Association of clinical attributes and treadmill walking performance in patients with claudication due to peripheral artery disease

Maximal calf conductance is associated with 6-minute walk distance in participants with and without peripheral artery disease

INTRODUCTION

The aims were (a) to compare the maximal calf conductance and 6-minute walk distance of participants with and without peripheral artery disease (PAD) and claudication, (b) to determine whether maximal calf conductance was more strongly associated with 6-minute walk distance in participants with PAD than in the controls, and (c) to determine whether this association was significant in participants with PAD after adjusting for ABI, as well as for demographic, anthropometric, and comorbid variables.

METHODS

Participants with PAD (n = 633) and without PAD (n = 327) were assessed on maximal calf conductance using venous occlusion plethysmography, and on 6-minute walk distance. Participants were further characterized on ABI, and on demographic, anthropometric, and comorbid variables.

RESULTS

The PAD group had lower maximal calf conductance than the control group (0.136 ± 0.071 vs 0.201 ± 0.113 mL/100 mL/min/mmHg, p < 0.001). Additionally, the PAD group had a lower 6-minute walk distance (375 ± 98 m vs 480 ± 107 m, p < 0.001). Maximal calf conductance was positively associated with 6-minute walk distance in both groups (p < 0.001) and was more strongly associated in the PAD group (p < 0.001). In adjusted analyses, maximal calf conductance remained positively associated with 6-minute walk distance in the PAD group (p < 0.001) and in the control group (p < 0.001).

CONCLUSIONS

Participants with PAD and claudication had impaired maximal calf conductance and a lower 6-minute walk distance than those without PAD, and maximal calf conductance was positively and independently associated with 6-minute walk distance within each group before and after adjusting for ABI, and for demographic, anthropometric, and comorbid variables.

The effect of peripheral arterial disease and intermittent claudication on gait regularity and symmetry

Peripheral arterial disease (PAD) affects 20-30% of older adults and is associated with intermittent claudication (IC), which is walking-induced pain. This study compared the regularity and symmetry of gait between healthy older adults and adults with PAD, and between IC and non-IC conditions in the PAD group. Eighteen control (70.7 ± 6.3 years) and 11 PAD participants (67.0 ± 10.1 years) walked overground at a continuous, self-selected speed. A waist-mounted accelerometer determined step time, stride time, gait speed and mediolateral (ML), vertical (V) and anteroposterior (AP) gait regularity (step/stride) and symmetry. Correlations between ankle-brachial index (ABI) scores and PAD gait regularity/symmetry were also investigated. PAD step and stride times were greater (p < 0.01), while gait speed, ML and AP step regularity and ML and V stride regularity were significantly less than the controls (p < 0.05). There were no significant differences in gait symmetry. Within the PAD group, post-IC step/stride time and speed increased and decreased, respectively, (p < 0.05), while post-IC step and stride regularity were significantly less in all three directions (p < 0.01). Similarly, ML and V post-IC gait asymmetry increased significantly (p < 0.05). ABI was significantly correlated with pre-and post-IC vertical stride regularity (p < 0.01), and with pre- and post-IC ML gait symmetry (p < 0.05). The results demonstrate that gait regularity decreases as a result of PAD and IC. The association between gait regularity/symmetry and ABI should be investigated further, as it may have clinical application to the assessment of PAD severity.

Multimodal Supervised Exercise Significantly Improves Walking Performances Without Changing Hemodynamic Parameters in Patients With Symptomatic Lower Extremity Peripheral Artery Disease

We evaluated the outcome of multimodal supervised exercise training (SET) on walking performances and different hemodynamic parameters (ankle/toe-brachial index [ABI/TBI], and transcutaneous oxygen pressure [TcPO₂]) in patients with symptomatic lower extremity peripheral artery disease (PAD). Whether hemodynamic parameters predict walking performances at baseline and following SET was also investigated. Fontaine stage II PAD's patients following a 3-month SET were retrospectively included. Hemodynamic parameters and walking performances (pain-free [PFWD], maximal [MWD], and 6-minute [6MWD] walking distance) were measured in each patient. Eighty-five symptomatic PAD patients were included. Following SET, PFWD, MWD, and 6MWD significantly increased (+142%, +94%, +14%; respectively; P ≤ .001). Toe-brachial index significantly increased (MD: 0.04 ± 0.01; P = .02), whereas ABI and TcPO₂ did not change significantly. At baseline, patients with higher TBI and TcPO₂ performed significantly better (PFWD: β = 0.25, P = .01 for TBI; PFWD: β = 0.30, P = .005, and MWD: β = 0.22, P = .04, for TcPO₂). No significant relationship was observed at baseline between ABI and walking performances. Baseline values of hemodynamic parameters did not significantly correlate with changes in walking performances. Multimodal SET significantly improves walking performances. Following SET, no significant changes in ABI and TcPO₂ were observed. Toe-brachial index values significantly improved after SET. However, this increase was very modest and its clinical relevance remains questionable. Although baseline TBI and supine TcPO₂ values predict baseline walking performances, no association was found between baseline hemodynamic parameters and changes in walking performances following SET.

