Exercise training for claudication

Low Intrinsic Aerobic Capacity Limits Recovery Response to Hindlimb Ischemia

Introduction: In this study, we determined the influence of intrinsic exercise capacity on the vascular adaptive responses to hind limb ischemia. High Capacity Running, HCR; Low Capacity Running, LCR, rats were used to assess intrinsic aerobic capacity effects on adaptive responses to ischemia.

Methods: Muscle samples from both ischemic and non-ischemic limb in both strains were compared, histologically for the muscle-capillary relationship, and functionally using microspheres to track blood flow and muscle stimulation to test fatigability. PCR was used to identify the differences in gene expression between the phenotypes following occlusive ischemia.

Results: Prior to ligation, there were not significant differences between the phenotypes in the exhaustion time with high frequency pacing. Following ligation, LCR decreased significantly in the exhaustion time compare with HCRs (437 ± 47 vs. 824 ± 56, p < 0.001). The immediate decrease in flow was significantly more severe in LCRs than HCRs (52.5 vs. 37.8%, p < 0.001). VEGF, eNOS, and ANG2 (but not ANG1) gene expression were decreased in LCRs vs. HCRs before occlusion, and increased significantly in LCRs 14D after occlusion, but not in HCRs. LCR capillary density (CD) was significantly lower at all time points after occlusion (LCR 7D = 564.76 ± 40.5, LCR 14D = 507.48 ± 54.2, both p < 0.05 vs. HCR for respective time point). NCAF increased significantly in HCR and LCR in response to ischemia.

Summary: These results suggest that LCR confers increased risk for ischemic injury and is subject to delayed and less effective adaptive response to ischemic stress.

Feasibility study to evaluate cycloidal vibration therapy for the symptomatic treatment of intermittent claudication

Introduction

Intermittent claudication (IC) is the most common symptom of peripheral arterial disease. Previous research has suggested that cycloidal vibration therapy (CVT) may induce angiogenesis and improvements in circulation. The objective of this feasibility study was to explore trial design and acceptability of the protocol to provide data to estimate the parameters required to design a definitive randomised control trial. This feasibility study specifically aimed to assess recruitment rate; attendance rates at baseline and follow-up; and safety, tolerability, and compliance with therapy device and additionally, to consider the potential efficacy of CVT as a novel treatment for intermittent claudication.

Methods

Patients with intermittent claudication (IC) were recruited and CVT was applied at home for 30 min twice a day for a period of 12 weeks. Primary outcomes were pain-free walking time (PFWT) and maximum walking time (MWT) after 12 weeks of treatment. Secondary outcomes included the ankle-brachial index and ankle systolic blood pressure. Participants were assessed during active therapy phase at baseline, week 4, week 8, and week 12.

Results

Thirty-four participants with IC were recruited: 30 (88%) male and 4 (12%) female. The rate of recruitment was 2.4 participants per month from a standard-size district general hospital. No participants left the study during the activity therapy stage, and no participant failed to attend their follow-up appointment. The general compliance with CVT was high. No participants dropped out during the treatment phase. The mean age of all participants was 68 years (IQR 60–75 years). Substantive improvements were seen in a comparison of differences in times to PFWT and MWT, in ABPI, and in systolic leg pressure in the treated leg. There was no evidence of a substantive difference from baseline in systolic leg pressure in the untreated leg. There were no immediate or delated treatment safety concerns of documented adverse effects with the treatment, all patients completed the required 12-week course indicated a high degree of patient acceptability.

Conclusion

The statistically significant and substantive improvements from baseline after 12 weeks observed in PFWT and MWT in participants experiencing IC are comparable to improvements seen from other treatment options such as supervised exercise as reported by Stewart et al. (N Engl J Med 347:1941–1951, 2002). The substantive improvement in systolic leg pressure in the treated leg and the concurrent absence of a substantive change in systolic leg pressure in the untreated leg over the same period suggests a causative effect.

This study has provided novel information relating to the number of potential eligible participants for a further research trial and potential association between CVT and improved symptoms. Additionally, it has established that CVT treatment is highly acceptable, as indicated by no participant drop-out in the treatment phase, and may potentially offer an alternative treatment option for patients experiencing IC. Furthermore, this study has assessed the variability of the primary outcome measure which provides vital information needed to calculate sample sizes for any future studies.

