Asymptomatic peripheral arterial disease is independently associated with impaired lower extremity functioning: the women's health and aging study

Aging and the burden of multimorbidity: associations with inflammatory and anabolic hormonal biomarkers

BACKGROUND

Multimorbidity increases with aging, but risk factors beyond age are unknown.

OBJECTIVE

To investigate the association of inflammatory and anabolic hormonal biomarkers with presence and prospective development of multimorbidity.

METHODS

Nine-year longitudinal study of 1018 participants aged 60 years or older (InCHIANTI Study). Multimorbidity was evaluated at baseline and follow-up visits as number of diagnosed diseases from a predefined list of 15 candidate chronic conditions, defined according to standard clinical criteria. Linear mixed models were used to test cross-sectional and longitudinal associations between candidate biomarkers and multimorbidity.

RESULTS

At baseline, multimorbidity was significantly higher in older participants (p < .001) and higher IL-6, IL-1ra, TNF-α receptor II (TNFAR2), and lower dehydroepiandrosterone sulfate were associated with higher number of diseases, independent of age, sex, body mass index, and education. The rate of longitudinal increase in number of chronic diseases was significantly steeper in participants who were older at baseline (p < .001). In addition, higher baseline IL-6 and steeper increase of IL-6 levels were significantly and independently associated with a steeper increase in multimorbidity over time (p < .001 and p = .003, respectively). Sensitivity analyses, performed using 15 different models obtained by removing each of 15 conditions included in the original list of candidate diseases, confirmed that results were not driven by any specific condition.

CONCLUSIONS

Accumulation of chronic diseases accelerates at older ages and in persons with higher baseline levels and steeper increase over time of IL-6. High IL-6 and increase in IL-6 may serve as early warning sign to better target interventions aimed at reducing the burden of multimorbidity.

Critical evaluation of stents in the peripheral arterial disease of the superficial femoral artery - focus on the paclitaxel eluting stent

The endovascular management of obstructive disease of the superficial femoral artery (SFA) is challenging due to unique anatomical and biomechanical forces. Obstructive lesions of the SFA make up the largest proportion of lesions leading to symptomatic peripheral arterial disease. Accordingly, endovascular treatment of SFA disease is becoming increasingly common and, in many cases, is the preferred initial therapy. The use of self-expanding nitinol stents have proven superior to percutaneous transluminal balloon angioplasty in the treatment of intermediate length SFA stenosis. However, achieving durable results, as well as attaining adequate therapy for long occlusions typically seen in clinical practice, remains problematic. Newer technologies, such as paclitaxel eluting stents, seem promising in improving outcomes.

Risk factors for peripheral artery disease among patients with diabetes in Saudi Arabia

Little is known about the risk factors for peripheral artery disease (PAD) among diabetic patients in Saudi Arabia. We therefore investigated the association of traditional and non-traditional PAD risk factors, as well as clinical markers, with the prevalence of PAD in 598 diabetic patients in Saudi Arabia. PAD was diagnosed as an ankle–brachial index (ABI) <0.9. Information on socio-demographic variables, smoking status, duration of diabetes, and medication were collected by questionnaire. Body weight, height, blood pressure and clinical markers were also measured. The prevalence of PAD in this population was 23.1%. Hypertension (OR (odds ratio) = 2.13, 95% CI: 1.29–3.52), obesity (OR=1.75, 95% CI: 1.13–2.73) and longer duration of diabetes (OR for ≥20 years vs 2–4 years = 3.30, 95% CI: 1.66–6.58) were independently and significantly associated with a higher prevalence of PAD. Participants with the highest quartile of fasting blood glucose and homocysteine levels had a 67% (OR=1.67, 95% CI: 0.89–3.31) and 78% (OR=1.78, 95% CI: 0.87–3.66) higher prevalence of PAD, respectively. Our study identified several important and largely modifiable risk factors for PAD in this Saudi population with diabetes. These findings underscored the importance of reducing cardiovascular risk factors in patients with diabetes.

Serum endostatin concentrations are higher in men with symptoms of intermittent claudication

Objectives. A cleavage fragment of collagen XVIII, endostatin, is released into the circulation and has been demonstrated to have antiangiogenic effects in animal models. We hypothesized that circulating endostatin would be increased in patients with symptoms of lower limb peripheral artery disease. Design. Cross-sectional study. Participants. Community dwelling older men. Measurements. Intermittent claudication was defined using the Edinburgh Claudication Questionnaire (ECQ). Serum endostatin was measured by a commercial ELISA. The association of serum endostatin with intermittent claudication was examined using logistic regression adjusting for age, diabetes, hypertension, dyslipidemia, coronary heart disease, and stroke. Results. Serum endostatin was measured in 1114 men who completed the ECQ. 106 men had intermittent claudication, 291 had atypical pain, and 717 had no lower limb pain. Mean (±standard deviation) serum endostatin concentrations (ng/mL) were 145.22 ± 106.93 for men with intermittent claudication, 129.11 ± 79.80 for men with atypical pain, and 116.34 ± 66.57 for men with no lower limb pain; P < 0.001. A 70 ng/mL increase in endostatin was associated with a 1.17-fold rise in the adjusted odds of having intermittent claudication (OR 1.17, 95% confidence interval 1.00–1.37, and P = 0.050). Conclusions. Serum endostatin is raised in older men who have symptoms of intermittent claudication. The role of endostatin in the genesis and outcome of peripheral artery disease requires further investigation.

Cross-country differences in the association between diabetes and disability

Purpose

This study tested possible cross-country differences in the associations between diabetes and activities of daily living (ADLs), and possible confounding / mediating effects of socio-economic status, obesity, and exercise.

Methods

Data came from Research on Early Life and Aging Trends and Effects (RELATE). The study included a total number of 25,372 community sample of adults who were 40 years or older. We used data from community based surveys in seven countries including China, Mexico, Barbados, Brazil, Chile, Cuba, and Uruguay. Demographics (age and gender), socio-economic status (education and income), obesity, exercise, and ADL (bath, dress, toilet, transfer, heavy, shopping, meals) were measured. Self-reported data on physician diagnosis of diabetes was the independent variable. We tested if diabetes is associated with ADL, before and after adjusting for socio-economics, obesity, and exercise in each country.

Results

Based on Model I (age and gender adjusted model), diabetes was associated with limitation in at least one ADL in Mexico, Barbados, Brazil, Chile, Cuba, and Uruguay, but not China. Based on Model II that also controlled for education and income, education explained the association between diabetes and limitation in ADL in Mexico and Uruguay. Based on Model III that also controlled for exercise and obesity, in Cuba and Brazil, exercise explained the link between diabetes and limitation in performing ADLs. Thus, the link between diabetes and ADL was independent of our covariates only in Chile and Barbados.

Conclusions

There are cross-country differences in the link between diabetes and limitation in ADL. There are also cross-country differences in how socio-economic status, obesity, and exercise explain the above association.

Development and validation of an ankle brachial index risk model for the prediction of cardiovascular events

BACKGROUND

The ankle brachial index (ABI) is related to risk of cardiovascular events independent of the Framingham risk score (FRS). The aim of this study was to develop and evaluate a risk model for cardiovascular events incorporating the ABI and FRS.

DESIGN

An analysis of participant data from 18 cohorts in which 24,375 men and 20,377 women free of coronary heart disease had ABI measured and were followed up for events.

METHODS

Subjects were divided into a development and internal validation dataset and an external validation dataset. Two models, comprising FRS and FRS + ABI, were fitted for the primary outcome of major coronary events.