Identification of new factors associated to walking impairment in patients with vascular-type claudication

OBJECTIVES

Mechanisms of walking limitation in arterial claudication are incompletely elucidated. We aimed to identify new variables associated to walking limitation in patients with claudication.

METHODS

We retrospectively analyzed data of 1120 patients referred for transcutaneous exercise oxygen pressure recordings (TcpO₂). The outcome measurement was the absolute walking time on treadmill (3.2 km/h, 10% slope). We used both: linear regression analysis and a non-linear analysis, combining support vector machines and genetic explanatory in 800 patients with the following resting variables: age, gender, body mass index, the presence of diabetes, minimal ankle to brachial index at rest, usual walking speed over 10 m (usual-pace), number of comorbid conditions, active smoking, resting heart rate, pre-test glycaemia and hemoglobin, beta-blocker use, and exercise-derived variables: minimal value of pulse oximetry, resting chest-TcpO₂, decrease in chest TcpO₂ during exercise, presence of buttock ischemia defined as a decrease from rest of oxygen pressure index ≤15 mmHg. We tested the models over 320 other patients.

RESULTS

Independent variables associated to walking time, by decreasing importance in the models, were: age, ankle to brachial index, usual-pace; resting TcpO₂, body mass index, smoking, buttock ischemia, heart rate and beta-blockers for the linear regression analysis, and were ankle to brachial index, age, body mass index, usual-pace, decrease in chest TcpO₂, smoking, buttock ischemia, glycaemia, heart rate for the non-linear analysis. Testing of models over 320 new patients gave r = 0.509 for linear and 0.575 for non-linear analysis (both p < 0.05).

CONCLUSION

Buttock ischemia, heart rate and usual-pace are new variables associated to walking time.

Relationship between walking capacity and ambulatory blood pressure in patients with intermittent claudication

OBJECTIVE

Patients with intermittent claudication (IC) often have high blood pressure (BP), which increases their cardiovascular risk. However, whether walking capacity is associated with BP levels in patients with IC remains unknown. Therefore, this study was designed to investigate whether the total walking distance is associated with ambulatory BP in patients with IC.

PARTICIPANTS AND METHODS

This was a cross-sectional study of 75 patients with IC (58 men; 17 women). A maximal treadmill test (Gardner protocol) was performed to assess total walking distance in these patients. Furthermore, ambulatory BP, heart rate, rate-pressure product, and BP load were obtained over a 24-h period. One-way analysis of variance and multiple linear regression were carried out.

RESULTS

Walking capacity was correlated negatively with the following: (i) asleep systolic BP, diastolic BP, mean BP and heart rate; (ii) 24-h, awake and asleep RPP; and (iii) awake and asleep systolic BP load (all P<0.05). These associations occurred irrespective of confounders such as age, sex, BMI, smoking status, and number of antihypertensive medications.

CONCLUSION

A better walking capacity is associated with lower ambulatory BP parameters in patients with IC.

Cilostazol does not improve peripheral arterial disease-linked oxidative stress

AIM

Cilostazol is a drug widely used to treat peripheral arterial disease (PAD) in patients with advanced atherosclerosis. It is an inhibitor of platelet aggregation and causes arterial vasodilatation. It has been speculated that cilostazol might act to improve oxidative stress in these patients.

METHODS

We analyzed 25 patients with demonstrated lower limb peripheral arterial disease to determine whether lipid peroxidation (LPO) or total antioxidant capacity (TAC) were modified after 6 months of cilostazol treatment (postintervention phase) with respect to the basal phase.

RESULTS

Analysis of plasma samples determined that LPO levels decreased significantly over the postintervention phase (26±15 vs. 11±7 pM, P=0.0003). However, when TAC levels were analyzed, no significant differences were observed (0.80±0.21 vs. 0.85±0.17 mM, P=0.42). Under basal conditions, LPO showed a positive correlation to treatment as judged by the ankle-brachial index (r=0.800, P=0.002) as well as uric acid (r=0.508, P=0.03) and CRP (r=0.481, P=0.05) levels. In contrast, TAC negatively correlated with triglycerides (r=-0.879, P<0.0001) and microalbuminuria (r=-0.868, P<0.0001). In the postintervention phase, TAC negatively correlated with HbA1c (r=-0.570, P=0.02) and triglycerides (r=-0.864, P<0.0001).

CONCLUSIONS

Our data indicate that cilostazol treatment does not improve oxidative stress in PAD patients after 6 months of treatment. However, lipid peroxidation and total antioxidant capacity were affected by cilostrazol treatment, which could be related to altered reactive oxygen species production. Further research may be needed to determine the critical dose of cilostazol to clarify the protective role of this drug in PAD.

