A high ankle-brachial index is associated with increased cardiovascular disease morbidity and lower quality of life

High ankle-brachial index participants experienced similar long-term mortality as peripheral artery disease in a national sample of community-dwelling adults

BACKGROUND

Only a few small studies have shown the association between high ankle-brachial pressure index (ABI >1.4) and adverse cardiovascular (CV) events and mortality. Although there is abundant literature depicting the association between ABI and overall systemic atherosclerosis, it typically focuses on low ABI. Furthermore, historically, many studies focusing on peripheral artery disease have excluded high ABI participants. We aimed to study the mortality outcomes of persons with high ABI in the National Health and Nutrition Examination Survey (NHANES).

METHODS

We obtained ABI from participants aged ≥40 years for survey years 1999 to 2004. We defined low a ABI as ≤0.9, normal ABI as 0.9 to 1.4, and high ABI as >1.4 or if the ankle pressures were >245 mm Hg. Demographics, various comorbidities, and laboratory test results were obtained at the time of the survey interview. Multivariable adjusted hazard ratios (HRs) along with 95% confidence intervals (CIs) were calculated for CV and all-cause mortality via Cox proportional hazards regression. Mortality was linked to all NHANES participants for follow-up through December 31, 2019, by the Centers for Disease Control and Prevention.

RESULTS

We identified 7639 NHANES participants with available ABI. Of these, 6787 (89%) had a normal ABI, 646 (8%) had a low ABI, and 206 (3%) had elevated ABI. Of participants with high ABI, 50% were men, 15% were African Americans, 10% were current smokers, 56% had hypertension, 33% had diabetes, 15% had chronic kidney disease (CKD), and 18% had concomitant coronary artery disease (CAD). Diabetes (odds ratio [OR], 2.4; 95% CI, 1.7-3.2), CAD (OR, 1.6; 95% CI, 1.0-2.4), and CKD (OR, 1.5; 95% CI, 1.0-2.3) at baseline were associated with having a high ABI, respectively. A high ABI was associated independently with elevated CV (HR, 2.6; 95% CI, 2.1-3.1; P < .0001) and all-cause mortality (HR, 2.5; 95% CI, 2.2-2.8; P < .0001) after adjusting for covariates, including diabetes, CKD, CAD, current smoking, cancer, and hypertension.

CONCLUSIONS

A high ABI is associated with an elevated CV and all-cause mortality, similar to patients with PAD. High ABI participants should receive the same attention and aggressive medical therapies as patients with PAD.

Relationship between objectively measured physical activity and subclinical cardiovascular disease: a systematic review

Introduction

The association of physical activity (PA) with subclinical cardiovascular disease (CVD) is unclear. Clarifying this relationship may inform cardiovascular prevention strategies.

Methods

We performed a systematic review (CRD42021226089) using Medline, Embase, CINAHL and Cochrane (1 January 2000 to 1 September 2023). Studies published with adult populations exploring the relationship between objectively measured PA and subclinical CVD were included. Subclinical CVD was assessed using: ankle-brachial index (ABI); arterial stiffness; carotid artery disease; coronary artery atherosclerosis; endothelial function; and measures of cardiac structure and function. The Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) and Cochrane Risk of Bias tools were used for quality review.

Results

Of 68 included studies, most supported an inverse relationship between PA and subclinical CVD. Arterial stiffness was the most common outcome (n=40), and 33 studies suggested that less sedentary behaviour (SB), increased PA and/or higher intensity PA was associated with less arterial stiffness. Ten studies of carotid artery disease (total n=18), six of endothelial function (n=10), two of coronary artery disease (n=3) and all of ABI (n=6) suggested that PA or less SB is associated with less subclinical disease. Five studies assessing cardiac structure/function (n=6) suggested alterations in structure/function with PA.

Conclusions

PA reduces the risk of CVD events, and this systematic review demonstrates that some of the benefits may be mediated by an inverse association between PA and subclinical CVD. Interventions to increase PA are important for CVD prevention, so we provide a comprehensive overview of which surrogate outcome measures may be most useful to assess future CVD prevention interventions.

PROSPERO registration number

CRD42021226089.

Prognostic Value of Ankle-Brachial Index in Prediction of Cardiovascular Events in an Asian Population with Multiple Atherosclerotic Risk Factors

We aimed to evaluate the incremental prognostic value after incorporation of the ankle-brachial index (ABI) into the 10-year pool cohort equation (PCE) risk model in patients with multiple risk factors (MRFs). A total of 4332 MRFs patients were divided into 2 groups as ABI ≤.9 or >.9. The primary outcome was hard cardiovascular events (hCVE: including cardiovascular death, myocardial infarction, or ischemic stroke) over a median follow-up of 36 months. The Cox proportional hazards survival model, C-statistic, and net reclassification indices (NRI) were used. The occurrence of the primary outcome in the ABI ≤.9 group (3.7%) was significantly greater than in the ABI > .9 group (1.3%), P < .001. ABI is an independent predictor of hCVE in addition to the variables in the standard risk model (age, gender, and smoking status). ABI modestly improved the C-index when added to the PCE risk model (PCE .70 vs ABI+PCE .74). The addition of ABI to the PCE risk model did not significantly improve the classification of patients (NRI -.029; 95% CI: -.215 to .130). Despite ABI being one of the independent predictors of hCVE, integration of ABI into the PCE model did not improve the efficacy of risk reclassification in patients with MRFs.

The ankle-brachial index for assessing the prevalence of peripheral artery disease and cardiovascular risk in patients with type 2 diabetes mellitus

BACKGROUND AND AIMS

Type 2 diabetes mellitus (T2DM) is an important risk factor for peripheral artery disease (PAD). Ankle-Brachial Index (ABI) was found associated with a higher cardiovascular (CV) risk and mortality. The main goals of this study were to establish the prevalence of PAD in a T2DM population, and assess the relationship between PAD and the CV risk calculated with the CUORE Project score (CPS) (https://www.cuore.iss.it/). The association between the ABI, the main risk factors for PAD and T2DM complications was also investigated.

METHODS AND RESULTS

Two hundred patients were consecutively enrolled. The prevalence of PAD in this population was 17%. The CV risk tended to be higher (p = 0.0712) in the group with a pathological ABI than in the group with a normal ABI. Glycated hemoglobin (r = -0.1591; p = 0.0244), total cholesterol (r = -0.1958; p = 0.0054), LDL cholesterol (r = -0.1708; p = 0.0156) and systolic blood pressure (r = -0.1523; p = 0.0313) correlated significantly and inversely with the left ABI. The frequency of diabetic retinopathy was significantly higher in the group with a pathological ABI (p = 0.0316).

CONCLUSIONS

The data reveal a high prevalence of PAD in patients with T2DM. The CPS confirmed that patients with a pathological ABI have tendency to a higher CV risk. The results point to the importance of an accurate CV assessment - also measuring individuals' ABI and calculating their CPS - to better pinpoint those at high risk of PAD, especially among patients with T2DM.

