Lower extremity arterial disease and the aging process: a review

Do Sociodemographic, Behavioral, Clinical, and Anthropometric Factors Influence the Association Between Sex and Functional Capacity in Patients with Peripheral Arterial Disease?

BACKGROUND

To explore the influence of sociodemographic, behavioral, clinical, and anthropometric factors on the association between sex and functional capacity in patients with peripheral arterial disease.

METHODS

A cross-sectional study was conducted with patients aged more than 45 years, diagnosed with peripheral artery disease (PAD), from 2 Brazilian hospitals. Data on sociodemographic characteristics, behavioral risk factors, clinical profile, and anthropometric measurements were collected. Functional capacity was assessed using the 6-min walk test and the Walking Impairment Questionnaire. Statistical analyses, including t-tests, chi-square tests, and logistic regression, were performed to assess the relationships between sex, functional capacity, and potential influencing factors.

RESULTS

Among the 262 patients with PAD, 67 were women and 113 were men. Women exhibited lower absolute functional capacity and lower Walking Impairment Questionnaire scores compared to men, even after adjusting for potential confounders. However, relative functional capacity did not significantly differ between sexes after adjusting for variables. Pain-free walking distance was also lower in women compared to that in men, but this association lost significance after adjusting for sociodemographic factors.

CONCLUSIONS

Women with PAD had lower absolute functional capacity compared to men, influenced by various factors such as sociodemographic, behavioral, clinical, and anthropometric factors. However, the relative functional capacity was similar between genders, being influenced only by behavioral factors, while for the distance walked until pain, the association was lost after adjustments for sociodemographic factors.

Machine Learning Confirms Nonlinear Relationship between Severity of Peripheral Arterial Disease, Functional Limitation and Symptom Severity

BACKGROUND

Peripheral arterial disease (PAD) involves arterial blockages in the body, except those serving the heart and brain. We explore the relationship of functional limitation and PAD symptoms obtained from a quality-of-life questionnaire about the severity of the disease. We used a supervised artificial intelligence-based method of data analyses known as machine learning (ML) to demonstrate a nonlinear relationship between symptoms and functional limitation amongst patients with and without PAD.

OBJECTIVES

This paper will demonstrate the use of machine learning to explore the relationship between functional limitation and symptom severity to PAD severity.

METHODS

We performed supervised machine learning and graphical analysis, analyzing 703 patients from an administrative database with data comprising the toe-brachial index (TBI), baseline demographics and symptom score(s) derived from a modified vascular quality-of-life questionnaire, calf circumference in centimeters and a six-minute walk (distance in meters).

RESULTS

Graphical analysis upon categorizing patients into critical limb ischemia (CLI), severe PAD, moderate PAD and no PAD demonstrated a decrease in walking distance as symptoms worsened and the relationship appeared nonlinear. A supervised ML ensemble (random forest, neural network, generalized linear model) found symptom score, calf circumference (cm), age in years, and six-minute walk (distance in meters) to be important variables to predict PAD. Graphical analysis of a six-minute walk distance against each of the other variables categorized by PAD status showed nonlinear relationships. For low symptom scores, a six-minute walk test (6MWT) demonstrated high specificity for PAD.

CONCLUSIONS

PAD patients with the greatest functional limitation may sometimes be asymptomatic. Patients without PAD show no relationship between functional limitation and symptoms. Machine learning allows exploration of nonlinear relationships. A simple linear model alone would have overlooked or considered such a nonlinear relationship unimportant.

Peripheral artery disease: how much inter-leg symmetry? A contrast-enhanced magnetic resonance angiography study

The aim of this observational retrospective study was to qualitatively and quantitatively evaluate the symmetry of atherosclerotic plaques in patients with peripheral artery disease (PAD) undergoing contrast-enhanced magnetic resonance angiography of lower limbs. We retrospectively evaluated the peripheral magnetic resonance angiography of 82 patients considering the iliac, femoral and tibial arteries. Stenosis was scored 0 (none), 1 (<50%), 2 (50%-74%), 3 (75%-99%), and 4 (occluded). Symmetry was quantified as the percentage of bilaterally-diseased arteries and using the inter-leg absolute score difference (0-4). Signs test and Cohen κ were also calculated. Seventy-one (87%) patients had ≥1 bilaterally-diseased artery, and 168 (20%) of 820 artery pairs were bilaterally affected. At least 1 bilateral stenosis was observed from 11% (right internal iliac) to 73% (right superficial femoral). All 10 arteries showed symmetry, none of the inter-leg comparisons being significantly different (P ≥ .100). Cohen κ ranged from 0.208 (common femoral) to 0.533 (internal iliac). This study showed that PAD was symmetrically distributed between the 2 legs, with the internal iliac artery being the most symmetric segment. Symmetry of PAD was quantified in 20%.

Astaxanthin Complexes to Attenuate Muscle Damage after In Vivo Femoral Ischemia-Reperfusion

(1) Background: Reperfusion injury refers to the cell and tissue damage induced, when blood flow is restored after an ischemic period. While reperfusion reestablishes oxygen supply, it generates a high concentration of radicals, resulting in tissue dysfunction and damage. Here, we aimed to challenge and achieve the potential of a delivery system based on astaxanthin, a natural antioxidant, in attenuating the muscle damage in an animal model of femoral hind-limb ischemia and reperfusion. (2) Methods: The antioxidant capacity and non-toxicity of astaxanthin was validated before and after loading into a polysaccharide scaffold. The capacity of astaxanthin to compensate stress damages was also studied after ischemia induced by femoral artery clamping and followed by varied periods of reperfusion. (3) Results: Histological evaluation showed a positive labeling for CD68 and CD163 macrophage markers, indicating a remodeling process. In addition, higher levels of Nrf2 and NQO1 expression in the sham group compared to the antioxidant group could reflect a reduction of the oxidative damage after 15 days of reperfusion. Furthermore, non-significant differences were observed in non-heme iron deposition in both groups, reflecting a cell population susceptible to free radical damage. (4) Conclusions: Our results suggest that the in situ release of an antioxidant molecule could be effective in improving the antioxidant defenses of ischemia/reperfusion (I/R)-damaged muscles.

Treatment of Critical Limb Ischemia by pIRES/VEGF165/HGF Administration

BACKGROUND

Prognosis of peripheral artery disease (PAD), especially critical limb ischemia (CLI), is very poor despite the development of endovascular therapy and bypass surgery. Many patients result in having leg amputation. We decided to investigate the safety and efficacy of plasmid of internal ribosome entry site/vascular endothelial growth factor (VEGF) 165/hepatocyte growth factor (HGF) gene therapy (GT) in patients suffered from CLI.

METHODS

Administration of plasmid of internal ribosome entry site/VEGF165/HGF was performed in 12 limbs of 12 patients with rest pain and ischemic ulcers due to CLI. Plasmid was injected into the muscles of the ischemic limbs. The levels of VEGF in serum and the ankle-brachial index (ABI) were measured before and after treatment.

RESULTS

Mean (±SD) plasma levels of VEGF increased nonsignificantly from 258 ± 81 pg/L to 489 ± 96 pg/L (P > 0.05) 2 weeks after therapy, and the ABI improved significantly from 0.27 ± 0.20 to 0.50 ± 0.22 (P < 0.001) 3 months after therapy. Ischemic ulcers healed in 9 limbs. Amputation was performed in 3 patients because of advanced necrosis and wound infection. However, the level of amputations was lowered below knee in these cases. Complications were limited to transient leg edema in 3 patients and fever in 2 patients.

CONCLUSIONS

Intramuscular administration of plasmid of internal ribosome entry site/VEGF165/HGF is safe, feasible, and effective for patients with critical leg ischemia.

Ankle Brachial Index (ABI) predicts 2-year mortality risk among older adults in the Republic of Congo: The EPIDEMCA-FU study

BACKGROUND AND AIMS

Peripheral artery disease (PAD) is known to be associated with mortality in high income countries but no data regarding Sub-Saharan Africa (SSA) populations are documented. This study aimed at assessing the prognostic value of the Ankle Brachial Index (ABI) among older adults in the Republic of Congo.

