Search

Screening for asymptomatic peripheral artery disease (aPAD) with the ankle-brachial index (ABI) test is hypothesized to reduce disease progression and cardiovascular (CV) events by identifying individuals who may benefit from early initiation of medical therapy. Using a Markov model, we evaluated the cost effectiveness of initiating medical therapy (e.g. statin and ACE-inhibitor) after a positive ankle-brachial index (ABI) screen in 65-year-old patients. We modeled progression to symptomatic PAD (sPAD) and CV events with and without ABI screening, evaluating differences in costs and quality-adjusted life years (QALYs). The cost of the ABI test, physician visit, new medication, CV events, and interventions for sPAD were incorporated in the model. We performed sensitivity analysis on model variables with uncertainty. Our model found an incremental cost of US $338 and an incremental QALY of 0.00380 with one-time ABI screening, resulting in an incremental cost-effectiveness ratio (ICER) of $88,758/QALY over a 35-year period. The variables with the largest effects in the ICER were aPAD disease prevalence, cost of monthly medication after a positive screen and 2-year medication adherence rates. Screening high-risk populations, such as tobacco users, where the prevalence of PAD may be 2.5 times higher, decreases the ICER to $24,092/QALY. Our analysis indicates the cost effectiveness of one-time screening for aPAD depends on prevalence, medication costs, and adherence to therapies for CV disease risk reduction. Screening in higher-risk populations under favorable assumptions about medication adherence results in the most favorable cost effectiveness, but limitations in the primary data preclude definitive assessment of cost effectiveness.

We compared the associations of diabetes mellitus (DM) and other cardiovascular disease (CVD) risk factors with decline in the ankle-brachial index (ABI) over 4 years in participants with and without peripheral artery disease (PAD). A total of 566 participants, 300 with PAD, were followed prospectively for 4 years. Mean (SD) baseline ABI values were 0.70 (0.13) for participants with both PAD and DM, 0.67 (0.14) for participants with only PAD, 1.10 (0.13) for participants with only DM, and 1.10 (0.10) for participants with neither PAD nor DM. After adjusting for age, sex, and baseline ABI, the corresponding ABI change from baseline to 4-year follow-up were -0.02, -0.04, +0.05, and +0.05, respectively. Compared to participants with neither PAD nor DM, participants with only PAD showed significantly more ABI decline (p

We sought to evaluate whether case ascertainment using administrative health data would be a feasible way to identify peripheral artery disease (PAD) patients from the community. Subjects’ ankle–brachial index (ABI) scores from two previous prospective observational studies were linked with International Classification of Diseases (ICD) and Canadian Classification of Interventions (CCI) codes from three administrative databases from April 2002 to March 2012, including the Alberta Inpatient Hospital Database (ICD-10-CA/CCI), Ambulatory Care Database (ICD-10-CA/CCI), and the Practitioner Payments Database (ICD-9-CM). We calculated diagnostic statistics for putative case definitions of PAD consisting of individual code or sets of codes, using an ABI score ⩽ 0.90 as the gold standard. Multivariate logistic regression was performed to investigate additional predictive factors for PAD. Different combinations of diagnostic codes and predictive factors were explored to find out the best algorithms for identifying a PAD study cohort. A total of 1459 patients were included in our analysis. The average age was 63.5 years, 66% were male, and the prevalence of PAD was 8.1%. The highest sensitivity of 34.7% was obtained using the algorithm of at least one ICD diagnostic or procedure code, with specificity 91.9%, positive predictive value (PPV) 27.5% and negative predictive value (NPV) 94.1%. The algorithm achieving the highest PPV of 65% was age ⩾ 70 years and at least one code within 443.9 (ICD-9-CM), I73.9, I79.2 (ICD-10-CA/CCI), or all procedure codes, validated with ABI < 1.0 (sensitivity 5.56%, specificity 99.4% and NPV 84.6%). In conclusion, ascertaining PAD using administrative data scores was insensitive compared with the ABI, limiting the use of administrative data in the community setting. [ABSTRACT FROM AUTHOR]