Association of arterial stiffness and neuropathy in diabetes: a systematic review and meta-analysis

Evidence is still emerging on the relationships of arterial stiffness with cardiac autonomic neuropathy (CAN) and peripheral neuropathy (PN). To our knowledge no systematic reviews or meta-analyses of these associations have been published. The purpose of our review was to assess the association of arterial stiffness with each type of neuropathy. Medline and Embase were systematically searched for observational studies of arterial stiffness and neuropathy.The systematic review of 60 studies (25 for CAN and 37 for PN), 59 including people with diabetes, showed arterial stiffness overall was higher in people with neuropathy than people without neuropathy. Forty-three studies were included in the meta-analysis. For CAN (19 studies), arterial stiffness was increased in people with neuropathy compared with without, as measured by pulse wave velocity (PWV) (mean difference: 1.32 m/s, 95% CI 0.82 to 1.81, p<0.00001), pulse pressure (PP) (mean difference: 6.25 mmHg, 95% CI 4.51 to 7.99, p<0.00001) or augmentation index (mean difference: 5.52%, 95% CI 3.46 to 7.58, p<0.0001). For PN (26 studies), arterial stiffness was increased in people with neuropathy compared with those without, as measured by PWV (mean difference: 1.22 m/s, 95% CI 0.87 to 1.58, p<0.00001) or PP (mean difference: 4.59 mmHg, 95% CI 2.96 to 6.22, p<0.00001). Only two cohort studies were located so the temporality of the association between arterial stiffness and neuropathy remains unclear. Increased arterial stiffness is associated with CAN and PN.PROSPERO registration number: CRD42019129563.

Peripheral Artery Disease and Subsequent Risk of Infectious Disease in Older Individuals: The ARIC Study

OBJECTIVE

To quantify the association of peripheral artery disease (PAD) with infection risk because PAD has been understudied despite recognition of atherosclerotic cardiovascular disease as a risk factor for infection.

METHODS

Among 5082 participants of the Atherosclerosis Risk in Communities study (aged 71 to 90 years during 2011-2013), we assessed the association of PAD status, based on clinical history and ankle-brachial index (ABI), with infection-related hospitalization (through December 2019) using multivariable Cox regression. We also cross-classified participants by PAD and coronary heart disease (CHD)/stroke status at baseline, with implications for polyvascular disease.

RESULTS

During the median follow-up of 6.5 years, there were 1677 infection-related hospitalizations. Peripheral artery disease (clinical history or ABI ≤0.90) was independently associated with the risk of overall infection (adjusted hazard ratio [HR], 1.66 [95% CI, 1.42 to 1.94] vs ABI of 1.11 to 1.20), as was borderline low ABI of 0.91 to 1.00 (adjusted HR, 1.75 [95% CI, 1.47 to 2.07]). Results were consistent across major types of infection (ie, cellulitis, bloodstream infection, pneumonia, and urinary tract infection). For overall infection, PAD plus CHD/stroke had the highest HR of hospitalized infection (1.9), and PAD alone and CHD/stroke alone showed similar HRs of 1.6. For subtypes of infection, PAD alone had the highest HR of approximately 2 for bloodstream infection; PAD alone and PAD plus CHD/stroke had a similar risk of urinary tract infection with HR of approximately 1.7.

CONCLUSION

Peripheral artery disease and borderline low ABI were robustly associated with infection-related hospitalization of older adults. The contribution of PAD to infection risk was comparable to that of CHD/stroke, warranting clinical attention to PAD for the prevention of infectious diseases.

Abnormal ankle-brachial index, cardiovascular risk factors and healthy lifestyle factors in hypertensive patients: prospective cohort study from a primary care urban population

Background

Peripheral arterial disease (PAD) and arterial stiffness (AS) may be hypertension-mediated vascular lesions. Both are determined by an abnormal ankle-brachial index (ABI) and are predictors of cardiovascular disease (CVD) and mortality. We assessed the relationship in urban hypertensive patients between an abnormal ABI and an ideal cardiovascular health (CVH) score, plus other healthy factors, with unfavourable outcomes.

Methods

We studied 243 hypertensive patients from a primary care urban population, followed for two years. Clinical data, comorbid conditions, including hypertension-mediated organ damage (HMOD) and hypertension-related comorbidities (HRC), hospitalizations and mortality were also recorded.

Results

A low prevalence of ideal CVH was observed in urban hypertensive patients. The ABI ≤ 0.9 group (n = 16) showed a higher proportion of prior CVD other than PAD, mortality and hospitalizations than the ABI > 1.4 group (n = 41), and a poorer lipid, metabolic and renal profile. An inverse relationship between CVH score and ABI ≤ 0.9 and unfavourable outcomes (HMOD, HRC, death or hospitalization) was observed. Chronic kidney disease (CKD) and diabetes were independently associated with an ABI ≤ 0.9. Age, sex, diabetes, CKD, ABI ≤ 0.9 and ideal cholesterol were also associated with outcomes, but not other CVH metrics.

Conclusions

Besides a low prevalence of ideal CVH, an inverse relationship between CVH score and ABI ≤ 0.9 and unfavourable outcomes was observed in hypertensive patients from an urban population. Stronger efforts to promote ideal CVH may improve outcomes in this particular population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-022-01837-1.

Sex as a Key Determinant of Peripheral Artery Disease – Epidemiology, Differential Outcomes, and Proposed Biological Mechanisms

Atherosclerotic peripheral artery disease (PAD) is associated with functional limitations and an increased risk of poor cardiovascular outcomes. Although men are traditionally viewed at higher risk of PAD than women, the true prevalence and incidence is inconsistent among available reports. Some of this variability is due to differences in PAD-related symptoms among women as well as sex-based differences in diagnostic tests, such as the ankle-brachial index, and it is critical for future epidemiologic studies to account for these differences. Generally, women with PAD experience greater functional impairment and decline then men and are less likely to receive guideline-directed medical therapy. In some settings, women are also more likely to present at later stages of disease and more often undergo lower limb amputation than men. Animal data exploring the biological underpinnings of these sex differences are limited, but several mechanisms have been postulated, including differential plaque morphology, alterations in the immune response, and hormonal variation and protection. Epidemiologic data suggest a link between inflammation and PAD and also reveal sex differences in lipid profiles associated with risk of PAD. In this review, we discuss available data on sex differences in PAD with additional focus on potential biological explanations for these differences. We also emphasize important knowledge gaps in this area, including under-representation of women in PAD clinical trials, to help guide future investigations and eliminate sex disparities in PAD.