Pathogenesis of the limb manifestations and exercise limitations in peripheral artery disease

Patients with peripheral artery disease have a marked reduction in exercise performance and daily ambulatory activity irrespective of their limb symptoms of classic or atypical claudication. This review will evaluate the multiple pathophysiologic mechanisms underlying the exercise impairment in peripheral artery disease based on an evaluation of the current literature and research performed by the authors. Peripheral artery disease results in atherosclerotic obstructions in the major conduit arteries supplying the lower extremities. This arterial disease process impairs the supply of oxygen and metabolic substrates needed to match the metabolic demand generated by active skeletal muscle during walking exercise. However, the hemodynamic impairment associated with the occlusive disease process does not fully account for the reduced exercise impairment, indicating that additional pathophysiologic mechanisms contribute to the limb manifestations. These mechanisms include a cascade of pathophysiological responses during exercise-induced ischemia and reperfusion at rest that are associated with endothelial dysfunction, oxidant stress, inflammation, and muscle metabolic abnormalities that provide opportunities for targeted therapeutic interventions to address the complex pathophysiology of the exercise impairment in peripheral artery disease.

Association between functional performance and executive cognitive functions in an elderly population including patients with low ankle-brachial index

Introduction

Peripheral arterial disease, as measured by the ankle–brachial index (ABI), is prevalent among the elderly, and is associated with functional performance, assessed by the 6-minute walk test (6MWT). Executive cognitive function (ECF) impairments are also prevalent in this population, but no existing study has investigated the association between ECF and functional performance in an elderly population including individuals with low ABI.

Aim

To investigate the association between functional performance, as measured by the 6MWT, and loss in ECF, in an elderly sample including individuals with low ABI.

Method

The ABI group was formed by 26 elderly individuals with low ABI (mean ABI: 0.63±0.19), and the control group was formed by 40 elderly individuals with normal ABI (mean ABI: 1.08±0.07). We analyzed functional performance using the 6MWT, global cognition using the Mini-Mental State Examination (MMSE), and ECF using the Digit Span for assessing attention span and working memory, the Stroop Color Word Test (SCWT) for assessing information processing speed and inhibitory control/impulsivity, and the Controlled Oral Word Association Test (COWAT) for assessing semantic verbal fluency and phonemic verbal fluency. We also used a factor analysis on all of the ECF tests (global ECF).

Results

Before adjustment, the ABI group performed worse on global cognition, attention span, working memory, inhibitory control/impulsivity, semantic verbal fluency, and phonemic verbal fluency. After adjustment, the ABI group performance remained worse for working memory and semantic verbal fluency. In a simple correlation analysis including all of the subjects, the 6MWT was associated with global cognition, attention span, working memory, information processing speed, inhibitory control/impulsivity, semantic verbal fluency, and global ECF. After adjustment, all the associations remained statistically significant.

Conclusion

This study found an independent association between functional performance and ECF in an elderly population including low ABI individuals, showing that, in elderly populations with functional impairment, ECF may also be impaired.

Limitações para caminhar em idosos com claudicação intermitente: a religiosidade como mecanismo de superação da dor

OBJETIVO: Analisar a percepção sobre a dor durante a caminhada em idosos com claudicação intermitente e como eles utilizam a religiosidade para superar o sintoma doloroso. MÉTODOS: A amostra foi composta por dez integrantes de um programa de treinamento físico que apresentavam sintomas de claudicação intermitente. Foi traçado um perfil da população, contendo dados sociodemográficos e religiosos; e realizou-se entrevista com base em roteiro de entrevista semiestruturada. Utilizou-se o procedimento da estatística descritiva para os dados numéricos e as falas dos sujeitos foram submetidas ao software Analysis of Qualitative Data (AQUAD) e posteriormente analisadas por meio da análise de conteúdo temática. RESULTADOS: Os resultados evidenciaram que os sujeitos apresentaram sentimentos negativos frente à dor ao caminhar, tais como aborrecimento, tristeza e medo. Ao mesmo tempo, eles acreditavam que a religião e a crença da existência de um Ser Superior os ajudavam a superar a dor nas pernas. CONCLUSÃO: A fé e a religiosidade parecem funcionar como ferramentas de superação da dor durante a caminhada dos idosos com claudicação intermitente.

Effect of surgical treatment on lipid peroxidation parameters and antioxidant status in the serum of patients with peripheral arterial disease

The various risk factors for peripheral arterial disease (PAD) are almost identical to those for atherosclerosis and include abnormal levels of lipids or lipoproteins. Lipid peroxidation parameters and total antioxidant capacity in the serum of male patients with PAD before surgery as well as 3–5 days and 7–10 days after surgery were measured. We also compared these parameters with those in a group of patients receiving simvastatin therapy. Concentrations of lipid hydroperoxides (LOOHs) and malondialdehyde, the total antioxidant capacity (assessed by ferric reducing antioxidant power assay), concentration of thiol (-SH) groups, and ceruloplasmin activity were determined spectrophotometrically in PAD patients treated surgically (Group I) or pharmacologically (Group II). The patients before surgical treatment had significantly higher concentrations of malondialdehyde but lower ceruloplasmin activity than those observed in Group II, treated with simvastatin. No significant differences before surgery in ferric reducing antioxidant power or thiol concentrations were found between the two groups. However, in Group I, both ferric reducing antioxidant power and thiol group concentrations decreased 3–5 days postoperatively, and ceruloplasmin activity increased 7–10 days after surgical treatment. The presented results demonstrate diverse oxidative stress responses to surgical treatment and confirm the beneficial effects of statin therapy in PAD.