Improved gait parameters following surgical revascularization in patients with intermittent claudication

Objective

Intermittent claudication (IC) is known to be associated with impaired gait parameters, with a higher incidence of falls and higher oxygen consumption due to uneconomic walking. However, the influence of arterial disobliteration in patients with IC on their gait pattern has rarely been investigated to date. The aim of this study was to examine the gait patterns before and after inflow revascularization by surgical disobliteration of pelvic and inguinal arteries (ie, common iliac artery, external iliac artery, common femoral artery, profound femoral artery, superficial femoral artery) in IC patients. Successful surgical disobliteration of inflow arteries (improvement of ankle brachial pressure index of ≥0.2 and patent common iliac, external iliac, common femoral, profound femoral, and superficial femoral arteries) is known to improve the painless walking distance for patients with IC due to peripheral arterial disease; however, its influence on gait parameters is unclear. We hypothesized that the gait parameters would also improve after surgery. Improved gait parameters can lead to a more economic walking process, lower oxygen consumption, a lower risk of falls, and a higher quality of life.

Methods

In a single-center, exploratory, longitudinal study, we examined the gait parameters of 20 IC inpatients of our hospital before and after surgical disobliteration of pelvic and inguinal arteries. Spatiotemporal parameters such as range of motion of the hip and knee joint, stance phase, cadence, and foot rotation were obtained using the Diers 4Dmotion Lab (Diers International). The gait parameters were obtained under painful walking conditions preoperatively and with the patients walking pain free at the same speed postoperatively.

Results

A total of 20 patients were examined. Surgical revascularization led to a higher walking cadence (mean, plus 7.88 steps; 95.5 steps/min vs 87.6 steps/min; P = .024), an increased range of motion of the hip joint (mean, plus 2.0°; 35.1° vs 33.1°; P = .038), and improved foot rotation (mean, plus 2.0°; 11.0° vs 9.0°; P = .02). Regarding other parameters such as step length, stance phase, and step duration, smaller differences were detected in this study.

Conclusions

In this exploratory study, we found that surgical revascularization of pelvic and inguinal arteries in IC patients improved certain gait parameters. Further studies with larger patient numbers are needed to confirm these data and provide more evidence on this subject.

Exercise therapy for chronic symptomatic peripheral artery disease

All guidelines worldwide strongly recommend exercise as a pillar of the management of patients affected by lower extremity peripheral artery disease (PAD). Exercise therapy in this setting presents different modalities, and a structured programme provides optimal results. This clinical consensus paper is intended for clinicians to promote and assist for the set-up of comprehensive exercise programmes to best advice in patients with symptomatic chronic PAD. Different exercise training protocols specific for patients with PAD are presented. Data on patient assessment and outcome measures are narratively described based on the current best evidence. The document ends by highlighting disparities in access to supervised exercise programmes across Europe and the series of gaps for evidence requiring further research.

Exercise therapy for chronic symptomatic peripheral artery disease

All guidelines worldwide strongly recommend exercise as a pillar in the management of patients affected by lower extremity peripheral artery disease (PAD). Exercise therapy in this setting presents different modalities, and a structured programme provides optimal results. This clinical consensus paper is intended to promote and assist the set up of comprehensive exercise programmes and best advice for patients with symptomatic chronic PAD. Different exercise training protocols specific for patients with PAD are presented. Data on patient assessment and outcome measures are described based on the current best evidence. The document ends by highlighting supervised exercise programme access disparities across Europe and the evidence gaps requiring further research.

Exercise Therapy for Chronic Symptomatic Peripheral Artery Disease: A Clinical Consensus Document of the European Society of Cardiology Working Group on Aorta and Peripheral Vascular Diseases in Collaboration With the European Society of Vascular Medicine and the European Society for Vascular Surgery

All guidelines worldwide strongly recommend exercise as a pillar in the management of patients affected by lower extremity peripheral artery disease (PAD). Exercise therapy in this setting presents different modalities, and a structured programme provides optimal results. This clinical consensus paper is intended to promote and assist the set up of comprehensive exercise programmes and best advice for patients with symptomatic chronic PAD. Different exercise training protocols specific for patients with PAD are presented. Data on patient assessment and outcome measures are described based on the current best evidence. The document ends by highlighting supervised exercise programme access disparities across Europe and the evidence gaps requiring further research.

Mechanical adaptations in walking using carbon fiber ankle foot orthoses for patients with peripheral artery disease

BACKGROUND

The effectiveness of community-based walking programs for patients with peripheral artery disease (PAD) can be limited by calf claudication during exercise. Recent evidence finds adding carbon fiber ankle foot orthoses (AFO) to a walking program can result in improvements in patient mobility and delay claudication onset when walking.

RESEARCH QUESTION

How may carbon fiber AFO alter ankle walking mechanics and corresponding triceps surae muscle recruitment in a manner that could improve patient mobility?

METHODS

In this repeated measures cohort study, fifteen patients with PAD were fit with bilateral AFO before completing self-paced gait analysis including electromyography. Patients were then given standard advice to walk at home using the devices for 12 weeks. Twelve patients completed follow-up testing.

RESULTS

There were no significant interactions between main effects for any variable of interest (p ≥ 0.189). Further, there were no within-subjects main effects for testing time for self-selected gait speed or any of the kinetic or kinematic variables (p ≥ 0.435). There were significant main effects for AFO use with reductions in dorsi flexion (p < 0.001), plantar flexion at toe off (p < 0.001), ankle plantar flexor moment (p = 0.037), and ankle plantar flexor power (p < 0.001). Triceps surae recruitment did not change between AFO conditions (p > 0.05).

SIGNIFICANCE

Adding carbon fiber AFO limits peak ankle motion and joint power during self-paced walking for people with PAD while maintaining their walking speed. These gait adaptions were maintained over our 12 weeks of walking practice time. A resulting decrease in plantar flexor power while maintaining gait speed may provide the mechanism by which AFO can delay claudication onset which are major barrier to PAD walking programs. Calf muscle recruitment was maintained when adding the AFO which suggests sufficient muscle exertion could exist to maintain muscle integrity with sustained AFO use.

A biomechanical perspective on walking in patients with peripheral artery disease

The most common symptom of peripheral artery disease (PAD) is intermittent claudication, which consists of debilitating leg pain during walking. In clinical settings, the presence of PAD is often noninvasively evaluated using the ankle-brachial index and imaging of the arterial supply. Furthermore, various questionnaires and functional tests are commonly used to measure the severity and negative effect of PAD on quality of life. However, these evaluations only provide information on vascular insufficiency and severity of the disease, but not regarding the complex mechanisms underlying walking impairments in patients with PAD. Biomechanical analyses using motion capture and ground reaction force measurements can provide insight into the underlying mechanisms to walking impairments in PAD. This review analyzes the application of biomechanics tools to identify gait impairments and their clinical implications on rehabilitation of patients with PAD. A total of 18 published journal articles focused on gait biomechanics in patients with PAD were studied. This narriative review shows that the gait of patients with PAD is impaired from the first steps that a patient takes and deteriorates further after the onset of claudication leg pain. These results point toward impaired muscle function across the ankle, knee, and hip joints during walking. Gait analysis helps understand the mechanisms operating in PAD and could also facilitate earlier diagnosis, better treatment, and slower progression of PAD.

