Peripheral neuropathy associated with ischemic vascular disease of the lower limbs

12. Vascular pain: Ischemic pain in the extremities and Raynaud's syndrome

INTRODUCTION

Peripheral artery diseases (PAD) and Raynaud's syndrome are associated with substantial morbidity. PAD, through the restriction of blood flow to the extremities, may lead to critical limb ischemia with symptoms of pain at rest which may eventually progress to severe limb ischemia with gangrene. This serious and painful clinical condition requires extensive medical care, is limb-threatening and, in case of delayed or unsuccessful treatment, is associated with a high mortality rate. In Raynaud's syndrome, the blood supply to certain parts of the body, usually the fingers and toes and less frequently the nose or ears, is restricted because of vasculopathy of the smaller vessels at acral sites. Under certain circumstances, with cold as the most well-known provoking factor, blood flow restriction occurs, leading to demarcated color changes and symptoms such as pain, paresthesia, and numbness. In severe cases of Raynaud syndrome tissue ischemia may lead to necrosis and the need for amputation of the affected area.

METHODS

In this narrative review, the literature on the diagnosis and interventional pain treatment of PAD and Raynaud's syndrome was updated and summarized.

OBJECTIVES

This review focused on interventional pain treatment. In PAD, the effects of the intervention on limb salvage, ulcer healing, and ischemic pain were summarized. Additionally, results with respect to skin microcirculation and quality of life were reported if available. In Raynaud's syndrome, we focused on the effect of the intervention on peripheral blood flow metrics and pain intensity during attacks.

RESULTS

In PAD, prevention and treatment of risk factors are important. Initially, conservative treatment and pharmacological therapy are preferred first-line therapies. However, when disease progression occurs, interventional management may be considered. The literature search yielded conflicting evidence for sympathectomy as a treatment for PAD. Spinal cord stimulation (SCS) as a treatment modality for advanced PAD had high-quality evidence for limb salvage in subgroups of patients but conflicting evidence for other outcome measures such as pain, wound healing, and quality of life. The literature search for interventional pain management in Raynaud's syndrome was limited to only one randomized controlled trial (RCT) studying the effect of thoracic sympathectomy. This study had several limitations and hence the level of evidence for this interventional treatment is very low. No RCTs studying SCS in patients with Raynaud's syndrome were found.

CONCLUSIONS

In both PAD and Raynaud's syndrome, additional RCTs are needed to substantiate interventional (pain) management and bolster the evidence base for sympathectomy and SCS as treatment options.

Foot Drop Following a Popliteal Sciatic Nerve Block with Ropivacaine, A Case Report and Literature Review

Although peripheral nerve blocks are deemed very safe, a significant number of patients for whom this anesthetic technique may be particularly appealing to apply may present with preexisting peripheral neuropathies, putting them at risk for further nerve damage. We present a case with a 74-year-old male with several risk factors for peripheral neuropathy who developed a foot drop following a popliteal sciatic nerve block with ropivacaine. We suggest that the vasoconstrictive properties of ropivacaine may have contributed to a preexisting neuronal ischemia, thus further damaging an already compromised nerve.

Risk Factors for Peripheral Nerve Injury Following Revision Total Knee Arthroplasty in 132,960 Patients

BACKGROUND

Peripheral nerve injury (PNI) following revision total knee arthroplasty (rTKA) is a potentially devastating injury for patients. This study assessed the frequency of and risk factors for postoperative PNI following rTKA.

METHODS

Patients who underwent rTKA from 2003 to 2015 were identified using the National Inpatient Sample. Demographics, medical histories, surgical details, and complications were compared between patients who sustained a PNI and those who did not to identify risk factors for the development of PNI after rTKA.

RESULTS

Overall, 132,960 patients who underwent rTKA were identified, and 737 (0.56%) sustained a postoperative PNI. After adjusting for confounders, patients with a history of a spine condition (adjusted odds ratio [aOR]: 1.7, 95%-confidence interval 1.2 to 2.4, P = .003) and postoperative anemia (aOR: 1.3, 95%-CI: 1.1 to 1.5, P = .004) had higher risk of PNI following rTKA. Intraoperative periprosthetic fracture (aOR: 1.3, 0.78 to 2.2, P = .308), rheumatoid arthritis (aOR: 1.0, 95%-CI: 0.68 to 1.6, P = .865), and history of knee dislocation (aOR: 1.1, 95%-CI: 0.85 to 1.5, P = .412), were not significantly associated with higher risk for PNI.

CONCLUSIONS

This study found a 0.56% incidence of PNI following rTKA, and patients who had preexisting spine conditions or postoperative anemia were at an increased risk for this complication. Orthopedic surgeons may use the results of this study to appropriately counsel patients on the potential for a PNI following rTKA.

Predictors of walking capacity in patients with peripheral arterial disease

BACKGROUND

Walking capacity is severely impaired in patients with peripheral arterial disease (PAD). Given the prognostic importance of walking capacity, the level of evidence on possible predictors of walking capacity in patients with PAD is insufficient.

AIMS

To investigate the predictors of walking capacity in patients with PAD.

METHODS

A total of 51 patients with PAD were included in this cross-sectional study. Walking capacity was determined with 6‑minute walk test (6MWT) and walking impairment questionnaire (WIQ). Functional mobility was assessed with repeated sit-to-stand test (RSS) and timed up and go test (TUG). Hand-held dynamometer was used to measurement lower extremity muscle strength. Balance was assessed with Biodex Balance System-limit of stability (BBS-LOS). Fatigue was evaluated with fatigue impact scale (FIS).

RESULTS

There was a strong correlation between 6MWT walking distance and WIQ, two methods of assessing walking capacity (r = 0.835 p < 0.001). The 6MWT was correlated with RSS, TUG, lower extremity muscle strength, BBS-LOS and FIS. The WIQ was correlated with RSS, TUG, BBS-LOS and FIS. The RSS and FIS were independent determinants of the 6MWT and WIQ, accounting for 68% and 57% of the variance, respectively.

CONCLUSION

This study demonstrated that functional mobility and fatigue were independent predictors of walking capacity in patients with PAD. Both subjective and objective measurement methods can be used for determining the level of walking capacity in the patients with PAD.