In conclusion, this study has established the feasibility of using CVT to improve patients’ symptoms of IC and provides essential information which will contribute to the design of future research investigating whether the improvements seen are directly related to CVT.

[Conservative treatment of chronic lower limb ischemia in ambulatory practice (in Russian only)]

Peripheral artery disease is still one of the most important surgical problems. General surgeons treat the majority of patients with chronic lower limb ischemia due to the lack of specialized surgical care. Current methods for risk factors adjustment, exercise therapy and the most common drugs for intermittent claudication management are reviewed in the article. The effect of these medicines on subjective (pain-free walking distance, maximal walking distance, etc.) and objective (ankle-brachial index) parameters and the incidence of complications are analyzed.

Treatment Strategies for the Claudicant

Peripheral arterial disease (PAD) is a prevalent, morbid, and mortal disease. Claudication represents an early, yet common manifestation of PAD. A clinical history and physical examination combined with an ankle-brachial index can help make a diagnosis of claudication. Due to the polyvascular nature of the underlying atherosclerosis, PAD is often associated with heart disease and stroke. Although health implications of PAD derive from both its limb and cardiovascular manifestations, claudication is life-threatening, less limb-threatening. Medical modification of cardiovascular risk factors and exercise are the cornerstone in the treatment of claudication. Revascularization in claudication is focused at improvement in claudication symptoms and functional status, rather than aggressive attempts at limb salvage. The aim of this article is to summarize the strategies in the treatment of claudication, to serve as a concise and informative reference for physicians who are managing these patients. A framework of the decision-making process in the management of patients with claudication is shown, which can be applied in clinical practice.

Exercise training in intermittent claudication: Effects on antioxidant genes, inflammatory mediators and proangiogenic progenitor cells

Exercise training remains a therapy of choice in intermittent claudication (IC). However, too exhaustive exercise may cause ischaemic injury and inflammatory response. We tested the impact of three-month treadmill training and single treadmill exercise on antioxidant gene expressions, cytokine concentrations and number of marrow-derived proangiogenic progenitor cells (PPC) in the blood of IC patients. Blood samples of 12 patients were collected before and after training, before and 1, 3 and 6 hours after the single exercise. PPCs were analysed with flow cytometry, cytokine concentrations were checked with Milliplex MAP, while expression of mRNAs and miRNAs was evaluated with qRT-PCR. Treadmill training improved pain-free walking time (from 144 ± 44 seconds [s] to 311 ± 134 s, p=0.02) and maximum walking time (from 578 ± 293 s to 859 ± 423 s, p=0.01) in IC patients. Before, but not after training, the single treadmill exercise increased the number of circulating CD45dimCD34+CD133-KDR+ PPCs (p=0.048), decreased expression of HMOX1 (p=0.04) in circulating leukocytes, reduced tumour necrosis factor-α (p=0.03) and tended to elevate myeloperoxidase (p=0.06) concentrations in plasma. In contrast, total plasminogen activator inhibitor-1 was decreased by single exercise only after, but not before training (p=0.02). Both before and after training the single exercise decreased monocyte chemoattractant protein (MCP)-1 (p=0.006 and p=0.03) concentration and increased SOD1 (p=0.001 and p=0.01) expression. Patients after training had also less interleukin-6 (p=0.03), but more MCP-1 (p=0.04) in the blood. In conclusion, treadmill training improves walking performance of IC patients, attenuates the single exercise-induced changes in gene expressions or PPC mobilisation, but may also lead to higher production of some proinflammatory cytokines.

Effect of supervised exercise on physical function and balance in patients with intermittent claudication

Background

The aim of the study was to identify whether a standard supervised exercise programme (SEP) for patients with intermittent claudication improved specific measures of functional performance including balance.

Methods

A prospective observational study was performed at a single tertiary vascular centre. Patients with symptomatic intermittent claudication (Rutherford grades 1–3) were recruited to the study. Participants were assessed at baseline (before SEP) and 3, 6 and 12 months afterwards for markers of lower-limb ischaemia (treadmill walking distance and ankle : brachial pressure index), physical function (6-min walk, Timed Up and Go test, and Short Physical Performance Battery (SPPB) score), balance impairment using computerized dynamic posturography with the Sensory Organization Test (SOT), and quality of life (VascuQoL and Short Form 36).