METHODS

Congolese subjects ≥65 years were included in a longitudinal population-based survey (EPIDEMCA-FU). Demographic, biological, and clinical data were collected at baseline. PAD was defined by an ABI≤0.90. Information on mortality was collected from key informants in participants' households. Cox proportional hazard models, adjusted for traditional and cardiovascular risk factors, were fitted to evaluate the association between an ABI≤0.90 and death.

RESULTS

1029 participants were recruited at baseline. ABI measurement was obtained from 927 participants, of whom 17.4% presented an ABI≤0.90. During a 2-year follow-up, a total of 83 (9.1%) deaths were recorded. Mortality was higher in the low-ABI group with 23 deaths (14.7%) vs. 57 (7.8%) and 3 (12.0%), respectively among those with 0.90 < ABI<1.4 and ABI≥1.40 (p = 0.039). After adjustment, an ABI≤0.90 was associated with an increased risk of mortality (HR = 1.86; 95%CI 1.04-3.87). Mortality was also independently associated with increasing age (HR = 1.05; 95%CI 1.02-1.09), dementia (HR = 2.73; 95% CI 1.15-8.05), alcohol use (HR = 0.51; 95%CI 0.29-0.88) and female sex (HR = 0.37; 95%CI 0.19-0.72).

CONCLUSIONS

In this study, a low ABI predicted an increased mortality risk among older people. ABI may represent a simple and inexpensive tool to identify older people at high risk of death in SSA.

Creating and validating a warfarin pharmacogenetic dosing algorithm for Colombian patients

Purpose

Warfarin is an oral anticoagulant associated with adverse reaction to drugs due to wide inter- and intra-individual dosage variability. Warfarin dosage has been related to non-genetic and genetic factors. CYP2C9 and VKORC1 gene polymorphisms affect warfarin metabolism and dosage. Due to the central role of populations’ ethnical and genetic origin on warfarin dosage variability, novel algorithms for Latin American subgroups are necessary to establish safe anticoagulation therapy.

Patients and methods

We genotyped CYP2C9*2 (c.430C > T), CYP2C9*3 (c.1075A > C), CYP4F2 (c.1297G > A), and VKORC1 (−1639 G > A) polymorphisms in 152 Colombian patients who received warfarin. We evaluated the impact on the variability of patients’ warfarin dose requirements. Multiple linear regression analysis, using genetic and non-genetic variables, was used for creating an algorithm for optimal warfarin maintenance dose.

Results

Median weekly prescribed warfarin dosage was significantly lower in patients having the VKORC1-1639 AA genotype and poor CYP2C9*2/*2,*2/*3 metabolizers than their wild-type counterparts. We found a 2.3-fold increase in mean dose for normal sensitivity patients (wild-type VKORC1/CYP2C9 genotypes) compared to the other groups (moderate and high sensitivity); 31.5% of the patients in our study group had warfarin sensitivity-related genotypes. The estimated regression equation accounted for 44.4% of overall variability in regard to warfarin maintenance dose. The algorithm was validated, giving 45.9% correlation (R²=0.459).

Conclusion

Our results describe and validate the first algorithm for predicting warfarin maintenance in a Colombian mestizo population and have contributed toward the understanding of pharmacogenetics in a Latin American population subgroup.

Endovascular revascularisation versus conservative management for intermittent claudication

BACKGROUND

Intermittent claudication (IC) is the classic symptomatic form of peripheral arterial disease affecting an estimated 4.5% of the general population aged 40 years and older. Patients with IC experience limitations in their ambulatory function resulting in functional disability and impaired quality of life (QoL). Endovascular revascularisation has been proposed as an effective treatment for patients with IC and is increasingly performed.

OBJECTIVES

The main objective of this systematic review is to summarise the (added) effects of endovascular revascularisation on functional performance and QoL in the management of IC.

SEARCH METHODS

For this review the Cochrane Vascular Information Specialist (CIS) searched the Specialised Register (February 2017) and the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 1). The CIS also searched trials registries for details of ongoing and unpublished studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing endovascular revascularisation (± conservative therapy consisting of supervised exercise or pharmacotherapy) versus no therapy (except advice to exercise) or versus conservative therapy (i.e. supervised exercise or pharmacotherapy) for IC.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, extracted data, and assessed the methodological quality of studies. Given large variation in the intensity of treadmill protocols to assess walking distances and use of different instruments to assess QoL, we used standardised mean difference (SMD) as treatment effect for continuous outcome measures to allow standardisation of results and calculated the pooled SMD as treatment effect size in meta-analyses. We interpreted pooled SMDs using rules of thumb (< 0.40 = small, 0.40 to 0.70 = moderate, > 0.70 = large effect) according to the Cochrane Handbook for Systematic Reviews of Interventions. We calculated the pooled treatment effect size for dichotomous outcome measures as odds ratio (OR).

MAIN RESULTS

We identified ten RCTs (1087 participants) assessing the value of endovascular revascularisation in the management of IC. These RCTs compared endovascular revascularisation versus no specific treatment for IC or conservative therapy or a combination therapy of endovascular revascularisation plus conservative therapy versus conservative therapy alone. In the included studies, conservative treatment consisted of supervised exercise or pharmacotherapy with cilostazol 100 mg twice daily. The quality of the evidence ranged from low to high and was downgraded mainly owing to substantial heterogeneity and small sample size.Comparing endovascular revascularisation versus no specific treatment for IC (except advice to exercise) showed a moderate effect on maximum walking distance (MWD) (SMD 0.70, 95% confidence interval (CI) 0.31 to 1.08; 3 studies; 125 participants; moderate-quality evidence) and a large effect on pain-free walking distance (PFWD) (SMD 1.29, 95% CI 0.90 to 1.68; 3 studies; 125 participants; moderate-quality evidence) in favour of endovascular revascularisation. Long-term follow-up in two studies (103 participants) showed no clear differences between groups for MWD (SMD 0.67, 95% CI -0.30 to 1.63; low-quality evidence) and PFWD (SMD 0.69, 95% CI -0.45 to 1.82; low-quality evidence). The number of secondary invasive interventions (OR 0.81, 95% CI 0.12 to 5.28; 2 studies; 118 participants; moderate-quality evidence) was also not different between groups. One study reported no differences in disease-specific QoL after two years.Data from five studies (n = 345) comparing endovascular revascularisation versus supervised exercise showed no clear differences between groups for MWD (SMD -0.42, 95% CI -0.87 to 0.04; moderate-quality evidence) and PFWD (SMD -0.05, 95% CI -0.38 to 0.29; moderate-quality evidence). Similarliy, long-term follow-up in three studies (184 participants) revealed no differences between groups for MWD (SMD -0.02, 95% CI -0.36 to 0.32; moderate-quality evidence) and PFWD (SMD 0.11, 95% CI -0.26 to 0.48; moderate-quality evidence). In addition, high-quality evidence showed no difference between groups in the number of secondary invasive interventions (OR 1.40, 95% CI 0.70 to 2.80; 4 studies; 395 participants) and in disease-specific QoL (SMD 0.18, 95% CI -0.04 to 0.41; 3 studies; 301 participants).Comparing endovascular revascularisation plus supervised exercise versus supervised exercise alone showed no clear differences between groups for MWD (SMD 0.26, 95% CI -0.13 to 0.64; 3 studies; 432 participants; moderate-quality evidence) and PFWD (SMD 0.33, 95% CI -0.26 to 0.93; 2 studies; 305 participants; moderate-quality evidence). Long-term follow-up in one study (106 participants) revealed a large effect on MWD (SMD 1.18, 95% CI 0.65 to 1.70; low-quality evidence) in favour of the combination therapy. Reports indicate that disease-specific QoL was comparable between groups (SMD 0.25, 95% CI -0.05 to 0.56; 2 studies; 330 participants; moderate-quality evidence) and that the number of secondary invasive interventions (OR 0.27, 95% CI 0.13 to 0.55; 3 studies; 457 participants; high-quality evidence) was lower following combination therapy.Two studies comparing endovascular revascularisation plus pharmacotherapy (cilostazol) versus pharmacotherapy alone provided data showing a small effect on MWD (SMD 0.38, 95% CI 0.08 to 0.68; 186 participants; high-quality evidence), a moderate effect on PFWD (SMD 0.63, 95% CI 0.33 to 0.94; 186 participants; high-quality evidence), and a moderate effect on disease-specific QoL (SMD 0.59, 95% CI 0.27 to 0.91; 170 participants; high-quality evidence) in favour of combination therapy. Long-term follow-up in one study (47 participants) revealed a moderate effect on MWD (SMD 0.72, 95% CI 0.09 to 1.36; P = 0.02) in favour of combination therapy and no clear differences in PFWD between groups (SMD 0.54, 95% CI -0.08 to 1.17; P = 0.09). The number of secondary invasive interventions was comparable between groups (OR 1.83, 95% CI 0.49 to 6.83; 199 participants; high-quality evidence).