The Influence of Treadmill Training on the Bioelectrical Activity of the Lower Limb Muscles in Patients with Intermittent Claudication

Aim: Intermittent claudication is the most common symptomatic manifestation of peripheral arterial disease (PAD), presenting as ischemic leg muscle pain and gait dysfunction. The aim of this study was to evaluate the changes in bioelectrical activity of the lower limb muscles activity in claudicating patients over a 12-week period of supervised treadmill training and to verify the hypothesis as to which muscles of lower limbs are activated by training treatment—the proximal, as compensatory mechanism, or the distal, which are the most ischemic. Methods: The study comprised 45 patients aged 60–70 years (height 168.8 ± 6.8 cm, weight 78.9 ± 9.2 kg) with PAD and unilateral intermittent claudication (Fontaine stage IIa/IIb), who participated in a 12-week supervised treadmill training program. Surface electromyography (sEMG) of the gastrocnemius lateralis (GaL), gastrocnemius medialis (GaM), tibialis anterior (TA), biceps femoris (BF), rectus femoris (RF) and gluteus medius (GM) muscles in the claudicated leg were continuously measured during the treadmill test. The average mean amplitude and mean amplitude range of the sEMG signal were analyzed. Results: During the treadmill test, after 12 weeks of training, the average mean amplitude of the GM (105 ± 43 vs. 74 ± 38%, p = 0.000008, ES = 0.76), BF (41 ± 22 vs. 33 ± 12%, p = 0.006, ES = 0.45) and GaM (134 ± 50 vs. 114 ± 30%, p = 0.007, ES = 0.48) muscles was significantly lower compared with baseline. The mean amplitude range was significantly decreased after 12 weeks of training in the GM (229 ± 64 vs. 181 ± 62%, p = 0.008, ES = 0.77) and BF (110 ± 69 vs. 84 ± 31%, p = 0.0002, ES = 0.48) muscles. After 12 weeks of training, the mean amplitude range of the TA muscle was significantly higher compared with baseline (104 ± 46 vs. 131 ± 53%, p = 0.001, ES = 0.54), but without significant changes in the average mean amplitude value. The most favorable changes, suggesting the lowest muscle fatigue and the highest walking capacity, were found in patients with the longest walking time. Conclusions: The obtained results may suggest that after 12 weeks of treadmill training, beneficial changes occurred in both the proximal and distal muscles. Therefore, greater foot plantar flexion and stronger push-off as well as greater hip extension may be considered the main mechanisms of observed gait pattern improvement. It may also be suggested that the therapy of gait alterations in patients with PAD should be focused not only on calf muscle pump improvement, but also on proximal hip extensor strengthening.

Supervised Exercise Training Improves 6 min Walking Distance and Modifies Gait Pattern during Pain-Free Walking Condition in Patients with Symptomatic Lower Extremity Peripheral Artery Disease

This study aimed to investigate the effects of supervised exercise training (SET) on spatiotemporal gait and foot kinematics parameters in patients with symptomatic lower extremity peripheral artery disease (PAD) during a 6 min walk test. Symptomatic patients with chronic PAD (Fontaine stage II) following a 3 month SET program were included. Prior to and following SET, a 6 min walk test was performed to assess the 6 min walking distance (6MWD) of each patient. During this test, spatiotemporal gait and foot kinematics parameters were assessed during pain-free and painful walking conditions. Twenty-nine patients with PAD (65.4 ± 9.9 years.) were included. The 6MWD was significantly increased following SET (+10%; p ≤ 0.001). The walking speed (+8%) and stride frequency (+5%) were significantly increased after SET (p ≤ 0.026). The stride length was only significantly increased during the pain-free walking condition (+4%, p = 0.001), whereas no significant differences were observed during the condition of painful walking. Similarly, following SET, the relative duration of the loading response increased (+12%), the relative duration of the foot-flat phase decreased (−3%), and the toe-off pitch angle significantly increased (+3%) during the pain-free walking condition alone (p ≤ 0.05). A significant positive correlation was found between changes in the stride length (r = 0.497, p = 0.007) and stride frequency (r = 0.786, p ≤ 0.001) during pain-free walking condition and changes in the 6MWD. A significant negative correlation was found between changes in the foot-flat phase during pain-free walking condition and changes in the 6MWD (r = −0.567, p = 0.002). SET was found to modify the gait pattern of patients with symptomatic PAD, and many of these changes were found to occur during pain-free walking. The improvement in individuals’ functional 6 min walk test was related to changes in their gait pattern.

Ankle-Brachial Index Is a Good Determinant of Lower Limb Muscular Strength but Not of the Gait Pattern in PAD Patients

The aim of this study was to evaluate the relationship of the ankle-brachial index (ABI) level with kinetic and kinematic parameters of the gait pattern and force-velocity parameters generated by lower limb muscles. Methods: The study group consisted of 65 patients with peripheral arterial disease (PAD). The ABI value, kinetic and kinematic parameters of gait and force-velocity parameters of knee and ankle extensors and flexors were determined in all subjects. The values obtained for right and left limbs as well as the limbs with higher and lower ABI were compared. Results: Regardless of the method of analysis, the values of the gait’s kinematic and kinetic parameters of both lower limbs did not differ significantly. However, significant differences were noted in the values of peak torque, work and power of the extensor muscles of the knee and the flexor muscles of the ankle with the higher and lower ABI. Conclusion: This study demonstrated that a higher degree of ischemia worsened the level of strength, endurance, and performance of ankle flexors and extensors of the knee joint. ABI is not related to the gait pattern. The above-mentioned relationship should be taken into account in the rehabilitation process and methodological assessment.

Location of ischemia and ischemic pain intensity affect spatiotemporal parameters and leg muscles activity during walking in patients with intermittent claudication

The ways in which locations of ischemia and ischemic pain affect spatiotemporal gait parameters and leg electromyographic activity during walking have never been investigated in patients with peripheral arterial disease presenting intermittent claudication. Two groups were classified according to unilateral location of ischemia (distal, n = 10, or proximo-distal, n = 12). Patients described pain and three gait phases-initial pain-free, onset of pain and maximum pain-were analyzed. Patients with proximo-distal ischemia walked less (230 ± 111 m vs 384 ± 220 m), with increased step length, step time (+ 5.4% and + 5.8%) and reduced cadence (- 8.2%), than patients with distal ischemia. In both, the peaks of vertical ground reaction force were reduced in maximum pain (Peak1-distal: - 11.4%, Peak1-proximo-distal: - 10.3%; Peak2-distal: - 11.8%, Peak2-proximo-distal: - 9.0%). In the proximo-distal group, tibialis anterior activation peak and time were lower than in the distal group (- 4.5% and - 19.7%). During the maximum pain phase, this peak decreased only in the proximo-distal group (- 13.0%), and gastrocnemius medialis activation peak and time decreased in both groups (- 2.5% in distal and - 4.5% in proximo-distal). Thus, proximo-distal ischemia leads to more adverse consequences in gait than distal ischemia only. Increasing ischemic pain until maximum, but not onset of pain, induced gait adaptations.

An exploratory investigation on spatiotemporal parameters, margins of stability, and their interaction in bilateral vestibulopathy

Integration of accurate vestibular, visual, and proprioceptive information is crucial in managing the centre of mass in relation to the base of support during gait. Therefore, bilateral loss of peripheral vestibular function can be highly debilitating when performing activities of daily life. To further investigate the influence of an impaired peripheral vestibular system on gait stability, spatiotemporal parameters, step-to-step variability, and mechanical stability parameters were examined in 20 patients with bilateral vestibulopathy and 20 matched healthy controls during preferred overground walking. Additionally, using a partial least squares analysis the relationship between spatiotemporal parameters of gait and the margins of stability was explored in both groups. Patients with bilateral vestibulopathy showed an increased cadence compared to healthy controls (121 ± 9 vs 115 ± 8 steps/min; p = 0.02; d = 0.77). In addition, although not significant (p = 0.07), a moderate effect size (d = 0.60) was found for step width variability (Coefficient of Variation (%); Bilateral vestibulopathy: 19 ± 11%; Healthy controls: 13 ± 5%). Results of the partial least squares analysis suggest that patients with peripheral vestibular failure implement a different balance control strategy. Instead of altering the step parameters, as is the case in healthy controls, they use the single and double support phases to control the state of the centre of mass to improve the mechanical stability.

Gait alterations in patient with intermittent claudication: Effect of unilateral vs bilateral ischemia

BACKGROUND

We seek to evaluate whether ischemia extent (unilateral or bilateral) impacts spatiotemporal and neuromuscular gait parameters differently in patients with peripheral arterial disease and presenting intermittent claudication (PAD-IC).

METHODS

Two groups of PAD-IC patients: unilateral (Unilat-IC; n = 15), bilateral (Bilat-IC; n = 15) and a group of control subjects with similar risk factors (n = 15) were evaluated during a constant load treadmill walking test. Spatiotemporal parameters and neuromuscular activation in tibialis anterior and gastrocnemius medialis were recorded. Patients were instructed to describe their pain during walking test, and three phases were analysed: pain-free, onset of pain and maximum pain in PAD-IC patients.