RESULTS

In predicting events in the external validation dataset, C-index for the FRS was 0.672 (95% CI 0.599 to 0.737) in men and 0.578 (95% CI 0.492 to 0.661) in women. The FRS + ABI led to a small increase in C-index in men to 0.685 (95% CI 0.612 to 0.749) and large increase in women to 0.690 (95% CI 0.605 to 0.764) with net reclassification improvement (NRI) of 4.3% (95% CI 0.0 to 7.6%, p = 0.050) and 9.6% (95% CI 6.1 to 16.4%, p < 0.001), respectively. Restricting the FRS + ABI model to those with FRS intermediate 10-year risk of 10 to 19% resulted in higher NRI of 15.9% (95% CI 6.1 to 20.6%, p < 0.001) in men and 23.3% (95% CI 13.8 to 62.5%, p = 0.002) in women. However, incorporating ABI in an improved newly fitted risk factor model had a nonsignificant effect: NRI 2.0% (95% CI 2.3 to 4.2%, p = 0.567) in men and 1.1% (95% CI 1.9 to 4.0%, p = 0.483) in women.

CONCLUSIONS

An ABI risk model may improve prediction especially in individuals at intermediate risk and when performance of the base risk factor model is modest.

Ankle brachial index values, leg symptoms, and functional performance among community-dwelling older men and women in the lifestyle interventions and independence for elders study

Background

The prevalence and significance of low normal and abnormal ankle brachial index (ABI) values in a community‐dwelling population of sedentary, older individuals is unknown. We describe the prevalence of categories of definite peripheral artery disease (PAD), borderline ABI, low normal ABI, and no PAD and their association with lower‐extremity functional performance in the LIFE Study population.

Methods and Results

Participants age 70 to 89 in the LIFE Study underwent baseline measurement of the ABI, 400‐m walk, and 4‐m walking velocity. Participants were classified as follows: definite PAD (ABI <0.90), borderline PAD (ABI 0.90 to 0.99), low normal ABI (ABI 1.00 to 1.09), and no PAD (ABI 1.10 to 1.40). Of 1566 participants, 220 (14%) had definite PAD, 250 (16%) had borderline PAD, 509 (33%) had low normal ABI, and 587 (37%) had no PAD. Among those with definite PAD, 65% were asymptomatic. Adjusting for age, sex, race, body mass index, smoking, and comorbidities, lower ABI was associated with longer mean 400‐m walk time: (definite PAD=533 seconds; borderline PAD=514 seconds; low normal ABI=503 seconds; and no PAD=498 seconds [P<0.001]). Among asymptomatic participants with and without PAD, lower ABI values were also associated with longer 400‐m walk time (P<0.001) and slower walking velocity (P=0.042).

Conclusion

Among older community‐dwelling men and women, 14% had PAD and 49% had borderline or low normal ABI values. Lower ABI values were associated with greater functional impairment, suggesting that lower extremity atherosclerosis may be a common preventable cause of functional limitations in older people.

Clinical Trial Registration

URL: http://clinicaltrials.gov/ Unique identifier: NCT01072500.

Comparison of global estimates of prevalence and risk factors for peripheral artery disease in 2000 and 2010: a systematic review and analysis

BACKGROUND

Lower extremity peripheral artery disease is the third leading cause of atherosclerotic cardiovascular morbidity, following coronary artery disease and stroke. This study provides the first comparison of the prevalence of peripheral artery disease between high-income countries (HIC) and low-income or middle-income countries (LMIC), establishes the primary risk factors for peripheral artery disease in these settings, and estimates the number of people living with peripheral artery disease regionally and globally.

METHODS

We did a systematic review of the literature on the prevalence of peripheral artery disease in which we searched for community-based studies since 1997 that defined peripheral artery disease as an ankle brachial index (ABI) lower than or equal to 0·90. We used epidemiological modelling to define age-specific and sex-specific prevalence rates in HIC and in LMIC and combined them with UN population numbers for 2000 and 2010 to estimate the global prevalence of peripheral artery disease. Within a subset of studies, we did meta-analyses of odds ratios (ORs) associated with 15 putative risk factors for peripheral artery disease to estimate their effect size in HIC and LMIC. We then used the risk factors to predict peripheral artery disease numbers in eight WHO regions (three HIC and five LMIC).

FINDINGS

34 studies satisfied the inclusion criteria, 22 from HIC and 12 from LMIC, including 112,027 participants, of which 9347 had peripheral artery disease. Sex-specific prevalence rates increased with age and were broadly similar in HIC and LMIC and in men and women. The prevalence in HIC at age 45-49 years was 5·28% (95% CI 3·38-8·17%) in women and 5·41% (3·41-8·49%) in men, and at age 85-89 years, it was 18·38% (11·16-28·76%) in women and 18·83% (12·03-28·25%) in men. Prevalence in men was lower in LMIC than in HIC (2·89% [2·04-4·07%] at 45-49 years and 14·94% [9·58-22·56%] at 85-89 years). In LMIC, rates were higher in women than in men, especially at younger ages (6·31% [4·86-8·15%] of women aged 45-49 years). Smoking was an important risk factor in both HIC and LMIC, with meta-OR for current smoking of 2·72 (95% CI 2·39-3·09) in HIC and 1·42 (1·25-1·62) in LMIC, followed by diabetes (1·88 [1·66-2·14] vs 1·47 [1·29-1·68]), hypertension (1·55 [1·42-1·71] vs 1·36 [1·24-1·50]), and hypercholesterolaemia (1·19 [1·07-1·33] vs 1·14 [1·03-1·25]). Globally, 202 million people were living with peripheral artery disease in 2010, 69·7% of them in LMIC, including 54·8 million in southeast Asia and 45·9 million in the western Pacific Region. During the preceding decade the number of individuals with peripheral artery disease increased by 28·7% in LMIC and 13·1% in HIC.

INTERPRETATION

In the 21st century, peripheral artery disease has become a global problem. Governments, non-governmental organisations, and the private sector in LMIC need to address the social and economic consequences, and assess the best strategies for optimum treatment and prevention of this disease.

FUNDING

Peripheral Arterial Disease Research Coalition (Europe).

Functional impairment in peripheral artery disease and how to improve it in 2013

Lower extremity peripheral artery disease (PAD) affects 8 million men and women in the United States and will be increasingly common as the U.S. population lives longer with chronic disease. People with PAD have poorer walking endurance, slower walking velocity, and poorer balance, compared with individuals without PAD. People with PAD may reduce their walking activity to avoid leg symptoms. Thus, clinicians should not equate stabilization or improvement in exertional leg symptoms with stabilization or improvement in walking performance in PAD. In addition, even asymptomatic PAD patients have greater functional impairment and faster functional decline than individuals without PAD. Of the 2 FDA-approved medications for treating claudication symptoms, pentoxifylline may not be more efficacious than placebo, whereas cilostazol confers a modest improvement in treadmill walking performance. Supervised treadmill walking exercise is associated with substantial improvement in walking endurance, but many PAD patients do not have access to supervised exercise programs. Unsupervised walking exercise programs may be beneficial in PAD, but data are mixed.

Factors associated with mobility outcomes in older people post-ankle fracture: an observational cohort study focussing on peripheral vessel function

INTRODUCTION

There are increasing numbers of older persons sustaining ankle fractures. This injury often results in a degree of functional limitation, particularly in older patients. There is currently limited research into factors associated with mobility outcomes.

DESIGN

Observational cohort study.

SETTING

Hospital Trauma Department, UK.

PARTICIPANTS

Persons aged 60 years or over who sustained an unstable ankle fracture with no established peripheral arterial disease pre-injury.