AUTHORS' CONCLUSIONS

In the management of patients with IC, endovascular revascularisation does not provide significant benefits compared with supervised exercise alone in terms of improvement in functional performance or QoL. Although the number of studies is small and clinical heterogeneity underlines the need for more homogenous and larger studies, evidence suggests that a synergetic effect may occur when endovascular revascularisation is combined with a conservative therapy of supervised exercise or pharmacotherapy with cilostazol: the combination therapy seems to result in greater improvements in functional performance and in QoL scores than are seen with conservative therapy alone.

Epidemiological characteristics of lower extremity arterial disease in Chinese diabetes patients at high risk: a prospective, multicenter, cross-sectional study

AIMS

To determine the epidemiological characteristics of lower extremity arterial disease (LEAD) in high-risk patients and identify practical gaps in LEAD management.

METHODS

This cross-sectional study consecutively enrolled 10681 patients with type 2 diabetes from 30 hospitals across China from June 2016 to January 2017. All patients were assessed for LEAD by the Ankle-Brachial Index in conjunction with lower limb ultrasonography according to local guidelines.

RESULTS

The mean age of patients was 64.2 years, and the median duration of diabetes was 9.0 years. The overall prevalence of LEAD was 21.2%, with 10.6% of patients diagnosed with LEAD before enrollment and 11.8% newly diagnosed at the present visit. Patients with older age, hypertension and dyslipidemia as well as those who smoked were at higher risk of developing LEAD. Only 55.0%, 28.2%, and 42.5% of participating patients reached the guideline-recommended goals for glycemic, blood pressure, and lipid control, respectively. Anti-hypertensive agents, lipid lowering therapies, anti-platelet agents, and vasodilators were underused, especially in newly diagnosed LEAD patients (44.1%, 46.2%, 35.3%, and 31.7%, respectively).

CONCLUSIONS

Despite the high prevalence of LEAD, it was still found to be underdiagnosed and undertreated in Chinese diabetes patients. More efforts should be directed at encouraging awareness of early LEAD and achieving guideline-recommended goals in type 2 diabetes patients.

Simultaneous pain intensity rating and quantification of ischemia throughout exercise and recovery in proximal versus distal arterial claudication

Data on simultaneous hemodynamic changes and pain rating estimation in arterial claudication while walking are lacking. This study was conducted to determine if a difference in transcutaneous oxygen pressure (tc pO2) exists between proximal and distal localization at pain appearance (PAINapp), maximal pain (PAINmax) and pain relief (PAINrel) in proximal or distal claudication and if a relationship exists between tc pO2 changes and pain intensity. We analyzed the pain rating (Visual Analog Scale (VAS)) to lower limb ischemia, measured with the decrease from rest of oxygen pressure (DROP) tc pO2 index during constant-load treadmill tests in patients with calf ( n = 41) or buttock ( n = 19) claudication. Calves versus buttocks results were analyzed with ANOVA tests. The R2 correlation coefficient between individual VAS versus DROP was calculated. Ischemia intensity versus pain rating changes were correlated. Significant ischemia was required for pain appearance, but pain disappeared despite the persistence of ischemia. We observed no statistical difference for DROP at PAINapp, PAINmax or PAINrel between proximal or distal claudication. A significant correlation between pain rating versus DROP was found: from PAINapp to PAINmax, R2 = 0.750 (calves) and 0.829 (buttocks), and from PAINmax to PAINrel, R2 = 0.608 (calves) and 0.560 (buttocks); p<0.05. Pain appeared after a significant decrease of hemodynamic parameters but disappeared while parameters were not normalized. No difference in pain rating was found in proximal versus distal claudication.

Preoperative Angiographic Criteria for Predicting Free-Flap Transfer Outcomes in Patients With Lower-Extremity Peripheral Arterial Disease

Patients scheduled for microsurgical reconstruction of the lower leg often receive preoperative assessment of recipient vessels using angiography. However, no clear standard is available for evaluating angiographic results to predict free-flap survival outcomes. We developed angiographic criteria for predicting surgical outcome in patients with lower-extremity peripheral arterial disease based on abnormality of the anterior tibial and posterior tibial arteries. We applied the criteria to a small number of patients scheduled for microsurgical reconstruction of the lower leg. Angiographies with arterial abnormalities were classified into 3 groups: favorable free-flap survival, compromised free-flap survival, and postsurgical pedal ischemia. The study enrolled 50 patients between 2005 and 2013. In 42% of patients, arterial abnormalities were observed by angiography. Age >65 years was the strongest risk factor for development of lower-leg arterial abnormality ( P < .001). The anterior tibial and peroneal arteries were significantly more stenotic than other vessels. In the favorable free-flap survival and compromised free-flap survival groups, free-flap transfers were attempted in 7 patients but intraoperatively abandoned in 2 patients, with postoperative failure in 1 patient. In the postsurgical pedal ischemia group, free-flap transfers were attempted in 10 patients but intraoperatively abandoned in 6 patients, with postoperative failure in 3.

Altered gait profile in subjects with peripheral arterial disease

The purpose of this study was to determine whether peripheral arterial disease (PAD) subjects had impaired temporal and spatial gait characteristics compared to non-PAD controls at preferred and rapid self-selected walking paces. A total of 28 PAD subjects with intermittent claudication (age = 71 -1; mean -SEM) and 15 non-PAD controls with at least one cardiovascular risk factor but no ambulatory leg pain (age = 71 -1) were recruited. Gait parameters consisting of velocity, cadence, stride length, swing time, stance time, single-support time, double-support time, and base of support were recorded at the preferred and rapid walking paces. At the rapid walking pace, velocity was 22% slower (p, 0.001) in the PAD subjects compared with the non-PAD controls (99.9 - 3.3 vs. 117.5 - 5.3 cm/s) due to an 8% (p = 0.019) slower cadence (99.9 - 1.7 vs. 103.3 - 2.4 steps/min) and a 14% (p, 0.001) shorter stride length (119.8 - 2.9 vs. 135.8 - 4.2 cm/stride). The PAD subjects spent 5% less of the gait cycle in the swing phase (p = 0.006) and 3% more in stance (p = 0.006) than their non-PAD counterparts. During the stance phase, the PAD subjects spent 5% less of the gait cycle in single-stance (p = 0.004) and 16% more in double-stance (p = 0.007). Similar results were obtained at the preferred walking pace. In conclusion, compared with the controls, PAD subjects adopted an ambulatory pattern that favored greater gait stability at the expense of greater walking speed at either their preferred or rapid self-selected paces.

The potential role of angiotensin-converting enzyme inhibition in peripheral arterial disease

Peripheral arterial disease (PAD) is associated with significant morbidity and mortality, and yet remains under-recognized and under-treated. Atherosclerosis is the most common cause of lower extremity PAD and pharmacological interventions that alter this central pathogenic role of atherosclerosis may alter the natural history of PAD. There is growing evidence that the renin-angiotensin system (RAS) is a significant mediator of this disease process and that treatment with angiotensin-converting enzyme (ACE) inhibitors is associated with vasculoprotective effects that are independent of the antihypertensive properties of these agents. Numerous lines of evidence suggest that ACE inhibitors directly inhibit the atherosclerotic process and improve vascular endothelial function. In patients with PAD, ACE inhibitors have been shown to improve peripheral circulation as measured by peripheral arterial blood pressure and by increases in peripheral blood flow. Preliminary evidence suggests that ACE inhibitors might improve clinical symptoms in patients with PAD. Recent evidence has confirmed that ACE inhibition is associated with a decrease in morbidity and mortality in patients with arterial disease without left ventricular dysfunction; this benefit was at least as great for the subset of patients with PAD. Overall, these data support a significant role for the RAS in the pathogenesis of all atherosclerotic diseases (including PAD) and suggest that the benefit is independent of the blood pressure lowering properties of these agents. These studies suggest that ACE inhibitor therapy should be considered in the routine management of individuals with PAD, regardless of whether they have hypertension or left ventricular dysfunction.

