pressure index (ABPI) (MD -0.01, 95% CI -0.05 to 0.04). Walking distances were also significantly improved: pain-free walking distance MD 82.19 metres (95% CI 71.73 to 92.65) and maximum walking distance MD 113.20 metres (95% CI 94.96 to 131.43). Improvements were seen for up to two years. The effect of exercise compared with placebo or usual care was inconclusive on mortality, amputation and peak exercise calf blood flow due to limited data.Evidence was generally limited for exercise compared with surgical intervention, angioplasty, antiplatelet therapy, pentoxifylline, iloprost and pneumatic foot and calf compression due to small numbers of trials and participants. Angioplasty may produce greater improvements than exercise in the short term but this effect may not be sustained.

AUTHORS' CONCLUSIONS

Exercise programmes were of significant benefit compared with placebo or usual care in improving walking time and distance in selected patients with leg pain from IC.

Local Versus Systemic Mechanisms Underlying Supervised Exercise Training for Intermittent Claudication

The mechanisms by which exercise training improves intermittent claudication remain unclear. In this article, the effects of local and systemic physiological factors on improved exercise tolerance after a supervised exercise program in claudicants are investigated. A total of 60 patients were randomized to 3 months of supervised exercise followed by 3 months of unsupervised exercise, or to exercise advice alone (control). Supervised exercise increased both pain-free and maximal walking distances. Heart rate during submaximal exercise and resting mean arterial pressure were lower after supervised exercise at 6 months. Serum lactate at maximum claudication increased significantly after 3 months in the supervised exercise group but this change had resolved by 6 months. Symptomatic improvement was accompanied by modest reductions in mean arterial pressure and submaximal heart rate on exercise. Increased serum lactate at maximum claudication subsequently declined despite continued improvement in walking distance, suggesting local adaptations to improve efficiency of muscle oxygen delivery and/or utilization.

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.

The case for early detection and integrated intervention in patients with peripheral arterial disease and intermittent claudication

Peripheral arterial disease (PAD) is defined as atherosclerotic disease of the aorta and arteries of the lower extremities. The most frequent manifestations of ischemia occur in the lower extremity arteries, with intermittent claudication as the most common symptom. Intermittent claudication, which is characterized by temporary pain brought on by muscle exertion, is usually experienced in the calf muscles and typically subsides with rest. The atherosclerotic nature of PAD/intermittent claudication makes it an important predictor of risk for cardio- and cerebrovascular disease, as well as limb loss. Thus, active screening and early diagnosis of PAD/intermittent claudication, in addition to aggressive management that incorporates risk factor modification, exercise therapy, platelet inhibition and other appropriate pharmacotherapy, and potential lifestyle changes, play important roles in overall patient management. Pharmacotherapy with cilostazol has been shown to improve maximal and pain-free walking distances. Uncontrolled and severely debilitating intermittent claudication may require revascularization.

The effects of exercise training on walking function and perception of health status in elderly patients with peripheral arterial occlusive disease

OBJECTIVE

To determine the effects of 12-week exercise programme on ambulatory function, free-living daily physical activity and health-related quality of life in disabled older patients with intermittent claudication.

DESIGN

Prospective, randomized controlled trial.

SETTING

University Medical Center and Veterans Affairs Medical Center, Taipei, Taiwan.

SUBJECTS

Thirty-two of 64 patients with Fontaine stage II peripheral arterial occlusive disease (PAOD) were randomized to exercise training and 32 to usual care control. Five patients from the exercise group and six patients from the control group dropped out, leaving 27 and 26 patients, respectively, completing the study in each group.

INTERVENTIONS

Twelve weeks of treadmill exercise training.

MAIN OUTCOME MEASURES

Treadmill walking time to onset of claudication pain and to maximal claudication pain, 6-min walk distance, self-reported ambulatory ability and perceived health-related quality of life (QOL).

RESULTS

Compliance of exercise programme was 83% of the possible sessions. Exercise training increased treadmill walking time to onset of claudication pain by 88% (P < 0.001), time to maximal pain by 70% (P < 0.001), and 6-min walk distance by 21% (P < 0.001).

SUBJECTS

Perception of health-related QOL improved from 12% to 178% in the exercise group. These improvements were significantly better than the changes in the control group (P < 0.05).