Parallels between the Developing Vascular and Neural Systems: Signaling Pathways and Future Perspectives for Regenerative Medicine

Neurovascular disorders, which involve the vascular and nervous systems, are common. Research on such disorders usually focuses on either vascular or nervous components, without looking at how they interact. Adopting a neurovascular perspective is essential to improve current treatments. Therefore, comparing molecular processes known to be involved in both systems separately can provide insight into promising areas of future research. Since development and regeneration share many mechanisms, comparing signaling molecules involved in both the developing vascular and nervous systems and shedding light to those that they have in common can reveal processes, which have not yet been studied from a regenerative perspective, yet hold great potential. Hence, this review discusses and compares processes involved in the development of the vascular and nervous systems, in order to provide an overview of the molecular mechanisms, which are most promising with regards to treatment for neurovascular disorders. Vascular endothelial growth factor, semaphorins, and ephrins are found to hold the most potential, while fibroblast growth factor, bone morphogenic protein, slits, and sonic hedgehog are shown to participate in both the developing vascular and nervous systems, yet have not been studied at the neurovascular level, therefore being of special interest for future research.

The association between pain, balance, fall, and disability in patients with lumbar spinal stenosis with vascular claudication

Background

The effect of lumbar spinal stenosis (LSS) and peripheral vascular disease (PVD), which occurs with similar degenerative conditions, when seen together, has not been studied. The aim of this study is to examine and compare the relationship between pain, balance, disability, fear of falling, and kinesiophobia in LSS patients with intermittent vascular claudication (IVC).

Methods

Seventy-two patients diagnosed with LSS using magnetic resonance imaging participated in this study. Thirty-five patients with IVC symptoms and showing vascular lesions by lower extremity venous and arterial Doppler ultrasonography imaging were included in the IVC-LSS group. The pain, static balance, dynamic balance, disability, fear of falling, and kinesiophobia were evaluated using the numeric rating scale, single leg stance test, Time Up and Go (TUG), the Oswestry Disability Index (ODI), Fall Efficacy Scale-International (FES-I), and Tampa Scale for Kinesiophobia (TSK), respectively.

Results

Age and female sex were found to be higher in the IVC-LSS group (P = 0.024; P = 0.012). The IVC-LSS group had a shorter single leg stance time and TUG test duration, pain intensity, ODI, FES-I, and TSK scores were higher than patients with LSS (P = 0.001). Pain, fear of falling, and kinesiophobia were moderately correlated with disability in the IVC-LSS group. No relationship was found between pain and dynamic balance. Also, the pain was not related to kinesiophobia.

Conclusions

The findings indicated that IVC causes loss of balance and an increase in pain, disability, fear of falling, and kinesophobia in patients with LSS.

Ischaemic monomelic neuropathy: A rare cause of unilateral foot drop

Ischaemic neuropathy is a rare phenomenon given the rich arterial collateral supply afforded to peripheral nerves by the vasa nervorum. We report an unusual case of unilateral foot drop secondary to long-segment popliteal artery occlusion. Without expedient vessel imaging and revascularisation of the occluded artery, this reversible cause of neurological deficit would likely have resulted in a poor functional outcome for our patient.

Measuring sensory and pain thresholds by Semmes-Weinstein monofilaments in patients with leg ulcers: a pilot study

OBJECTIVE

Pain is a common and disabling symptom in patients with leg ulcers. Clinical quantification of pain mostly depends on subjective pain reports, which do not reveal underlying mechanisms. The aim of this pilot study is to identify mechanisms underlying the pain in patients with leg ulcers by documenting alterations in pain processing using quantitative sensory testing.

METHODS

In nine ulcer patients the mechanical sensory thresholds and the mechanical pain thresholds were determined by Semmes-Weinstein monofilaments (SWM) at three different sites: on the contralateral (unaffected) leg, on the skin of the affected leg 10cm from the ulcer margin, and on the affected leg, close (1-2cm) to the ulcer margin. Besides the mechanical sensory thresholds and mechanical pain thresholds, pain at the site of the ulcer, using an 11-point numeric rating scale (NRS), was documented.

RESULTS

Mechanical sensory thresholds were increased in all subjects. Almost half (44%) of patients consistently showed allodynia at the unaffected site. The lowering of mechanical pain thresholds correlated with higher scores on the NRS.

CONCLUSION

All patients showed diminished touch and/or protective sensation, which might have contributed to ulcer development via (partial) loss of protective function. The allodynia at the unaffected site suggests the presence of central sensitisation of pain processing.

Peripheral arterial disease and risk of hip fracture: A systematic review and meta-analysis of cohort studies

Background

Previous studies have suggested an increased risk of hip fracture among patients with peripheral arterial disease (PAD), however, the results have been inconsistent. This meta-analysis was conducted with the aim to summarize all available evidence to better characterize the risk of incident hip fracture among these patients.

Materials and Methods

A comprehensive literature review was conducted using the MEDLINE and EMBASE databases through October 2017 to identify all cohort and case-control studies that compared the risk of subsequent hip fracture between patients with PAD and individuals without PAD. Effect estimates of the included studies were extracted and combined using the random-effect, generic inverse variance method of DerSimonian and Laird.

Results

The systematic review process yielded six eligible cohort studies comprising 15,895 patients with PAD. There was a significant association between incident hip fracture and PAD with the pooled relative risk (RR) of 1.64 (95% CI, 1.17-2.29; I2, 80%), comparing patients with PAD and individuals without PAD. Subgroup analysis by study design revealed significant results for both prospective studies (pooled RR 1.60; 95% CI, 1.12-2.28; I2, 0%) and retrospective studies (pooled RR 1.72; 95% CI, 1.07-2.77; I2, 92%). The funnel plot is relatively asymmetric suggesting publication bias.

Conclusion

This study found a significant association between PAD and hip fracture with the pooled RR of 1.64 (95% CI, 1.17-2.29) on comparing patients with PAD and individuals without PAD. Major limitations include high between-study heterogeneity, possibility of publication bias, and lack of data on the characteristics and type of hip fracture which may limit the clinical significance of the observations.

Risk and outcomes of fracture in peripheral arterial disease patients: two nationwide cohort studies

Using national insurance claims data of Taiwan, we found that patients with peripheral arterial disease (PAD) had increased risk of fracture during the follow-up period of 2000-2013. History of PAD was also associated with adverse outcomes in hospitalized fracture patients. Prevention strategies were needed in this susceptible population.

INTRODUCTION

Limited information was available on the association between PAD and fracture. The purpose of this study is to evaluate fracture risk and post-fracture outcomes in patients with PAD.