The high normal ankle brachial index is associated with left ventricular hypertrophy in hypertension patients among the Han Chinese

Left ventricular hypertrophy (LVH) is the most common target organs damage in the hypertension patients. Abnormal low (≤0.9) or high (≥1.40) ankle brachial index (ABI) are associated with an increased risk of cardiovascular events. However, the relationships between a high ABI in the normal range (0.9–1.4) and LVH in Han Chinese hypertension are not entirely elucidated. This study included 3953 hypertension patients aged 40–75 years among Han Chinese. Hypertension was defined as systolic blood pressure≥140 mm Hg, diastolic blood pressure≥90 mm Hg, or history of antihypertensive drug use. Left ventricular mass (LVM) was measured by transthoracic echocardiography. LVH was diagnosed by using the criteria of LVM ≥49.2 g/m^2.7 for men and 46.7 g/m^2.7 for women. Our study suggested that the ABI was higher in patients with LVH than in those without (1.13±0.11, 1.11±0.11, p < 0.001). The prevalence of LVH in patients with the lowest (0.9 < ABI≤1.03), second (1.04≤ABI≤1.11), the third (1.12≤ABI≤1.20), and the highest quartile (1.21≤ABI < 1.40) of ABI was 37.2%, 38.2%, 45.5%, 45.7%, respectively. Logistic regression analysis suggested that the highest and third quartile of ABI were significantly associated with increased LVH risk (multivariate‐adjusted OR of highest group:1.83; third group:1.61). The association of ABI at second quartile with LVH was nonsignificant. Similar results were observed in less than 60 years and without coronary heart disease or diabetes group. Our observations in Chinese patients with hypertension indicated high ABI may be an important risk factor for LVH in hypertension patients among Han Chinese, even in the normal range.

Pre-operative ankle-brachial index for cardiovascular risk assessment in simultaneous pancreas-kidney transplant recipients: a simple and elegant strategy!

Background

Patients with insulin-dependent diabetes mellitus type 1 (IDDM1) and end-stage kidney disease (ESKD) undergoing simultaneous pancreas kidney transplantation (SPKT) are a population with diffuse atherosclerosis and elevated risk of cardio- and cerebrovascular morbidity and mortality. We aimed to investigate the feasibility of preoperative screening for peripheral arterial disease (PAD), specifically ankle-brachial index (ABI) testing, to predict peri- and postoperative outcomes in SPKT recipients.

Methods

Medical data (2000–2016) from all patients with IDDM and ESKD undergoing SPKT at our transplant center were retrospectively analyzed. The correlation between PAD (defined by an abnormal ABI before SPKT and graft failure and mortality rates as primary end points, and the occurrence of acute myocardial infarction, cerebrovascular and peripheral vascular complications as secondary end points were investigated after adjustment for known cardiovascular risk factors.

Results

Among 101 SPKT recipients in our transplant population who underwent structured physiological arterial studies, 17 patients (17%) were diagnosed with PAD before transplantation. PAD, as defined by a low ABI index, was an independent and significant predictor of death (HR, 2.99 (95% CI 1.00–8.87), p = 0.049) and pancreas graft failure (HR, 4.3 (95% CI 1.24–14.91), p = 0.022). No significant differences were observed for kidney graft failure (HR 1.85 (95% CI 0.76–4.50), p = 0.178). In terms of the secondary outcomes, patients with PAD were more likely to have myocardial infarction, stroke, limb ischemia, gangrene or amputation (HR, 2.90 (95% CI 1.19–7.04), p = 0.019).

Conclusions

Pre-transplant screening for PAD and cardiovascular risk factors with non-invasive ABI testing may help to reduce perioperative complications in high-risk patients. Future research on long-term outcomes might provide more in depth insights in optimal treatment strategies for PAD among SPKT recipients.

Abnormal vascular physiology in the lower extremities as a risk factor for ischemic stroke and mortality

CONTEXT

Peripheral artery disease (PAD) is highly prevalent in the general population, affecting up to 25% of patients 55 years of age or older. There is a known association with acute ischemic stroke, but limited large cohort studies exist pertaining to the relationship between PAD severity and incident ischemic stroke.

OBJECTIVES

To evaluate the risk of incident ischemic stroke and mortality along the spectrum of low and elevated ankle brachial index (ABI) measurement.

METHODS

We performed a retrospective extraction of ABI data of all adult patients who underwent lower extremity physiology study for any indication from January 1, 1996 to June 30, 2018 in the Mayo Clinic health system. PAD was categorized into severe, moderate, mild, and borderline based on ABI measurements and poorly compressible arteries (PCA). These were compared with normal ABI measurements. Associations of PAD/PCA with new ischemic stroke events and all cause mortality were analyzed. Hazard ratios (HR) were calculated using multivariable Cox proportional regression with 95% confidence intervals.

RESULTS

A total of 39,834 unique patients were included with a median follow up duration of 4.59 years. All abnormal ABI groups, except borderline PAD, were associated with increased risk of incident ischemic stroke after multivariate regression compared to normal ABI. A severity-dependent association was observed between PAD and ischemic stroke with moderate (HR, 1.22 [95% CI, 1.10-1.35]) and severe (HR, 1.19 [95% CI, 1.02-1.40]) categories conferring similar risk in comparison to normal ABI. Patients with PCA carried the greatest ischemic stroke risk (HR, 1.30 [95% CI, 1.15-1.46]). Similarly, abnormal ABI groups were associated with a significant risk for all cause mortality in a severity-dependent manner, with severe PAD conferring the greatest risk (HR, 3.07 [95% CI, 2.88-3.27]).

CONCLUSIONS

This study adds to the growing body of evidence that both PAD and PCA are independent risk factors for incident ischemic stroke and all cause mortality. The association of PAD severity and PCA with risk of ischemic stroke may help clinicians with risk stratification and determining treatment intensity.

Estimating the diagnostic accuracy of the ankle-brachial pressure index for detecting peripheral arterial disease in people with diabetes: A systematic review and meta-analysis

AIM

To systematically evaluate research investigating the accuracy of the ankle-brachial index (ABI) for diagnosing peripheral artery disease (PAD) in people with diabetes, as the accuracy is thought to be reduced in this cohort.

METHODS

A database search of EBSCO Megafile Premier, Embase and The Cochrane Library was conducted to 28 February 2019. Prospective and retrospective investigations of the diagnostic accuracy of the ABI for PAD in people with diabetes using an imaging reference standard were eligible. Sensitivity and specify of the ABI and bivariate meta-analysis against reference tests, or a standard summary receiver operating curve analysis (SROC) was performed.

RESULTS

Thirty-three studies met the inclusion criteria. ABI was compared with angiography in 12 studies and with colour duplex ultrasound (CDUS) in 21 studies. A SROC analysis of studies using angiography as the reference standard found a diagnostic odds ratio (DOR) of 9.06 [95% confidence interval (CI) 3.61 to 22.69], and area under the curve (AUC) of 0.76 (95% CI 0.66 to 0.86). Bivariate analysis of studies using CDUS demonstrated mean sensitivity of 0.60 (95% CI 0.48 to 0.71; P = 0.097) and mean specificity of 0.87 (95% CI 0.78 to 0.92; P < 0.001) with a DOR of 9.76 (95% CI 5.24 to 18.20; P < 0.0001) and AUC 0.72.