FINDINGS

Single leg stance in the asymptomatic leg of Unilat-IC increases and becomes higher than the symptomatic leg and the Bilat-IC legs at maximum pain. Step time is higher and cadence is lower in PAC-IC than in controls. Tibialis anterior activation peak in Unilat-IC continuously decreases between phases and becomes lower than in Bilat-IC during maximum pain. Tibialis anterior activation time is higher in Bilat-IC and in the asymptomatic leg than in the symptomatic of Unilat-IC during all the phases. Gastrocnemius medialis activation peak in Bilat-IC decreases with pain. Gastrocnemius medialis activation time in the symptomatic leg of Unilat-IC presents a significant decrease between pain-free and maximum pain phases.

INTERPRETATION

Ischemia impacts gait in PAD-IC patients differently according to its extent between legs compared to controls. Imbalance between legs in Unilat-IC induces compensatory mechanism and an asymmetrical pattern. Bilat-IC should not be simply considered as a 'double' Unilat-IC when evaluating gait.

Gait changes after supervised exercise training in patients with symptomatic lower extremity peripheral artery disease

This study aimed to investigate the effects of supervised exercise training (SET) on walking performance and spatiotemporal gait changes in patients with symptomatic lower extremity peripheral artery disease (PAD). In this single-arm prospective nonrandomized cohort study, patients with Fontaine stage II PAD following a 3-month SET program were included. Before and after SET, a constant-load treadmill test was performed to determine the pain-free and maximal walking distances (PFWD and MWD, respectively). During this test, spatiotemporal gait parameters were assessed. The ankle-brachial index (ABI) and toe-brachial index (TBI) were also measured. Twenty-seven patients with PAD (64.0 ± 1.9 y, 74% men) were included. Following SET, the PFWD (+68%; p = 0.001) and MWD (+79%; p ⩽ 0.001) significantly increased. The ABI and TBI did not change significantly. Following SET, the stride duration, stride frequency, stride length, and double support phase duration did not change significantly. In contrast, subphases of stance showed significant changes: the loading response (+8%; p = 0.03) and foot-flat (+2%; p = 0.01) phases were significantly longer, whereas the push-off phase (-7%; p = 0.002) was significantly shorter. A significant positive correlation was found between changes in the foot-flat phase and changes in PFWD (r = 0.43, p = 0.03). A significant negative correlation was found between changes in the push-off phase and changes in PFWD (r = -0.39, p = 0.05). No significant correlations were found between changes in relative durations of the subphases of stance and MWD. These results indicate that changes in temporal gait parameters during the foot contact phase potentially constitute an underlying mechanism of delayed claudication distance in patients with symptomatic PAD.

Effects of Physical Rehabilitation on Spatiotemporal Gait Parameters and Ground Reaction Forces of Patients with Intermittent Claudication

Chronic ischemia of the lower extremities often presents as intermittent claudication characterized by lower limb pain which subsides after a short break. This study aimed to provide an assessment of the spatiotemporal parameters of gait and ground reaction forces in patients with PAD participating in three forms of supervised physical training. A total of 80 subjects completed a three-month supervised physical rehabilitation program with three sessions per week. The subjects were assigned to one of three programs: group 1—standard walking training on a treadmill (TT); group 2—Nordic walking (NW) training; group 3—strength and endurance training comprised of NW with isokinetic resistance training (NW + ISO). Gait biomechanics tests (kinematic and kinetic parameters of gait) and a six-minute walk test were carried out before and after three months of physical training. Nordic walking training led to the greatest improvements in the gait pattern of patients with PAD and a significant increase in the absolute claudication distance and total gait distance. Combined training (NW + ISO) by strengthening the muscles of the lower extremities increased the amplitude of the general center of gravity oscillation to the greatest extent. Treadmill training had little effect on the gait pattern. Nordic walking training should be included in the rehabilitation of patients with PAD as a form of gait training, which can be conducted under supervised or unsupervised conditions.

An investigation of the spatio-temporal parameters of gait and margins of stability throughout adulthood

Age-related changes in the way of walking may induce changes in dynamic stability. Therefore, the relationship between age, spatio-temporal characteristics and margins of stability was examined. One hundred and five healthy adults aged between 20 and 89 years old were analysed on spatio-temporal characteristics and margins of stability using three-dimensional motion analysis. Subjects walked barefoot over a 12-m-long walkway at their preferred walking speed. Covariance among gait characteristics was reduced using a factor analysis, identifying domains of gait. The influence of age, gender, body mass index (BMI) and leg length on domains of gait and margins of stability was investigated using linear mixed models. A stepwise linear regression identified domains of gait predicting the variance in margins of stability. Four domains of gait explaining 74.17% of the variance were identified. Age had a significant influence on the medio-lateral margin of stability and the 'variability', 'pace' and 'base of support' domain. BMI significantly influenced the medio-lateral margin of stability; gender and leg length had no influence on either of the margins of stability. The 'base of support' domain predicted 26% of the variance in the medio-lateral margin of stability. When considering the margins of stability, especially when comparing multiple groups, age, BMI and spatio-temporal parameters should be taken into account.

Relationship between lower limb vascular characteristics, peripheral arterial disease and gait in rheumatoid arthritis

OBJECTIVES

Rheumatoid arthritis (RA) is associated with higher risk of atherosclerotic vascular disease, including peripheral arterial disease (PAD). The aim of this study was to measure lower limb vascular characteristics (indicative of PAD), using non-invasive chairside testing methods, in people with RA compared to matched controls, and to determine the association between vascular characteristics and gait velocity as a measure of functional capacity in people with RA.

METHODS

This was a cross-sectional pilot study which measured lower limb vascular characteristics (bilateral continuous wave Doppler, toe brachial index [TBI] and ankle brachial index [ABI]) and gait velocity (6-m walk test) in people with RA and controls. Differences in vascular characteristics between groups were determined using linear regression models, and associations between vascular characteristics and gait were determined using logistic regression models.

RESULTS

Seventy-two participants were included: 34 participants with RA mean disease duration 26.2 (SD 12.1) and 38 age- and sex-matched controls. The control group contained 30 females (79%), and the RA group had 28 females (82%). There were no significant differences between the RA and control groups for lower limb vascular characteristics. People with RA walked significantly slower compared to controls (1.10 m/s vs 0.91 m/s, P < .001). People with RA who had abnormal TBI, or abnormal qualitative Doppler walked significantly slower compared to those with normal TBI (0.86 m/s vs 0.95 m/s, P = .043 and 0.81 m/s, vs 0.93 m/s, P = .028). There was no significant association between ABI and gait velocity.

CONCLUSION

This study did not identify different lower limb vascular characteristics in people with RA compared to matched controls. However, in people with RA, abnormal Doppler and TBI results are associated with slower walking velocity.

Mitochondrial transplantation ameliorates acute limb ischemia

OBJECTIVE

Acute limb ischemia (ALI), the most challenging form of ischemia-reperfusion injury (IRI) in skeletal muscle tissue, leads to decreased skeletal muscle viability and limb function. Mitochondrial injury has been shown to play a key role in skeletal muscle IRI. In previous studies, we have demonstrated that mitochondrial transplantation (MT) is an efficacious therapeutic strategy to replace or to augment mitochondria damaged by IRI, allowing enhanced muscle viability and function in cardiac tissue. In this study, we investigated the efficacy of MT in a murine ALI model.

METHODS

C57BL/6J mice (male, 10-12 weeks) were used in a model of ALI. Ischemia was induced by applying a tourniquet on the left hindlimb. After 2 hours of ischemia, the tourniquet was released, and reperfusion of the hindlimb was re-established; either vehicle alone (n = 15) or vehicle containing mitochondria (n = 33) was injected directly into all the muscles of the hindlimb. Mitochondria were delivered at concentrations of 1 × 10⁶ to 1 × 10⁹ per gram wet weight to each muscle, and the animals were allowed to recover. Sham mice received no ischemia or injections but were anesthetized for 2 hours and allowed to recover. After 24 hours of recovery, limb function was assessed by DigiGait (Mouse Specifics Inc, Boston, Mass), and animals were euthanized; the gastrocnemius, soleus, and vastus medialis muscles were collected for analysis.