Results

Fifty-one participants underwent SEP, which significantly improved initial treadmill walking distance (P = 0·001). Enrolment in a SEP also resulted in improvements in physical function as determined by 6-min maximum walking distance (P = 0·006), SPPB score (P &lt; 0·001), and some domains of both generic (bodily pain, P = 0·025) and disease-specific (social domain, P = 0·039) quality of life. Significant improvements were also noted in balance, as determined by the SOT (P &lt; 0·001).

Conclusion

Supervised exercise improves both physical function and balance impairment.

Diabetic women are poor responders to exercise rehabilitation in the treatment of claudication

BACKGROUND

It is not clear whether subgroups of patients with peripheral artery disease (PAD) and claudication respond more favorably to exercise rehabilitation than others. We determined whether sex and diabetes were factors associated with the response to exercise rehabilitation in patients with claudication.

METHODS

Eighty patients were randomized to home-based and supervised exercise programs, and 60 finished with complete exercise intervention data. Exercise consisted of intermittent walking to near maximal claudication pain for 3 months. Primary outcome measures included claudication onset time (COT) and peak walking time. Patients were partitioned into diabetic and nondiabetic groups and then further partitioned by sex to form four groups.

RESULTS

Overall, exercise adherence was high (84%), and there was no significant difference (P > .05) in the amount of exercise completed among the four groups. All groups had significant improvements (P < .05) in COT and peak walking time after exercise rehabilitation, except for diabetic women (P > .05). Only 37% of women with diabetes had an increase in COT compared with 100% of men with diabetes (P < .01), and their risk ratio for nonresponse was 9.2 (P < .0001).

CONCLUSIONS

Women with PAD and claudication, particularly those with diabetes, represent a vulnerable subgroup of patients who respond poorly to a program of exercise rehabilitation. Diabetic women with PAD and claudication may need a greater dose of exercise or another intervention separate from or in combination with exercise to elicit improvements in claudication measures that are similar to nondiabetic women and to diabetic and nondiabetic men.

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.

Optimal exercise program length for patients with claudication

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Increasing walking in patients with intermittent claudication: protocol for a randomised controlled trial

BACKGROUND

People with intermittent claudication are at increased risk of death from heart attack and stroke compared to matched controls. Surgery for intermittent claudication is for symptom management and does not reduce the risk of cardiovascular morbidity and mortality. Increasing physical activity can reduce claudication symptoms and may improve cardiovascular health. This paper presents the pilot study protocol for a randomised controlled trial to test whether a brief psychological intervention leads to increased physical activity, improvement in quality of life, and a reduction in the demand for surgery, for patients with intermittent claudication.

METHODS/DESIGN

We aim to recruit 60 patients newly diagnosed with intermittent claudication, who will be randomised into two groups. The control group will receive usual care, and the treatment group will receive usual care and a brief 2-session psychological intervention to modify illness and walking beliefs and develop a walking action plan. The primary outcome will be walking, measured by pedometer. Secondary outcomes will include quality of life and uptake of surgery for symptom management. Participants will be followed up after (a) 4 months, (b) 1 year and (c) 2 years.

DISCUSSION

This study will assess the acceptability and efficacy of a brief psychological intervention to increase walking in patients with intermittent claudication, both in terms of the initiation, and maintenance of behaviour change. This is a pilot study, and the results will inform the design of a larger multi-centre trial.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN28051878.

Supervised Exercise in Intermittent Claudication: A Sedentary Notion?

The benefit of exercise in the management of intermittent claudication has been explored through extensive research in the preceding decades. Within the clinical setting, there is often little differentiation between home-based and supervised exercise regimens. We examined the history and qualification of supervised exercise as a distinct treatment modality from nonsupervised exercise in intermittent claudication. A Medline, Embase, Ovid, Cochrane Database, and Google Scholar search was performed on all studies published until December 31, 2007, investigating the use of supervised exercise in peripheral arterial disease. Supervised exercise is well grounded in evidence to support its superiority over nonsupervised exercise in the management of intermittent claudication, conveying marked improvement in symptomatology, function, and quality of life. Further research is required to determine the nature of the advantage that supervision affords.