CONCLUSIONS

These results suggest the ABI has a high specificity but lower sensitivity in detecting imaging diagnosed PAD in people with diabetes. The low probability of the testing being able to rule diagnosis in or out suggest that the ABI has limited effectiveness for early detection of PAD in this cohort.

High ankle brachial index predicts high risk of cardiovascular events amongst people with peripheral artery disease

Ankle-brachial pressure index (ABPI) is commonly measured in people referred to vascular specialists. This study aimed to assess the association of high ABPI (≥ 1.4) with cardiovascular events in people with peripheral artery disease (PAD). 1533 participants with PAD diagnosed by a vascular specialist were prospectively recruited from four out-patient clinics in Australia. ABPI was measured at recruitment and the occurrence of myocardial infarction (MI), stroke or cardiovascular death (major cardiovascular events; MACE) and any amputation were recorded over a median (inter-quartile range) follow-up of 3.3 (1.0-7.1) years. The association of high, compared to normal, low (0.5-0.9) or very low (<0.5), ABPI with clinical events was estimated using Cox proportional hazard analyses, adjusting for traditional risk factors and reported as hazard ratio with 95% confidence intervals. 596 (38.9%), 676 (44.1%), 157 (10.2%) and 104 (6.8%) participants had normal, low, very low and high ABPI, respectively. Participants with high ABPI had increased risk of MACE, MI and death by comparison to those with either normal ABPI [1.69 (1.07, 2.65), 1.93 (1.07, 3.46) and 1.67 (1.09, 2.56)] or either low or very low ABPI [1.51 (1.02, 2.23), 1.92 (1.16, 3.19) and 1.47 (1.02, 2.14)] after adjusting for other risk factors. Findings were similar in a sensitivity analysis excluding people with ABPI only measured in one leg (n = 120). Participants with high ABPI also had an increased risk of MACE and MI compared to those with very low ABPI alone. High ABPI is a strong indicator of excess risk of cardiovascular events amongst people with PAD.

Warfarin Accelerates Medial Arterial Calcification in Humans

Objective:

Warfarin is associated with medial arterial calcification in humans, but the magnitude and specificity of this effect and the role of other risk factors are unknown. Using serial mammograms, progression of arterial calcification was compared in women receiving no anticoagulants, warfarin, or other anticoagulants, and before, during, and after warfarin use.

Approach and Results:

Warfarin users with mammograms were identified by computerized searches of medical records that included renal function and diabetes mellitus. Lengths of calcified arterial segments were measured, with progression expressed as millimeters per breast per year and presented as medians and interquartile range (IQR). In women with normal renal function (estimated glomerular filtration rate >60 mL/minute per 1.73 m 2 ), progression was 3.9-fold greater in warfarin users: 9.9 (3.8–16) versus 2.5 (0.7–6.7) in controls, P =0.0003, but not increased in users of other anticoagulants. In longitudinal analyses, progression increased from 2.1 (IQR, 0.3–3.9) to 13.8 (IQR, 7.8–38.7; P =0.011) after starting warfarin (n=11) and decreased from 8.8 (IQR, 1.1–10) to 1.9 (IQR, −10 to 6.7; P =0.024) after discontinuation of warfarin (n=13). Progression of calcification was similar in warfarin users with chronic kidney disease (7.3 [IQR, 3.6–17], n=29) but markedly accelerated in warfarin users with end-stage renal disease (47 [IQR, 31–183], n=11; P =0.0002). Progression was similar in diabetic and nondiabetic warfarin users (10.1 [IQR, 3.8–24] versus 7.8 [IQR, 3.6–15]) and did not correlate with age ( r =0.09) or duration of warfarin therapy ( r =0.12).

Conclusions:

Warfarin significantly accelerates medial arterial calcification in humans. This effect is markedly augmented in end-stage renal disease.

Performance of prognostic markers in the prediction of wound healing or amputation among patients with foot ulcers in diabetes: A systematic review

Clinical outcomes of patients with diabetes, foot ulceration, and peripheral artery disease (PAD) are difficult to predict. The prediction of important clinical outcomes, such as wound healing and major amputation, would be a valuable tool to help guide management and target interventions for limb salvage. Despite the existence of a number of classification tools, no consensus exists as to the most useful bedside tests with which to predict outcome. We here present an updated systematic review from the International Working Group of the Diabetic Foot, comprising 15 studies published between 1980 and 2018 describing almost 6800 patients with diabetes and foot ulceration. Clinical examination findings as well as six non-invasive bedside tests were evaluated for their ability to predict wound healing and amputation. The most useful tests to inform on the probability of healing were skin perfusion pressure ≥ 40 mmHg, toe pressure ≥ 30 mmHg, or TcPO₂  ≥ 25 mmHg. With these thresholds, all of these tests increased the probability of healing by greater than 25% in at least one study. To predict major amputation, the most useful tests were ankle pressure < 50 mmHg, ABI < 0.5, toe pressure < 30 mmHg, and TcPO₂  < 25 mmHg, which increased the probability of major amputation by greater than 25%. These indicative values may be used as a guide when deciding which patients are at highest risk for poor outcomes and should therefore be evaluated for revascularization at an early stage. However, this should always be considered within the wider context of important co-existing factors such as infection, wound characteristics, and other comorbidities.

Hypertension and high ankle brachial index: the overlooked combination

OBJECTIVE

Assessment of asymptomatic organ damage in the management of hypertension includes low (<0.9) ankle brachial index (ABI) values. No recommendations are given for patients with high ABI (≥1.3), despite evidence of an association with increased risk. We aimed to study the association of high ABI with all-cause mortality and cardiovascular outcomes in a hypertensive population.

METHODS

In anonymized clinical records from the Catalan Primary Care (SIDIAP) database, we designed a large cohort of hypertensive patients aged 35-85 years at the start date. Participants were excluded if they had previous heart failure, coronary heart disease, stroke, diabetes mellitus, or chronic kidney disease. The study population was categorized according to ABI values. Cox proportional hazards models were used to assess all-cause mortality, heart failure, acute myocardial infarction, and stroke.

RESULTS

From 2006 through 2015, SIDIAP records included 44 657 hypertensive patients with an ABI measurement 9126 of whom met inclusion criteria. The median follow-up (first to third quartiles) was 6.0 years (4.7-7.6). High ABI (≥ 1.3) was associated with an increase in mortality risk, hazard ratio, and 95% confidence interval: 1.44 (1.10-1.88), similar to the group with ABI at least 0.9 and less than 1.1, hazard ratio 1.36 (1.12-1.65), and lower than all groups with ABI less than 0.9. High ABI values tended to associate with heart failure, hazard ratio 1.34 (0.95-1.91), but the relation of high ABI with acute myocardial infarction and stroke was nonsignificant, hazard ratios 1.30 (0.72-2.35) and 0.97 (0.65-1.42), respectively.