CONCLUSIONS

Significant improvements in claudication following 12-week exercise training in elderly PAOD patients were observed. Increase in treadmill walking time to maximal claudication pain in these patients translated into the improvement of perceived physical health, which enabled the patients to become more functionally independent.

Effects of long-term exercise rehabilitation on claudication distances in patients with peripheral arterial disease: a randomized controlled trial

PURPOSE

To determine if improvements in physical function and peripheral circulation after 6 months of exercise rehabilitation could be sustained over a subsequent 12-month maintenance exercise program in older patients with intermittent claudication.

METHODS

Seventeen patients randomized to exercise rehabilitation and 14 patients randomized to usual care control completed this 18-month study. Patients exercised three times per week during the first 6 months of a progressive exercise program, followed by two times per week during the final 12 months of a maintenance program. Patients were studied at baseline, 6 months, and 18 months during the study.

RESULTS

Eighteen months of exercise rehabilitation increased the initial claudication distance by 373 meters (189%) (P <.001), the absolute claudication distance by 358 meters (80%) (P <.001), walking economy by 11% (P <.001), 6-minute walk distance by 10% (P <.001), daily physical activity by 31%, and maximal calf blood flow by 18% (P <.001). These changes were similar to those found after 6 months of exercise rehabilitation (P = NS), and were significantly greater than the changes in the control group throughout the study (P <.05).

CONCLUSION

Improvements in claudication distances, walking economy, 6-minute walk distance, physical activity level, and peripheral circulation after 6 months of exercise rehabilitation are sustained for an additional 12 months in older patients with intermittent claudication using a less frequent exercise maintenance program.

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.

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 rehabilitation improves functional outcomes and peripheral circulation in patients with intermittent claudication: a randomized controlled trial

OBJECTIVE

To determine the effects of a 6-month exercise program on ambulatory function, free-living daily physical activity, peripheral circulation, and health-related quality of life (QOL) in disabled older patients with intermittent claudication.

DESIGN

Prospective, randomized controlled trial.

SETTING

University Medical (Center and Veterans Affairs Medical Center, Baltimore, Maryland.

PARTICIPANTS

Thirty-one of 61 patients with Fontaine stage II peripheral arterial occlusive disease (PAOD) were randomized to exercise rehabilitation and 30 to usual-care control. Three patients from the exercise group and six patients from the control group dropped out, leaving 28 and 24 patients, respectively, completing the study in each group.

INTERVENTION

Six months of exercise rehabilitation.

MEASUREMENTS

Treadmill distance walked to onset of claudication and to maximal claudication, ambulatory function, peripheral circulation, perceived QOL, and daily physical activity.

RESULTS

Compliance with the exercise program was 73% of the possible sessions. Exercise rehabilitation increased treadmill distance walked to onset of claudication by 134% (P < .001) and to maximal claudication by 77% (P < .001), walking economy by 12% (P = .003), 6-minute walk distance by 12% (P < .001), and maximal calf blood flow by 30% (P < .001). Changes in distance walked to maximal pain correlated with changes in walking economy (r = -.50, P = .013) and changes in maximal calf blood flow (r = .38, P = .047). Exercise rehabilitation increased accelerometer-derived daily physical activity by 38% (P < .001); this change correlated with the change in distance walked to maximal pain (r = .45, P = .020). These improvements were significantly better than the changes in the control group (P < .05).

CONCLUSION

Improvements in claudication following exercise rehabilitation in older PAOD patients are dependent on improvements in peripheral circulation and walking economy. Improvement in treadmill claudication distances in these patients translated into increased accelerometer-derived physical activity in the community, which enabled the patients to become more functionally independent.

Improved functional outcomes following exercise rehabilitation in patients with intermittent claudication

BACKGROUND

The purposes of this study were to identify predictors of increased claudication distances following exercise rehabilitation in peripheral arterial occlusive disease (PAOD) patients with intermittent claudication and determine whether improved claudication distances translated into increased free-living daily physical activity in the community setting.

METHODS

Sixty-three patients were recruited (age, 68+/-1 years, mean +/- standard error). Patients were characterized on treadmill claudication distances, walking economy, peripheral circulation, cardiopulmonary function, self-perceived ambulatory function, body composition, baseline comorbidities, and free-living daily physical activity before and after a 6-month treadmill exercise program.