METHODS

This study investigated the association between ankle-brachial pressure index (ABPI) and extended timed 'up and go' (TUG) measures. Associations between TUG outcomes and age, pre-morbid functional mobility (Olerud-Molander Ankle Score) and fracture severity (number of malleoli injured) were also explored.

ANALYSIS

Complete cases (n=76; 84% of cohort) were entered into univariate and multivariate linear regression.

RESULTS

No association was found between ABPI and TUG at 6 months in unadjusted and adjusted analyses. Pre-morbid functional mobility (B=-0.34, 95% confidence interval (CI) -0.45 to -0.23, p<0.001) and age (B=0.46, 95% CI 0.25-0.66, p<0.001) were associated with extended TUG values (r2=0.53, p<0.001). Fracture severity was not a significant independent predictor variable.

CONCLUSIONS

Peripheral vessel function and fracture severity may have a limited independent influence on mobility outcome after ankle fracture in those patients who do not have established pre-injury peripheral arterial disease. Age and pre-morbid mobility gave an indication of mobility outcome, but a substantial amount of variance remains unexplained. Limitations of this study, including missing data and potential residual confounding, indicate the need for caution in generalising these results. The study provides a basis on which to plan larger studies of the factors associated with mobility outcome after ankle fracture in older populations.

Peripheral arterial disease in older people with intellectual disability in The Netherlands using the ankle-brachial index: results of the HA-ID study

Older people with an intellectual disability (ID) have been shown to have similar to increased cardiovascular risks as compared to the general population. Peripheral arterial disease (PAD), atherosclerosis distal from the aortic bifurcation, is associated with increased cardiovascular morbidity and mortality. The prevalence of PAD has not been investigated in this population. Therefore, the aim of the present study was to determine the prevalence of PAD in older people with ID in The Netherlands, the rate of prior diagnoses, and correlations with participant characteristics, and to compare the prevalence with PAD in the general Dutch population. 771 people aged 50 years and over participated in ankle-brachial index (ABI) measurement as part of a multi-centre cross-sectional study (HA-ID study). PAD was defined as an ABI<0.9. After excluding those, who met the exclusion criteria, 629 participants remained. PAD was present in 20.7% of the participants and 97% had not been diagnosed before. People with higher age, smokers and people who lived in central settings, walked with support and were more dependent in activities of daily living were more at risk of PAD. Prevalence of PAD is higher than in the general population (17.4% of 562 eligible participants with ID, as compared to 8.1% of 917 Dutch participants of the PANDORA study, a pan-European study into the prevalence of PAD) through all age groups. Because the high prevalence of PAD implies a serious health risk for older people with ID, we recommend that ankle-brachial index measurement is to be routinely performed as part of the cardiovascular risk management in this group.

Comparison between oscillometric- and Doppler-ABI in elderly individuals

Peripheral arterial disease (PAD) generally remains under-recognized, mainly due to the specialized technical skills required to detect the low values of the ankle-brachial index (ABI). As a simpler and faster alternative to the standard method using continuous-wave Doppler ultrasound, we evaluated automated oscillometric ABI measurement by VP-2000 with an elderly cohort of 113 subjects (age range, 61 to 88 years). The standard deviation in ABIs measured by the Doppler method was statistically greater than that measured by the oscillometric method for each of the two legs (P < 0.001). Correlations in ABIs between the two methods were 0.46 for the left leg and 0.61 for the right leg; this result appears to have been caused by interobserver variation in the Doppler ABI measurements. While the trend showing greater differences between average oscillometric- and Doppler-ABIs was significant at the lower ABI ranges, there was little indication of differences in measurements having an average ABI > 1.1. The difference between the methods was suggestively larger in subjects who were smokers than in non-smokers (P = 0.09), but the difference was not affected by other potential atherosclerotic risk factors, including age at examination (P > 0.50). A larger difference at lower ABIs led to better PAD detection by the Doppler method compared to the oscillometric method (sensitivity = 50%, specificity = 100%), although the overall agreement was not small (Cohen’s Kappa = 0.65). Our findings indicate that oscillometric devices can provide more accurate estimation of the prevalence of PAD in elderly individuals than the conventional Doppler method.

Diagnosis and management of peripheral artery disease in women

Peripheral artery disease (PAD) is a significant cause of morbidity and mortality in the USA. Not only is it a major cause of functional impairment and limb loss, but it is also strongly associated with an increased risk of myocardial infarction, stroke, and death. Large population studies have demonstrated high rates of PAD in women, but this is not widely recognized by the public or by clinicians. One potential reason for this is that women with PAD are more likely than men to be asymptomatic or have atypical symptoms. In addition, women with PAD experience higher rates of functional decline and may have poorer outcomes after surgical treatment for PAD compared with men. Currently, it is not known if there are sex-specific differences in risk factors for the onset, progression, and surgical outcomes of PAD. This review will focus on the diagnosis and management of PAD in women and examine sex-specific differences in the prevalence, risk factors, presentation, and outcomes of this disease.

Predictors of decrease in ankle-brachial index among patients with diabetes mellitus

AIM

Screening for peripheral arterial disease, a complication among patients with diabetes, is performed by periodic assessment of ankle-brachial index. We aimed to study the degree of ankle-brachial index change over time and factors associated with significant change.

METHOD

We assessed difference between two ankle-brachial index measurements over time in a consecutive series of 82 patients with Type 2 diabetes. All patients had ankle-brachial index > 0.9 but ≤ 1.3 for the first measurement, and significant ankle-brachial index decrease was defined as a decrease of > 0.1 in the follow-up measurement compared with the baseline.

RESULTS

The mean follow-up duration was 27.6 (median 30.0) months. Significant ankle-brachial index decrease was seen in 20.7% of patients, including 5% with follow-up ankle-brachial index of ≤ 0.9, consistent with the diagnosis of peripheral arterial disease. After adjusting for age and gender, higher baseline HbA(1c) and serum creatinine levels, increase in follow-up serum LDL cholesterol levels compared with baseline and history of retinopathy were predictors of significant ankle-brachial index decrease.

CONCLUSIONS

Our study suggests that, within two years, one in five patients with diabetes and a normal ankle-brachial index may have significant progression of peripheral arterial disease. Annual ankle-brachial index assessment and better control of hyperlipidaemia may thus be required for at-risk patients with poor glycaemic control, renal impairment and retinopathy.

African Americans and Peripheral Arterial Disease: A Review Article

Peripheral arterial disease (PAD)—atherosclerosis of the abdominal aorta and arteries of the lower extremities—affects 12 million Americans. African Americans (AAs) are more than twice as likely as non-Hispanic whites to suffer from PAD. When compared to non-Hispanic whites with PAD, AAs with PAD have more severe disease and a greater reduction in walking distance, speed, and/or stair climbing. AAs with PAD are at increased risk for disease progression and worsening lower limb function. Reasons for the higher risk for disease progression have not been defined. One potential modifiable risk is a lower level of physical activity. Lower levels of physical activity are more common among African American seniors. Walking is a common type of physical activity. The benefits of walking therapy are only realized if the patient adheres to such therapy. Efforts are needed to increase walking in AAs with PAD. Additionally, risk factor management is key to reducing adverse events in AAs with PAD-yet few studies have targeted this high-risk group. In this paper, we discuss the management of PAD in AAs. Identifying current gaps will help to inform clinicians, researchers, and policy makers on next steps in identifying innovative approaches to increase home-based walking and reduce walking impairment in AAs with PAD.