CONCLUSION

Patients with high ABI values and hypertension presented an increased all-cause mortality risk that could be considered when advising such patients.

Relation between high Ankle-Brachial Index and cardiovascular outcomes in the general population and cardiovascular disease: a meta-analysis

INTRODUCTION

Conflicting findings have been reported on the association between high Ankle-Brachial Index (ABI) and cardiovascular outcomes. This meta-analysis aimed to assess the association of abnormally high ABI and cardiovascular outcomes in the general population and suspected or established cardiovascular disease (CVD) patients.

EVIDENCE ACQUISITION

A comprehensive literature search was conducted in PubMed and Embase databases through November 10th, 2018. All observational studies evaluating the association of high ABI with cardiovascular events including stroke, coronary heart disease (CHD), congestive heart failure, and composite of CVD/all-cause mortality in the general population and suspected or established CVD patients were included. We pooled risk ratios (RR) with 95% confidence intervals (CI) for the abnormally high ABI (> 1.3 or >1.4) versus the reference normal ABI category.

EVIDENCE SYNTHESIS

We identified 10 cohort studies enrolling 39,421 participants. A random effect model meta-analysis indicated that the pooled RR of composite of CVD/all-cause mortality was 1.07 (95% CI 0.83-1.38) in the general population and 1.26 (95% CI 1.03-1.55) in suspected or established CVD patients. Moreover, participants with abnormally high ABI did not increase the risk of stroke (RR 1.60; 95% CI 0.83-3.06) and CHD (RR 1.40; 95% CI 0.87-2.24) in the general population.

CONCLUSIONS

Abnormally high ABI appears to be associated with an increased risk of a composite of CVD/all-cause mortality in suspected or established CVD patients but not in the general population. However, additional well-designed studies are required to support the current findings.

Impact of Body Mass Index on the Association of Ankle-Brachial Index With All-Cause and Cardiovascular Mortality: Results from the National Health and Nutrition Examination Survey

OBJECTIVE

To assess the influence of body-mass index (BMI) on the association of ankle-brachial index (ABI) with mortality.

PATIENTS AND METHODS

We conducted a prospective study of National Health and Nutrition Examination Survey participants enrolled from January 1, 1999 to December 31, 2002 with BMI and ABI data available. ABI categories were <0.9 (low), 0.9 to 1.3 (reference), and >1.3 (high). BMI categories were <30 kg/m² (nonobese) and ≥30 kg/m² (obese). Cardiovascular (CV) and all-cause mortality were assessed by National Death Index records. Cox proportional-hazards models and Kaplan-Meier survival estimates were used to compare groups.

RESULTS

In total, 4614 subjects were included, with mean age 56±12 years and BMI 28±6 kg/m². Median follow-up was 10.3 years (interquartile range [IQR]: 9.3 to 11.4 years). Low and high ABI were present in 7% and 8%, respectively. After adjustment, low ABI was associated with increased all-cause and CV mortality in nonobese (hazard ratio [HR] 1.5, 95% CI, 1.1-2.1 for all-cause and 3.0 [1.8-5.1] for CV mortality) and obese individuals (1.8 [1.2-2.7] and 2.5 [1.2-5.6], respectively) compared with reference. High ABI was associated with increased CV mortality in nonobese (2.2 [1.1-4.5]) but not obese patients; it was not associated with all-cause mortality overall or when stratified by BMI.

CONCLUSION

In a US cohort, weight influenced the prognostic significance of high ABI. This may be related to technical factors reducing compressibility of the calf arteries in obese persons compared with those who are nonobese.

Ankle-Brachial Index is a Predictor of Future Incident Chronic Kidney Disease in a General Japanese Population

AIMS

The ankle-brachial index (ABI) can be a prognostic marker for chronic kidney disease (CKD) in Western populations. Since there is little relevant evidence for Asian populations, we investigated the relationship between ABI and the risk of incident CKD in a general Japanese population.

METHODS

The cohort included 5,072 participants aged 30-79 without a history of renal disease or cerebro-cardiovascular disease. Incident CKD, defined as an estimated glomerular filtration rate ＜60 (mL/min/1.73 m2) and/or proteinuria (≥ 1＋ on urine dipstick), was compared among participants grouped according to baseline ABI: 0.90-0.99, 1.00-1.09, 1.10-1.19, 1.20-1.29, and 1.30-1.39. Hazard ratios for incident CKD were estimated using a Cox proportional hazards model, with the ABI 1.10-1.19 group serving as the reference.

RESULTS

The CKD incidence rate (/100 person-years) was 1.80 during the mean follow-up period of 5.1 years. The CKD incidence rate was 3.04 in the ABI category 0.90-0.99, 1.58 in ABI 1.00-1.09, 1.72 in ABI 1.10-1.19, 2.01 in ABI 1.20-1.29, and 3.33 in ABI 1.30-1.39. The hazard ratios for developing CKD were 2.14 (95% confidence interval 1.16-3.92) in ABI 0.90-0.99, 1.08 (0.83-1.41) in ABI 1.00-1.09, 1.03 (0.83-1.29) in ABI 1.20-1.29, and 1.37 (0.77-2.47) in ABI 1.30-1.39, after adjusting for age, sex, systolic blood pressure, diabetes, and other confounding factors.

CONCLUSIONS

In a general Japanese population, an ABI of 0.90-0.99 was associated with an increased risk of incident CKD, independent of traditional cardiovascular risk factors.

Cardiovascular disease risk prediction using automated machine learning: A prospective study of 423,604 UK Biobank participants

BACKGROUND

Identifying people at risk of cardiovascular diseases (CVD) is a cornerstone of preventative cardiology. Risk prediction models currently recommended by clinical guidelines are typically based on a limited number of predictors with sub-optimal performance across all patient groups. Data-driven techniques based on machine learning (ML) might improve the performance of risk predictions by agnostically discovering novel risk predictors and learning the complex interactions between them. We tested (1) whether ML techniques based on a state-of-the-art automated ML framework (AutoPrognosis) could improve CVD risk prediction compared to traditional approaches, and (2) whether considering non-traditional variables could increase the accuracy of CVD risk predictions.