RESULTS

Exercise rehabilitation increased distance to onset of claudication pain by 115% (178+/-22 m to 383+/-34 m; p < .001) and distance to maximal claudication pain by 65% (389+/-29 m to 641+/-34 m; p < .001). The increased distance to onset of pain was independently related to a 27% increase in calf blood flow (r = .42, p < .001) and to baseline age (r = -.26, p < .05), and the increased distance to maximal pain was predicted by a 10% increase in peak oxygen uptake (r = .41, p < .001) and by a 10% improvement in walking economy (r = -.34, p < .05). Free-living daily physical activity increased 31% (337+/-29 kcal/day to 443+/-37 kcal/day; p < .001) and was related to the increases in treadmill distances to onset (r = .24, p < .05) and to maximal pain (r = .45, p < .001).

CONCLUSIONS

Increased claudication distances following exercise rehabilitation are mediated through improvements in peripheral circulation, walking economy, and cardiopulmonary function, with younger patients having the greatest absolute ambulatory gains. Furthermore, improved symptomatology translated into enhanced community-based ambulation.

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.

Effects of exercise rehabilitation on cardiovascular risk factors in older patients with peripheral arterial occlusive disease

OBJECTIVE

The purpose of this study was to determine whether a 6-month exercise rehabilitation program can improve cardiovascular risk factors in patients with peripheral arterial occlusive disease (PAOD).

METHODS

Thirty-four patients (mean age, 68 +/- 8 years; range 54-84 years) with PAOD with intermittent claudication (Fontaine stage II) and 14 longitudinal controls of comparable age with stage II PAOD enrolled in an exercise intervention at the University Medical Center and Veterans Affairs Medical Center at Baltimore, Maryland. The main outcome measures were lipid profile (total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol [LDL-C]), fasting glucose, blood pressure, body mass index, treadmill times to onset and maximal claudication pain, cardiopulmonary function (peak oxygen uptake), and ankle/brachial index.

RESULTS

With exercise rehabilitation, treadmill times to onset and maximal claudication pain increased by 106% and 64% (P <.0001), whereas peak oxygen uptake increased 7% (P <.05). Exercise rehabilitation lowered total cholesterol and LDL-C levels by 5.2% (P <.005) and 8% (P <.01), respectively. Systolic blood pressure declined by 5.7% (P <.05) with no change in diastolic blood pressure. These changes in cholesterol and LDL-C concentrations were related to their initial values. All other cardiovascular risk factors measured did not change. There was no correlation between improvement of cardiovascular risk factors and functional performance measurements. None of the variables measured changed significantly in the control group.

CONCLUSIONS

Exercise rehabilitation not only improves functional performance, but also results in favorable alterations in cardiovascular risk factor profile, which is an important element in the management of PAOD.

Exercise for intermittent claudication

BACKGROUND

Exercise is an inexpensive, low risk option compared with other more invasive therapies for leg pain on walking (intermittent claudication).

OBJECTIVES

The objective of this review was to determine the effects of exercise for leg pain.

SEARCH STRATEGY

The reviewers searched the Cochrane Peripheral Vascular Diseases Group trials register, Embase, reference lists of relevant articles, and contacted principal investigators of trials.

SELECTION CRITERIA

Randomised trials of exercise regimens in patients with leg pain on walking (intermittent claudication).

DATA COLLECTION AND ANALYSIS

At least two reviewers extracted and assessed data trial quality independently. The reviewers contacted investigators to obtain information or data needed for the review that could not be found in published reports.

MAIN RESULTS

Fifteen trials were identified that met the inclusion criteria, but five were subsequently excluded because of poor quality. The remaining ten trials involved a total of almost 250 male and female patients with stable leg pain. The follow-up ranged from 12 weeks to 15 months. There was also some variation in the exercise regimens used, although all recommended at least two weekly sessions of, mostly, supervised exercise. All trials used a treadmill walking test as one of the outcome measures. The overall quality of the included trials was generally good, though the trials were all small (20-49 patients). Exercise therapy significantly improved maximal walking time (minutes) (weighted mean difference 6.51, 95% confidence interval 4.36 to 8.66, fixed effect model [FE]), with an overall improvement in walking ability of approximately 150% (range 74% to 230%). Exercise produced significant improvements in walking time compared with both angioplasty at six months (weighted mean difference 3.30, 95% confidence interval 2.21 to 4.39, FE) and antiplatelet therapy (weighted mean difference 1.06, 95% confidence interval 0.15 to 1.97, FE), and did not differ significantly from surgical treatment. In one small trial, exercise was less effective than pentoxifylline (weighted mean difference -0.45, 95% confidence interval -0.66 to -0.24, FE).