The Group Oriented Arterial Leg Study (GOALS) to improve walking performance in patients with peripheral arterial disease

People with lower extremity peripheral artery disease (PAD) have greater functional impairment and faster functional decline than those without PAD. We describe methods for the Group Oriented Arterial Leg Study (GOALS), an ongoing randomized controlled clinical trial designed to determine whether a Group-Mediated Cognitive Behavioral (GMCB) intervention improves functional performance in PAD participants, compared to a health education control condition. In GOALS, PAD participants were randomized to either an intervention or a health education control condition in a parallel design. Both conditions consist of weekly group sessions with other PAD participants. In the intervention, cognitive behavioral techniques are used to assist participants in setting and adhering to home-based walking exercise goals. Participants are encouraged to walk for exercise at home at least 5 days/week. In the control condition, participants receive lectures on health-related topics. After 6 months of on-site weekly sessions, participants are transitioned to telephone follow-up for another 6 months. Participants in the intervention are asked to continue home walking exercise. The primary outcome is change in six-minute walk performance between baseline and six-month follow-up. Secondary outcomes include change in six-minute walk performance at 12-month follow-up, and change in treadmill walking performance, the Walking Impairment Questionnaire, quality of life, and physical activity at six and 12-month follow-up. In conclusion, if our group-mediated cognitive behavioral intervention is associated with improved walking performance in individuals with PAD, results will have major public health implications for the large and growing number of people with PAD.

Association of body mass index with peripheral arterial disease in older adults: the Cardiovascular Health Study

The authors hypothesized that the absence of cross-sectional associations of body mass index (BMI; weight (kg)/height (m)(2)) with peripheral arterial disease (PAD) in prior studies may reflect lower weight among persons who smoke or have poor health status. They conducted an observational study among 5,419 noninstitutionalized residents of 4 US communities aged ≥ 65 years at baseline (1989-1990 or 1992-1993). Ankle brachial index was measured, and participants reported their history of PAD procedures. Participants were followed longitudinally for adjudicated incident PAD events. At baseline, mean BMI was 26.6 (standard deviation, 4.6), and 776 participants (14%) had prevalent PAD. During 13.2 (median) years of follow-up through June 30, 2007, 276 incident PAD events occurred. In cross-sectional analysis, each 5-unit increase in BMI was inversely associated with PAD (prevalence ratio (PR) = 0.92, 95% confidence interval (CI): 0.85, 1.00). However, among persons in good health who had never smoked, the direction of association was opposite (PR = 1.20, 95% CI: 0.94, 1.52). Similar results were observed between BMI calculated using weight at age 50 years and PAD prevalence (PR = 1.30, 95% CI: 1.11, 1.51) and between BMI at baseline and incident PAD events occurring during follow-up (hazard ratio = 1.32, 95% CI: 1.00, 1.76) among never smokers in good health. Greater BMI is associated with PAD in older persons who remain healthy and have never smoked. Normal weight maintenance may decrease PAD incidence and associated comorbidity in older age.

Automatic quantification of muscle volumes in magnetic resonance imaging scans of the lower extremities

Muscle volume measurements are essential for an array of diseases ranging from peripheral arterial disease, muscular dystrophies, neurological conditions to sport injuries and aging. In the clinical setting, muscle volume is not routinely measured due to the lack of standardized ways for its repeatable quantification. In this paper, we present magnetic resonance muscle quantification (MRMQ), a method for the automatic quantification of thigh muscle volume in magnetic resonance imaging (MRI) scans. MRMQ integrates a thigh segmentation and nonuniform image gradient correction step, followed by feature extraction and classification. The classification step leverages prior probabilities, introducing prior knowledge to a maximum a posteriori classifier. MRMQ was validated on 344 slices taken from 60 MRI scans. Experiments for the fully automatic detection of muscle volume in MRI scans demonstrated an averaged accuracy, sensitivity and specificity for leave-one-out cross-validation of 88.3%, 93.6% and 87.2%, respectively.

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.

Effect of nitric oxide on neointimal hyperplasia based on sex and hormone status

Nitric oxide (NO)-based therapies decrease neointimal hyperplasia; however, studies have been performed only in male animal models. Thus, we sought to evaluate the effect of NO on vascular smooth muscle cells (VSMC) in vitro and neointimal hyperplasia in vivo based on sex and hormone status. In hormone-replete medium, male VSMC proliferated at greater rates than female VSMC. In hormone-depleted medium, female VSMC proliferated at greater rates than male VSMC. However, in both hormone environments, NO inhibited proliferation and migration to a greater extent in male compared to female VSMC. These findings correlated with greater G₀/G₁ cell cycle arrest and changes in cell cycle protein expression in male compared to female VSMC after exposure to NO. Next, the rat carotid artery injury model was used to assess the effect of NO on neointimal hyperplasia in vivo. Consistent with the in vitro data, NO was significantly more effective at inhibiting neointimal hyperplasia in hormonally intact males compared to females using weight-based dosing. An increased weight-based dose of NO in females was able to achieve efficacy equal to that in males. Surprisingly, NO was less effective at inhibiting neointimal hyperplasia in castrated animals of both sexes. In conclusion, these data suggest that NO inhibits neointimal hyperplasia more effectively in males compared to females and in hormonally intact compared to castrated rats, indicating that the effects of NO in the vasculature may be sex- and hormone-dependent.

Lipoprotein(a), inflammation, and peripheral arterial disease in a community-based sample of older men and women (the InCHIANTI study)

Lipoprotein(a) (Lp[a]) may represent an independent risk factor for peripheral arterial disease of the lower limbs (LL-PAD), but prospective data are scant. We estimated the association between baseline Lp(a) with prevalent and incident LL-PAD in older subjects from the InCHIANTI Study. LL-PAD, defined as an ankle-brachial index <0.90, was assessed at baseline and over a 6-year follow-up in a sample of 1,002 Italian subjects 60 to 96 years of age. Plasma Lp(a) and potential traditional and novel cardiovascular risk factors (including a score based on relevant inflammatory markers) were entered in multivariable models to assess their association with prevalent and incident LL-PAD. At baseline, Lp(a) concentration was directly related to the number of increased inflammatory markers (p <0.05). There were 125 (12.5%) prevalent cases of LL-PAD and 57 (8.3%) incident cases. After adjustment for potential confounders, participants in the highest quartile of the Lp(a) distribution (>/=32.9 mg/dl) were more likely to have LL-PAD compared to those in the lowest quartile (odds ratio [OR] 1.83, 95% confidence interval [CI] 1.01 to 3.33). The association was stronger (OR 3.80, 95% CI 1.50 to 9.61) if LL-PAD was defined by harder criteria, namely an ankle-brachial index <0.70. Compared to subjects in the lowest Lp(a) quartile, those in the highest quartile showed a somewhat increased risk of incident LL-PAD (lowest quartile 7.7%, highest quartile 10.8%), but the association was not statistically significant (OR 1.52, 95% CI 0.71 to 3.22). In conclusion, Lp(a) is an independent LL-PAD correlate in the cross-sectional evaluation, but further prospective studies in larger populations, with longer follow-up and more definite LL-PAD ranking, might be needed to establish a longitudinal association.