METHODS AND FINDINGS

Using data on 423,604 participants without CVD at baseline in UK Biobank, we developed a ML-based model for predicting CVD risk based on 473 available variables. Our ML-based model was derived using AutoPrognosis, an algorithmic tool that automatically selects and tunes ensembles of ML modeling pipelines (comprising data imputation, feature processing, classification and calibration algorithms). We compared our model with a well-established risk prediction algorithm based on conventional CVD risk factors (Framingham score), a Cox proportional hazards (PH) model based on familiar risk factors (i.e, age, gender, smoking status, systolic blood pressure, history of diabetes, reception of treatments for hypertension and body mass index), and a Cox PH model based on all of the 473 available variables. Predictive performances were assessed using area under the receiver operating characteristic curve (AUC-ROC). Overall, our AutoPrognosis model improved risk prediction (AUC-ROC: 0.774, 95% CI: 0.768-0.780) compared to Framingham score (AUC-ROC: 0.724, 95% CI: 0.720-0.728, p < 0.001), Cox PH model with conventional risk factors (AUC-ROC: 0.734, 95% CI: 0.729-0.739, p < 0.001), and Cox PH model with all UK Biobank variables (AUC-ROC: 0.758, 95% CI: 0.753-0.763, p < 0.001). Out of 4,801 CVD cases recorded within 5 years of baseline, AutoPrognosis was able to correctly predict 368 more cases compared to the Framingham score. Our AutoPrognosis model included predictors that are not usually considered in existing risk prediction models, such as the individuals' usual walking pace and their self-reported overall health rating. Furthermore, our model improved risk prediction in potentially relevant sub-populations, such as in individuals with history of diabetes. We also highlight the relative benefits accrued from including more information into a predictive model (information gain) as compared to the benefits of using more complex models (modeling gain).

CONCLUSIONS

Our AutoPrognosis model improves the accuracy of CVD risk prediction in the UK Biobank population. This approach performs well in traditionally poorly served patient subgroups. Additionally, AutoPrognosis uncovered novel predictors for CVD disease that may now be tested in prospective studies. We found that the "information gain" achieved by considering more risk factors in the predictive model was significantly higher than the "modeling gain" achieved by adopting complex predictive models.

Identification of new factors associated to walking impairment in patients with vascular-type claudication

OBJECTIVES

Mechanisms of walking limitation in arterial claudication are incompletely elucidated. We aimed to identify new variables associated to walking limitation in patients with claudication.

METHODS

We retrospectively analyzed data of 1120 patients referred for transcutaneous exercise oxygen pressure recordings (TcpO₂). The outcome measurement was the absolute walking time on treadmill (3.2 km/h, 10% slope). We used both: linear regression analysis and a non-linear analysis, combining support vector machines and genetic explanatory in 800 patients with the following resting variables: age, gender, body mass index, the presence of diabetes, minimal ankle to brachial index at rest, usual walking speed over 10 m (usual-pace), number of comorbid conditions, active smoking, resting heart rate, pre-test glycaemia and hemoglobin, beta-blocker use, and exercise-derived variables: minimal value of pulse oximetry, resting chest-TcpO₂, decrease in chest TcpO₂ during exercise, presence of buttock ischemia defined as a decrease from rest of oxygen pressure index ≤15 mmHg. We tested the models over 320 other patients.

RESULTS

Independent variables associated to walking time, by decreasing importance in the models, were: age, ankle to brachial index, usual-pace; resting TcpO₂, body mass index, smoking, buttock ischemia, heart rate and beta-blockers for the linear regression analysis, and were ankle to brachial index, age, body mass index, usual-pace, decrease in chest TcpO₂, smoking, buttock ischemia, glycaemia, heart rate for the non-linear analysis. Testing of models over 320 new patients gave r = 0.509 for linear and 0.575 for non-linear analysis (both p < 0.05).

CONCLUSION

Buttock ischemia, heart rate and usual-pace are new variables associated to walking time.

Neutrophil to Lymphocyte Ratio as a Predictor of Outcomes after Amputation

BACKGROUND

The neutrophil-to-lymphocyte ratio (NLR) has become a prognostic marker for proinflammatory states. It is associated with outcomes in many clinical processes including critical limb ischemia. We sought to identify predictors of amputation failure and mortality, in addition to the role of NLR in patients undergoing above-knee amputations (AKAs) or below-knee amputations (BKAs).

METHODS

All patients undergoing BKA or AKA between 2004 and 2014 at 3 institutions were identified and analyzed (n = 513). Patients were excluded if they did not have a complete blood count with differential within 7 days prior to their operations. Comparison groups were formed between patients requiring unplanned revision and those who did not, and additionally between survivors and nonsurvivors at 30 days postamputation. Patient demographics, intraoperative data, and postoperative courses were compared. A multinomial logistic regression model was created to further compare the groups.

RESULTS

Four hundred and ten patients were included for analysis, of which 142 (35%) required unplanned revision. Nearly 5% of patients (19/410) died within 30 days of the initial amputation. On univariate analysis, those requiring revision were more likely to be current smokers compared to former smokers (P = 0.004 and P = 0.021, respectively), have a lower ankle-brachial index (ABI) (P = 0.019), and have undergone a BKA (P < 0.001). Patients with congestive heart failure (CHF) were less likely to require a revision after an amputation (P = 0.007). Postoperative NLR was higher in patients requiring revision (9.9 vs. 7.0, P < 0.001) and both preoperative and postoperative NLRs were higher in those with 30-day mortality (21.0 vs. 7.0, P < 0.001; 19.4 vs. 7.5, P < 0.001). A multinomial logistic regression model identified CHF (P = 0.004), ABI (P = 0.041), and elevated body mass index (BMI, P = 0.045) as predictors of revision, while coronary artery disease (CAD, P = 0.031), CHF (P = 0.029), and postoperative NLR (P < 0.001) were predictive of 30-day mortality.

CONCLUSIONS

Postoperative elevated NLR, CAD, and CHF are predictors of 30-day mortality in patients undergoing major limb amputation, while CHF, elevated ABI, and high BMI are predictors of revision. This study suggests that NLR may have a role as a biomarker for poor outcomes in patients with underlying peripheral vascular disease and warrants further investigation.

Higher Serum Calcium Levels Are Associated with Preclinical Peripheral Arterial Disease among the Apparently Healthy Individuals

Background

Epidemiological studies suggest that serum calcium levels correlate with cardiovascular events. An ankle-brachial index (ABI) between 0.9 and 1.00 is a surrogate estimation of preclinical peripheral arterial disease (PAD). Prior studies have shown that an ABI of 0.9–1.0 is also associated with endothelial dysfunction. Therefore, we sought to investigate the relationship between serum calcium levels and preclinical PAD in apparently healthy Korean individuals.

Methods

We evaluated the association between serum calcium levels and preclinical PAD in 596 participants (334 males, 262 females) in a health examination program. Preclinical PAD was defined by an ABI of 0.9–1.0. Multiple logistic regression analysis was used to determine whether the serum calcium level was an independent determinant of preclinical PAD.