RESULTS

After 24 hours of hindlimb reperfusion, infarct size (percentage of total mass) and apoptosis were significantly decreased (P < .001, each) in the gastrocnemius, soleus, and vastus medialis muscles in MT mice compared with vehicle mice for all mitochondrial concentrations (1 × 10⁶ to 1 × 10⁹ per gram wet weight). DigiGait analysis at 24 hours of reperfusion showed that percentage shared stance time was significantly increased (P < .001) and stance factor was significantly decreased (P = .001) in vehicle compared with MT and sham mice. No significant differences in percentage shared stance time (P = .160) or stance factor (P = .545) were observed between MT and sham mice.

CONCLUSIONS

MT ameliorates skeletal muscle injury and enhances hindlimb function in the murine model of ALI.

Do spatiotemporal parameters and gait variability differ across the lifespan of healthy adults? A systematic review

BACKGROUND

Aging is often associated with changes in the musculoskeletal system, peripheral and central nervous system. These age-related changes often result in mobility problems influencing gait performance. Compensatory strategies are used as a way to adapt to these physiological changes.

RESEARCH QUESTION

The aim of this review is to investigate the differences in spatiotemporal and gait variability measures throughout the healthy adult life.

METHODS

This systematic review was conducted according to the PRISMA guidelines and registered in the PROSPERO database (no. CRD42017057720). Databases MEDLINE (Pubmed), Web of Science (Web of Knowledge), Cochrane Library and ScienceDirect were systematically searched until March 2018.

RESULTS

Eighteen of the 3195 original studies met the eligibility criteria and were included in this review. The majority of studies reported spatiotemporal and gait variability measures in adults above the age of 65, followed by the young adult population, information of middle-aged adults is lacking. Spatiotemporal parameters and gait variability measures were extracted from 2112 healthy adults between 18 and 98 years old and, in general, tend to deteriorate with increasing age. Variability measures were only reported in an elderly population and show great variety between studies.

SIGNIFICANCE

The findings of this review suggest that most spatiotemporal parameters significantly differ across different age groups. Elderly populations show a reduction of preferred walking speed, cadence, step and stride length, all related to a more cautious gait, while gait variability measures remain stable over time. A preliminary framework of normative reference data is provided, enabling insights into the influence of aging on spatiotemporal parameters, however spatiotemporal parameters of middle-aged adults should be investigated more thoroughly.

Gait pattern in patients with peripheral artery disease

Background

The aim of the present paper is to assess the gait pattern of patients with Peripheral Artery Disease (PAD). A more specific aim is to compare the gait pattern of PAD patients before and after the appearance of intermittent claudication symptoms.

Methods

The study involved 34 PAD patients with a claudication distance ≥200 m and 20 participants without PAD, who formed the control group. The gait pattern of PAD patients was assessed twice: before the appearance of intermittent claudication symptoms (pain-free conditions) and after the appearance of intermittent claudication symptoms (pain conditions).

Results

Compared to the control group, PAD patients presented a statistically significant decrease in step length both during pain-free conditions (52.6 ± 12.5 vs. 72.8 ± 18.5 cm, p = 0.008) and in pain conditions (53.3 ± 13.3 vs. 72.8 ± 18.5 cm, p = 0.006). As for the remaining spatiotemporal parameters, there were no differences observed between the patient group and the controls. Intermittent claudication symptom induced by the walking test on the treadmill did not bring about any new abnormalities in the gait pattern or intensify the existing abnormalities of the gait.

Conclusions

PAD patients have a tendency to shorten their step length regardless of the presence of intermittent claudication.

Intermittent gait disturbance in idiopathic normal pressure hydrocephalus

OBJECTIVES

We identified intermittent gait disturbance (IGD) observed in the mild stage of idiopathic normal pressure hydrocephalus (iNPH). The first purpose of this study was to clarify the temporal gait profile of IGD during long-distance gait. The second purpose was to confirm the difference in treatment effect after cerebrospinal fluid (CSF) shunting in patients with and without IGD.

MATERIALS AND METHODS

Fourteen consecutive iNPH patients with mild gait disturbance with a timed up-and-go (TUG) of <20 seconds were prospectively enrolled in the study. All patients were asked "Do you experience gait difficulty after over five minutes of walking?" Seven "yes" patients formed the IGD group, and seven "no" patients formed the persistent gait disturbance (PGD) group. One day before and 7 days after CSF shunting, gait function was evaluated by the 6-minute walk test (6MWT) and TUG.

RESULTS

Preoperatively, all patients in the IGD group demonstrated features of IGD during the 6MWT, characterized by a progressive pattern of decreased gait speed and step length with increased cadence and absence of leg pain. Post-operatively, these features of IGD improved in all patients. In the PGD group, preoperative walking did not significantly worsen during the 6MWT and did not significantly change 7 days after treatment. Improvement of gait symptoms 1 week after CSF shunting could be detected with 6MWT instead of TUG.

CONCLUSIONS

Intermittent gait disturbance is not a rare symptom in mild stage of iNPH and may serve as an important clinical diagnostic marker for identifying mild iNPH patients.

Gait kinematics and kinetics are affected more by peripheral arterial disease than by age

Peripheral arterial disease (PAD) produces abnormal gait and disproportionately affects older individuals. The current study investigated PAD gait biomechanics in younger (<65 yr) and older (>/=65 yr) subjects. The study included 61 patients with PAD (31 younger, age: 57.4 +/- 5.3 yr, and 30 older, age: 71.9 +/- 5.2 yr) and 52 nondisabled age-matched control subjects. Patients with PAD were tested during pain-free walking and compared with control subjects. Joint kinematics and kinetics (torques) were compared using a 2 x 2 analysis of variance (groups: patients with PAD vs control subjects, age: younger vs older). Patients with PAD had significantly increased ankle and decreased hip range of motion during the stance phase as well as decreased ankle dorsiflexor torque compared with control subjects. Gait changes in older individuals are largely constrained to time-distance parameters. Joint kinematics and kinetics are significantly altered in patients with PAD during pain-free walking. Symptomatic PAD produces a consistent ambulatory deficit across ages definable by advanced biomechanical analysis. The most important finding of the current study is that gait, in the absence of PAD and other ambulatory comorbidities, does not decline significantly with age based on advanced biomechanical analysis. Therefore, previous studies must be examined in the context of patients with potential PAD being present in the population, and future ambulatory studies must include PAD as a confounding factor when assessing the gait function of elderly individuals.

Sarcopenia in Peripheral Arterial Disease: Prevalence and Effect on Functional Status

OBJECTIVES

(1) To determine the prevalence of sarcopenia in older men with peripheral arterial disease (PAD); (2) to compare a subgroup of the group with age-, race-, sex-, and body mass index (BMI)-matched non-PAD control counterparts, and (3) to compare the functional status of those with PAD with and without sarcopenia.

DESIGN

Cohort study.

SETTING

Medical center.

PARTICIPANTS

Sedentary community-dwelling men (N=108; age, >50y) with a confirmed diagnosis of PAD (44% blacks; BMI, 27.8±0.4kg/m²; ankle-brachial index, .62±.01).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Dual-energy x-ray absorptiometry scans were used to assess appendicular lean mass and determine the prevalence of sarcopenia by/height². Treadmill tests were used to determine claudication onset time, peak walking time, and claudication recovery time. 6-Minute walk distance was also measured.

RESULTS

Sarcopenia prevalence in our PAD cohort was 25%. The PAD subgroup (n=42) matched with control counterparts in terms of race, sex, age, and BMI had higher prevalence rates than did their non-PAD counterparts (23.8% vs 2.4%; P<.05). Individuals with sarcopenia (n=28) had a shorter 6-minute walk distance (326±18.8m vs 380±9.7m; P<.05) and higher claudication recovery time (592±98s vs 395±29s; P<.05) than did individuals with PAD but without sarcopenia (n=80). There was no difference in claudication onset time or peak walking time between the PAD groups.

CONCLUSIONS

Men with PAD demonstrate a high prevalence of sarcopenia. Those with sarcopenia and PAD demonstrate decreased mobility function.