The ankle-brachial index is associated with the magnitude of impaired walking endurance among men and women with peripheral arterial disease

Previous reports suggest that the severity of peripheral arterial disease (PAD), measured by the ankle-brachial index (ABI), is not associated with the magnitude of walking impairment, measured by treadmill testing. These prior studies have had small sample sizes and included only PAD participants with symptoms of intermittent claudication. We studied the association of the ABI with diverse measures of walking performance in a cross-sectional study of 156 participants with PAD with and without intermittent claudication symptoms. Outcomes included the Gardner-Skinner treadmill test, 6-minute walk, 4-meter walking velocity at usual and fastest pace, and the walking impairment questionnaire (WIQ). Adjusting for age, sex, race, comorbidities, leg symptoms, and other confounders, lower ABI values were associated with shorter distance achieved in the 6-minute walk (ABI < 0.50: 286 meters; ABI 0.50-0.70: 316 meters; ABI 0.71-0.95: 355 meters, p trend < 0.001), shorter maximal treadmill walking time (ABI < 0.50: 6.0 minutes; ABI 0.50-0.70: 6.9 minutes; ABI 0.71-0.95: 8.3 minutes, p trend = 0.009), and lower WIQ distance scores (p trend = 0.007) among PAD participants. The ABI was not associated significantly with walking velocity over 4 meters, treadmill time to onset of leg symptoms, or the WIQ speed or stair-climbing scores. In conclusion, among 156 participants with PAD with and without intermittent claudication, lower ABI values are associated significantly with poorer walking endurance, assessed by three distinct measures. Clinical Trial Registration - URL: http://www.clinicaltrials.gov. Unique identifier: NCT00106327.

Admixture mapping of ankle-arm index: identification of a candidate locus associated with peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD) is associated with significant morbidity and mortality, and has a higher prevalence in African Americans than Caucasians. Ankle-arm index (AAI) is the ratio of systolic blood pressure in the leg to that in the arm, and, when low, is a marker of PAD.

METHODS

The authors used an admixture mapping approach to search for genetic loci associated with low AAI. Using data from 1040 African American participants in the observational, population based Health, Aging, and Body Composition Study who were genotyped at 1322 single nucleotide polymorphisms (SNPs) that are informative for African versus European ancestry and span the entire genome, we estimated genetic ancestry in each chromosomal region and then tested the association between AAI and genetic ancestry at each locus.

RESULTS

The authors found a region of chromosome 11 that reaches its peak between 80 and 82 Mb associated with low AAI (p<0.001 for rs12289502 and rs9665943, both within this region). 753 African American participants in the observational, population based Cardiovascular Health Study were genotyped at rs9665943 to test the reproducibility of this association, and this association was also statistically significant (odds ratio (OR) for homozygous African genotype 1.59, 95% confidence interval (CI) 1.12 to 2.27). Another candidate SNP (rs1042602) in the same genomic region was tested in both populations, and was also found to be significantly associated with low AAI in both populations (OR for homozygous African genotype 1.89, 95% CI 1.29 to 2.76).

CONCLUSION

This study identifies a novel region of chromosome 11 representing an area with a potential candidate gene associated with PAD in African Americans.

Ankle–Brachial Index Screening for Peripheral Artery Disease in Asymptomatic Patients between 50 and 70 Years of Age

Asymptomatic peripheral arterial disease (PAD) can be easily identified using the ankle–brachial index (ABI). This study was designed to investigate the benefits of performing ABI in patients aged 50-70 years. A random sample of 107 patients was chosen and data on gender, age, risk factors and laboratory tests were collected and the ABI measured. Twenty (19%) patients were found to have PAD. Smoking, high total cholesterol, high triglycerides and diabetes mellitus were shown to be associated with a low ABI and the presence of PAD. Age, diabetes and smoking were identified as the strongest predictors of PAD. Having more risk factors for PAD also predicted a lower ABI. These results suggest that measuring ABI is not necessary in patients aged 50-70 years if they only have one risk factor, with the exception of patients with diabetes and those who smoke. In contrast, measuring ABI seems to be useful for patients with multiple risk factors for PAD, although additional studies are required.

[Evidence-based recommendations on primary diagnostics of peripheral arterial occlusive disease in geriatric patients]

The prevalence of peripheral arterial occlusive disease (PAOD) is high in elderly patients and its clinical manifestation is often atypical. Comorbidity and morbidity as a consequence of PAOD are significant. Therefore, standardized primary diagnostics are required among geriatric patients. Drawn from a search of the literature, evidence-based recommendations are provided. Pulse palpation and the evaluation of a patient's medical history are obligatory components of primary diagnostics, even in the absence of typical symptoms. In the case of pathological and ambiguous findings, measuring Doppler ankle pressures is suggested as the next diagnostic step. Further measures depend on the following factors: the presence of lesions on the leg with disturbed blood flow, predominantly in the foot and lower leg areas, degree of PAOD-related ailments, and, finally, intended surgery of the affected leg for other medical reasons.

Treadmill exercise and resistance training in patients with peripheral arterial disease with and without intermittent claudication: a randomized controlled trial

CONTEXT

Neither supervised treadmill exercise nor strength training for patients with peripheral arterial disease (PAD) without intermittent claudication have been established as beneficial.

OBJECTIVE

To determine whether supervised treadmill exercise or lower extremity resistance training improve functional performance of patients with PAD with or without claudication.

DESIGN, SETTING, AND PARTICIPANTS

Randomized controlled clinical trial performed at an urban academic medical center between April 1, 2004, and August 8, 2008, involving 156 patients with PAD who were randomly assigned to supervised treadmill exercise, to lower extremity resistance training, or to a control group.

MAIN OUTCOME MEASURES

Six-minute walk performance and the short physical performance battery. Secondary outcomes were brachial artery flow-mediated dilation, treadmill walking performance, the Walking Impairment Questionnaire, and the 36-Item Short Form Health Survey physical functioning (SF-36 PF) score.

RESULTS

For the 6-minute walk, those in the supervised treadmill exercise group increased their distance walked by 35.9 m (95% confidence interval [CI], 15.3-56.5 m; P < .001) compared with the control group, whereas those in the resistance training group increased their distance walked by 12.4 m (95% CI, -8.42 to 33.3 m; P = .24) compared with the control group. Neither exercise group improved its short physical performance battery scores. For brachial artery flow-mediated dilation, those in the treadmill group had a mean improvement of 1.53% (95% CI, 0.35%-2.70%; P = .02) compared with the control group. The treadmill group had greater increases in maximal treadmill walking time (3.44 minutes; 95% CI, 2.05-4.84 minutes; P < .001); walking impairment distance score (10.7; 95% CI, 1.56-19.9; P = .02); and SF-36 PF score (7.5; 95% CI, 0.00-15.0; P = .02) than the control group. The resistance training group had greater increases in maximal treadmill walking time (1.90 minutes; 95% CI, 0.49-3.31 minutes; P = .009); walking impairment scores for distance (6.92; 95% CI, 1.07-12.8; P = .02) and stair climbing (10.4; 95% CI, 0.00-20.8; P = .03); and SF-36 PF score (7.5; 95% CI, 0.0-15.0; P = .04) than the control group.

CONCLUSIONS

Supervised treadmill training improved 6-minute walk performance, treadmill walking performance, brachial artery flow-mediated dilation, and quality of life but did not improve the short physical performance battery scores of PAD participants with and without intermittent claudication. Lower extremity resistance training improved functional performance measured by treadmill walking, quality of life, and stair climbing ability.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00106327.

Peripheral arterial disease, diabetes and postural balance among elderly Finns: a population-based study

BACKGROUND AND AIMS

Little is known about the role of peripheral arterial disease (PAD) in the development of balance impairment. The aim of this study was to assess postural balance among people having PAD or PAD combined with diabetes.

METHODS

As part of the comprehensive health examination of the Health 2000 survey (two-stage stratified cluster sampling), 1323 people aged 65 years or older took part in balance assessments using a force platform system. The presence of PAD was confirmed with data from the National Hospital Discharge Registry. Individuals with hospitalization due to PAD were regarded as having severe disease, whereas those with solely self-reported diagnosis were considered possible cases. Diabetes was ascertained on the basis of self-reported physicians' diagnoses subsequently confirmed in a clinical examination.