Results

The overall prevalence of preclinical PAD was 14.3%. The mean age was 44.0±12.5 years in the non-PAD group and 48.3±11.4 years in the preclinical PAD group (P=0.001). After adjusting for age, gender, systolic blood pressure, fasting plasma glucose, high-density lipoprotein cholesterol, triglycerides, C-reactive protein, g-glutamyltransferase, uric acid, hypertension medication, diabetes medication, and hyperlipidemia medication, the odds ratio (95% confidence intervals) for preclinical PAD was 2.28 (1.02–5.11) with a 1-mg/dL increase in the serum calcium.

Conclusion

These findings suggest that increased serum calcium is independently and positively associated with preclinical PAD regardless of the presence of classic cardiovascular risk factors.

Long-term effects of air pollution on ankle-brachial index

BACKGROUND

Ankle-brachial index (ABI) has been linked to the risk of cardiovascular events. However, the association between long-term exposure to air pollution and abnormal ABI has not been fully investigated.

METHODS

This cross-sectional study involved 4544 participants from the KORA Study (2004-2008) in the region of Augsburg, Germany. Participants' residential annual mean concentrations of particulate matter (PM) and nitrogen dioxide (NO₂) were predicted with land-use regression models, and the traffic information was collected from geographic information systems. We applied multinomial logistic regression models to assess the effects of air pollution on the prevalence of low and high ABI, and quantile regression models to explore the non-monotonic relationship between air pollution and ABI. We also examined effect modification by individual characteristics.

RESULTS

Long-term exposure to PM with an aerodynamic diameter ≤ 10 μm (PM₁₀) and ≤ 2.5 μm (PM_2.5) was significantly associated with a higher prevalence of low ABI, with the respective odds ratios (ORs) of 1.82 (95%CI: 1.11-2.97) and 1.59 (95%CI: 1.01-2.51) for a 5th to 95th percentile increment in pollutants. Positive associations with the prevalence of high ABI were observed for PM (e.g., PM₁₀: OR = 1.63, 95%CI: 1.07-2.50) and NO₂ (OR = 1.84, 95%CI: 1.15-2.94). Quantile regression analyses revealed similar non-monotonic results. The effects of air pollution on having abnormal ABI were stronger in physically inactive, hypertensive, or non-diabetic participants.

CONCLUSIONS

Long-term exposure to PM and NO₂ was associated with a higher prevalence of both low and high ABI, indicating the adverse effects of air pollution on atherosclerosis and arterial stiffness in the lower extremities.

A high ankle-brachial index is associated with obesity and low serum 25-hydroxyvitamin D in patients with diabetes

Peripheral artery disease (PAD), when present with diabetes, is associated with significant morbidity and mortality. The spectrum of PAD in diabetes includes atherosclerosis with stenotic disease; and diffuse medial calcification with non-compliant arteries, as reflected by high ankle brachial index. The clinical characteristics of a high ABI are less well characterized than that of low ABI.

The aim of this study was to determine the unique clinical phenotype of patients with diabetes who have high ankle brachial index (ABI) reading. We performed a cross sectional observational study including 360 patients. Subjects were grouped according to normal (≥ 0.8 ≤ 1.3), low (<0.8) or high ABI (>1.3) result. Subjects with high ABI were characterised by higher BMI, higher waist/height ratio (WHtR), and lower serum lower vitamin D. Although reduced renal function and neuropathy was present more frequently in those with high ABI, this was also the case in those with low ABI. Similarly to those with low ABI result, a high ABI result was associated with increased risk of diabetic foot complications including amputation. When adjusted for known risk factors for PAD, higher WHtR and lower vitamin D were significant predictors of high ABI. These results suggest an association between increased WHtR and low vitamin D with high ABI; whether there is a causal relationship requires further exploration.

Ankle brachial index and cognitive function among Hispanics/Latinos: Results from the Hispanic Community Health Study/Study of Latinos

BACKGROUND AND AIMS

The Ankle-Brachial index (ABI) is a well-accepted measure of peripheral artery disease (arterial stenosis and stiffness) and has been shown to be associated with cognitive function and disorders; however, these associations have not been examined in Hispanics/Latinos. Therefore, we sought to examine relationships between ABI and cognitive function among diverse middle-age and older Hispanics/Latinos.

METHODS

We used cross-sectional data on n = 7991 participants aged 45-74 years, without stroke or coronary heart disease, from the Hispanic Community Health Study/Study of Latinos. Our primary outcome, global cognition (GC), was a continuous composite score of four cognitive domains (verbal learning and memory, verbal fluency, executive function, and mental status). Secondary outcomes were the individual tests representing these domains. The ABI was analyzed continuously and categorically with standard clinical cut-points. We tested associations using generalized survey regression models incrementally adjusting for confounding factors. Age, sex, hypertension, diabetes, and dyslipidemia moderations were examined through interactions with the primary exposure.

RESULTS

In age, sex, and education adjusted models, continuous ABI had an inverse u-shape association with worse GC. We found similar associations with measures of verbal learning and memory, verbal fluency, executive function, but not with low mental status. The associations were attenuated, but not completely explained, by accounting for the confounders and not modified by age, sex, education, and vascular disease risks.

CONCLUSIONS

In addition to being a robust indicator of arterial compromise, our study suggests that abnormal ABI readings may also be useful for early signaling of subtle cognitive deficits.

Ankle-Brachial Index and Long-Term (10 Years) Survival of Nondiabetic Hemodialysis Patients

Low (<0.9) and high (>1.4) ankle brachial index (ABI) is associated with a higher cardiovascular (CV) mortality in the general and hemodialysis (HD) population. The aim of our study was to determine the impact of ABI on long-term survival of 52 non-diabetic HD patients. The ABI was determined using an automated, non-invasive waveform analysis device. Patients were divided into three groups: low (<0.9), normal (0.9-1.4) and high (>1.4) ABI. Patients were observed from the date of ABI measurement until their death or ten years. Survival analysis showed higher risk for CV death in HD patients with high ABI compared to normal ABI (log rank test P < 0.027). In Cox regression model adjusted for arterial hypertension, smoking, serum cholesterol and triglycerides, high ABI (P < 0.049) remained a predictor of mortality. The results indicate an association between ABI and long-term survival of non-diabetic HD patients and only high ABI was associated with higher CV mortality.

High alert! Alarming rise in the Prevalence of cardiovascular risk events among the students of medical profession in India

Cardiovascular disease (CVD) risk events increase at an alarming rate among student of medical profession (SMP) in India. By estimating the prevalence, awareness could be created and further consequences could be prevented at early stage. The prevalence of CVD risk events was found to be 12.4% among SMP in India. Because evidence suggests that at early stage pathophysiological process for CVD begins.