Hip flexor muscle dysfunction during walking at self-selected and fast speed in patients with aortoiliac peripheral arterial disease

OBJECTIVE

Intermittent claudication aggravates physical function and is associated with an increased risk of death in patients with peripheral arterial disease (PAD). Previous studies on kinetic parameters (joint moment and power) of lower limbs in these patients have largely focused on the decline in the ankle plantar flexor moment and power at self-selected (SS) walking speed, which may not be an optimal condition to induce claudication pain. In the present study, we investigated the abnormalities in joint kinetic parameters in patients with PAD at both SS and at fast walking speeds.

METHODS

We recruited 16 patients with aortoiliac PAD (4 unilateral and 12 bilateral) and 10 healthy controls. The participants were instructed to walk at SS and fast speeds along a 7-meter walkway embedded with a force plate. Spatiotemporal parameters and joint kinetic parameters of the lower limbs during the stance phase were recorded using a three-dimensional motion analysis device.

RESULTS

Compared with the controls, patients with PAD showed a significant reduction in their walking speed, step length, stride length, and cadence. Further, a reduction in peak hip flexor moment at fast walking speed and in peak hip flexor generation power was observed in both modes of walking. However, no significant between-group differences were observed for the peak ankle plantar flexor moment or power at either walking speed. Multiple regression analysis showed peak hip flexor generation power was a strong contributor to reduction at both SS and fast walking speeds in patients with PAD.

CONCLUSIONS

Patients with aortoiliac PAD walk slowly and show reduced kinetic parameters of the hip joint at both SS and fast walking speeds. Our results suggest that hip flexor muscles may be a useful target for exercise training in patients with aortoiliac PAD.

Muscle strength and control characteristics are altered by peripheral artery disease

OBJECTIVE

Peripheral artery disease (PAD), a common manifestation of atherosclerosis, is characterized by lower leg ischemia and myopathy in association with leg dysfunction. Patients with PAD have impaired gait from the first step they take with consistent defects in the movement around the ankle joint, especially in plantar flexion. Our goal was to develop muscle strength profiles to better understand the problems in motor control responsible for the walking impairment in patients with PAD.

METHODS

Ninety-four claudicating PAD patients performed maximal isometric plantar flexion contractions lasting 10 seconds in two conditions: pain free (patient is well rested and has no claudication symptoms) and pain induced (patient has walked and has claudication symptoms). Sixteen matched healthy controls performed the pain-free condition only. Torque curves were analyzed for dependent variables of muscle strength and motor control. Independent t-tests were used to compare variables between groups, and dependent t-tests determined differences between conditions.

RESULTS

Patients with PAD had significantly reduced peak torque and area under the curve compared with controls. Measures of control differed between PAD conditions only. Load rate and linear region duration were greater in the pain condition. Time to peak torque was shorter in the pain condition.

CONCLUSIONS

This study conclusively demonstrates that the plantar flexor muscles of the PAD patient at baseline and without pain are weaker in patients with PAD compared with controls. With the onset of claudication pain, patients with PAD exhibit altered muscle control strategies and further strength deficits are manifest compared to baseline levels. The myopathy of PAD legs appears to have a central role in the functional deterioration of the calf muscles, as it is evident both before and after onset of ischemic pain.

Prediction of 6-minute walk performance in patients with peripheral artery disease

BACKGROUND

Peripheral artery disease (PAD) is a highly prevalent disease that impairs walking ability. Walking tests, such as the 6-minute walk test (6MWT) and 4-meter walk test, are commonly used to assess exercise endurance and ambulatory function over a short distance, respectively. The 6MWT performance is predictive of PAD severity and disease outcomes, but it is not feasible in many clinical settings because it requires a long walkway to serve as the test route and lengthens clinic visits. As an alternative, the 4-meter walk test is convenient, inexpensive, and repeatable, but whether it accurately predicts endurance performance in the long-distance 6MWT is not known. The goal of this study was to develop a statistical model to predict 6MWT gait speed from 4-meter walk test results and clinical characteristics among patients with PAD.

METHODS

Measures of 6MWT gait speed were derived from 183 patients with symptomatic PAD who were evaluated at the University of Oklahoma Health Sciences Center (2004-2012). The testing procedures and research personnel remained constant throughout the duration of the study. Independent variables included demographic and clinical information and 4-meter walk test gait speed. Fivefold cross validation and manual backward selection were used for model selection. Adjusted R² and corrected Akaike information criterion were applied to quantify the predictive performance of the regression models.

RESULTS

A total of 183 people (54% male; mean age, 65 [standard deviation (SD), 10] years) with moderate PAD severity (ankle-brachial index [ABI]; mean, 0.72 [SD, 0.24]) performed the walking tests. Participants covered an average distance of 335 (SD, 97) m distance in the 6MWT. The 4-meter walk gait speed, ABI, and dyspnea were independent predictors of 6MWT speed in the multivariate model (adjusted R² = 0.55). The model resulted in 95% prediction interval widths of 30 m for mean and 260 m for individual predicted 6MWT distance measures.

CONCLUSIONS

Slower 4-meter walking speed, lower ABI, and presence of dyspnea all predict slower 6MWT gait speed, which corresponds to shorter 6MWT distance. Prediction of group means is reasonably precise; however, prediction of individual patient 6MWT performance is imprecise relative to between-group differences that are clinically important.

Alterations in gait parameters with peripheral artery disease: The importance of pre-frailty as a confounding variable

Although poor walking is the most common symptom of peripheral artery disease (PAD), reported results are inconsistent when comparing gait parameters between PAD patients and healthy controls. This inconsistency may be due to frailty, which is highly prevalent among PAD patients. To address this hypothesis, 41 participants, 17 PAD (74±8 years) and 24 aged-matched controls (76±7 years), were recruited. Gait was objectively assessed using validated wearable sensors. Analysis of covariate (ANCOVA) tests were used to compare gait parameters between PAD and non-PAD groups, considering age, gender, and body mass index as covariates, while stratified based on frailty status. According to the Fried frailty index, 47% of PAD and 50% of control participants were non-frail and the rest were classified as pre-frail. Within non-frail participants, gait speed, body sway during walking, stride length, gait cycle time, double-support, knee range of motion, speed variability, mid-swing speed, and gait initiation were significantly different between PAD and control groups (effect size d = 0.75±0.43). In the pre-frail group, however, most of the gait differences were diminished except for gait initiation and gait variability. Results suggest that gait initiation is the most sensitive parameter for detecting gait impairment in PAD participants when compared to controls, regardless of frailty status (d = 1.30-1.41; p<0.050). The observed interaction effect between frailty and PAD on gait parameters confirms the importance of assessing functionality in addition to age to provide more consistency in detecting motor performance impairments due to PAD.

Association between gait characteristics and endothelial oxidative stress and inflammation in patients with symptomatic peripheral artery disease

The aim of the study was to determine whether gait characteristics were associated with endothelial cell inflammation, oxidative stress, and apoptosis and with circulating biomarkers of inflammation and antioxidant capacity in older patients with symptomatic peripheral artery disease (PAD). Gait measurements of 231 symptomatic men and women with PAD were assessed during a 4-m walk test. Patients were further characterized on endothelial effects of circulating factors present in the sera using a cell culture-based bioassay on primary human arterial endothelial cells and on circulating inflammatory and vascular biomarkers. In a multivariate regression model for gait speed, the significant independent variables were age (p < 0.001), intercellular cell adhesion molecule-1 (ICAM-1) (p < 0.001), diabetes (p = 0.003), sex (p = 0.003), and history of cerebrovascular accidents (p = 0.021). In multivariate analyses for gait cadence, the significant independent predictors included high-sensitivity C-reactive protein (HsCRP) (p < 0.001), diabetes (p = 0.001), and hypertension (p = 0.001). In a multivariate regression model for gait stride length, the significant independent variables were HsCRP (p < 0.001), age (p < 0.001), ICAM-1 (p < 0.001), hypertension (p = 0.002), cellular reactive oxygen species production (p = 0.007), and sex (p = 0.008). Higher levels of circulating biomarkers of inflammation and endothelial cell oxidative stress were associated with slower gait speed, slower cadence, and shorter stride length in older symptomatic patients with PAD. Additionally, this profile of impaired gait was more evident in older patients, in women, and in those with diabetes, hypertension, and history of cerebrovascular accidents.