METHODS

We identified 6647 adults aged ≥ 20 years with newly diagnosed PAD using the Taiwan National Health Insurance Research Database in 2000-2004. Comparison cohort consisted of 26,588 adults without PAD randomly selected with frequency matching in age and sex. Events of fracture were identified during the follow-up period from January 1, 2000 until December 31, 2013, to evaluate adjusted hazard ratios (HR) and 95% confidence interval (CI) of fracture associated with PAD. Another nested cohort study of 799,463 hospitalized fracture patients analyzed adjusted odds ratios (ORs) and 95% CIs of adverse events after fracture among patients with and without PAD in 2004-2013.

RESULTS

Incidences of fracture in people with and without PAD were 22.1 and 15.5 per 1000 person-years, respectively (P < .0001). Compared with control, the adjusted HR of fracture was 1.59 (95% CI, 1.48-1.69) for PAD patients. In the nested cohort study, patients with PAD had higher post-fracture mortality (OR = 1.16; 95% CI, 1.09-1.25) and various complications. PAD patients also had comparatively higher medical expenditure (2691 vs. 2232 USD, P < .0001) and longer hospital stay (10.6 vs. 9.0 days, P < 0.0001) during fracture admission.

CONCLUSIONS

Increased risk of fracture and post-fracture adverse outcomes were associated with PAD. This susceptible population needs care to prevent fracture and to minimize adverse outcomes after it occurs.

Limb hemodynamics are not predictive of functional capacity in patients with PAD

To the practicing clinician, it seems obvious that limb hemodynamics would be the primary determinant of walking distance. However, other determinants, such as skeletal muscle metabolism, may play a role. Accordingly, in the current study, we examined the relationship between measures of limb hemodynamics and walking capacity in patients with peripheral arterial disease (PAD). We measured toe and ankle pressures for calculation of toe-(TBI) and ankle (ABI)-brachial indices; basal and hyperemic calf blood flow (CBF; by plethysmography); and initial (ICT) and absolute (ACT) claudication time using the Skinner-Gardner protocol. As expected, PAD patients had impaired limb hemodynamics with reduced TBI, ABI and a reduction in ABI post-exercise. However, there was no relationship between any of the hemodynamic variables (including ABI, ABI reduction post-exercise, TBI, baseline or maximal CBF) and walking distance as assessed by ICT or ACT. A subset of PAD patients with an ACT >750 s (n =16; ‘long claudicators’) were compared with a subset of PAD patients with an ACT <260 s (n = 16; ‘short claudicators’). The average ACT in the long claudicants was over fivefold greater than the short claudicators. Surprisingly, there were no differences between the two groups in any of the hemo-dynamic variables. There was also no relationship between the initial ABI, TBI, toe pressure, baseline or hyperemic CBF, and the improvement in ACT over the 3-month course of the study. This study found little relationship between hemodynamic variables and functional capacity in PAD. Accordingly, to assess the response to therapeutic interventions, exercise performance and functional status need to be directly measured, and cannot be predicted from hemodynamic measurements.

Analysis of isokinetic muscle function and postural control in individuals with intermittent claudication

BACKGROUND:

Intermittent claudication (IC) is a debilitating condition that mostly affects elderly people. IC is manifested by a decrease in ambulatory function. Individuals with IC present with motor and sensory nerve dysfunction in the lower extremities, which may lead to deficits in balance.

OBJECTIVE:

This study aimed to measure postural control and isokinetic muscle function in individuals with intermittent claudication.

METHOD:

The study included 32 participants of both genders, 16 IC participants (mean age: 64 years, SD=6) and 16 healthy controls (mean age: 67 years, SD=5), which were allocated into two groups: intermittent claudication group (ICG) and control group (CG). Postural control was assessed using the displacement and velocity of the center of pressure (COP) during the sensory organization test (SOT) and the motor control test (MCT). Muscle function of the flexor and extensor muscles of the knee and ankle was measured by an isokinetic dynamometer. Independent t tests were used to calculate the between-group differences.

RESULTS:

The ICG presented greater displacement (p =0.027) and speed (p =0.033) of the COP in the anteroposterior direction (COPap) during the MCT, as well as longer latency (p =0.004). There were no between-group differences during the SOT. The ICG showed decreased muscle strength and power in the plantar flexors compared to the CG.

CONCLUSION:

Subjects with IC have lower values of strength and muscle power of plantiflexores, as well as changes in postural control in dynamic conditions. These individuals may be more vulnerable to falls than healthy subjects.

Prevalence and Risk Factors for the Peripheral Neuropathy in Patients with Peripheral Arterial Occlusive Disease

PURPOSE

Peripheral neuropathy (PN) is known as a major contributor of the worsening of ischemic symptoms and the foot ulceration in patients with peripheral arterial occlusive disease (PAOD). However, there are few studies reporting the prevalence and risk factors for PN in PAOD. This study aimed to evaluate these issues for PN and to establish the importance of screening as additional treatment target for PN in PAOD.

MATERIALS AND METHODS

A total of 52 limbs with PAOD were enrolled from January 2011 to December 2012. PN was divided into radiculopathy, ischemic PN (IPN), and diabetic PN (DPN), based on electromyographic findings. We investigated the prevalence of overall PN and subtypes of PN and then analyzed the risk factors.

RESULTS

The prevalence of overall PN in PAOD was 43 of 52 limbs (82.7%). In terms of subtypes of PN, the prevalence rate of radiculopathy and IPN was 30.8% and 23.1%, respectively. DPN showed in 22 limbs (73.3%) among 30 diabetic limbs. There was no significant correlation between each type of PN and ischemic symptoms. Our analysis showed that coronary artery disease (CAD) was a significant risk factor (P=0.01) for IPN, however, did not identify any significant risk factors for DPN.

CONCLUSION

This present study indicated that most patients with PAOD had PN and CAD was a risk factor for IPN. In particular, PAOD with diabetes represented a higher prevalence for DPN. Our study suggests that PN should be evaluated and considered as another treatment target in patients with PAOD.

Neurological and electrophysiological parameters as outcome measurements for peripheral arterial occlusive disease

BACKGROUND

Ischemic monomelic neuropathy is not an uncommon complication of peripheral arterial occlusive disease (PAOD). However, many investigators have used revascularization, limb salvage, and complete wound healing rates instead of neurologic and electrophysiological parameters as outcome measurements of PAOD. The aim of the study is to investigate the neurologic and electrophysiological parameters associated with PAOD and to find the ideal tools for assessing PAOD.

