A new device for the measurement of disease severity in patients with intermittent claudication

Body CoM Acceleration for Rapid Analysis of Gait Variability and Pedestrian Effects on Structures

Knowledge of body motion features and walk-induced effects is of primary importance for the vibration analysis of structures, especially low-frequency slabs and lightweight and/or slender systems, as well as for clinical applications. Structurally speaking, consolidated literature procedures are available for a wide set of constructional solutions and typologies. A basic assumption consists in the description of walking humans’ effects on structures through equivalent deterministic loads, in which the ground vertical reaction force due to pedestrians depends on their mass and motion frequency. However, a multitude of additional parameters should be taken into account and properly confirmed by dedicated laboratory studies. In this paper, the focus is on the assessment of a rapid analysis protocol in which attention is given to pedestrian input, based on a minimized sensor setup. The study of gait variability and related effects for structural purposes is based on the elaboration of single Wi-Fi sensor, body centre of mass (CoM) accelerations. A total of 50 walking configurations was experimentally investigated in laboratory or in field conditions (for more than 500 recorded gaits), with the support of an adult volunteer. Parametric gait analysis is presented considering different substructure conditions and motion configurations. Body CoM acceleration records are then used for the analysis of a concrete slab, where the attention is focused on the effects of (i) rough experimental body CoM input, or (ii) experimentally derived synthetized gait input. The effects on the structural side of rough experimental walk time histories or synthetized experimental stride signals are discussed.

Clinical Interest of Ambulatory Assessment of Physical Activity and Walking Capacity in Peripheral Artery Disease

The purpose of the present review was to provide, for the first time, a comprehensive analysis and synthesis of the available studies that highlighted the clinical interest of the ambulatory assessment of either physical activity (PA) or walking capacity in patients with lower extremity peripheral artery disease (PAD). We identified 96 related articles published up to March 2015 through a computer-assisted search of the MEDLINE, EMBASE, and Web of Science databases. Ambulatory-measured PA or related energy expenditure (EE) in PAD patients was performed in 87 of the 96 included studies. The main clinical interests of these measurements were (a) the assessment of PA/EE pattern; (b) the characterization of walking pattern; and (c) the control of training load during home-based walking programs. Ambulatory-measured walking capacity was performed in the remaining studies, using either Global Positioning System receivers or the Peripheral Arterial Disease Holter Control device. Highlighted clinical interests were (a) the assessment of community-based walking capacity; (b) the use of new outcomes to characterize walking capacity, besides the conventional absolute claudication distance; and (c) the association with the patient's self-perception of walking capacity. This review also provides for the clinicians step-by-step recommendations to specifically assess PA or walking capacity in PAD patients.

The walking impairment questionnaire: an effective tool to assess the effect of treatment in patients with intermittent claudication

OBJECTIVE

Assessment of walking distance by treadmill testing is the most commonly used method to evaluate the effect of treatment in patients with peripheral arterial disease. However, treadmill testing is time consuming, relatively expensive, and does not adequately reflect real life functional ability. We hypothesized that the Walking Impairment Questionnaire (WIQ) could be an alternative tool to assess objective improvement in functional walking ability of patients with intermittent claudication.

METHODS

This was a validation study. It was conducted through the outpatient clinic for vascular surgery. Patients with intermittent claudication were referred for supervised exercise therapy. Treadmill testing (absolute claudication distance [ACD]), WIQ, and quality of life questionnaires (RAND-36 and EuroQol) were administered at study onset and after 3 months of supervised exercise therapy. Responsiveness was determined by mean changes in and correlation coefficients of WIQ, ACD, and quality of life questionnaires. Patients were categorized into quartiles based on the increase in ACD, which were subsequently related to change in WIQ and quality of life.