REVIEWER'S CONCLUSIONS

Exercise is of significant benefit to patients with leg pain.

Hemoglobin oxygen affinity in patients suffering from arterial occlusive disease of the legs

Parameters characterizing the hemoglobin oxygen affinity were determined in blood of 12 male patients suffering from arterial occlusive disease (AOD) of the legs and compared with data obtained earlier from healthy human subjects (controls). Due to a COHb content of 4.8% +/- 2.2% in the cigarette-smoking AOD patients, the standard oxygen dissociation curve (ODC) was left-shifted, the half-saturation pressure (P50) amounted to 24.8 +/- 1.7 mmHg (3.30 +/- 0.23 kPa), although the 2,3-diphosphoglycerate concentration was increased to 15.3 +/- 1.7 mumol/g Hb. Correcting the effects of elevated COHb shifts the P50 to 26.3 mmHg (3.5 kPa) and increases the steepness of the ODC (Hill's "n") from 2.79 +/- 0.27 to about 2.99, which is significantly different from controls. The Bohr coefficients after acidification of blood with lactic acid (BCLac) show high values at low oxygen saturations of hemoglobin (-0.50 +/- 0.04 in AOD patients, -0.32 +/- 0.04 in controls; P less than 0.05 at 10% SO2). The cause of the alterations in hemoglobin oxygen affinity may be a reduced mean erythrocyte age, but also the influence of unknown factors generated, e.g., from anaerobic muscle metabolism in AOD.

Graded exercise testing and training after renal transplantation: a preliminary study

Aerobic exercise training has been used as part of the treatment for a variety of chronic disorders, most notably cardiovascular disease. In order to determine the feasibility and utility of regular exercise after renal transplantation, the responses of 10 patients to graded exercise testing were compared before training (T1), immediately after a program of supervised exercise training (T2), and a mean of 2.2 years after completion of the supervised program (T3). Supervised exercise sessions began a mean of 17 days postoperatively and continued for a mean of 5.5 weeks. Patients were encouraged to continue regular unsupervised exercise thereafter. All patients easily tolerated the supervised exercise sessions, which consisted of treadmill walking and cycle ergometry. Exercise capacity improved 90% between T1 and T2 and an additional 12% between T2 and T3. On the average, patients achieved a normal exercise capacity by 8 weeks after transplantation. Of the 10 patients, 7 had continued regular exercise training at T3. The observed increase in aerobic exercise capacity was probably related to improved renal function, an increased hemoglobin concentration, and the surgical healing process as well as the exercise training. We conclude that supervised exercise training for selected patients after renal transplantation is feasible and worthwhile.

Effects of ethaverine hydrochloride on the walking tolerance of patients with intermittent claudication

The effect of ethaverine hydrochloride on exercise tolerance of patients with intermittent claudication was evaluated in a double-blind, placebo-controlled study conducted at three sites. Forty-five patients with symptoms of occlusive arterial insufficiency of the lower extremities were randomly assigned to receive ethaverine 200 mg or placebo four times daily. The patients were evaluated biweekly for 12 weeks with treadmill claudication tests, patient and investigator assessments of symptom severity, and reports of adverse reactions. Doppler ankle/brachial pressure ratios were recorded for 26 patients. Walking tolerance improved for patients in both groups during the course of the study. Increases in distance-to-claudication were significantly greater for patients receiving ethaverine after 6, 8, 10, and 12 weeks of therapy. Ankle/brachial pressure index after exercise was unchanged in both groups. Incidence of adverse reactions was similar for the two groups. Although patients were generally unaware of any improvement in symptoms, the investigators judged significant relief of claudication among those receiving ethaverine compared to those receiving placebo. It was concluded that ethaverine safely increased distance-to-claudication in patients with intermittent claudication.