RESULTS

Forty-five (3.4%) individuals had previously been hospitalized due to PAD, and 32 (2.4%) reported that they had been diagnosed with the disease. 413 (31%) participants had diabetes. Compared with people without PAD, those with confirmed diagnoses exhibited significantly increased movement of the center of pressure while standing, indicating deteriorated balance. Those with possible PAD formed an intermediate group. Diabetes exacerbated the deterioration in balance, but the interaction term between PAD and diabetes did not reach statistical significance. The risk of failing tandem stance tests was over three-fold (OR 3.20, 95% CI 1.09-9.37) among those with confirmed PAD and almost one and a half-fold (OR 1.44, 95% CI 1.07-1.93) among those with diabetes, in comparison to those without these diseases.

CONCLUSIONS

Individuals over 65 years of age with severe PAD showed increased balance impairment, a known risk factor for falls and disability in aged people. Diabetes affected balance somewhat less than PAD, but there was no formal evidence of the synergetic effect of the two diseases. Additional studies are indicated to reveal the possible effect of proper treatment of PAD and diabetes, combined with suitable training interventions on slowing down the progression of balance impairment.

Management of peripheral arterial disease patients: comparing the ACC/AHA and TASC-II guidelines

BACKGROUND

Peripheral arterial disease (PAD) is a common manifestation of systemic atherosclerosis associated with a high risk of morbidity and mortality from cardiovascular events. Despite this, PAD is often undiagnosed and, therefore, undertreated.

OBJECTIVE

The purpose of this review is to highlight and provide clinical insight into the similarities and differences between the available PAD treatment guidelines developed by the American College of Cardiology/American Heart Association (ACC/AHA) and the Trans-Atlantic Inter-Society Consensus II (TASC II) working group.

METHODS

Recommendations from the ACC/AHA 2005 Practice Guidelines for the Management of Patients with Peripheral Arterial Disease (Lower Extremity, Renal, Mesenteric, and Abdominal Aortic) and TASC II Inter-Society Consensus for the Management of Peripheral Arterial users for personal Disease, initiated in 2004 and published in 2007, were compared. Supplemental information was obtained by searching the PubMed and MEDLINE databases using relevant terms. Unintentional bias may have been introduced into the manuscript by not performing a systematic review of the literature with pre-defined search terms.

FINDINGS AND CONCLUSIONS

While some variation exists in the content of the recommendations, both documents agree on the need for aggressive management of patients with PAD. In spite of these recommendations, there is a general lack of adherence to the current guidelines-a critical concern considering the high morbidity and mortality associated with the disease. However, the results of ongoing clinical trials may serve to increase awareness of the importance of aggressive management of PAD.

Ankle brachial index combined with Framingham Risk Score to predict cardiovascular events and mortality: a meta-analysis

CONTEXT

Prediction models to identify healthy individuals at high risk of cardiovascular disease have limited accuracy. A low ankle brachial index (ABI) is an indicator of atherosclerosis and has the potential to improve prediction.

OBJECTIVE

To determine if the ABI provides information on the risk of cardiovascular events and mortality independently of the Framingham risk score (FRS) and can improve risk prediction.

DATA SOURCES

Relevant studies were identified. A search of MEDLINE (1950 to February 2008) and EMBASE (1980 to February 2008) was conducted using common text words for the term ankle brachial index combined with text words and Medical Subject Headings to capture prospective cohort designs. Review of reference lists and conference proceedings, and correspondence with experts was conducted to identify additional published and unpublished studies.

STUDY SELECTION

Studies were included if participants were derived from a general population, ABI was measured at baseline, and individuals were followed up to detect total and cardiovascular mortality.

DATA EXTRACTION

Prespecified data on individuals in each selected study were extracted into a combined data set and an individual participant data meta-analysis was conducted on individuals who had no previous history of coronary heart disease.

RESULTS

Sixteen population cohort studies fulfilling the inclusion criteria were included. During 480,325 person-years of follow-up of 24,955 men and 23,339 women, the risk of death by ABI had a reverse J-shaped distribution with a normal (low risk) ABI of 1.11 to 1.40. The 10-year cardiovascular mortality in men with a low ABI (< or = 0.90) was 18.7% (95% confidence interval [CI], 13.3%-24.1%) and with normal ABI (1.11-1.40) was 4.4% (95% CI, 3.2%-5.7%) (hazard ratio [HR], 4.2; 95% CI, 3.3-5.4). Corresponding mortalities in women were 12.6% (95% CI, 6.2%-19.0%) and 4.1% (95% CI, 2.2%-6.1%) (HR, 3.5; 95% CI, 2.4-5.1). The HRs remained elevated after adjusting for FRS (2.9 [95% CI, 2.3-3.7] for men vs 3.0 [95% CI, 2.0-4.4] for women). A low ABI (< or = 0.90) was associated with approximately twice the 10-year total mortality, cardiovascular mortality, and major coronary event rate compared with the overall rate in each FRS category. Inclusion of the ABI in cardiovascular risk stratification using the FRS would result in reclassification of the risk category and modification of treatment recommendations in approximately 19% of men and 36% of women.

CONCLUSION

Measurement of the ABI may improve the accuracy of cardiovascular risk prediction beyond the FRS.

Investigating the complex genetic architecture of ankle-brachial index, a measure of peripheral arterial disease, in non-Hispanic whites

Background

Atherosclerotic peripheral arterial disease (PAD) affects 8–10 million people in the United States and is associated with a marked impairment in quality of life and an increased risk of cardiovascular events. Noninvasive assessment of PAD is performed by measuring the ankle-brachial index (ABI). Complex traits, such as ABI, are influenced by a large array of genetic and environmental factors and their interactions. We attempted to characterize the genetic architecture of ABI by examining the main and interactive effects of individual single nucleotide polymorphisms (SNPs) and conventional risk factors.

Methods

We applied linear regression analysis to investigate the association of 435 SNPs in 112 positional and biological candidate genes with ABI and related physiological and biochemical traits in 1046 non-Hispanic white, hypertensive participants from the Genetic Epidemiology Network of Arteriopathy (GENOA) study. The main effects of each SNP, as well as SNP-covariate and SNP-SNP interactions, were assessed to investigate how they contribute to the inter-individual variation in ABI. Multivariable linear regression models were then used to assess the joint contributions of the top SNP associations and interactions to ABI after adjustment for covariates. We reduced the chance of false positives by 1) correcting for multiple testing using the false discovery rate, 2) internal replication, and 3) four-fold cross-validation.

Results

When the results from these three procedures were combined, only two SNP main effects in NOS3, three SNP-covariate interactions (ADRB2 Gly 16 – lipoprotein(a) and SLC4A5 – diabetes interactions), and 25 SNP-SNP interactions (involving SNPs from 29 different genes) were significant, replicated, and cross-validated. Combining the top SNPs, risk factors, and their interactions into a model explained nearly 18% of variation in ABI in the sample. SNPs in six genes (ADD2, ATP6V1B1, PRKAR2B, SLC17A2, SLC22A3, and TGFB3) were also influencing triglycerides, C-reactive protein, homocysteine, and lipoprotein(a) levels.

Conclusion

We found that candidate gene SNP main effects, SNP-covariate and SNP-SNP interactions contribute to the inter-individual variation in ABI, a marker of PAD. Our findings underscore the importance of conducting systematic investigations that consider context-dependent frameworks for developing a deeper understanding of the multidimensional genetic and environmental factors that contribute to complex diseases.

Asymptomatic peripheral arterial disease is associated with more adverse lower extremity characteristics than intermittent claudication

BACKGROUND

This study assessed functional performance, calf muscle characteristics, peripheral nerve function, and quality of life in asymptomatic persons with peripheral arterial disease (PAD).