RESULTS

The mean pre- and post-treatment total WIQ scores of 91 patients were 0.45 (0.22) and 0.58 (0.22), respectively. The correlation coefficient between the change in total WIQ score and ACD was 0.331 (P = .004). A 0.1 change in total WIQ score corresponded to a change of 345 meters in ACD. Analysis of the four quartiles compared to an increase in ACD showed that a greater increase in ACD corresponded with a greater increase in WIQ score, from 0.06 to 0.25 (P = .011).

CONCLUSION

These data indicate that the WIQ is a valid tool to detect improvement or deterioration in the daily walking ability of patients with intermittent claudication. Hence, the WIQ can be used as an alternative to treadmill testing for objective assessment of functional walking ability, both in daily practice and in clinical trials.

Measurement of Walking Distance and Speed in Patients With Peripheral Arterial Disease

Background— The maximal walking distance (MWD) performed on a treadmill test remains the “gold standard” in estimating the walking capacity of patients who have peripheral arterial disease with intermittent claudication, although treadmills are not accessible to most physicians. We hypothesized that global positioning system (GPS) recordings could monitor community-based outdoor walking and provide valid information on walking capacity in patients with peripheral arterial disease.

Methods and Results— We studied 24 patients (6 women) with arterial claudication (median [25th to 75th percentile] values: 57 years old [48 to 67 years], 169 cm tall [164 to 172 cm], weight 81 kg [71 to 86 kg], and ankle-brachial index 0.64 [0.56 to 0.74]). MWD on the treadmill was 184 m (144 to 246 m), which was compared with the results of self-reported MWD, the distance score from the Walking Impairment Questionnaire, MWD observed during a 6-minute walking test, and MWD measured over a GPS-recorded unconstrained outdoor walk in a public park. Self-reported MWD, Walking Impairment Questionnaire distance score, 6-minute walking test score, and GPS-measured MWD were 300 m (163 to 500 m), 28% (15% to 47%), 405 m (338 to 441 m), and 609 m (283 to 1287 m), respectively. The best correlation with MWD on the treadmill test was obtained with the MWD measured by the GPS (Spearman r =0.81, P <0.001).

Conclusions— Outdoor walking capacity measured by a low-cost GPS is a potentially innovative way to study the walking capacity of patients with peripheral arterial disease. It opens new perspectives in the study of walking capacity for vascular patients with claudication under free-living conditions or for physicians who do not have a treadmill.

Correlação entre o índice tornozelo-braço antes e após teste de deslocamento bidirecional progressivo

CONTEXTO: A alteração de fluxo sangüíneo observada nos pacientes com doença arterial obstrutiva periférica (DAOP) contribui para a redução da capacidade deambulatórida. Entretanto, ainda existe uma grande variabilidade nas correlações entre medidas inferenciais de comprometimento de fluxo e testes de deslocamento. OBJETIVO: Estabelecer o nível de correlação entre as medidas do índice tornozelo-braço (ITB), pré e pós-esforço, com um novo teste de deambulação chamado teste de deslocamento bidirecional progressivo (TDBP). MÉTODOS: Vinte e um pacientes claudicantes, com diagnóstico de DAOP, tiveram registrados o ITB antes e após a realização de um teste de caminhada no solo, com controle externo e progressivo de velocidade (TDBP). RESULTADOS: Foram registrados a distância (261,07±160,63 metros), o tempo (292,30±122,61 segundos) e a velocidade (1,23±0,34 m/s) obtidos no início do surgimento de sintoma claudicante, bem como durante o surgimento de sintoma limitante (369,52±157,97 metros, 377,71±104,60 segundos, 1,46±0,29 m/s, respectivamente). A média do ITB de repouso foi de 0,66±0,14, e de pós-esforço foi de 0,42±0,19. Não se observou nenhuma correlação importante entre as variáveis do teste (distância, tempo e velocidade) com o ITB de repouso e nem após esforço. CONCLUSÃO: O tempo, velocidade e distância de surgimento de sintoma claudicante e de sintoma claudicante limitante durante o teste de caminhada progressiva são independentes da medida inferencial de fluxo sangüíneo através do ITB de repouso e pós-exercício.