Inpatient utilization of medical services associated with peripheral arterial disease-related inpatient procedures in the Department of Defense

The objective of this study was to describe the inpatient procedural medical care utilization the first 10 years after initial inpatient confirmation of peripheral arterial disease (PAD). A retrospective review was carried out of the computer records of all the army beneficiaries of the Department of Defense healthcare system since 1971. Over 8000 subjects with an initial inpatient confirmation of PAD between January 1, 1980 and December 31, 1985 were reviewed for 10 years following the initial visit. The utilization of PAD-related invasive procedures gradually increased over the first 8 years, and rose sharply in the ninth and tenth years after initial diagnosis, while the utilization of examination procedures was highest in the first, fifth to seventh, ninth and tenth years. Procedures involving bypass and amputation had the highest utilization among invasive procedures, while procedures involving arteriography and ultrasonography accounted for 88% of all examination procedures. Bypass and repair of vessel procedures gradually rose throughout the 10 years after initial diagnosis, while amputations and skin grafts remained relatively constant. Procedures involving arteriography rose until year 5 and then tapered off, while utilization of ultrasonography rose in year 7 and tapered off. These results suggest that PAD-related studies should consider the progression of the disease past the fifth year after the initial inpatient visit for PAD when measuring a change in outcomes.

Leptospirosis and Peripheral Artery Occlusive Disease: A Nationwide Cohort Analysis

Data on the association between peripheral artery occlusive disease (PAOD) and leptospirosis are limited. We conducted a retrospective cohort study for determining whether leptospirosis is one of the possible risk factors for PAOD. Patients diagnosed with leptospirosis by using 2000 to 2010 data from the Taiwan National Health Insurance Research Database. Patients with leptospirosis without a history of PAOD were selected. For each leptospirosis patient, 4 controls without a history of leptospirosis and PAOD were randomly selected and frequency-matched for sex, age, the year of the index date, and comorbidity diseases. The follow-up period was from the time of the initial diagnosis of leptospirosis to the diagnosis date of PAOD, or December 31, 2011. The Cox proportional hazard regression models were used for analyzing the risk of PAOD. During the follow-up period, the cumulative incidence of PAOD was higher among the patients from the leptospirosis cohort than among the nonleptospirosis cohort (log-rank test, P < 0.001). In total, 29 patients with PAOD from the leptospirosis cohort and 81 from the nonleptospirosis cohort were observed with the incidence rates of 2.1 and 1.3 per 1000 person-years, respectively, yielding a crude hazards ratio (HR) of 1.62 (95% confidence interval [CI] = 1.44-1.81) and adjusted HR (aHR) of 1.75 (95% CI = 1.58-1.95).The risk of PAOD was 1.75-fold higher in the patients with leptospirosis than in the general population.

Combined autologous bone marrow mononuclear cell and gene therapy as the last resort for patients with critical limb ischemia

INTRODUCTION

Our study was designed to investigate the safety and efficacy of combined autologous bone marrow mononuclear cell (MNC) and gene therapy in comparison to conventional drug therapy in patients with critical limb ischemia (CLI).

MATERIAL AND METHODS

Thirty-two patients with CLI persisting for 12-48 months (average time 27.5 months) were randomized into 2 groups, each group consisting of 16 patients. In the first group, administration of autologous bone marrow MNC and vascular endothelial growth factor (VEGF) plasmid was performed. The patients from the second group were treated pharmacologically with pentoxifylline. Ankle-brachial index (ABI) was measured and angiography was performed before and finally 3 months after treatment. The pain was evaluated using the Visual Analog Scale (VAS) before and after 3 months.

RESULTS

Ankle-brachial index improved significantly from 0.29 ±0.21 to 0.52 ±0.23 (p < 0.001) in 12 patients (75.0%) 3 months after the experimental therapy in group 1. In this group angiography showed the development of collateral vessels. Ischemic ulcers healed completely in 11 patients (68.75%). In group 2 the ABI did not improve in any patient; moreover the complete healing of skin ulcers was not found in any of the patients of this group. Amputation was performed in 4 (25.0%) patients in group 1, and in 8 patients (50%) from group 2.

CONCLUSIONS

These data after 3-month follow-up indicate that intramuscular injection of MNC combined with gene therapy in patients with chronic CLI is safe, and a more feasible and effective method of treatment than the conventional therapy. However, both therapies are limited by the degree of microcirculation damage.

V.O2 Kinetics and clinical factors among patients with peripheral artery disease

PURPOSE

To investigate the association between oxygen uptake (V.O2) kinetics and demographic, behavioral, and clinical factors among patients with peripheral artery disease (PAD).

METHODS

A total of 85 PAD patients with intermittent claudication performed a constant load treadmill test, and breath-by-breath (V.e.)O2 was obtained to assess V.O2 kinetics. Demographic information, anthropometry, cardiovascular risk factors, and comorbid conditions were recorded.

RESULTS

Using univariate analyses, higher values of tau ([τ], i.e., slowed V.O2 kinetics) were associated with female gender, non-Caucasian race, hypertension, dyslipidemia, and age ≤66 years. Smoking, diabetes, obesity, metabolic syndrome, height, and ankle brachial index were not significantly related to V.O2 kinetics. Using multiple regression procedures, the identified predictors of slowed V.O2 kinetics were female gender (4.76 [95% CI: 1.49-8.03] seconds; P = .0049), non-Caucasian race (4.70 [95% CI: 1.29-8.12] seconds; P = .0075), hypertension (12.06 [95% CI: 8.83-15.28] seconds; P < .0001), and age ≤66 years (4.97 [95% CI: 1.95-7.99] seconds; P = .0015).

CONCLUSIONS

In PAD patients, slowed V.O2 kinetics are associated with demographic and clinical factors. The clinical significance is that female, non-Caucasian, and hypertensive PAD patients present central and/or peripheral limitations that may partially account for their walking impairment.

A prospective cohort study of prognostic factors for the healing of heel pressure ulcers

BACKGROUND

pressure ulcers, 25-30% of which are on the heels are a major burden to patients and healthcare systems. A better understanding of factors associated with healing is required to inform treatment and research priorities.

OBJECTIVES

to identify patient and pressure ulcer characteristics associated with the healing of heel pressure ulcers.

STUDY DESIGN AND SETTING

patients with heel pressure ulcers were recruited to a prospective cohort study in a large teaching hospital in the UK, with a maximum 18-month follow-up. Cox proportional hazards model regression analysis was used to identify prognostic factors for healing.

RESULTS

one hundred and forty of 148 patients recruited were analysed. They had 183 pressure ulcers: 77 ulcers healed, 5 were on limbs amputated prior to ulcer healing, 88 were on patients who died prior to healing, 11 were present at the end of the study and 2 were lost to follow-up. The median time to healing was 121 (range 8-440) days. Of 12 variables associated with healing (P ≤ 0.2), multi-variable analysis identified two factors which were independently predictive of healing including the presence of a severe (versus superficial) ulcer (hazard ratio = 0.48, P < 0.1) and the presence of peripheral arterial disease (hazard ratio = 0.40, P < 0.1).

CONCLUSIONS

increased ulcer severity and the presence of peripheral arterial disease significantly reduced the probability of healing. Treatments for heel pressure ulcers should consider the severity of the ulcer and the presence of peripheral arterial disease.

Pressure-relieving devices for treating heel pressure ulcers

BACKGROUND

Pressure ulcers are areas of localised damage to the skin and underlying tissue caused by pressure or shear. Pressure redistribution devices are used as part of the treatment to reduce the pressure on the ulcer. The anatomy of the heel and the susceptibility of the foot to vascular disease mean that pressure ulcers located there require a particular approach to pressure relief.

OBJECTIVES

To determine the effects of pressure-relieving interventions for treating pressure ulcers on the heel.

SEARCH METHODS

In May 2013, for this first update, we searched the Cochrane Wounds Group Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid EMBASE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); and EBSCO CINAHL. No language or publication date restrictions were applied.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared the effects of pressure-relieving devices on the healing of pressure ulcers of the heel. Participants were treated in any care setting. Interventions were any pressure-relieving devices including mattresses and specific heel devices.