METHODS

A total of 38 PAOD patients (68.5 ± 8.1 years old, male:female = 32:6) with a total of 76 lower limbs were enrolled in the study. Primary outcomes were neurological symptoms scores (NSSs) and neurological impairment scores (NISs) for the lower extremities. Secondary outcomes were taken from nerve conduction studies (NCSs) and included the following: sensory nerve action potential (SNAP) amplitudes of the sural, superficial peroneal, and medial plantar nerves and the compound muscle action potential (CMAP) amplitudes of the posterior tibial and common peroneal nerves.

RESULTS

Female patients with old age, hypertension, low body weights, low body mass indices (BMIs), decreased ankle-brachial indices (ABIs), and poorer Fontaine classifications exhibited worse NSSs and NISs indices. Patients with old age, diabetes mellitus, hypertension, histories of social alcohol consumption, low body weights, low BMIs, and poorer Fontaine classifications exhibited decreased SNAP and CMAP amplitudes in the sensory and motor NCSs. Decreased ABI was associated with decreased SNAP amplitudes in the sensory NCSs.

CONCLUSIONS

Neurologic and electrophysiological parameters can be good tools for the assessment of PAOD. NSSs and NISs are particularly good candidates for outcome measures of PAOD.

Peripheral vascular insufficiency impairs functional capacity in patients with heart failure

INTRODUCTION: Heart failure (HF) is a complex syndrome in which effort limitation is associated with deterioration of peripheral musculature. Improving survival rates among these patients have led to the appearance of cases in which other pathologies are associated with HF, such as peripheral vascular insufficiency (PVI). The combination of these two pathologies is common, with significant repercussions for affected patients. OBJECTIVE: To compare functional limitations and quality of life between patients with HF in isolation or HF + PVI. METHOD: Twelve patients with HF+PVI were paired to 12 patients with HF in isolation. All had ejection fraction <40%. The following were conducted: 6 minute walk test (6MWT), chair test (CT), step test (ST), one repetition maximum test (1RM) and quality of life questionnaire. RESULTS: The results for the 6MWT (311±27 vs. 447±29), ST (49±3 vs. 81±10) and CT (17±1 vs. 21±1) were lower in the HF+PVI group than in the HF group (p<0.05). The HF+PVI group exhibited a reduction in the number of steps taken from the first to the second minute of the ST, in relation to the HF group. The HF group exhibited better HR recovery than the HF+PVI group (50±4 vs. 26±3; p<0.05). No differences were found in results for the Borg scale, the peripheral muscle strength test (1RM) or the questionnaires (p>0.05). CONCLUSIONS: The study participants who had mixed disease exhibited a greater degree of functional impairment than the group with HF, without reporting worsened quality of life.

Desert hedgehog promotes ischemia-induced angiogenesis by ensuring peripheral nerve survival

RATIONALE

Blood vessel growth and patterning have been shown to be regulated by nerve-derived signals. Desert hedgehog (Dhh), one of the Hedgehog family members, is expressed by Schwann cells of peripheral nerves.

OBJECTIVE

The purpose of this study was to investigate the contribution of Dhh to angiogenesis in the setting of ischemia.

METHODS AND RESULTS

We induced hindlimb ischemia in wild-type and Dhh(-/-) mice. First, we found that limb perfusion is significantly impaired in the absence of Dhh. This effect is associated with a significant decrease in capillary and artery density in Dhh(-/-). By using mice in which the Hedgehog signaling pathway effector Smoothened was specifically invalidated in endothelial cells, we demonstrated that Dhh does not promote angiogenesis by a direct activation of endothelial cells. On the contrary, we found that Dhh promotes peripheral nerve survival in the ischemic muscle and, by doing so, maintains the pool of nerve-derived proangiogenic factors. Consistently, we found that denervation of the leg, immediately after the onset of ischemia, severely impairs ischemia-induced angiogenesis and decreases expression of vascular endothelial growth factor A, angiopoietin 1, and neurotrophin 3 in the ischemic muscle.

CONCLUSIONS

This study demonstrates the crucial roles of nerves and factors regulating nerve physiology in the setting of ischemia-induced angiogenesis.

Vascular factors predict polyneuropathy in a non-diabetic elderly population

We prospectively examined whether vascular factors are related to an increased incidence of Chronic Idiopathic Distal Symmetric Neuropathy (CI-DSN) in a non-diabetic elderly population. In 8 Italian municipalities, 2,512 men and women without both diabetes and CI-DSN at baseline are examined. Potential effect of vascular factors was estimated by regressing new onset CI-DSN on the occurrence of several vascular diseases and risk factors. Multivariate relative risks of CI-DSN were estimated by Cox proportional hazards models. After 3.8 (±2.4) years of follow-up, we documented 51 incident CI-DSN cases. At univariate analysis, age, comorbidity, waist circumference, leg length, peripheral artery disease, and coronary heart disease proved to increase the risk of developing CI-DSN. By multivariate analyses, only age (RR = 1.08; 95 % CI, 1.02-1.14), leg length (RR = 1.05; 95 % CI, 1.01-1.1) and peripheral artery disease (RR = 2.75; 95 % CI, 1.15-6.56) proved significant predictors of CI-DSN. Separate analyses by gender show that age is an independent predictor of CI-DSN both in men and in women, while PAD predicts the disease only in men, together with body height. Incidence of CI-DSN is higher in individuals carrying vascular conditions. In men, the presence at baseline of peripheral artery disease is associated with a threefold increase in the risk of developing CI-DSN. The incidence of neuropathy in non-diabetic individuals is associated with potentially modifiable vascular factors.

Impaired somatosensation in patients with isolated proximal-without-distal exercise-related lower-limb ischemia

OBJECTIVES

Isolated proximal-without-distal (buttock but not calf) exercise-related lower-limb ischemia (IPI) might develop in the presence of arterial lesions impairing the blood flow supply toward the hypogastric vascular bed. In IPI, lower-limb sensory nerve dysfunction might occur from the sacral nerve plexus becoming ischemic during exercise. The purpose of this study was to compare patients with IPI with healthy controls for the presence of sensory nerve dysfunction, as assessed using somatosensory testing (SST).

METHODS

Seventeen nondiabetic patients with IPI and 17 age-matched and sex-matched healthy controls underwent SST of both the upper and lower limbs.

RESULTS

The upper-limb SST data did not differ between groups (P>0.05). In contrast, lower-limb testing showed that patients with IPI had impaired warm (43.4±2.7 vs. 40.5±4.9°C) and vibration (5.0±2.3 vs. 6.4±1.4 arbitrary units) detection thresholds compared with healthy controls (P≤0.05). Furthermore, lower-limb mechanical detection threshold and Neuropathy Symptom and Disability Scores tended to be higher in the patients (P≤0.10).