Altered joint kinematics and increased electromyographic muscle activity during walking in patients with intermittent claudication

BACKGROUND

Patients with intermittent claudication (IC) tend to walk at a slower pace, have less lower leg muscle strength, and consume approximately 40% more oxygen during walking compared with healthy individuals. An unfavorable locomotion pattern has been suggested to explain this metabolic inefficiency. However, knowledge on gait patterns in IC is limited. Muscle activity patterns during walking measured using surface electromyography (EMG) have not been investigated in this patient population.

METHODS

In this cross-sectional study, gait pattern of patients newly diagnosed with IC and age-matched controls were evaluated using kinematic parameters and medial gastrocnemius (MG) and tibialis anterior (TA) muscles activity patterns. The protocol included pain-free and painful (only IC patients) treadmill walking sessions.

RESULTS

A total of 22 IC patients and 22 healthy control subjects were included. Patients walked 1.4 km/h slower (3.2 km/h vs 4.6 km/h; P < .001) than control subjects, coinciding with a 10% slower cadence (110 steps/min vs 122 steps/min; P < .001). The kinematic analysis resulted in a patient's ankle plantar flexion reduction of 45% during the propulsion phase, and ankle dorsal flexion reduction of 41% at initial contact. No additional kinematic changes were observed when claudication pain presented. Interestingly, kinematic differences did not influence the muscle activity duration during walking, because equal duration of muscle activity was found in IC patients and healthy controls. However, the amount of muscle activity in microvolts did significantly increase in IC patients when claudication pain presented (TA: Δ23%; P < .001; MG: Δ54%; P = .007).

CONCLUSIONS

Patients with IC show significant kinematic changes during walking. These alterations did not affect EMG activity duration of MG and TA muscles. However, EMG amplitude of both muscles did significantly increase during painful walking in IC patients.

Effects of 12-week supervised treadmill training on spatio-temporal gait parameters in patients with claudication

The purpose of the study was to evaluate selected temporal and spatial gait parameters in patients with intermittent claudication after completion of 12-week supervised treadmill walking training. The study included 36 patients (26 males and 10 females) aged: mean 64 (SD 7.7) with intermittent claudication. All patients were tested on treadmill (Gait Trainer, Biodex). Before the programme and after its completion, the following gait biomechanical parameters were tested: step length (cm), step cycle (cycle/s), leg support time (%), coefficient of step variation (%) as well as pain-free walking time (PFWT) and maximal walking time (MWT) were measured. Training was conducted in accordance with the current TASC II guidelines. After 12 weeks of training, patients showed significant change in gait biomechanics consisting in decreased frequency of step cycle (p < 0.05) and extended step length (p < 0.05). PFWT increased by 96% (p < 0.05). MWT increased by 100% (p < 0.05). After completing the training, patients' gait was more regular, which was expressed via statistically significant decrease of coefficient of variation (p < 0.05) for both legs. No statistically significant relation between the post-training improvement of PFWT and MWT and step length increase and decreased frequency of step cycle was observed (p > 0.05).

IMPLICATIONS FOR REHABILITATION

Twelve-week treadmill walking training programme may lead to significant improvement of temporal and spatial gait parameters in patients with intermittent claudication. Twelve-week treadmill walking training programme may lead to significant improvement of pain-free walking time and maximum walking time in patients with intermittent claudication.

Physical activity monitoring in patients with peripheral arterial disease: validation of an activity monitor

OBJECTIVES

The daily life physical activity (PA) of patients with peripheral arterial disease (PAD) may be severely hampered by intermittent claudication (IC). From a therapeutic, as well as research, point of view, it may be more relevant to determine improvement in PA as an outcome measure in IC. The aim of this study was to validate daily activities using a novel type of tri-axial accelerometer (Dynaport MoveMonitor) in patients with IC.

METHODS

Patients with IC were studied during a hospital visit. Standard activities (locomotion, lying, sitting, standing, shuffling, number of steps and "not worn" detection) were video recorded and compared with activities scored by the MoveMonitor. Inter-rater reliability (expressed in intraclass correlation coefficients [ICC]), sensitivity, specificity, and positive predictive values (PPV) were calculated for each activity.

RESULTS

Twenty-eight hours of video observation were analysed (n = 21). Our video annotation method (the gold standard method) appeared to be accurate for most postures (ICC > 0.97), except for shuffling (ICC = 0.38). The MoveMonitor showed a high sensitivity (>86%), specificity (>91%), and PPV (>88%) for locomotion, lying, sitting, and "not worn" detection. Moderate accuracy was found for standing (46%), while shuffling appeared to be undetectable (18%). A strong correlation was found between video recordings and the MoveMonitor with regard to the calculation of the "number of steps" (ICC = 0.90).

CONCLUSIONS

The MoveMonitor provides accurate information on a diverse set of postures, daily activities, and number of steps in IC patients. However, the detection of low amplitude movements, such as shuffling and "sitting to standing" transfers, is a matter of concern. This tool is useful in assessing the role of PA as a novel, clinically relevant outcome parameter in IC.

Exercise performance and peripheral vascular insufficiency improve with AMPK activation in high-fat diet-fed mice

Intermittent claudication is a form of exercise intolerance characterized by muscle pain during walking in patients with peripheral artery disease (PAD). Endothelial cell and muscle dysfunction are thought to be important contributors to the etiology of this disease, but a lack of preclinical models that incorporate these elements and measure exercise performance as a primary end point has slowed progress in finding new treatment options for these patients. We sought to develop an animal model of peripheral vascular insufficiency in which microvascular dysfunction and exercise intolerance were defining features. We further set out to determine if pharmacological activation of 5'-AMP-activated protein kinase (AMPK) might counteract any of these functional deficits. Mice aged on a high-fat diet demonstrate many functional and molecular characteristics of PAD, including the sequential development of peripheral vascular insufficiency, increased muscle fatigability, and progressive exercise intolerance. These changes occur gradually and are associated with alterations in nitric oxide bioavailability. Treatment of animals with an AMPK activator, R118, increased voluntary wheel running activity, decreased muscle fatigability, and prevented the progressive decrease in treadmill exercise capacity. These functional performance benefits were accompanied by improved mitochondrial function, the normalization of perfusion in exercising muscle, increased nitric oxide bioavailability, and decreased circulating levels of the endogenous endothelial nitric oxide synthase inhibitor asymmetric dimethylarginine. These data suggest that aged, obese mice represent a novel model for studying exercise intolerance associated with peripheral vascular insufficiency, and pharmacological activation of AMPK may be a suitable treatment for intermittent claudication associated with PAD.

Peripheral arterial disease affects the frequency response of ground reaction forces during walking

BACKGROUND

Walking is problematic for patients with peripheral arterial disease. The purpose of this study was to investigate the frequency domain of the ground reaction forces during walking to further elucidate the ambulatory impairment of these patients.

METHODS

Nineteen bilateral peripheral arterial disease patients and nineteen controls were included in this study. Subjects were matched for age and gait speed. Participants walked over a force plate sampling at 600 Hz. PAD patients were tested before (pain-free condition) after the onset of claudication symptoms (pain). We calculated median frequency, frequency bandwidth, and frequency containing 99.5% of the signal for the vertical and anterior-posterior ground reaction forces.

FINDINGS

Our results showed reduced median frequency in the vertical and anterior-posterior components of the ground reaction forces between the control group and both peripheral arterial disease conditions. We found reduced frequency bandwidth in the anterior-posterior direction between controls and the peripheral arterial disease pain-free condition. There were no differences in median frequency or bandwidth between peripheral arterial disease pain-free and pain conditions, but an increase in the frequency content for 99.5% of the signal was observed in the pain condition.

INTERPRETATION

Reduced frequency phenomena during gait in peripheral arterial disease patients compared to velocity-matched controls suggests more sluggish activity within the neuromotor system. Increased frequency phenomena due to pain in these patients suggest a more erratic application of propulsive forces when walking. Frequency domain analysis thus offers new insights into the gait impairments associated with this patient population.