DATA COLLECTION AND ANALYSIS

Both review authors independently reviewed titles and abstracts and selected studies for inclusion. Both review authors independently extracted data and assessed studies for risk of bias.

MAIN RESULTS

In our original review, only one study met the inclusion criteria. This study (141 participants) compared two mattress systems; however, losses to follow up were too great to permit reliable conclusions. We did not find any further relevant studies during this first update.

AUTHORS' CONCLUSIONS

This review identified one small study at moderate to high risk of bias which provided no evidence to inform practice. More research is needed.

Apolipoprotein profiles in subjects with and without peripheral artery disease

We compared plasma apolipoprotein profiles in subjects with peripheral artery disease (PAD) treated with statin medications (n = 21), subjects with PAD who are untreated with statins (n = 18), and control subjects (n = 70). Subjects were assessed on plasma apolipoproteins, medical history, physical examination, ankle-brachial index, and exercise performance using a treadmill test. The percentage of subjects with an abnormal value of apolipoprotein B (ApoB) (≥ 95 mg/dL) was 53% in the PAD group untreated with statins, 29% in the treated PAD group, and 13% in the controls (p < 0.001). The PAD group untreated with statins had higher values for ApoB (p < 0.001), triglycerides (p < 0.01), low-density lipoprotein (LDL)-cholesterol / high-density lipoprotein (HDL)-cholesterol ratio (p < 0.05), and glucose (p < 0.01) than the control group. In contrast, when the statin-treated PAD group was compared with controls, none of the variables were different except that the treated PAD group had lower LDL-cholesterol (p < 0.01) and higher glucose (p < 0.01). Furthermore, the PAD group treated with statins had lower ApoB (p < 0.01), triglycerides (p < 0.001), LDL-cholesterol (p < 0.05), LDL-cholesterol / HDL-cholesterol ratio (p < 0.05), and non-HDL-cholesterol (p < 0.05) than the untreated PAD group. In conclusion, subjects with PAD who are untreated with statin medications have higher levels of ApoB than controls, whereas subjects treated with statins have a more favorable risk profile, characterized by lower ApoB, LDL-C, LDL-C / HDL-C ratio, and non-HDL-C concentrations. Statin therapy may be efficacious for improving apolipoprotein profiles in subjects with PAD and intermittent claudication.

The relevance of mouse models for investigating age-related bone loss in humans

Mice are increasingly used for investigation of the pathophysiology of osteoporosis because their genome is easily manipulated, and their skeleton is similar to that of humans. Unlike the human skeleton, however, the murine skeleton continues to grow slowly after puberty and lacks osteonal remodeling of cortical bone. Yet, like humans, mice exhibit loss of cancellous bone, thinning of cortical bone, and increased cortical porosity with advancing age. Histologic evidence in mice and humans alike indicates that inadequate osteoblast-mediated refilling of resorption cavities created during bone remodeling is responsible. Mouse models of progeria also show bone loss and skeletal defects associated with senescence of early osteoblast progenitors. Additionally, mouse models of atherosclerosis, which often occurs in osteoporotic participants, also suffer bone loss, suggesting that common diseases of aging share pathophysiological pathways. Knowledge of the causes of skeletal fragility in mice should therefore be applicable to humans if inherent limitations are recognized.

Ankle-brachial pressure index and mini nutritional assessment in community-dwelling elderly people

BACKGROUND

A low ankle-brachial pressure index (an ABPI value <0.90) is considered predictive of cardiovascular disease, and is widely thought to increase morbidity and mortality in the elderly. However, good nutrition is beneficial both for the health and the ability to resist and recover from the disease.

OBJECTIVE

The aim of the present study was to evaluate the relationship between the ankle-brachial pressure index and the nutritional status of the elderly in a city of Kochi prefecture, Japan.

METHODS

This was a cross-sectional study in which a total of 100 elderly people, both males and females, were screened for ankle-brachial pressure index (ABPI), nutritional status (through the use of the short form of the mini nutritional assessment), activities of daily living, lifestyle, gait speed (10MWT), postural stability (OLST), and functional mobility (TUG).

RESULTS

About 67% of the participants were found to have a normal nutritional status, 27% were at risk of malnutrition, and six percent were classified as malnourished. The mean ABPI of the participants was 1.08±0.10, and three participants had an ABPI lower than 0.90. The ABPI was statistically higher in well nourished participants compared with those at risk of malnutrition or the malnourished. The mean ABPI was significantly higher in non-smokers compared with former smokers. The ABPI was found to correlate negatively with gait speed and with TUG score.

CONCLUSION

Well-nourished elderly had a higher normal ankle-brachial pressure index as compared with the malnourished elderly. This study provides supportive evidence for the necessity of adequate nutrition for elderly people.

Angiogenic factor AGGF1 promotes therapeutic angiogenesis in a mouse limb ischemia model

BACKGROUND

Peripheral arterial disease (PAD) is a common disease accounting for about 12% of the adult population, and causes significant morbidity and mortality. Therapeutic angiogenesis using angiogenic factors has been considered to be a potential treatment option for PAD patients. In this study, we assessed the potential of a new angiogenic factor AGGF1 for therapeutic angiogenesis in a critical limb ischemia model in mice for PAD.

METHODS AND RESULTS

We generated a unilateral hindlimb ischemia model in mice by ligation of the right common iliac artery and femoral artery. Ischemic mice with intrasmuscular administration of DNA for an expression plasmid for human AGGF1 (AGGF1 group) resulted in increased expression of both AGGF1 mRNA and protein after the administration compared with control mice with injection of the empty vector (control group). Color PW Doppler echocardiography showed that the blood flow in ischemic hindlimbs was significantly increased in the AGGF1 group compared to control mice at time points of 7, 14, and 28 days after DNA administration (n = 9/group, P = 0.049, 0.001, and 0.001, respectively). Increased blood flow in the AGGF1 group was correlated to increased density of CD31-positive vessels and decreased necrosis in muscle tissues injected with AGGF1 DNA compared with the control tissue injected with the empty vector. Ambulatory impairment was significantly reduced in the AGGF1 group compared to the control group (P = 0.004). The effect of AGGF1 was dose-dependent. At day 28 after gene transfer, AGGF1 was significantly better in increasing blood flow than FGF-2 (P = 0.034), although no difference was found for tissue necrosis and ambulatory impairment.

CONCLUSIONS

These data establish AGGF1 as a candidate therapeutic agent for therapeutic angiogenesis to treat PAD.

[Critical ischemia in patients over 80: waiting or evidence-based surgical treatment?]

Critical ischemia is defined by continuous pain, impending sleep, with ankle pressure less than 50mm Hg, and/or first toe pressure less than 30 mm Hg (Dormandy et Rutherford, 2000; Norgren et al., 2007). Treatment of patients aged over 80 requires specific knowledge of arteriopathy at this age and an evaluation of co-morbidity factors (diabetes mellitus, renal failure, ischemic cardiopathy). Assessment should include: the degree of ischemia, the extension of arterial disease, the co-morbidity factors, and the diffusion of the atherosclerotic disease. A transatlantic consensus conference has enabled a classification of arterial lesions determining therapeutic indications. Aorto-iliac lesions may be treated by surgery or angioplasty. Femoro-popliteal or crural lesions may be treated by surgery or angioplasty. Type C or D lesions should be treated by femoro-popliteal or crural bypass. Bypass to the ankle or foot are done on high peripheral resistances. These bypasses require a venous graft. Several authors have shown the utility of short grafts: popliteo-tibial, tibiotibial, tibiopedal artery bypass, tibioplantar artery bypass. In patients over 80, the presence of arteriopathy is an important mortality factor, which is four or five times more important than in the normal population. Twenty-five percent of patients will require amputation.

Correlation between peripheral arterial disease and coronary artery disease using ankle brachial index-a study in Indian population

OBJECTIVE

To study the prevalence of peripheral arterial disease (PAD) of the lower limbs in a high-risk population and its correlation with coronary artery disease (CAD), using the ankle brachial index (ABI).

METHODS

The present study was conducted in randomly selected indoor patients >45 years of age with one or more risk factors for PAD admitted in the cardiology and medicine wards in a tertiary care institute.

RESULTS

Based on ABI <0.9, PAD was diagnosed in 32 of the 182 (18%) patients. Coronary artery disease was present in 15 cases of PAD which was statistically significant.