DISCUSSION

The SST data suggest that patients with IPI have abnormal functioning of Aβ-fiber and C-fiber inputs in their affected limb(s). These sensory abnormalities might contribute to the exercise-induced ischemic symptoms experienced by these patients.

Peripheral arterial disease affects kinematics during walking

OBJECTIVE

Claudication is the most common manifestation of peripheral arterial disease (PAD) producing significant ambulatory compromise. The purpose of this study was to use advanced biomechanical analysis to characterize the kinematic ambulatory pattern of claudicating patients. We hypothesized that compared with control subjects, claudicating patients have altered kinematic gait patterns that can be fully characterized utilizing advanced biomechanical analysis.

METHODS

The study examined fourteen PAD patients (age: 58 +/- 3.4 years; weight: 80.99 +/- 15.64 kg) with clinically diagnosed femoro-popliteal occlusive disease (Ankle Brachial Index (ABI): 0.56 +/- 0.03, range 0.45 to 0.65) and five healthy controls (age: 53 +/- 3.4 years; weight: 87.38 +/- 12.75 kg; ABI >or= 1). Kinematic parameters (hip, knee, and ankle joint angles in the sagittal plane) were evaluated during gait in patients before and after the onset of claudication pain and compared with healthy controls. Joint angles were calculated during stance time. Dependent variables were assessed (maximum and minimum flexion and extension angles and ranges of motion) and mean ensemble curves were generated. Time to occurrence of the discrete variables was also identified.

RESULTS

Significantly greater ankle plantar flexion in early stance and ankle range of motion during stance was observed in PAD patients (P < .05). Time to maximum ankle plantar flexion was shorter and time to maximum ankle dorsiflexion was longer in PAD patients (P < .05). These differences were noted when comparing PAD patients prior to and after the onset of claudication with healthy controls. The analysis of the kinematic parameters of the knee and the hip joints revealed no significant differences between PAD patients and controls.

CONCLUSION

PAD patients with claudication demonstrate significant gait alterations in the ankle joint that are present prior to the onset of claudication pain. In contrast, the joint motion of the hip and knee did not differ in PAD patients when compared with controls. Further research is needed to verify our findings and assess the impact of more proximal disease in PAD patients as well as the effect of revascularization on joint kinematics.

Impact of endovascular intervention on pain and sensory thresholds in nondiabetic patients with intermittent claudication: a pilot study

Pain and sensory neuropathy are common in patients with peripheral arterial disease. So far it is unknown to what extent pain and sensory parameters can be ameliorated by endovascular intervention used to resolve the arterial obstruction. Seventeen nondiabetic patients with intermittent claudication were investigated in the present study. The patients had to undergo percutaneous transluminal angioplasty (PTA) to improve blood flow in the affected leg. To acquire detailed information of their sensory state quantitative sensory testing (QST) was performed before and 24 hours and 3 months after PTA. QST is a standardized clinical testing procedure for the detection of sensory changes that consists of multiple tests for thermal and mechanical detection and pain thresholds as well as vibratory thresholds and stimulus response functions. An age-matched control group was investigated with an interval of 3 months. Pain during exercise decreased by 60% (examined by numerical rating scale) after endovascular intervention, whereas the ankle/brachial-index-representing the peripheral hemodynamic situation-increased by 29%. Sensory function determined by QST did not change significantly following PTA over a 3-month period. Successfully performed PTA is highly effective in reducing exercise induced pain in patients with intermittent claudication.

PERSPECTIVE

The study demonstrates that successfully performed PTA is a highly effective tool in reducing exercise induced pain in patients with intermittent claudication. However, the pain reduction observed cannot be verified by evaluating sensory functions using standardized quantitative sensory testing.

A new rat model for thrombus-induced ischemic pain (TIIP); development of bilateral mechanical allodynia

Patients with peripheral arterial disease (PAD) commonly suffer from ischemic pain associated with severe thrombosis. However, the pathophysiology of peripheral ischemic pain is not fully understood due to the lack of an adequate animal model. In this study, we developed a new rodent model of thrombus-induced ischemic pain (TIIP) to investigate the neuronal mechanisms underlying ischemic pain. Ischemia was induced by application of 20% FeCl(2) onto the surface of the femoral artery for 20min. Induction of peripheral ischemia was confirmed by measurement of the concentration of Evans blue and by increases in the ischemia-specific markers, hypoxia-inducible factor-1 alpha and vascular endothelial growth factor in the ipsilateral plantar muscles. Ischemic pain, as indicated by the presence of mechanical allodynia, developed bilaterally and peaked at days 3-9 post-FeCl(2) application and gradually decreased through day 31. Systemic heparin pretreatment dose dependently suppressed ischemic pain, suggesting that thrombosis-induced ischemia might be a key factor in TIIP. Intraplantar injection of BMS-182874, an ET(A) (endothelin-A) receptor antagonist, at day 3 selectively blocked ipsilateral pain, indicating that ET(A) receptor activity mediated TIIP. Spinal GFAP expression was significantly increased by FeCl(2) and intrathecal injection of carbenoxolone (an astrocyte gap junction decoupler) at day 3 significantly reduced TIIP, suggesting that spinal astrocyte activation plays an important role. However, the anti-inflammatory agent, ibuprofen, did not affect TIIP. In conclusion, we have developed a novel animal model of TIIP that should be useful in investigating the pathophysiological mechanisms that underlie human peripheral ischemic pain.

Diabetic neuropathy in older adults

Diabetic neuropathy is a heterogeneous disease with diverse pathology. Recognition of the clinical homolog of these pathologic processes is necessary in achieving appropriate intervention. Treatment should be individualized so the particular manifestation and underlying pathogenesis of each patient's clinical presentation are considered. In older adults, special care should be taken to manage pain while optimizing daily function and mobility, with the fewest adverse medication side effects. Older adults are at great risk for falling and fractures because of instability and weakness, and require strength exercises and coordination training. Ultimately agents that address large fiber dysfunction will be essential to reduce the gross impairment of quality of life and activities of daily living that neuropathy visits older people who have diabetes.

[Therapy of chronic ischemic pain in peripheral arterial disease. A survey among physicians]

BACKGROUND

The intention of this study was to determine the status quo of commonly used pain therapies amongst treating physicians of different specialties and to examine their view on the problem of chronic ischemic pain.