METHODS AND RESULTS

PAD participants (n=465) had an ankle brachial index <0.90. Non-PAD participants (n=292) had an ankle brachial index of 0.90 to 1.30. PAD participants were categorized into leg symptom groups including intermittent claudication (n=215) and always asymptomatic (participants who never experienced exertional leg pain, even during the 6-minute walk; n=72). Calf muscle was measured with computed tomography. Analyses were adjusted for age, sex, race, ankle brachial index, comorbidities, and other confounders. Compared with participants with intermittent claudication, always asymptomatic PAD participants had smaller calf muscle area (4935 versus 5592 mm(2); P<0.001), higher calf muscle percent fat (16.10% versus 9.45%; P<0.001), poorer 6-minute walk performance (966 versus 1129 ft; P=0.0002), slower usual-paced walking speed (P=0.0019), slower fast-paced walking speed (P<0.001), and a poorer Short-Form 36 Physical Functioning score (P=0.016). Compared with an age-matched, sedentary, non-PAD cohort, always asymptomatic PAD participants had smaller calf muscle area (5061 versus 5895 mm(2); P=0.009), poorer 6-minute walk performance (1126 versus 1452 ft; P<0.001), and poorer Walking Impairment Questionnaire speed scores (40.87 versus 57.78; P=0.001).

CONCLUSIONS

Persons with PAD who never experience exertional leg symptoms have poorer functional performance, poorer quality of life, and more adverse calf muscle characteristics compared with persons with intermittent claudication and a sedentary, asymptomatic, age-matched group of non-PAD persons.

Prognostic value of functional performance for mortality in patients with peripheral artery disease

OBJECTIVES

Among persons with lower extremity peripheral artery disease (PAD), we determined whether objective measures of walking performance predict mortality independently of the ankle brachial index (ABI).

BACKGROUND

The ability of office-based functional performance measures to predict mortality in patients with PAD is unknown.

METHODS

Participants were 444 persons with PAD followed prospectively for 4.8 years. The 6-min walk and 4-m walks at usual and fastest pace were measured at baseline. Cox proportional hazard models were used to assess relations between baseline measures of lower extremity performance with mortality, adjusting for confounders.

RESULTS

One hundred twenty-seven patients (28.6%) died during follow-up. Adjusting for age, gender, race, comorbidities, ABI, and other confounders, participants in the poorest baseline quartile of 6-min walk performance had significantly increased total mortality (hazard ratio [HR] 2.36 [95% confidence interval (CI) 1.33 to 4.18]) and cardiovascular mortality (HR 5.59 [95% CI 1.97 to 15.9]) compared with the best quartile of baseline performance. Participants in the poorest baseline quartile of normal-paced 4-m walking speed had significantly increased total mortality (HR 1.86 [95% CI 1.06 to 3.29]) and cardiovascular mortality (HR 2.55 [95% CI 1.01 to 6.46]) compared with the best quartile of baseline performance.

CONCLUSIONS

This study demonstrates for the first time that performance-based measures, which can be administered in an office setting, provide prognostic information regarding mortality in persons with PAD beyond that provided by the ABI.

Incident physical disability in people with lower extremity peripheral arterial disease: the role of cardiovascular disease

OBJECTIVES

To evaluate the risk of incident physical disability and the decline in gait speed over a 6-year follow-up associated with a low ankle-arm index (AAI) in older adults.

DESIGN

Observational cohort study.

SETTING

Forsyth County, North Carolina; Sacramento County, California; Washington County, Maryland; and Allegheny County, Pennsylvania.

PARTICIPANTS

Four thousand seven hundred five older adults, 58% women and 17.6% black, participating in the Cardiovascular Health Study.

MEASUREMENTS

AAI was measured in 1992/93 (baseline). Self-reported mobility, activity of daily living (ADL), and instrumental activity of daily living (IADL) disability and gait speed were recorded at baseline and at 1-year intervals over 6 years of follow-up. Mobility disability was defined as any difficulty walking half a mile and ADL and IADL disability was defined as any difficulty with 11 specific ADL and IADL tasks. Individuals with mobility, ADL, or IADL disability at baseline were excluded from the respective incident disability analyses.

RESULTS

Lower baseline AAI values were associated with increased risk of mobility disability and ADL/IADL disability. Clinical cardiovascular disease (CVD), diabetes mellitus, and interim CVD events partially explained these associations for mobility disability and clinical CVD and diabetes mellitus partially explained these associations for ADL and IADL disability. Individuals with an AAI less than 0.9 had on average a mean decrease in gait speed of 0.02 m/s per year, or a decline of 0.12 m/s over the 6-year follow-up. Prevalent CVD partly explained this decrease but interim CVD events did not further attenuate it.

CONCLUSION

Low AAI serves as marker of future disability risk. Reduction of disability risk in patients with a low AAI should consider cardiovascular comorbidity and the prevention of additional disabling CVD events.

Persistent depressive symptoms and functional decline among patients with peripheral arterial disease

OBJECTIVE

Because depressive symptoms are prevalent among patients with peripheral arterial disease (PAD), our goal was to study the effect of depressive symptoms over time on functional decline among patients with PAD.

METHODS

We conducted a prospective cohort study of 417 patients with PAD followed annually for 2 years. A Geriatric Depression Scale Short Form (GDS-S) score >5 was considered positive for depressive symptoms. Depressive symptom categories based on annual GDS-S measures included persistent, new, resolved, and no depressive symptoms. Outcome variables were change in 6-minute walk distance, 4-meter fast walking velocity, and short physical performance battery (0-12 scale, 12 = best). Results are adjusted for age, sex, race, body mass index, marital status, exercise level, smoking, ankle brachial index, leg symptoms, comorbidities, beta-blocker medication use, anti-depressant medications, and interim medical events.

RESULTS

In adjusted analyses, patients with new depressive symptoms had greater annual decline in fast walking velocity compared with that of patients with no depressive symptoms (-0.08 versus -0.01 meters/second per year, p = .02). Patients with persistent depressive symptoms had greater annual decline in 6-minute walk distance (-86.4 versus -41.5 feet/yr, p = .04), fast walking velocity (-0.08 versus -0.01 meters/second per year, p = .004), and short physical performance battery (-0.73 versus -0.18 per year, p = .005) compared with that of patients with no depressive symptoms.

CONCLUSIONS

Among patients with PAD, persistent and new depressive symptoms are associated with greater annual decline in functional performance. Further study is needed to determine the mechanisms of these associations and whether treatment of depressive symptoms prevents functional decline in persons with PAD.

Measures of arterial stiffness and wave reflection are associated with walking distance in patients with peripheral arterial disease

We hypothesized that measures of arterial stiffness and wave reflection influence functional capacity of patients with peripheral arterial disease (PAD). Consecutive patients (n=106, 69+/-10 years, 66% men) referred for lower extremity arterial evaluation were studied. Radial artery pulse waveforms were obtained by applanation tonometry and an ascending aortic pressure waveform derived by a transfer function. Aortic augmentation index (AIx) is the difference between the first and second systolic peak of the ascending aortic pressure waveform indexed to the pulse pressure (PP) and T(r) is the reflected wave arrival time. Ankle-brachial index (ABI) and walking distance were measured as per laboratory protocol after excluding patients with non-compressible vessels (ABI>1.5) and severe PAD (ABI<0.5). To account for right-censoring of walking distances in patients completing the 5 min walk (n=56), we used survival analysis to identify variables associated with walking distance. Mean (+/-S.D.) values were: AIx, 31.2+/-10.9%; T(r), 134+/-18 ms; PP, 66.5+/-17.1 mmHg; ABI, 0.87+/-0.22; walking distance, 177+/-75 m. In both multivariable accelerated failure time (AFT) and Cox proportional-hazards models, older age, female sex, greater body mass index, lower ABI, and a measure of arterial stiffness (higher AIx and PP, lower T(r)) were associated with a lower walking distance. Higher AIx and lower T(r) were associated with a lower walking distance even after adjustment for PP as well as in the subset of patients with PAD (ABI<0.9 at rest or post-exercise, n=82). In conclusion, measures of arterial stiffness and wave reflection are associated with walking distance in patients with PAD and may be a target of therapy in such patients.