CONCLUSION

There is a definite and strong correlation between PAD and CAD. Correct diagnosis and supervision of patients with PAD is important for preventing the local progression of the disease and effective secondary prevention of future coronary and cerebrovascular events.

Health-related quality of life, surgical and aesthetic outcomes following microvascular free flap reconstructions: an 8-year institutional review

INTRODUCTION

Microvascular free flap reconstruction has revolutionised the reconstruction of complex defects of traumatic, oncological, congenital and infectious aetiologies. Complications of microvascular free flap procedures impact negatively on patient post-operative course and outcome.

METHODS

We performed a retrospective analysis of 102 consecutive patients undergoing 108 free flap procedures at a tertiary referral centre over an 8-year period. Logistic regression analysis was used to identify factors predictive of free flap complications. Health-related quality of life (HRQoL) and aesthetic outcomes were assessed using the Short Form 36 questionnaire and a satisfaction visual analogue scale respectively.

RESULTS

In total, 108 free tissue transfers were performed; 23% were fasciocutaneous free flaps, 69% musculocutaneous and 8% osteoseptocutaneous. The overall flap success rate was 92.6%. Over a third of patients (34.3%) had flap-related complications ranging from minor wound dehiscence to total flap loss. ASA (American Society of Anesthesiologists) grade ≥2 (OR: 16.9, 95% CI: 15.3-18.1, p<0.009), history of smoking (OR: 6.1, 95% CI: 5.5-7.2, p<0.049), body mass index ≥25 kg/m(2) (OR: 21.3, 95% CI: 20.8-22.1, p<0.003), low albumin (odds ratio [OR]: 2.2, 95% confidence interval [CI]: 1.2-3.9, p<0.003) and peripheral vascular disease (OR: 6.9, 95% CI: 5.9-7.5, p<0.036) were identified as factors independently predictive of free flap complications.

CONCLUSIONS

Patients undergoing uncomplicated free flap surgery and those reporting superior post-operative flap aesthesis have higher HRQoL scores. Microvascular free tissue transfer has revolutionised our approach to the reconstruction of complex defects, providing a safe, reliable procedure to restore functionality and quality of life for patients.

Pressure-relieving devices for treating heel pressure ulcers

BACKGROUND

Pressure ulcers are areas of localised damage to the skin and underlying tissue caused by pressure or shear. Pressure redistribution devices are used as part of the treatment to reduce the pressure on the ulcer. The anatomy of the heel and the susceptibility of the foot to vascular disease mean that pressure ulcers located there require a particular approach to pressure relief.

OBJECTIVES

To determine the effects of pressure-relieving interventions for treating pressure ulcers on the heel.

SEARCH STRATEGY

We searched the Cochrane Wounds Group Specialised Register (searched 25 March 2011); The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1); Ovid MEDLINE (1948 to March Week 3 2011); Ovid EMBASE (1980 to 2011 Week 12);Ovid MEDLINE (In-Process & Other Non-Indexed Citations March 29, 2011); and EBSCO CINAHL (1982 to 25 March 2011). We applied no language or publication date restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared the effects of pressure-relieving devices on the healing of pressure ulcers of the heel. Participants were treated in any care setting. Interventions were any pressure-relieving devices including mattresses and specific heel devices.

DATA COLLECTION AND ANALYSIS

Both review authors independently reviewed titles and abstracts and selected studies for inclusion. Both review authors independently extracted data and assessed studies for risk of bias.

MAIN RESULTS

One study met the inclusion criteria. This study (141 participants) compared two mattress systems however losses to follow up were too great to permit reliable conclusions.

AUTHORS' CONCLUSIONS

This review identified one small study at moderate to high risk of bias which provided no evidence to inform practice. More research is needed.

Oxygen uptake before and after the onset of claudication during a 6-minute walk test

OBJECTIVE

This study compared oxygen uptake before and after the onset of claudication in individuals with peripheral artery disease (PAD) during a 6-minute walk test, and identified predictors of the change in oxygen uptake after the onset of claudication pain.

METHODS

The study included 50 individuals with PAD. During a 6-minute walk test, 33 experienced claudication (pain group), and 17 were pain-free (pain-free group). Oxygen uptake and ambulatory cadence were the primary outcomes evaluated during the 6-minute walk test.

RESULTS

The pain group experienced onset of claudication pain at a mean (standard deviation) of 179 (45) meters and continued to walk to achieve a 6-minute walk distance of 393 (74) meters, which was similar to the 401 (76) meters walked in the pain-free group (P = .74). Oxygen uptake increased (P < .0001) after the onset of pain in the pain group, and this change was greater (P = .025) than the increase in oxygen uptake from the second to fifth minutes of walking in the pain-free group. Ambulatory cadence decreased after the onset of pain in the pain group (P = .0003). The change in oxygen uptake was associated with metabolic syndrome (P = .0023), 6-minute walk distance (P = .0037), age (P = .0041), and oxygen uptake during the second minute of the test (P = .012).

CONCLUSION

Claudication increases oxygen uptake of self-paced, over-the-ground ambulation, despite a decrease in cadence. The pain-mediated increase in oxygen uptake was blunted in individuals with metabolic syndrome, suggesting that the ability to increase oxygen uptake during ambulation is impaired. The clinical significance is that claudication increases the metabolic cost of ambulation, thereby increasing the relative intensity of exercise and reducing the tolerance to sustain ambulation.

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.

Dietary intake of participants with peripheral artery disease and claudication

We compared the dietary intake of participants with peripheral artery disease (PAD) and claudication with diet recommendations of the National Cholesterol Education Program (NCEP) and dietary reference intake values recommended by the Institute of Medicine (IOM) of the National Academy of Sciences. Forty-six participants consumed a mean macronutrient composition of 17% protein, 51% carbohydrate, and 30% fat. Compared to the NCEP and IOM recommendations, few participants met the recommended daily intake for sodium (0%), vitamin E (0%), folate (13%), saturated fat (20%), fiber (26%), and cholesterol (39%). Participants with PAD and claudication have poor nutrition, with diets particularly high in saturated fat, sodium, and cholesterol, and low in fiber, vitamin E, and folate intakes. Participants should be encouraged to reduce consumption of dietary fat, saturated fat, cholesterol, and sodium and to increase fiber and vitamin intakes to meet recommendations of the NCEP and IOM.

Gender differences in daily ambulatory activity patterns in patients with intermittent claudication

OBJECTIVES

To compare the pattern of daily ambulatory activity in men and women with intermittent claudication, and to determine whether calf muscle hemoglobin oxygen saturation (StO2) is associated with daily ambulatory activity.

METHODS

Forty men and 41 women with peripheral arterial disease limited by intermittent claudication were assessed on their community-based ambulatory activity patterns for 1 week with an ankle-mounted step activity monitor and on calf muscle StO2 during a treadmill test.

RESULTS

Women had lower adjusted daily maximal cadence (mean±SE) for 5 continuous minutes of ambulation (26.2±1.2 strides/min vs 31.0±1.2 strides/min; P=.009), for 1 minute of ambulation (43.1±0.9 strides/min vs 47.2±0.9 strides/min; P=.004), and for intermittent ambulation determined by the peak activity index (26.3±1.2 strides/min vs 31.0±1.2 strides/min; P=.009). Women also had lower adjusted time to minimum calf muscle StO2 during exercise (P=.048), which was positively associated with maximal cadence for 5 continuous minutes (r=0.51; P<.01), maximal cadence for 1 minute (r=0.42; P<.05), and peak activity index (r=0.44; P<.05). These associations were not significant in men.

CONCLUSION

Women with intermittent claudication ambulate slower in the community setting than men, particularly for short continuous durations of up to 5 minutes and during intermittent ambulation at peak cadences. Furthermore, the daily ambulatory cadences of women are correlated with their calf muscle StO2 during exercise, as women who walk slower in the community setting reach their minimum calf muscle StO2 sooner than those who walk at faster paces. Women with intermittent claudication should be encouraged to not only walk more on a daily basis, but to do so at a pace that is faster than their preferred speed.

Resting energy expenditure in patients with intermittent claudication and critical limb ischemia

OBJECTIVE

The primary aim of this study was to compare the resting energy expenditure of patients with intermittent claudication and critical limb ischemia. A secondary aim was to identify predictors of resting energy expenditure.