Sedentary behavior is an adverse health risk factor that is independent of physical activity. The relationship between sedentary behavior, exercise activity and the ankle-brachial index (ABI) is not well understood. We analyzed data from the National Health and Nutrition Examination Survey (NHANES) 2003–2004. Accelerometer data were used to quantify exercise and sedentary time for each participant. A low ABI was defined as a value <1.0 (including borderline values). Multi-variable adjusted logistic regression analyses were performed with sedentary and exercise times as independent variables, adjusting for important confounders. There were 1443 asymptomatic participants (mean age 61 years, 49% female, 55% current/prior smokers) with mean daily sedentary and exercise times of 454±144 and 18±20 minutes, respectively. Of the participants, 23% had an ABI <1.0 (8.7% with ABI <0.9). Sedentary time was positively associated with a low ABI (odds ratio [OR] 1.22 per 1 standard deviation [SD], [95% confidence interval (CI), 1.03–1.43]; p=0.02) while exercise time was inversely associated with a low ABI (OR 0.71 per 1 SD, [95% CI, 0.57–0.89]; p=0.003). Sedentary time is associated with low ABI values in the asymptomatic population. This association appears to be independent of exercise time and warrants further investigation. [ABSTRACT FROM AUTHOR]

Pentraxin 3 (PTX3) is a novel inflammatory cytokine produced in atherosclerotic plaque. We hypothesized that this marker may be a better predictor of peripheral artery disease (PAD) than C-reactive protein (CRP) in hemodialysis (HD) patients. The ankle–brachial index (ABI) was measured in HD patients. PTX3 levels in 116 HD patients and 30 healthy blood donors were measured by ELISA. A total of 116 HD patients (age: 56.44 ± 14.08 years) were enrolled; 21 (18%) patients had PAD. PTX3 was significantly higher in PAD versus non-PAD patients (5.55 ± 2.63 vs 2.32 ± 1.29 ng/mL; p < 0.001). In a univariate analysis, ABI correlated significantly with age, blood glucose and triglycerides, and plasma PTX3 (r = -0.548, p < 0.001) and high-sensitivity (hs)CRP (r = -0.495, p < 0.001). Using ROC curve analysis for PAD, PTX3 (cut-off value 4.06 ng/mL, AUC 0.901, p < 0.0001) showed a significantly better positive predictive value than hsCRP (cut-off value 3.33 mg/L, AUC 0.640, p < 0.05). Logistic regression analysis further confirmed that PTX3 (OR = 9.755, p = 0.001) was an independent predictor of PAD. In conclusion, we demonstrated that PTX3 may be a better marker of PAD than hsCRP, and independently correlated with PAD in HD patients. [ABSTRACT FROM PUBLISHER]

We studied associations of the number and size of magnetic resonance angiography (MRA)-assessed lower extremity collateral vessels with the ankle–brachial index (ABI), severity of superficial femoral artery (SFA) plaque, and leg symptoms in participants with peripheral artery disease (PAD). A total of 303 participants with PAD underwent time-resolved MRA at the thigh station. Collaterals were categorized by number (Category 1: 0–3 collaterals; Category 2: 4–7 collaterals; Category 3: ≥ 8 collateral vessels) and size (Grade 1: ≤ 5 small collaterals; Grade 2: > 5 small vessels; Grade 3: ≤ 5 large collaterals; Grade 4: > 5 large collaterals). Adjusting for age, sex, race, comorbidities and other covariates, more numerous collateral vessels were associated with lower ABI values (Category 1: 0.79; Category 2: 0.67; Category 3: 0.60; p trend < 0.001). Similarly, larger collateral vessels were associated with lower ABI values (Grade 1: 0.75; Grade 2: 0.65; Grade 3: 0.62; Grade 4: 0.59; p trend < 0.001). More numerous (p < 0.001) and larger (p < 0.001) collateral vessels were associated with greater mean SFA plaque area (p trend < 0.001). More numerous (p trend = 0.007) and larger (p trend = 0.017) collateral vessels were associated with a lower prevalence of asymptomatic PAD. In conclusion, among participants with PAD, larger and more numerous collaterals, measured by MRA, were associated with lower ABI values, greater plaque area in the SFA, and a lower prevalence of asymptomatic PAD. Further study is needed to determine the role of collateral vessels in maintaining functional performance in PAD. [ABSTRACT FROM AUTHOR]