Plantar Flexion as an Alternative to Treadmill Exercise for Evaluating Patients with Intermittent Claudication

OBJECTIVE

The aim of this study was to examine whether the plantar flexion test could adequately replace treadmill testing in patients who were unable to exercise.

DESIGN

Prospective observational study.

PATIENTS

Twenty-seven patients with intermittent claudication secondary to peripheral arterial disease (PAD).

METHODS

Patients performed two treadmill tests and two plantar flexion tests. Ankle pressure, near infrared spectroscopy (NIRS) data, heart rate and blood pressures were monitored along with pain-free and maximum walking distances for treadmill, pain-free and maximum exercise time for plantar flexion.

RESULTS

Maximum exercise time and walking distance were well correlated (R=0.74). Eleven patients (41%) developed non-claudicating symptoms during the treadmill test but not during the flexion test. Rate pressure product was significantly higher after the treadmill but not after the plantar flexion.

CONCLUSIONS

Plantar flexion test showed good reliability and correlation. Plantar flexion may serve as an alternative to treadmill testing in evaluating muscle pain in patients with intermittent claudication.

The PADHOC Device is a Better Guide to the Actual Incapacity Suffered by Claudicants than the Gold Standard Constant Load Treadmill Test

BACKGROUND

The Constant Load Treadmill Test (CLTT) is currently the primary method used to measure walking impairment in patients with peripheral vascular disease. The aim of this study was to compare the CLTT and PADHOC device as assessments of walking impairment.

METHODS

55 patients with intermittent claudication underwent a CLTT and a Double Physiological Walking Test (DPWT) using the PADHOC device. Health-related quality of life was measured using the Short Form 36 and the Claudication Scale.

RESULTS

The initial claudication and maximum walking distance from the first part of the DPWT showed the best correlation with domains of pain and physical function.

CONCLUSIONS

The DPWT is more representative of the functional incapacity experienced by patients with intermittent claudication. We believe that the PADHOC is a suitable alternative to the CLTT in the assessment of this patient group.

Treadmill versus shuttle walk tests of walking ability in intermittent claudication

PURPOSE

To compare treadmill and shuttle walk tests for assessing functional capacity in patients with intermittent claudication, with respect to test-retest reliability, cardiovascular responses, and patient preferences.

METHODS

Patients with stable intermittent claudication (N = 55, ages 52-85 yr, median age 68 yr) were recruited from the Sheffield Vascular Institute at the Northern General Hospital, Sheffield, UK. Each patient performed an incremental shuttle walk test, a constant-pace shuttle walk test, and a standardized treadmill test (3.2 km x h(-1), 12% gradient), each on three occasions. The incremental shuttle walk began at 3 km x h(-1) and increased by 0.5 km x h(-1) every minute, whereas the constant-pace shuttle walk was performed at the fixed pace of 4 km x h(-1). Claudication distance (CD), maximum walking distance (MWD), heart rate (HR), and blood pressure were assessed in each testing session. The patients also completed a test preference questionnaire.

RESULTS

CD and MWD for both shuttle walks were greater than the corresponding walking distances achieved in the treadmill test (P < 0.001). Average coefficients of variation for repeated incremental shuttle walk, constant-pace shuttle walk, and treadmill tests were 15.9%, 21.1%, and 18.7%, respectively, for MWD, corresponding to average intraclass correlation coefficients of 0.87, 0.82, and 0.87. Treadmill walking evoked greater increases in HR and blood pressure (P < 0.001), and fewer patients expressed a preference for it (24 vs 43% for shuttle walking).

CONCLUSION

These findings indicated that shuttle walk testing exhibits similar test-retest reliability as treadmill testing, but that it evoked a lower level of cardiovascular stress and is preferred to treadmill testing by a large proportion of patients.