METHODS

One hundred patients limited by intermittent claudication and 40 patients with critical limb ischemia participated in this study. Patients were assessed on resting energy expenditure, body composition, ankle brachial index (ABI), and calf blood flow.

RESULTS

Patients with critical limb ischemia had a lower resting energy expenditure than patients with intermittent claudication (1429 +/- 190 kcal/day vs 1563 +/- 229 kcal/day; P = .004), and higher body fat percentage (34.8 +/- 7.8% vs 31.5 +/- 7.8%; P = .037), higher fat mass (30.0 +/- 9.3 kg vs 26.2 +/- 8.9 kg;P = .016), and lower ABI (0.31 +/- 0.11 vs 0.79 +/- 0.23; P < .001). Resting energy expenditure was predicted by fat free mass (P < .0001), age (P < .0001), ABI (P < .0001), ethnicity (P < .0001), calf blood flow (P = .005), and diabetes (P = .008). Resting energy expenditure remained lower in the patients with critical limb ischemia after adjusting for clinical characteristics plus fat free mass (1473 +/- 27.8 kcal/day [mean +/- SEM] vs 1527 +/- 19.3 kcal/day; P = .031), but it was no longer different between groups after further adjustment for ABI and calf blood flow (1494 +/- 25.2 kcal/day vs 1505 +/- 17.7 kcal/day; P = .269).

CONCLUSION

Resting energy expenditure is decreased with a progression in peripheral arterial disease (PAD) symptoms from intermittent claudication to critical limb ischemia. Furthermore, patients with critical limb ischemia who are most susceptible for decline in resting energy expenditure are older, African American patients with diabetes. The lower resting energy expenditure of patients with critical limb ischemia, combined with their sedentary lifestyle, suggests that they are at high risk for long-term positive energy balance and weight gain.

Prevalence of Metabolic Syndrome in Patients With Intermittent Claudication and its Correlation With the Segment of Arterial Obstruction

The metabolic syndrome (MetS) is associated with increased cardiovascular morbidity and mortality. Intermittent claudication reflects the presence of peripheral arterial disease (PAD). The aim of this study is to determine the prevalence of the MetS in claudicants and its correlation with age, gender, localization of arterial obstruction, and symptomatic coronary disease. Patients (n = 170) with intermittent claudication were studied. The mean age was 65 years (33-89). Metabolic syndrome was diagnosed in 98 patients (57.6%). The mean age of patients with MetS was 63.5 years compared with 67.0 years for patients without MetS ( P = .027). Considering patients aged ≥65 years, MetS was present in 46 (48.9%) individuals and in 52 (68.4%) patients younger than 65 years ( P = .011). Metabolic syndrome must be actively searched for in claudicant patients.

Gender and ethnic differences in arterial compliance in patients with intermittent claudication

OBJECTIVE

To assess the gender and ethnic differences in arterial compliance in patients with intermittent claudication.

METHODS

A total of 114 patients participated, including 38 Caucasian men, 32 Caucasian women, 16 African American men, and 28 African American women. Patients were assessed on large artery elasticity index (LAEI), small artery elasticity index (SAEI), age, weight, body mass index, ankle-brachial index (ABI), smoking status, and metabolic syndrome components.

RESULTS

Group differences were found for LAEI (P = .042), SAEI (P = .019), body mass index (P = .020), prevalence of elevated fasting glucose (P = .001), and prevalence of abdominal obesity (P = .025). Significant covariates for LAEI included age (P = .0002) and elevated triglycerides (P = .0719). LAEI (units = 10 mL x mm Hg) adjusted for age and triglycerides was 39% lower (P = .0005) in African Americans (11.4 +/- .90; mean +/- SE) than in Caucasians (15.8 +/- 0.72), whereas no significant difference (P = .7904) existed between men (13.8 +/- 0.81) and women (13.5 +/- 0.79). Significant covariates for SAEI included age (P = .0001), abdominal obesity (P = .0030), and elevated blood pressure (P = .0067). SAEI (units = 100 mL x mm Hg) adjusted for age, abdominal obesity, and elevated blood pressure was 32% lower (P = .0007) in African-Americans (2.8 +/- 0.3) than in Caucasians 4.1 +/- 0.2), and was 18% lower (P = .0442) in women (3.1 +/- 0.2) than in men (3.8 +/- 0.2).

CONCLUSION

African American patients with intermittent claudication have more impaired macrovascular and microvascular function than Caucasian patients, and women have more impaired microvascular function than men. These ethnic and gender differences in arterial compliance are evident even though ABI was similar among groups, suggesting that arterial compliance provides unique information to quantify vascular impairment in patients with intermittent claudication.

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.

Long-term survival after initial hospital admission for peripheral arterial disease in the lower extremities

BACKGROUND

As the population ages, peripheral arterial disease (PAD) in the lower extremities will become a larger public health problem. Awareness in patients as well clinicians of the high risk of morbidity and mortality is important but seems currently low. Insights in absolute mortality risks following admission for PAD in the lower extremities can be useful to improve awareness as they are easy to interpret.

METHODS

A nationwide cohort of 4,158 patients with an initial admission for PAD in the lower extremities was identified through linkage of the national hospital and population register in 1997 and 2000.

RESULTS

Over 60% of 4,158 patients were men. 28 days, 1 year and 5 year mortality risk were 2.4%, 10.3% and 31.0% for men and 3.5%, 10.4% and 27.4% for women. Coronary heart disease and stroke were frequent cause of death. Five years mortality risk was higher for men compared to women (HR 1.36, 95% CI 1.21-1.53).

CONCLUSION

In conclusion, our findings demonstrate that, 5 year mortality risk is high, especially in men and comparable to that of patients admitted for acute myocardial infarction or ischemic stroke. Though, in general population the awareness of the severity of PAD in the lower extremities is significantly lower than that for any other cardiovascular disease and it seems that cardiovascular risk factor management for prevention in PAD patients is very modest.

Increased lipid oxidation causes oxidative stress, increased peroxisome proliferator-activated receptor-gamma expression, and diminished pro-osteogenic Wnt signaling in the skeleton

Loss of bone mass with advancing age in mice is because of decreased osteoblast number and is associated with increased oxidative stress and decreased canonical Wnt signaling. However, the underlying mechanisms are poorly understood. We report an age-related increase in the lipid oxidation product 4-hydroxynonenal (4-HNE) as well as increased expression of lipoxygenase and peroxisome proliferator-activated receptor-gamma (PPARgamma) in the murine skeleton. These changes together with decreased Wnt signaling are reproduced in 4-month-old mice bearing a high expressing allele of the lipoxygenase Alox15. The addition of 4-HNE to cultured osteoblastic cells increases oxidative stress, which in turn diverts beta-catenin from T-cell-specific transcription factors to Forkhead box O (FoxO) transcription factors, thereby attenuating the suppressive effect of beta-catenin on PPARgamma gene expression. Oxidized lipids, acting as ligands of PPARgamma, promote binding of PPARgamma2 to beta-catenin and reduce the levels of the latter, and they attenuate Wnt3a-stimulated proliferation and osteoblast differentiation. Furthermore, oxidized lipids and 4-HNE stimulate apoptosis of osteoblastic cells. In view of the role of oxidized lipids in atherogenesis, the adverse effects of lipoxygenase-mediated lipid oxidation on the differentiation and survival of osteoblasts may provide a mechanistic explanation for the link between atherosclerosis and osteoporosis.

Resting energy expenditure in subjects with and without intermittent claudication

Subjects with peripheral arterial disease and intermittent claudication have ischemia of the lower extremities, but little is known how this influences resting energy expenditure. The objective of the study was to compare the resting energy expenditure of subjects with and without intermittent claudication. One hundred six subjects limited by intermittent claudication and 77 controls who did not have peripheral arterial disease and intermittent claudication participated in this study. Subjects were assessed on resting energy expenditure, body composition, ankle/brachial index (ABI), and calf blood flow. Subjects with intermittent claudication had a lower resting energy expenditure (1585 +/- 251 vs 1716 +/- 277 kcal/d, P = .019), higher body fat percentage (33.4% +/- 10.7% vs 29.6% +/- 7.7%, P = .016), higher fat mass (29.6 +/- 10.6 vs 24.2 +/- 8.9 kg, P = .011), and lower ABI (0.66 +/- 0.20 vs 1.19 +/- 0.12, P < .001). Resting energy expenditure was predicted by fat-free mass (P < .001), ABI (P = .027), and calf blood flow (P = .040). Resting energy expenditure remained lower in the subjects with intermittent claudication after adjusting for clinical characteristics plus fat-free mass (1611 +/- 171 vs 1685 +/- 209 kcal/d, P = .035), but was no longer different between groups after further adjustment for ABI and calf blood flow (1622 +/- 165 vs 1633 +/- 185 kcal/d, P = .500). Subjects with intermittent claudication have lower resting energy expenditure than controls, which is partially explained by ABI and calf blood flow.