The pathophysiology and time course of an individual converting from asymptomatic peripheral artery disease (PAD) to symptomatic claudication is unclear. The objectives of this study were: (1) to characterize the extent of atherosclerotic disease in individuals with an abnormal ankle–brachial index (ABI), but without claudication; and over 1 year of follow-up to (2) evaluate the progression of PAD using ultrasound imaging, (3) determine changes in the ABI and leg pain symptoms, and (4) correlate PAD progression with changes in the ABI and leg symptoms. We hypothesized that PAD progression would be associated with the development of claudication and changes in the ABI, 6-minute walk distance (6-MWD), and walking quality of life. Individuals with a reduced ABI but without typical intermittent claudication noted on community screening were invited to undergo baseline and 1-year follow-up assessment, including duplex ultrasound. The initial and repeat evaluations included measurement of the ABI, lower extremity duplex arterial mapping, and assessment of leg pain and functional status. Of the 50 people studied, 44 (88%) had significant atherosclerotic lesions in the lower extremity arteries, affecting 80 legs. A total of 33 of 50 individuals (66%) returned for the 1-year follow-up visit. On ultrasound examination, two of 18 normal legs developed PAD, and in 48 legs with PAD at baseline, 17 legs (35%) developed new or progressive lesions. Thirteen legs developed new claudication. Overall, there was no significant worsening in the ABI, 6-MWD, or the Walking Impairment Questionnaire (WIQ). However, legs with new lesions or lesion progression were significantly more likely to develop claudication, and the 13 legs (seven subjects) developing claudication showed a significant decline in the 6-MWD. In conclusion, these data indicate that a significant number of people with asymptomatic PAD show progression over 1 year, that such individuals are more likely to develop claudication, and that those developing claudication have a significant decrease in their 6-MWD. [ABSTRACT FROM AUTHOR]

We hypothesized that, in the absence of clinically recognized dementia, cognitive dysfunction measured by the clock draw test (CDT) is associated with greater functional impairment in men and women with peripheral artery disease (PAD). Participants were men and women aged 60 years and older with Mini-Mental Status Examination scores ≥ 24 with PAD (n = 335) and without PAD (n = 234). We evaluated the 6-minute walk test, 4-meter walking velocity at usual and fastest pace, the Short Physical Performance Battery (SPPB), and accelerometer-measured physical activity. CDTs were scored using the Shulman system as follows: Category 1 (worst): CDT score 0—2; Category 2: CDT score 3; Category 3 (best): CDT score 4—5. Results were adjusted for age, sex, race, education, ankle—brachial index (ABI), and comorbidities. In individuals with PAD, lower CDT scores were associated with slower 4-meter usual-paced walking velocity (Category 1: 0.78 meters/second; Category 2: 0.83 meters/second; Category 3: 0.86 meters/second; p-trend = 0.025) and lower physical activity (Category 1: 420 activity units; Category 2: 677 activity units; Category 3: 701 activity units; p-trend = 0.045). Poorer CDT scores were also associated with worse functional performance in individuals without PAD (usual and fast-paced walking velocity and SPPB, p-trend = 0.022, 0.043, and 0.031, respectively). In conclusion, cognitive impairment identified with CDT is independently associated with greater functional impairment in older, dementia-free individuals with and without PAD. Longitudinal studies are necessary to explore whether baseline CDT scores and changes in CDT scores over time can predict long-term decline in functional performance in individuals with and without PAD. [ABSTRACT FROM AUTHOR]