METHODS

A total of 281 physicians treating patients with chronic ischemic pain were surveyed. The surveyed physicians were mainly specialists in the fields of surgery, pain therapy, and internal medicine.

RESULTS

Mainly a pharmacological therapy (metamizol/paracetamol, weak and strong opioids) was used in the treatment of chronic ischemic pain. We found differences between the specialties, for instance pain specialists used antidepressants and anticonvulsants more often than others. Therapeutic options were also evaluated differently by surgeons, pain therapists, and internal specialists: 57% of the surgeons considered the available symptomatic treatment options as sufficient whereas only 21% of the pain specialists agreed with that opinion.

CONCLUSION

The differences among the specialties and the fact that the majority of physicians characterized the available symptomatic treatment options as insufficient point towards a need to review the treatment of ischemic pain in an interdisciplinary approach.

The myopathy of peripheral arterial occlusive disease: Part 2. Oxidative stress, neuropathy, and shift in muscle fiber type

In recent years, an increasing number of studies have demonstrated that a myopathy is present, contributes, and, to a certain extent, determines the pathogenesis of peripheral arterial occlusive disease. These works provide evidence that a state of repetitive cycles of exercise-induced ischemia followed by reperfusion at rest operates in patients with peripheral arterial occlusive disease and mediates a large number of structural and metabolic changes in the muscle, resulting in reduced strength and function. The key players in this process appear to be defective mitochondria that, through multilevel failure in their roles as energy, oxygen radical species, and apoptosis regulators, produce and sustain a progressive decline in muscle performance. In this 2-part review, the currently available evidence that characterizes the nature and mechanisms responsible for this myopathy is highlighted. In part 1, the functional and histomorphological characteristics of the myopathy were reviewed, and the main focus was on the biochemistry and bioenergetics of its mitochondriopathy. In part 2, accumulating evidence that oxidative stress related to ischemia reperfusion is probably the major operating mechanism of peripheral arterial occlusive disease myopathy is reviewed. Important new findings of a possible neuropathy and a shift in muscle fiber type are also reviewed. Learning more about these mechanisms will enhance our understanding of the degree to which they are preventable and treatable.

Peripheral arterial disease affects ground reaction forces during walking

OBJECTIVE

Claudication is the most common manifestation of peripheral arterial disease (PAD), producing significant ambulatory compromise. The gait of claudicating patients has been evaluated using primarily temporal and spatial parameters. With the present study, we used advanced biomechanical measures to further delineate the ambulatory impairment of claudicating patients. We hypothesized that the claudicating legs of PAD patients have an altered kinetic gait pattern compared with normal legs from control subjects.

METHODS

Ambulation kinetics (ground reaction forces) were evaluated in claudicating patients and compared with age-matched healthy controls. Forces were analyzed in the vertical, anterior-posterior, and medial-lateral directions. Time from heel touch-down to toe-off (stance time) and time spent in double-limb support were also evaluated.

RESULTS

The study recruited 14 PAD patients (age, 58 +/- 3.4 years; weight, 80.99 +/- 15.64 kg) with femoropopliteal occlusive disease (ankle-brachial index [ABI], 0.56 +/- 0.03) and five controls (age, 53 +/- 3.4 years; weight, 87.38 +/- 12.75 kg; ABI, >or=1.00). Vertical force curve evaluation demonstrated significant flattening in claudicating patients resulting in a lower and less fluctuant center of mass when ambulating. In the anterior-posterior direction, claudicating patients demonstrated significantly decreased propulsion forces. In the medial-lateral direction, they had significantly increased forces consistent with wider steps and an inability to swing their legs straight through. Claudicating patients demonstrated a greater stance time and time in double limb support compared with healthy controls. Most importantly, gait abnormalities were present before the onset of claudication, with gait worsening after the onset of claudication.

CONCLUSION

Claudicating patients demonstrate significant gait impairments that are present even before they experience any limb discomfort. These alterations may make them feel more stable and secure while attempting to minimize use of the affected limb. Advanced biomechanical analysis, using ambulation kinetics, permits objective and quantitative evaluation of the gaits of claudicating patients. Such evaluation may point to new rehabilitation strategies and provide objective measurement of functional outcomes after medical and surgical therapy.

Sensory neuropathy and signs of central sensitization in patients with peripheral arterial disease

Patients with peripheral arterial disease (PAD) may develop a broad range of peripheral nerve dysfunctions including pain and sensory deficiencies due to chronic ischemia mostly involving the lower limbs. To investigate the degree of sensory abnormalities in such patients quantitative sensory testing (QST) might be a useful tool. Forty-five patients and 20 controls were enrolled in the present study and underwent QST according to the protocol of the German Research Network on Neuropathic Pain. PAD was graded according to the Rutherford classification. PAD patients were divided into two groups: 16 patients with critical limb ischemia (severe PAD) and 29 patients with intermittent claudication (moderate PAD). QST revealed impaired cold and warm detection, increased mechanical and vibration detection thresholds, and increased perceptual wind-up on the affected leg (all p<0.001). Paradoxical heat sensation (p<0.05) and dynamic mechanical allodynia (p<0.01) were also observed. Subgroup analysis of patients without diabetes (control n=20, moderate PAD n=21, severe PAD n=8) confirmed most of these findings. In patients with severe PAD, sensory deficits were more pronounced than in patients with moderate PAD and were detected even in the face. These data indicate that QST can detect sensory abnormalities in PAD patients. While the pattern of decreased perception suggests deafferentation for Abeta-, Adelta-, and C-fiber inputs, the presence of allodynia suggests that central sensitization also plays a role in the pain state of PAD patients. Subgroup analysis points towards a PAD-associated peripheral neuropathy independent of diabetes.

Sympathetic skin response in patients with peripheral arterial occlusive disease

OBJECTIVE

The current study aimed to assess the viability of sympathetic sudomotor fibers in patients suffering from mild peripheral arterial occlusive disease (PAD).

METHODS

Sympathetic skin response (SSR) from the hand (electrical stimulation) and sole (electrical and magnetic stimulation) of 25 patients with PAD (19 males and 6 females with mean age 62.7 +/- 10.2 years) was recorded unilaterally depending on the side of the affected limb (18 right side, 7 left side). Electrophysiological data were also collected and correlated with the SSR results. Twenty-five, age- and gender-matched healthy volunteers served as controls.

