Frank Quigley

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

OBJECTIVE The purpose of the study was to examine the effects of a 12-month exercise program on lower limb mobility (temporal-spatial gait parameters and gait kinematics), walking performance, peak physiological responses, and physical activity levels in individuals with symptoms of intermittent claudication due to peripheral arterial disease (PAD-IC). METHODS Participants (n = 21) with an appropriate history of PAD-IC, ankle-brachial pressure index (ABI) <0.9 in at least one leg and a positive Edinburgh claudication questionnaire response were prospectively recruited. Participants were randomly allocated to either a control PAD-IC group (CPAD-IC) (n = 11) that received standard medical therapy and a treatment PAD-IC group (TPAD-IC) (n = 10), which also took part in a 12-month supervised exercise program. A further group of participants (n = 11) free of PAD (ABI >0.9) and who were non-regular exercisers were recruited from the community to act as age and mass matched controls (CON). Lower limb mobility was determined via two-dimensional video motion analysis. A graded treadmill test was used to assess walking performance and peak physiological responses to exercise. Physical activity levels were measured via a 7-day pedometer recording. Differences between groups were analyzed via repeated measures analysis of variance (ANOVA). RESULTS The 12-month supervised exercise program had no significant effect on lower limb mobility, peak physiological responses, or physical activity levels in TPAD-IC compared with CPAD-IC participants. However, the TPAD-IC participants demonstrated significantly greater walking performance (171% improvement in pain free walking time and 120% improvement in maximal walking time compared with baseline). CONCLUSION The results of this study confirm that a 12-month supervised exercise program will result in improved walking performance, but does not have an impact on lower limb mobility, peak physiological responses, or physical activity levels of PAD-IC patients.

Determinants of Endothelial Function in a Cohort of Patients with Peripheral Artery Disease

Objectives: Endothelial dysfunction assessed by brachial artery flow-mediated dilatation (FMD) has been associated with cardiovascular events. There have been relatively few studies examining FMD or other measures of endothelial function in patients with peripheral artery disease (PAD). The aim of this study was to examine determinants of FMD in a homogenous cohort of patients with PAD. Methods: We prospectively assessed patients presenting with life style-limiting intermittent claudication to establish the presence of cardiovascular risk factors, obesity and metabolic syndrome. Fasting serum was assayed for lipids, C-reactive protein, adiponectin, leptin, resistin and osteoprotegerin (OPG). FMD was measured by high-resolution ultrasound. Results: Serum concentrations of OPG were elevated in patients with obesity and metabolic syndrome. FMD was impaired in patients with obesity and metabolic syndrome and negatively correlated with serum concentrations of OPG. By multiple regression analysis, metabolic syndrome was independently associated with impaired FMD after adjustment for age, smoking, ischaemic heart disease, cerebrovascular disease and severity of PAD. Conclusions: Our findings suggest that metabolic syndrome is an important determinant of endothelial function in patients with PAD, and OPG may be a useful biomarker of this effect.

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

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

Lower limb movement variability in patients with peripheral arterial disease

BACKGROUND Peripheral arterial disease is a chronic obstructive disease of the arteries of the lower limb caused by atherosclerosis. The resultant decrease in blood flow can result in symptoms of pain in the lower limb on exercise known as intermittent claudication. Exercise induced pain is experienced in the calves, thigh or buttocks restricting activities of daily living and thus reducing quality of life. METHODS This study investigated lower limb movement variability in individuals with peripheral arterial disease-intermittent claudication (n=28) compared to individuals without peripheral arterial disease-intermittent claudication (control, n=25). A further aim was to examine the efficacy of various techniques used to describe single joint movement variability. All participants underwent two-dimensional angular kinematics analysis of the lower limb during normal walking. Single joint movement variability was measured using linear (spanning set and coefficient of variation) techniques. Between group differences were examined by one-way ANOVA. FINDINGS The peripheral arterial disease-intermittent claudication participants displayed significantly higher levels of lower limb movement variability in all joints when assessed using the coefficient of variation technique. There were no significant between group differences using the spanning set technique. INTERPRETATION Individuals with peripheral arterial disease-intermittent claudication have higher levels of lower limb movement variability and reduced walking speed compared to healthy age and mass matched controls. This variability may be an adaptation to the gradual onset of ischaemic pain in this population.

The influence of a long term exercise program on lower limb movement variability and walking performance in patients with peripheral arterial disease.