Patients with peripheral arterial disease exhibit reduced joint powers compared to velocity-matched controls

Previous studies have shown major deficits in gait for individuals with peripheral arterial disease before and after the onset of pain. However, these studies did not have subjects ambulate at similar velocities and potential exists that the differences in joint powers may have been due to differences in walking velocity. The purpose of this study was to examine the joint moments and powers of peripheral arterial disease limbs for subjects walking at similar self-selected walking velocities as healthy controls prior to onset of any symptoms. Results revealed peripheral arterial disease patients have reduced peak hip power absorption in midstance (p=0.017), reduced peak knee power absorption in early and late stance (p=0.037 and p=0.020 respectively), and reduced peak ankle power generation in late stance (p=0.021). This study reveals that the gait of patients with peripheral arterial disease walking prior to the onset of any leg symptoms is characterized by failure of specific and identifiable muscle groups needed to perform normal walking and that these gait deficits are independent of reduced gait velocity.

Gait variability of patients with intermittent claudication is similar before and after the onset of claudication pain

BACKGROUND

Recent research demonstrated that intermittent claudication patients have increased gait variability prior to the onset of claudication. However, it is unknown if these patients experience additional gait adaptations after the onset of claudication. Thus, we sought to determine how gait variability is affected by claudication in an effort to contribute to improved clinical management.

METHODS

Twenty-six intermittent claudication patients and 20 controls walked on a treadmill at self-selected speed; intermittent claudication patients were tested before (pain free) and after (pain) the onset of claudication. Variability of the ankle, knee, and hip joint angles was assessed using the largest Lyapunov exponent, standard deviation and coefficient of variation. Dependent t-tests were used to compare the pain free and pain conditions. Independent t-tests were used to compare intermittent claudication patients and controls.

FINDINGS

Pain free and pain conditions were not significantly different for any of the parameters evaluated except the ankle. Compared to controls, patients had significantly greater values for the largest Lyapunov exponent in both conditions for all joints.

INTERPRETATION

Gait variability was essentially the same before and after the onset of claudication at the knee and the hip, and was increased in both conditions compared to controls. This indicates altered cooperation between components of the locomotor system of intermittent claudication patients, likely due to the associated myopathy since differences were present even before the onset of claudication. This research helps provide essential biomechanical knowledge of intermittent claudication that contributes to improved clinical management.

Abnormal joint powers before and after the onset of claudication symptoms

OBJECTIVE

Claudication is the most common manifestation of peripheral arterial disease, producing significant ambulatory compromise. Our study evaluated patients with bilateral lower limb claudication and characterized their gait abnormality based on advanced biomechanical analysis using joint torques and powers.

METHODS

Twenty patients with bilateral claudication (10 with isolated aortoiliac disease and 10 with combined aortoiliac and femoropopliteal disease) and 16 matched controls ambulated on a walkway while 3-dimensional biomechanical data were collected. Patients walked before and after onset of claudication pain. Joint torques and powers at early, mid, and late stance for the hip, knee, and ankle joints were calculated for claudicating patients before and after the onset of claudication pain and were compared to controls.

RESULTS

Claudicating patients exhibited significantly reduced hip and knee power at early stance (weight-acceptance phase) due to decreased torques produced by the hip and knee extensors. In mid stance (single-limb support phase), patients had significantly reduced knee and hip power due to the decreased torques produced by the knee extensors and the hip flexors. In late stance (propulsion phase), reduced propulsion was noted with significant reduction in ankle plantar flexor torques and power. These differences were present before and after the onset of pain, with certain parameters worsening in association with pain.

CONCLUSIONS

The gait of claudication is characterized by failure of specific and identifiable muscle groups needed to perform normal walking (weight acceptance, single-limb support, and propulsion). Parameters of gait are abnormal with the first steps taken, in the absence of pain, and certain of these parameters worsen after the onset of claudication pain.

Treatment with Pharmacological Agents in Peripheral Arterial Disease Patients Does Not Result in Biomechanical Gait Changes

Pharmacological treatment has been used to alleviate the claudication symptoms and improve walking performance in peripheral arterial disease (PAD) patients. However, the effects of claudication treatments on gait mechanics have not been objectively indentified with biomechanical techniques. For this study, 20 PAD patients were assigned to take either pentoxifylline (n= 11) or cilostazol (n= 9), the two FDA-approved pharmacological therapies used to treat intermittent claudication symptoms. All patients completed a gait evaluation protocol that involved the acquisition of kinematic and kinetic gait data before use of the medication and after 12 weeks of treatment. Results showed that treatment with either pentoxifylline or cilostazol resulted in limited overall improvement in gait parameters including joint angles and joint moments. Walking speed was unchanged, in either treatment group, as a result of the medication. These results suggest that to improve biomechanical walking parameters of PAD patients, clinicians cannot rely on drug therapies alone.

Kinematic adaptations to ischemic pain in claudicants during continuous walking

Intermittent claudication has been associated with impaired gait and balance. The study aim was to compare gait adaptations over time between claudicants classified with good versus poor balance. Kinematic data were collected from 24 claudicants during continuous walking. Balance was assessed using; Timed Up and Go test (TUG), and Sensory Organisation (SOT) and Motor Control (MCT) Tests using NeuroCom Equitest®. 'Good balance' (GB) was operationally defined as those claudicants achieving normal scores on at least 2 of 3 tests whereas 'poor balance' (PB) claudicants achieved normal scores on 0 or 1 test. Temporal-spatial and sagittal plane joint kinematics were analysed at three time intervals; 'no pain' (prior to onset), 'initial pain' and 'maximal pain' (unable to continue walking). A two-way mixed design ANOVA was performed. Claudicants demonstrated a significant decrease in walking speed, step frequency and increased time in double support (p<0.05). Inter-group analysis showed no differences between GB and PB on any temporal-spatial or kinematic parameters (p>0.05). There was no significant time and group interaction for any temporal-spatial or kinematic variable except hip flexion. GB claudicants demonstrated increased hip flexion as pain progressed but this adaptive strategy was not seen in PB claudicants. Claudicants make adaptations to walking by slowing (down) when in pain. Differences between GB and PB were not seen in temporal-spatial or ankle, knee and pelvic kinematic gait parameters. However adaptation to pain in GB claudicants involved a hip strategy, not seen in PB claudicants.

The effect of pharmacological treatment on gait biomechanics in peripheral arterial disease patients

Background

Pharmacological treatment has been advocated as a first line therapy for Peripheral Arterial Disease (PAD) patients suffering from intermittent claudication. Previous studies document the ability of pharmacological treatment to increase walking distances. However, the effect of pharmacological treatment on gait biomechanics in PAD patients has not been objectively evaluated as is common with other gait abnormalities.

Methods

Sixteen patients were prescribed an FDA approved drug (Pentoxifylline or Cilostazol) for the treatment of symptomatic PAD. Patients underwent baseline gait testing prior to medication use which consisted of acquisition of ground reaction forces and kinematics while walking in a pain free state. After three months of treatment, patients underwent repeat gait testing.

Results

Patients with symptomatic PAD had significant gait abnormalities at baseline during pain free walking as compared to healthy controls. However, pharmacological treatment did not produce any identifiable alterations on the biomechanics of gait of the PAD patients as revealed by the statistical comparisons performed between pre and post-treatment and between post-treatment and the healthy controls.

Conclusions

Pharmacological treatment did not result in statistically significant improvements in the gait biomechanics of patients with symptomatic PAD. Future studies will need to further explore different cohorts of patients that have shown to improve significantly their claudication distances and/or their muscle fiber morphology with the use of pharmacological treatment and determine if this is associated with an improvement in gait biomechanics. Using these methods we may distinguish the patients who benefit from pharmacotherapy and those who do not.

Walking economy before and after the onset of claudication pain in patients with peripheral arterial disease

PURPOSE

To determine the walking economy before and after the onset of claudication pain in patients with peripheral arterial disease (PAD), and to identify predictors of the change in walking economy following the onset of claudication pain.

METHODS

A total of 39 patients with PAD were studied, in which 29 experienced claudication (Pain group) during a constant load, walking economy treadmill test (speed = 2.0 mph, grade = 0%) and 10 were pain-free during this test (Pain-Free group). Patients were characterized on walking economy (ie, oxygen uptake during ambulation), as well as on demographic characteristics, cardiovascular risk factors, baseline exercise performance measures, and the ischemic window calculated from the decrease in ankle systolic blood pressure following exercise.