Association of polymorphisms in NOS3 with the ankle-brachial index in hypertensive adults

We investigated the association of 14 polymorphisms in the endothelial nitric oxide synthase gene (NOS3) with ankle brachial index (ABI) in non-Hispanic white hypertensives belonging to hypertensive sibships. Subjects (n=659, mean age 61+/-9 years, 54% women) underwent measurement of ABI using a standard protocol, and the lowest of 4 ABI values was used in the analyses. Non-synonymous SNPs with a minor allele frequency >0.02 and tag SNPs selected based on a measure of linkage disequilibrium (r(2)) were genotyped. We reduced the chance of false positives by testing for replication, randomly selecting 1 hypertensive sib from each sibship to create Subset 1 (n=330) and Subset 2 (n=329). Multivariable linear regression models were used to assess the associations of single NOS3 polymorphisms and haplotypes with ABI after adjustment for covariates (age, sex, body mass index, smoking, total cholesterol, HDL cholesterol, and diabetes). Two specific SNPs in significant LD with each other (rs891512 and rs1808593) were significantly associated with ABI in both subsets. Based on a sliding window approach with a window size of 2, estimated haplotypes from 2 SNP pairs (rs2070744-rs3918226 and rs1808593-rs7830) were also significantly associated with ABI in both subsets. In conclusion, specific NOS3 SNPs and haplotypes were associated with inter-individual variation in ABI, a non-invasive marker of peripheral arterial disease, in replicate subsets of hypertensive subjects. These findings motivate further investigation of the role of NOS3 variants in determining susceptibility to peripheral arterial disease.

Extensive Revascularization or Primary Amputation: Which Patients with Critical Limb Ischemia Should Not Be Revascularized?

The commitment of vascular specialists to preserve the lower extremity has pushed the limits of revascularization. It is not uncommon for patients with severe distal disease to undergo extensive vascular reconstruction, bringing a bypass graft down to the ankle and beyond. Such procedures, when well-planned and well-executed, can result in a preserved and fully functional lower extremity with complete healing of all necrotic tissue. As noted in the guidelines presented by the TransAtlantic Inter-Society Consensus Working Group, there are patients who will benefit from primary amputation rather than extensive revascularization. Patients who are unable to tolerate the planned procedure or unlikely to have a functional extremity despite restoration of distal flow, should be considered for major amputation that eliminates the source of rest pain and all necrotic tissue. Although morbidity and mortality of major amputation continues to be significant, advances in prosthetic development and amputation technique can lead to preserved ambulatory ability and improved quality of life.

The significance of lower extremity peripheral arterial disease

The role of the cardiologist is expanding and involves the management of patients with lower extremity atherosclerotic occlusive arterial disease. Peripheral arterial disease (PAD) remains an underdiagnosed and undertreated disease. The purpose of this review is to educate the clinician on the significance of lower extremity atherosclerotic occlusive arterial disease. Pathophysiology and anatomy are briefly reviewed. The definition of PAD is based upon both anatomic and functional considerations. Risk factors for PAD include traditional atherosclerotic risk factors. There is a considerable overlap between coronary and cerebrovascular diseases and PAD. Diagnosis is made mainly by history and physical examination. Noninvasive and invasive tests help diagnosis and localize disease. Expanded therapies to improve outcomes include lifestyle changes, medical treatment, interventional cardiovascular procedures, or surgical intervention.

Quality of Life and Peripheral Arterial Disease

Peripheral arterial disease (PAD) is a common disease entity with the potential to cause considerable impairment in the quality of life (QoL) of millions of Americans. As there is no exact cure for PAD, thus representing a chronic illness, the goal of treatment is disease management including the prevention of cardiovascular events, and improving QoL by helping people with PAD live productive and satisfying lives. Disagreement exists between patients' clinically inferred QoL status and their perceptions of QoL exist concerning PAD. Whereas a clinician may be concerned with a physiological or anatomical abnormality that may ultimately lead to disease and discomfort, a patient may be more concerned with their overall sense of QoL, which is only in part related to their clinical health status. Thus, to truly understand the outcomes of PAD and its treatment, it is necessary to supplement the traditional clinical outcome measures with information from the patient point of view. In this article, we review measurement instruments available to assess patient-reported QoL, and discuss the potential these tools have for providing accurate and meaningful information to complement traditional clinical outcome data.

Absent pedal pulse and impaired balance in older people: a cross-sectional and longitudinal study

BACKGROUND AND AIMS

The purpose of this study was to determine the relationship between abnormal pedal pulse status and postural balance in older people.

METHODS

Prospective, population-based cohort study of older residents in the city of Jyväskylä, Finland. A total of 419 individuals aged 75 or 80 at baseline, with known lower extremity pulse status and balance tests performed on a force platform, were eligible for analysis.

RESULTS

Cross-sectionally, persons with both dorsal pedal artery pulses absent were found to sway more (p=0.047 anteroposterior velocity, normal standing eyes-open position). The risk of being unable to do the full tandem stance was twofold (OR=2.20, 95% CI 1.29-3.78) for persons without palpable dorsal pedal arteries compared with those with normal pulse status. Balance deterioration was observed at five years (p<0.001 for time) but without group-by-time interaction. At ten years, however, the interaction term became significant for the normal standing eyes-closed position (p=0.025 for anteroposterior velocity and p=0.026 for mediolateral velocity), indicating greater balance deterioration among those with both dorsal pedal artery pulses absent.

CONCLUSIONS

According to our study, the absence of both dorsal pedal artery pulses is associated with impaired balance in older people. The association was observed both cross-sectionally and longitudinally. In addition, as diminished pedal pulses are frequently associated with impaired lower extremity circulation, our results have also produced information on the possible pathophysiological mechanisms of balance deterioration in older people, which warrant further study.

Markers of vascular inflammation are associated with the extent of atherosclerosis assessed as angiographic score and treadmill walking distances in patients with peripheral arterial occlusive disease

The importance of inflammation in atherosclerosis is well established in cardiovascular disease. However, limited data exist on the relationship between vascular inflammation and the severity of peripheral arterial occlusive disease (PAD). We investigated the relationship between biochemical markers of vascular inflammation and the diagnostic measures of PAD: ankle-brachial pressure index (ABI), maximum treadmill walking distance and angiographic score. In 127 patients (mean age 66 years; 64% males) with angiographically verified PAD, fasting blood samples were drawn for determination of selected soluble cell adhesion molecules, cytokines and chemokines. Tumor necrosis factor-alpha (TNFalpha), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1) and CD40 ligand (CD40L) were all significantly correlated with the angiographic score (p < 0.05 for all). After adjustment for relevant co-variates, MCP-1 and CD40L remained statistically significant (p < 0.01 for both). IL-6 was, independent of other risk factors, inversely correlated with the maximum treadmill walking distance (p < 0.01). Our cross-sectional study in PAD patients showed that the vascular inflammatory markers MCP-1, CD40L and IL-6 were significantly associated with the extent of atherosclerosis, assessed by angiographic score and maximum treadmill walking distance. These findings indicate that vascular inflammation is implicated in PAD, which might be of importance in future diagnosis and treatment of the disease.