RESULTS

No evidence of nerve conduction abnormalities was recorded from the group of patients. Intact SSR recordings were obtained from the upper limb of patients. Nine patients (36%) had absent SSR in the lower limb following electrical stimulation, whilst the same 9 patients had absent SSR following magnetic stimulation. Significant differences occurred between groups in the SSR latency scores recorded from the lower limb. Following electrical stimulation the mean SSR latency in patients was significantly prolonged, compared to that of controls (P = 0.000), whilst the same applied following magnetic stimulation (P = 0.000). There was no correlation between SSR abnormalities and nerve conduction measurements. The manifestation of intermittent claudication at a walking distance of 250 m was strongly correlated with absent lower limb SSR (r = 0.71, P = 0.035).

CONCLUSIONS

SSR abnormalities appeared to be an early and independent finding of neural impairment in our patients.

SIGNIFICANCE

SSR study, performed at an early stage of PAD may prove useful in differentiating PAD-induced neuropathy from other neuropathic processes.

Generalised wavelet analysis of cutaneous flowmotion during post-occlusive reactive hyperaemia in patients with peripheral arterial obstructive disease

The purpose of the present study was to assess whether the generalised wavelet analysis (GWA) of the leg cutaneous laser Doppler (LD) flowmotion waves recorded during baseline (Bsl) and after skin post-occlusive hyperaemia (POH) can provide information on the leg cutaneous microcirculatory adaptation to stage II peripheral arterial obstructive disease (PAOD). With this aim the flowmotion was characterised in 20 healthy subjects (HS) and 20 stage II PAOD patients by GWA of LDF tracings during Bsl and POH test. The vascular endothelial and smooth muscle function was also evaluated exploring the arm skin vasodilatory response to iontophoretically delivered acetylcholine (Ach) and sodium nitroprusside (SNP) using LD. During Bsl there was no significant difference in leg skin perfusion between HS and PAOD patients (7.3+/-5.6 vs. 5.8+/-2.9 AU, respectively). PAOD patients revealed higher peak powers in the frequency interval of 0.007-0.02 Hz (120+/-82 vs. 85+/-62 AU(2)/Hz; P < 0.05), 0.02-0.06 Hz (116+/-128 vs. 63+/-48 AU(2)/Hz, respectively; P < 0.05) and 0.06-0.2 Hz (39+/-49 vs. 14+/-10 AU(2)/Hz; P < 0.05). These flowmotion frequencies are related to vascular endothelium activity, sympathetic activity and vessel wall myogenic activity, respectively. During POH the mean peak power of the flowmotion waves increased significantly (P < 0.05) in HS respect to Bsl with the only exception of the 0.02-0.06 Hz band. In the PAOD patients, compared to Bsl the amplitude of the flowmotion waves did not significantly change during POH. In addition, the PAOD patients presented an increased time from release to peak-flux (18.25+/-15.5 vs. 2.16+/-1.28 s, respectively; P < 0.05), an increased time from release to recovery of the basal perfusion (90.26+/-39.14 vs. 26.55+/-14.05 s, respectively; P < 0.05) and a lower slope of the POH curve (10+/-15 vs. 54+/-17 degrees , respectively; P < 0.05), compared with HS. The cutaneous arm vasodilatory response to Ach and to SNP was reduced in PAOD patients in comparison with HS (P < 0.001). In conclusion, our findings showed an increased amplitude of the frequency interval 0.007-0.02, 0.02-0.06 and 0.06-0.2 Hz during Bsl in PAOD patients which did not change during the POH test. All data suggest that in stage II PAOD patients the leg skin perfusion is not impaired during Bsl because of a compensatory mechanism related to increased endothelial, myogenic and sympathetic activities. However during reactive hyperaemia these mechanisms appear to be exhausted in accordance with the reduced vasoreactivity to Ach and SNP.

Classic intermittent claudication is an uncommon manifestation of lower extremity peripheral arterial disease in hospitalized patients with coronary artery disease

Synchronous peripheral arterial disease (PAD) and coronary artery disease (CAD) is common. Standardized questionnaires such as the Rose/WHO questionnaire and later the Edinburgh modification of this questionnaire were developed to screen for PAD. Little data are available on the sensitivity of these questionnaires in hospitalized patients with CAD. The aim of this study was to determine the accuracy of these questionnaires and the prevalence of classic intermittent claudication in hospitalized patients with CAD. Medically stable patients with CAD were invited to participate before hospital discharge. The patients answered both the Rose/WHO and Edinburgh modification claudication questionnaires and had an ankle-brachial index (ABI) measured. An ABI less than or equal to 0.9 was considered to be indicative of significant PAD. Patients who had undergone previous lower extremity revascularization for PAD and had a corrected ABI greater than 0.9 were excluded. Ninety-five patients (66 men) were recruited. By measuring the ABI, 35 patients (25 men) were found to have significant PAD. An additional 3 patients who had an ABI corrected by lower extremity revascularization were excluded from the analysis. The Rose/WHO questionnaire had a sensitivity, specificity, and overall accuracy (95% CI) of 14.3% (2.7-25.9%), 96.7% (92.1-100%), and 66.3% (56.8-75.8%), respectively. The Edinburgh modification of the Rose/WHO questionnaire had a sensitivity, specificity, and overall accuracy (95% CI) of 28.6% (13.6-43.5%), 90.0% (82.4-97.6%), 67.4% (57.9-76.8%), respectively. Despite the high incidence of synchronous PAD in hospitalized patients with CAD, traditional claudication questionnaires are insensitive to PAD detection. Classic claudication is an uncommon manifestation of PAD in hospitalized patients with CAD.

Axonal neuropathy in chronic peripheral arterial occlusive disease

Chronic peripheral arterial occlusive disease of the lower limbs may cause tissue damage. Type and extent of peripheral nerve involvement is controversial. We examined 25 patients with peripheral arterial occlusive disease in various grades of severity and 37 age-matched healthy controls using conventional angiography and motor and sensory nerve conduction tests. Subjects with confounding factors for peripheral neuropathies were excluded. We found prolongation of distal motor latencies, decrease of motor and sensory nerve conduction velocities, and reduction in amplitude of the compound muscle action potential. Amplitudes of the compound muscle action potentials were lower in patients with pain at rest than in patients with intermittent claudication and decreased with increasing neurological disability score. Sural nerve conduction velocity, peroneal nerve F-wave chronodispersion, and tibial nerve F-wave persistence were the most frequent abnormal findings. Therefore we concluded that chronic peripheral arterial occlusive disease causes axonal degeneration, resulting in axonal polyneuropathy.