RESULTS

During the constant load treadmill test, the Pain group experienced onset of claudication pain at 323 +/- 195 seconds (mean +/- standard deviation) and continued to walk until maximal pain was attained at 759 +/- 332 seconds. Walking economy during pain-free ambulation (9.54 +/- 1.42 ml x kg(-1) x min(-1)) changed (P < .001) after the onset of pain (10.18 +/- 1.56 ml x kg(-1) x min(-1)). The change in walking economy after the onset of pain was associated with ischemic window (P < .001), hypertension (P < .001), diabetes (P = .002), and height (P = .003). In contrast, the Pain-Free group walked pain-free for the entire 20-minute test duration without a change in walking economy (P = .36) from the second minute of exercise (9.20 +/- 1.62 ml x kg(-1) x min(-1)) to the nineteenth minute of exercise (9.07 +/- 1.54 ml x kg(-1) x min(-1)).

CONCLUSION

Painful ambulation at a constant speed is associated with impaired walking economy, as measured by an increase in oxygen uptake in patients limited by intermittent claudication, and the change in walking economy is explained, in part, by severity of PAD, diabetes, and hypertension.

The effect of claudication pain on temporal and spatial gait measures during self-paced ambulation

We determined the effect of claudication pain on temporal and spatial gait characteristics, and on ambulatory symmetry at preferred and rapid self-selected walking paces in patients with unilateral peripheral arterial disease (PAD). Twenty-eight patients with PAD limited by intermittent claudication were studied. Patients ambulated at their preferred and rapid paces over a 7.3-meter portable gait mat system while they were pain-free and after experiencing claudication pain. The order of the pain-free and painful walking trials was randomized, and the following gait parameters were obtained: velocity, cadence, stride length, swing time, stance time, single-support time, and double-support time. During the self-selected rapid pace, patients walked 3% slower (p = 0.020) while in pain due to a 3% shorter stride length (p < 0.001), and they were in double-stance longer (p = 0.024). Claudication pain in the symptomatic leg resulted in an increase in single-stance (p = 0.007). Furthermore, gait became asymmetrical with pain, as the symptomatic leg spent a higher percentage of the gait cycle in the swing phase (p < 0.01) and lower percentages in stance (p < 0.01) and single-stance (p < 0.01) than the asymptomatic leg. Ambulation was symmetrical for all measures during the pain-free trial. In conclusion, claudication pain slows ambulatory velocity at preferred and rapid paces, and increases asymmetry when ambulatory function is challenged with rapid walking. The reduced ambulatory speed with the development of claudication pain may be an adaptation to elicit a safer and less destabilizing gait pattern.

Marcha de pacientes com doença arterial obstrutiva periférica e claudicação intermitente

INTRODUÇÃO: Pacientes com doença arterial obstrutiva periférica (DAOP) e claudicação intermitente (CI) apresentam prejuízo no desempenho de caminhada e alterações nos parâmetros espaço-temporais da marcha, mesmo na ausência de dor. OBJETIVO: Analisar os parâmetros espaço-temporais da marcha de pacientes com DAOP e CI participantes de programa de reabilitação. MÉTODOS: A amostra foi constituída por 12 pacientes com DAOP e CI, sendo 75% do sexo masculino e idade média de 63,3 ± 8,6 anos. Todos os pacientes participavam de programa de reabilitação e apresentavam melhora no desempenho de caminhada após os tratamentos; sete foram avaliados em longo prazo (de seis a 24 meses) e cinco em curto prazo (dois meses). Velocidade, comprimento da passada e cadência foram analisados antes e logo após o início da claudicação em pista de 6m de papel. A claudicação foi induzida por meio de caminhada em esteira ergométrica. As avaliações foram realizadas ao final dos tratamentos e analisadas inter e intragrupos. RESULTADOS: Velocidade de marcha (1,06m/s ± 0,29 vs 1,10m/s ± 0,06), comprimento da passada (1,34m ± 0,27 vs 1,33m ± 0,11) e cadência (93,81 passos/min ± 7,20 vs 99,84 passos/min ± 8,99) foram similares entre os grupos tratados em curto e em longo prazos (p > 0,05). Na avaliação intragrupos, ocorreu diminuição significativa no comprimento da passada dos pacientes tratados em curto prazo após a indução da claudicação (1,34m ± 0,27 vs 1,09m ± 0,03), com p = 0,05. CONCLUSÃO: Não ocorreram diferenças significativas nos parâmetros espaço-temporais da marcha entre os grupos. As características da marcha persistem, inclusive na ausência da dor e com a melhora do desempenho de caminhada, em pacientes participantes de programa de reabilitação.

Gait variability is altered in patients with peripheral arterial disease

OBJECTIVE

Claudication is the most common presentation of peripheral arterial disease (PAD), producing significant ambulatory compromise. Claudicating patients, most of whom are elderly, have reduced mobility and poor health outcomes, including an increased risk of falls. The gait of elderly fallers is characterized by increased variability. Increase in the variability of the locomotor system makes the gait more noisy and unstable. The purpose of this study is to investigate gait variability in patients with PAD.

METHODS

Nineteen symptomatic PAD patients (age, 63.6 +/- 9.8 years; body mass, 82.1 +/- 18.5 kg; height, 1.71 +/- 0.06 m) walked on a treadmill in the absence of pain or claudication symptoms while joint flexion and extension kinematics were captured. Results were compared with results obtained from 17 matched healthy controls (age, 65.2 +/- 12.5 years; body mass, 82.0 +/- 25.9.5 kg; height, 1.73 +/- 0.08 m). Relative joint angles were calculated for the ankle, knee, and hip flexion/extension, and the stride-to-stride variability of joint flexion and extension was calculated from at least 30 consecutive footfalls. Variability was expressed using the largest Lyapunov exponent, standard deviation, and coefficient of variation. Independent t tests were used to compare gait variability between groups.

RESULTS

Symptomatic PAD patients had significantly higher largest Lyapunov exponent values and coefficient of variation values for all joints, and higher standard deviation values at the ankle and the hip (P < .05).

CONCLUSION

Symptomatic PAD patients have increased gait variability at the ankle, knee, and hip joints at baseline ambulation in the absence of claudication pain. Our findings indicate significant baseline deterioration in the locomotor system of symptomatic PAD patients. This deterioration results in increased noise and instability of gait and is a potential contributing factor to the falls and mobility problems experienced by symptomatic PAD patients.

Association between daily ambulatory activity patterns and exercise performance in patients with intermittent claudication

PURPOSE

To determine the association between daily ambulatory activity patterns and exercise performance in patients with intermittent claudication.

METHODS

One hundred thirty-three patients limited by intermittent claudication participated in this study. Patients were assessed on their ambulatory activity patterns for 1 week with a small, lightweight step activity monitor attached to the ankle using elastic velcro straps above the lateral malleolus of the right leg. The step activity monitor recorded the number of strides taken on a minute-to-minute basis and the time spent ambulating. Patients also were characterized on ankle-brachial index (ABI), ischemic window (IW) after a treadmill test, as well as initial claudication distance (ICD), and absolute claudication distance (ACD) during treadmill exercise.

RESULTS

The patient characteristics (mean +/- SD) were as follows: ABI = 0.71 +/- 0.23, IW = 0.54 +/- 0.72 mm Hg.min.meter(-1), ICD = 236 +/- 198 meters, and ACD = 424 +/- 285 meters. The patients took 3366 +/- 1694 strides/day, and were active for 272 +/- 103 min/day. The cadence for the 30 highest, consecutive minutes of each day (15.1 +/- 7.2 strides/min) was correlated with ICD (r = 0.316, P < .001) and ACD (r = 0.471, P < 0.001), and the cadence for the 60 highest, consecutive minutes of each day (11.1 +/- 5.4 strides/min) was correlated with ICD (r = 0.290, P < .01) and ACD (r = 0.453, P < .001). Similarly, the cadences for the highest 1, 5, and 20 consecutive minutes, and the cadence for the 30 highest, nonconsecutive minutes all were correlated with ICD and ACD (P < .05). None of the ambulatory cadences were correlated with ABI (P > .05) or with ischemic window (P > .05).

CONCLUSION

Daily ambulatory cadences are associated with severity of intermittent claudication, as measured by ACD and ICD, but not with peripheral hemodynamic measures.