The 9p21 myocardial infarction risk allele increases risk of peripheral artery disease in older people

BACKGROUND

A common variant at chromosome 9p21 (tagged by the rs1333049 or rs10757278 single-nucleotide polymorphism) is strongly associated with myocardial infarction and major arterial aneurysms. An association with peripheral arterial disease (PAD) was also reported in a sample younger than 75 years, but this disappeared on removal of respondents with a myocardial infarction history, resulting in an odds ratio of 1.09 for PAD (P=0.075). We aimed at estimating the association of this variant with an Ankle-Brachial Index (ABI) and PAD in 3 older populations.

METHODS AND RESULTS

We used data from the InCHIANTI, Baltimore Longitudinal Study of Aging, and Health, Aging, and Body Composition studies. In 2630 white individuals (mean age, 76.4 years), the C allele at rs1333049 was associated with lower mean ABI measures and with an increased prevalence of PAD. These associations remained after removal of baseline and incident myocardial infarction cases over a 6-year follow-up for both ABI (-0.017 ABI units; 95% CI, -0.03 to -0.01; P = 1.3 x 10(-4)) and PAD (per allele odds ratio, 1.29; 95% CI, 1.06 to 1.56; P = 0.012). These associations also remained after adjustment for known atherosclerosis risk factors, including diabetes mellitus, smoking, hypercholesterolemia, and hypertension.

CONCLUSIONS

The C allele at rs1333049 is associated with an increased prevalence of PAD and lower mean ABI. This association was independent of the presence of diagnosed myocardial infarction and atherosclerotic risk factors in 3 older white populations.

Peripheral arterial disease and cognitive function

As a marker of generalized atherosclerosis, peripheral arterial disease (PAD) has implications not only for the affected lower extremity but also to overall cardiovascular health. It confers an increased risk of non-fatal and fatal vascular events which increases with the severity of the disease. Patient-based studies have shown that individuals with advanced PAD tend to perform poorly on cognitive tests compared to controls. In population studies, PAD is associated with an increased cognitive decline independently of previous cerebrovascular disease and cardiovascular risk factors. A low ankle-brachial index (ABI) may be an early predictor of cognitive decline and of potential value in identifying individuals at increased risk of cognitive impairment. In patients with PAD, secondary preventive measures directed at decreasing the long-term systemic vascular complications may also be important to the preservation of cognitive health. However, evidence suggests that PAD patients may be undertreated with regard to atherosclerotic risk factors, as demonstrated by an undue emphasis on symptom relief rather than essential risk factor reduction. More research needs to be carried out to determine the predictors of cognitive function in PAD patients, whether subtle cognitive disturbances are related to activities of daily living, including medical treatment compliance, and whether neuroprotective strategies and atherosclerotic risk factor control positively influence cognitive function in these high-risk patients.

Sex differences in calf muscle hemoglobin oxygen saturation in patients with intermittent claudication

PURPOSES

We tested the hypotheses that women have greater impairment in calf muscle hemoglobin oxygen saturation (StO(2)) in response to exercise than men, and that the sex-related difference in calf muscle StO(2) would partially explain the shorter claudication distances of women.

METHODS

The study comprised 27 men and 24 women with peripheral arterial disease limited by intermittent claudication. Patients were characterized on calf muscle StO(2) before, during, and after a graded treadmill test, as well as on demographic and cardiovascular risk factors, ankle-brachial index (ABI), ischemic window, initial claudication distance (ICD), and absolute claudication distance (ACD).

RESULTS

Women had a 45% lower ACD than men (296 +/- 268 m vs 539 +/- 288 m; P = .001) during the treadmill test. Calf muscle StO(2) declined more rapidly during exercise in women than in men; the time to reach minimum StO(2) occurred 54% sooner in women (226 +/- 241 vs 491 +/- 426 seconds; P = .010). The recovery time for calf muscle StO(2) to reach the resting value after treadmill exercise was prolonged in women (383 +/- 365 vs 201 +/- 206 seconds; P = .036). Predictors of ACD included the time from start of exercise to minimum calf muscle StO(2), the average rate of decline in StO(2) from rest to minimum StO(2) value, the recovery half-time of StO(2), and ABI (R(2) = 0.70; P < .001). The ACD of women remained lower after adjusting for ABI (mean difference, 209 m; P = .003), but was no longer significantly lower (mean difference, 72 m; P = .132) after further adjustment for the StO(2) variables for the three calf muscles.

CONCLUSION

In patients limited by intermittent claudication, women have lower ACD and greater impairment in calf muscle StO(2) during and after exercise than men, the exercise-mediated changes in calf muscle StO(2) are predictive of ACD, and women have similar ACD as men after adjusting for calf StO(2) and ABI measures.

Magnetic resonance angiography: current status in the planning and follow-up of endovascular treatment in lower-limb arterial disease

Magnetic resonance angiography (MRA) has become an established imaging modality in the management of lower-limb arterial disease, with emerging roles in treatment planning and follow-up. Contrast-enhanced MRA is now the most widely used technique with clinically acceptable results in the majority of patients. Difficulties in imaging and image interpretation are recognised in certain subgroups, including patients with critical limb ischaemia as well as patients with stents. Although newer contrast agents and refined imaging protocols may offer some solutions to these problems, this optimism is balanced by concerns about the toxicity of certain gadolinium chelates. Further development of interventional MRA remains one of the most significant challenges in the development of magnetic resonance imaging-guided peripheral vascular intervention. The status of MRA in managing patients with lower-limb arterial disease in current clinical practice is reviewed.

Limb ischemia after iliac ligation in aged mice stimulates angiogenesis without arteriogenesis

OBJECTIVE

Older patients are thought to tolerate acute ischemia more poorly than younger patients. Since aging may depress both angiogenesis and arteriogenesis, we determined the effects of age on both angiogenesis and arteriogenesis in a model of severe acute limb ischemia.

METHODS

Young adult (3-months-old) and aged (18-months-old) C57BL/6 mice underwent right common iliac artery and vein ligation and transection. Data were collected on days 0, 7, and 14. Perfusion was measured with a laser Doppler scan and compared to the contralateral limb. Functional deficits were evaluated with the Tarlov scale. Capillary density and endothelial progenitor cell (EPC) number were determined by direct counting lectin-positive/alpha-actin-negative cells and VEGFR2/CXCR4 dually-positive cells, respectively; angiography was performed to directly assess arteriogenesis.

RESULTS

Young adult and aged mice had a similar degree of decreased perfusion after iliac ligation (young, n = 15: 20.4 +/- 1.9%, vs aged, n = 20: 19.6 +/- 1.3%; P = .72, analysis of variance [ANOVA]); however, young mice recovered faster and to a greater degree than aged mice (day 7, 35 +/- 6% vs 17 +/- 4%, P = .046; day 14, 60 +/- 5% vs 27 +/- 7%, P = .0014). Aged mice had worse functional recovery by day 14 compared to young mice (2.3 +/- 0.3 vs 4.3 +/- 0.4; P = .0021). Aged mice had increased capillary density (day 7, 12.9 +/- 4.4 vs 2.8 +/- 0.3 capillaries/hpf; P = .02) and increased number of EPC incorporated into the ischemic muscle (day 7, 8.1 +/- 0.9 vs 2.5 +/- 1.9 cells; P = .007) compared to young mice, but diminished numbers of collateral vessels to the ischemic limb (1 vs 9; P = .01), as seen on angiography.

CONCLUSION

After severe hind limb ischemia, aged animals become ischemic to a similar degree as young animals, but aged animals have significantly impaired arteriogenesis and functional recovery compared to younger animals. These results suggest that strategies to stimulate arteriogenesis may complement those that increase angiogenesis, and may result in improved relief of ischemia.