Does lower limb revascularization result in an improvement in sensory perception thresholds?

Patients with peripheral vascular disease are susceptible to neuropathy from chronic hypoxia. We wished to determine whether revascularization of chronically ischemic limbs results in any clinical changes in peripheral sensory thresholds. We prospectively measured quantitative vibration perception thresholds (VPT) using a Horwell neurothesiometer (in volts) in patients undergoing infrainguinal bypass, preoperatively and up to 6 month postoperatively. The bypassed limbs' preoperative VPT values were higher (lesser sensory perception) than the contralateral control limbs' preoperative values (mean score differences: 6 +/- 2 and 4 +/- 10 at toe and foot levels respectively; p ? 0.004). Preoperative VPT values were not different from the 6-month postoperative values for the revascularized legs at toe and foot levels for all 55 patients (mean score change of ?0.84 and ?1.32, p > 0.5). The contralateral limbs' VPT values did not change significantly over the 6-month period (mean change scores of 2.9, p > 0.15, and 2, p > 0.30, for toe and foot, respectively). A comparison of preoperative values between limbs that were eventually amputated and saved revealed no statistically significant differences. This study suggests that revascularization does not result in a clinically detectable improvement in sensory neuropathy. It may, however, prevent further degradation. The degree of preoperative neuropathy does not affect outcome in terms of limb salvage.

Is cardiovascular disease a risk factor in the development of axonal polyneuropathy?

OBJECTIVES

To determine if cardiovascular disease may be a risk factor in the development of chronic idiopathic axonal polyneuropathy (CIAP).

METHODS

In this incidence case-control study, the prevalence of cardiovascular disease and risk factors in 97 patients with CIAP (mean age 67.5 (SD 7.9) years) and the prevalence of neuropathic features in 97 patients with peripheral arterial disease (PAD) (mean age 67.1 (SD 7.3) years) were investigated. The results were compared with those for 96 age and sex matched controls without diagnosed PAD or polyneuropathy (mean age 67.5 (SD 9.1) years). In a randomly chosen subgroup of 23 patients with CIAP, 42 patients with PAD, and 48 controls, an electrodiagnostic investigation was performed.

RESULTS

Patients with CIAP more often had manifest cardiovascular disease and cardiovascular risk factors than controls (stroke 18% v 6% of patients, odds ratio (OR) 3.2 (95% confidence interval (CI) 1.8 to 5.9); heart disease 29% v 15%, OR 2.4 (95% CI 1.2 to 4.9); family history of cardiovascular disease 42% v 21%, OR 2.8 (95% CI (1.5 to 5.2); hypertension 56% v 39%, OR 2.0 (95% CI 1.1 to 3.6); hypercholesterolaemia 46% v 21%, OR 3.3 (95% CI 1.5 to 7.3); current smoking 38% v 23%, OR 2.1 (95% CI 1.1 to 3.9)). The prevalence of cardiovascular disease and cardiovascular risk factors was lower than in patients with PAD. Patients with PAD more often had polyneuropathy than controls (15% v 5%, OR 3.3 (95% CI 1.1 to 10.0)). There was a trend towards lower nerve conduction velocities and lower amplitudes on electrodiagnostic investigation compared with controls.

CONCLUSION

This study shows that cardiovascular disease and CIAP often coexist, and therefore cardiovascular disease may be a cofactor in the development of CIAP.

The relationship between history of falling and physical function in subjects with peripheral arterial disease

The purpose of this study was to determine whether peripheral arterial disease (PAD) subjects with a history of falling had more impaired physical function than their non-falling counterparts. A total of 120 PAD subjects (26%) who had fallen over the past year and 346 PAD subjects (74%) who had not fallen were evaluated. Additionally, subjects were characterized on physical function, consisting of balance, strength, ambulatory function, and monitored physical activity, as well as PAD-specific measures of ankle/brachial pressure index (ABPI) and treadmill claudication distances. Full-tandem stance time was 19% shorter (p < 0.001) in the fallers than in the non-fallers (7.2 +/- 0.3 vs 8.9 +/- 0.1 s; mean +/- SEM), and the self-reported ability to climb stairs was 36% lower (27 +/- 4 vs 42 +/- 2%). Furthermore, the fallers were 126% more likely (p < 0.001) to report ambulatory stumbling and unsteadiness, took 14% longer (p = 0.022) to perform five sequential sit-to-stand transfers using an armless chair, covered 16% shorter distance (p < 0.001) during a 6-min walk test, and were 25% less physically active than the non-fallers. The groups had similar ABPI and treadmill claudication distances (p < 0.05). A history of falling was independently related to the self-reported ability to climb stairs, the full-tandem stance time, self-reported ambulatory stumbling and unsteadiness, and daily physical activity (multiple R = 0.47, p < 0.001). In conclusion, impairments in multiple domains of physical function were associated with a history of falling in PAD subjects with intermittent claudication. Furthermore, the link between poor physical function and falling was independent of PAD severity.

Lower extremity strength deficits in peripheral arterial occlusive disease patients with intermittent claudication

The purposes of this study were to quantify the degree and distribution of lower extremity weakness in patients with peripheral arterial occlusive disease (PAOD) compared to apparently healthy older patients and to determine if performance of a simple functional measure correlates with lower extremity strength. Older patients (n = 46), 31 with PAOD (mean age = 69.9 years; mean ankle-brachial index = 0.67) and 15 without PAOD (mean age = 62.6 years; mean ankle-brachial index = 1.20), underwent isometric strength testing of hip, knee, and ankle musculature. In patients with PAOD, dorsiflexion strength was 15% lower (p < 0.05) in the more affected limb (55 +/- 4 Newton-meters; mean +/- SE) versus the less affected limb (65 +/- 5 Newton-meters). Overall, the dorsiflexor muscles of the more affected extremity were 22% weaker (p < 0.05) in the PAOD group than in the non-PAOD group (73 +/- 6 Newton-meters). No other significant differences in strength were found between the PAOD and the healthy elderly groups or between the more affected and less affected limbs in the PAOD patients. The time to perform five sequential sit-to-stand transfers using an armless chair was 23% greater (p < 0.01) in the PAOD group (13.0 +/- 0.5 s) than in the healthy elderly (10.7 +/- 0.9 s). In the PAOD patients, dorsiflexor strength was correlated with chair stand time (r = -0.37, p < 0.05). The authors conclude that PAOD patients with intermittent claudication are functionally limited by dorsiflexion weakness, impairing their ability to perform tasks requiring distal lower extremity strength.