Peripheral artery disease (PAD) is a manifestation of systemic atherosclerosis and is associated with increased cardiovascular morbidity and mortality. We describe the prevalence and risk factors of PAD in a multi-ethnic Asian population (Chinese, Malays and Indians) in Singapore. The Singapore Prospective Study Program recruited 4132 individuals between 2004 and 2006 in which the ankle—brachial index (ABI) was measured using the Smartdop™ 20EX bi-directional blood flow detector. PAD was defined as ≤ 0.9 and a high ABI > 1.4, with ABI 1.11—1.20 as reference. The mean age (SD) of individuals in the study was 49.9 (11.8) years, with 51.8% females. PAD was present in 4.3% of the population and a high ABI (> 1.4) was rare. Malays and Indians had a higher risk (especially in females). Compared to those with an ABI between 1.11 and 1.20, those with PAD were more likely to be of Malay and Indian ethnicity, female sex, with higher systolic blood pressure and pulse pressure, with increased prevalence of diabetes mellitus, hypertension, albuminuria and renal impairment, and with a past history of stroke. In conclusion, in this large multi-ethnic Asian population, we document the distribution and risk factor associations for PAD. PAD shows an ethnic distribution similar to that of coronary artery disease in Singapore, with differences in sex distribution. Apart from traditional vascular risk factors, pulse pressure, renal impairment and a past history of stroke are important determinants of PAD. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the association between chronic kidney disease (CKD) and peripheral arterial disease (PAD) and examine the combined effect of CKD and PAD on all-cause and cardiovascular disease (CVD) mortality. The Chinese Ankle Brachial Index Cohort consisted of 3732 adults aged 35 years or older enrolled in 2004 and followed-up in 2007. Complete baseline data were compiled on 3610 people which were examined in the final analysis. Mortality surveillance was completed from December 2007 to February 2008. Survival analysis was used to compare the survival rate in different CKD/PAD groups. The relative risks (RR) of death from all-cause and CVD were compared using a Cox regression model. It was found that the prevalence of PAD in patients with and without CKD was 41.9% and 22.3%, respectively (p < 0.001). The survival rate for the CKD and PAD group was significantly lower than that for any single disease, for both all-cause and CVD mortality (log-rank: p < 0.001). In conclusion, CKD is a risk factor for PAD. The combined CKD and PAD patients had the highest risk for all-cause and CVD mortality. Early recognition of risk can be made by taking an ankle-brachial index measurement of PAD; a corresponding laboratory assessment should be used as a measurement of renal function for PAD patients. [ABSTRACT FROM AUTHOR]

The ankle-brachial index (ABI) is the standard test used in clinical practice to detect peripheral artery disease (PAD) and is a powerful predictor of adverse cardiovascular outcomes. This study sought to measure the baseline knowledge of the ABI test among a sample of internal medicine residents and to examine the impact of an educational intervention on performance of the test. A total of 29 residents were asked to perform three tasks, with the performance of each task being assessed using a point-based scoring system: measure an ABI on a normal volunteer (15 points), calculate the ABI based on data from a hypothetical patient (3 points), and interpret a range of ABI values (6 points). A standardized educational intervention was then provided and post-education performance was assessed for each task using the same scoring system. At baseline, 4% of residents correctly measured the ABI, 10% correctly calculated the ABI, and 45% correctly interpreted the ABI. Baseline performance was unaffected by year of residency training. Following the educational intervention, 50% of residents correctly measured the ABI, 75% correctly calculated the ABI, and 88% correctly interpreted the ABI. The mean score for the tasks of ABI measurement, calculation and interpretation between baseline and post-education were 4.6 ± 3 and 13.9 ± 1.6 (p < 0.0001), 1 ± 0.9 and 2.3 ± 1.2 (p = 0.002), and 4.9 ± 1.6 and 5.9 ± 0.3 (p = 0.008), respectively. In conclusion, baseline knowledge of the ABI test was poor among a sample of internal medicine residents. These results suggest that instruction regarding the ABI test is deficient in medical school and residency programs and requires action by those responsible for the education of medical students and residents. [ABSTRACT FROM AUTHOR]

The ankle-brachial index (ABI), a marker of generalized atherosclerosis, is related to cognitive impairment in older adults. We investigated whether ABI is associated specifically with age-related cognitive decline. We measured ABI at recruitment and 5 and 12 years later in a sample of individuals aged 55-74 years. Cognition was measured in 717 of these participants 10 years after recruitment and 5 years later. It was found that ABI was associated with the level of cognitive function, even after adjustment for estimated premorbid function and concurrently measured anxiety and depression (standardized coefficient of 0.07), but this was attenuated by anxiety and depression. ABI was not associated with change in cognitive function. In conclusion, over long time periods, low ABI may be associated with reduced cognitive function in older adults, at least partly because the associated poor health creates anxiety and depression. [ABSTRACT FROM AUTHOR]