The purpose of this study was to examine the effects of a 12month exercise program on lower limb movement variability in patients with peripheral arterial disease (PAD). Participants (n=21) with an appropriate history of PAD and intermittent claudication (IC) volunteered for this study and were randomly allocated to either a control group (CPAD-IC) (n=11), which received normal medical therapy and a treatment group (TPAD-IC) (n=10), which received normal medical therapy treatment and a 12month supervised exercise program. All participants underwent 2D joint angular kinematic analysis during normal walking to assess lower limb movement variability and walking speed. Between-group differences were analyzed via mixed measures ANOVA. The 12month supervised exercise program made no significant impact on the lower limb movement variability or walking speed of the TPAD-IC group as determined by either intralimb joint coordination or single joint analysis techniques. Long term supervised exercise programs do not appear to influence the lower limb movement variability of PAD-IC patients.

Association of impaired fasting glucose, diabetes and their management with the presentation and outcome of peripheral artery disease: a cohort study

BackgroundPre-diabetes and untreated diabetes are common in patients with peripheral artery disease however their impact on outcome has not been evaluated. We examined the association of impaired fasting glucose, diabetes and their treatment with the presentation, mortality and requirement for intervention in peripheral artery disease patients.MethodsWe prospectively recruited 1637 patients with peripheral artery disease, measured fasting glucose, recorded medications for diabetes and categorised them by diabetes status. Patients were followed for a median of 1.7 years.ResultsAt entry 22.7% patients were receiving treatment for type 2 diabetes by oral hypoglycaemics alone (18.1%) or insulin (4.6%). 9.2% patients had non-medicated diabetes. 28.1% of patients had impaired fasting glucose (5.6-6.9 mM). Patients with non-medicated diabetes had increased mortality and requirement for peripheral artery intervention (hazards ratio 1.62 and 1.31 respectively). Patients with diabetes prescribed insulin had increased mortality (hazard ratio 1.97). Patients with impaired fasting glucose or diabetes prescribed oral hypoglycaemics only had similar outcomes to patients with no diabetes.ConclusionsNon-medicated diabetes is common in peripheral artery disease patients and associated with poor outcomes. Impaired fasting glucose is also common but does not increase intermediate term complications. Peripheral artery disease patients with diabetes requiring insulin are at high risk of intermediate term mortality.

Growth and Risk Factors for Expansion of Dilated Popliteal Arteries

OBJECTIVES The aims of this study were to investigate the change in maximum diameter of ectatic popliteal arteries during ultrasound surveillance and assess clinical predictors of their expansion. METHODS Over a ten year period 67 patients with ectasia affecting one (n = 1) or both (n = 66) popliteal arteries entered this surveillance study. Patients were followed for a median of 3.1 years, at a median scan interval of 7.6 months. RESULTS Growth of ectatic popliteal arteries was typically slow (<1 mm/yr). Initial artery diameter at entry to the study was not found to be predictive of subsequent growth. Seven patients followed for a median of 2 years had an expansion in popliteal artery diameter to >or=20 mm during follow-up. All of these patients had undergone aneurysm repairs at other arterial sites and none of them had diabetes. These participants also had a significantly higher rate of previous intervention of the contralateral popliteal artery in comparison to those that did not reach the 20 mm threshold (p < 0.001). Growth profiles of arteries that underwent significant expansion during surveillance were frequently characterised by a staccato pattern. CONCLUSIONS Expansion of ectatic popliteal arteries is typically slow but difficult to predict. Trends observed in this study suggest that patients with extra-popliteal aneurysms, patients with previously treated contralateral popliteal artery ectasia and those who are not diabetics may be more prone to significant expansion. Further studies are required to validate these potential growth predictors.

Serum homocysteine is associated with the severity of primary chronic venous disease

Objective This study was conducted to assess whether serum homocysteine concentration was associated with the severity of primary chronic venous disease. Design Cross-sectional study. Methods A total of 282 primary chronic venous disease patients were enrolled from outpatient vascular services. The severity of venous disease was graded using the Clinical Etiology Anatomy Pathophysiology classification system. The association of serum homocysteine concentration with advanced primary chronic venous disease (C4-6) was assessed using the Mann Whitney U test and logistic regression analysis. Results Median (interquartile range) serum homocysteine concentrations were 9.10 µM (7.55–10.75) and 10.40 µM (8.85–13.10) in patients with primary chronic venous disease classified by C1-3 (n = 209) and C4-6 (n = 73) grades, respectively, p < 0.001. Serum homocysteine concentration was positively associated with clinical grade 4–6 after adjusting for other risk factors including age, diabetes, male sex, hypertension, recurrent varicose veins and stroke. Patients with serum homocysteine in the third (odds ratio, 2.76, 95% confidence interval, 1.01–7.54) and fourth (odds ratio 3.29, 95% confidence interval 1.15–9.43) quartiles were more likely to have grade C4-6 chronic venous disease than subjects with serum homocysteine in the first quartile. Conclusions Serum homocysteine is positively associated with the severity of primary chronic venous disease and therefore could play a role in promoting chronic venous disease complications.