Non-compressible ABIs are associated with an increased risk of major amputation and major adverse cardiovascular events in patients with critical limb ischemia

Ankle-brachial indices (ABIs) are important for the assessment of disease burden among patients with peripheral artery disease. Although low values have been associated with adverse clinical outcomes, the association between non-compressible ABI (ncABI) and clinical outcome has not been evaluated among patients with critical limb ischemia (CLI). The present study sought to compare the clinical characteristics, angiographic findings and clinical outcomes of those with compressible (cABI) and ncABI among patients with CLI. Consecutive patients undergoing endovascular evaluation for CLI between 2006 and 2013 were included in a single center cohort. Major adverse cardiovascular events (MACE) were then compared between the two groups. Among 284 patients with CLI, 68 (24%) had ncABIs. These patients were more likely to have coronary artery disease ( p=0.003), diabetes ( p<0.001), end-stage renal disease ( p<0.001) and tissue loss ( p=0.01) when compared to patients with cABI. Rates of infrapopliteal disease were similar between the two groups ( p=0.10), though patients with ncABI had lower rates of iliac ( p=0.004) or femoropopliteal stenosis ( p=0.003). Infrapopliteal vessels had smaller diameters ( p=0.01) with longer lesions ( p=0.05) among patients with ncABIs. After 3 years of follow-up, ncABIs were associated with increased rates of mortality (HR 1.75, 95% CI: 1.12-2.78), MACE (HR 2.04, 95% CI: 1.35-3.03) and major amputation (HR 1.96, 95% CI: 1.11-3.45) when compared to patients with cABIs. In conclusion, ncABIs are associated with higher rates of mortality and adverse events among those undergoing endovascular therapy for CLI.

Asymptomatic peripheral artery disease can limit maximal exercise capacity in chronic obstructive pulmonary disease patients regardless of airflow obstruction and lung hyperinflation

Background Silent/asymptomatic peripheral artery disease may occur in patients with chronic obstructive pulmonary disease, but it is poorly investigated. The primary aim of this study was to evaluate in chronic obstructive pulmonary disease patients the impact of asymptomatic/silent peripheral artery disease on maximal exercise capacity; the secondary aim was to search for predictors of peripheral artery disease. Methods We prospectively enrolled chronic obstructive pulmonary disease outpatients. Data on anthropometric characteristics, lung function, cardiopulmonary exercise test and ankle-brachial index were recorded. The cut-off of ankle-brachial index used to define patients with peripheral artery disease was ≤0.90. Results We studied 47 patients and found 24 patients (51%) who showed peripheral artery disease. As compared to patients without peripheral artery disease, patients with peripheral artery disease had lower values of peak oxygen uptake, peak workload, energy expenditure (metabolic equivalents) and heart rate recovery, but showed the same degree of airflow obstruction and static and dynamic hyperinflation. In a multivariate linear regression model performed to identify variables predicting metabolic equivalents, ankle-brachial index (β 2.59; 95% confidence interval 0.51-4.67; p = 0.016) was an independent variable. In the search for predictors of peripheral artery disease, heart rate recovery (odds ratio 8.80; 95% confidence interval 1.30-59.35; p = 0.026) increased the risk of peripheral artery disease, whereas metabolic equivalents (odds ratio 0.50; 95% confidence interval 0.26-0.94, p = 0.033) and inhaled corticosteroids+long-acting β₂ agonists (odds ratio 0.13; 95% confidence interval 0.02-0.83; p = 0.030) reduced this risk. Conclusions In chronic obstructive pulmonary disease outpatients, asymptomatic/silent peripheral artery disease affects the maximal exercise capacity regardless of airflow obstruction and lung hyperinflation. A delay of heart rate recovery increase the risk of peripheral artery disease, whereas high values of metabolic equivalents and the use of inhaled corticosteroids+long-acting β₂ agonists reduces this risk.

Peripheral Arterial Disease and Its Association With Arsenic Exposure and Metabolism in the Strong Heart Study

At high levels, inorganic arsenic exposure is linked to peripheral arterial disease (PAD) and cardiovascular disease. To our knowledge, no prior study has evaluated the association between low-to-moderate arsenic exposure and incident PAD by ankle brachial index (ABI). We evaluated this relationship in the Strong Heart Study, a large population-based cohort study of American Indian communities. A total of 2,977 and 2,966 PAD-free participants who were aged 45-74 years in 1989-1991 were reexamined in 1993-1995 and 1997-1999, respectively, for incident PAD defined as either ABI <0.9 or ABI >1.4. A total of 286 and 206 incident PAD cases were identified for ABI <0.9 and ABI >1.4, respectively. The sum of inorganic and methylated urinary arsenic species (∑As) at baseline was used as a biomarker of long-term exposure. Comparing the highest tertile of ∑As with the lowest, the adjusted hazard ratios were 0.57 (95% confidence interval (CI): 0.32, 1.01) for ABI <0.9 and 2.24 (95% CI: 1.01, 4.32) for ABI >1.4. Increased arsenic methylation (as percent dimethylarsinate) was associated with a 2-fold increased risk of ABI >1.4 (hazard ratio = 2.04, 95% CI: 1.02, 3.41). Long-term low-to-moderate ∑As and increased arsenic methylation were associated with ABI >1.4 but not with ABI <0.9. Further studies are needed to clarify whether diabetes and enhanced arsenic metabolism increase susceptibility to the vasculotoxic effects of arsenic exposure.

Clinical Characteristics and Outcomes of Patients with High Ankle-Brachial Index from the IMPACT-ABI Study

Background

Reduced ankle–brachial index (ABI) is a predictor of cardiovascular events. However, the significance of high ABI remains poorly understood. This study aimed to assess the characteristics and outcomes of patients with high ABI.

Methods

The IMPACT-ABI study was a retrospective cohort study that enrolled and examined ABI in 3,131 patients hospitalized for cardiovascular disease between January 2005 and December 2012. From this cohort, 2,419 patients were identified and stratified into two groups: high ABI (> 1.4; 2.6%) and normal ABI (1.0–1.4; 97.3%). The primary endpoint was the cumulative incidence of major adverse cardiovascular events (MACE), including cardiovascular-associated death, myocardial infarction, and stroke.

Results

Compared with the normal ABI group, patients in the high ABI group showed significantly lower body mass index (BMI) and hemoglobin level, but had higher incidence of chronic kidney disease and hemodialysis. Multivariate logistic regression analysis revealed that hemodialysis was the strongest predictor of high ABI (odds ratio, 6.18; 95% confidence interval (CI), 3.05–12.52; P < 0.001). During the follow-up (median, 4.7 years), 172 cases of MACE occurred. Cumulative MACE incidence in patients with high ABI was significantly increased compared to that in those with normal ABI (32.5% vs. 14.5%; P = 0.005). In traditional cardiovascular risk factors-adjusted multivariate Cox proportional hazard analysis, high ABI was an independent predictor of MACE (hazard ratio, 2.07; 95% CI, 1.02–4.20; P = 0.044).

Conclusion

Lower BMI, chronic kidney disease, and hemodialysis are more frequent in patients with high ABI. Hemodialysis is the strongest predictor of high ABI. High ABI is a parameter that independently predicts MACE.

What's new: Management of venous leg ulcers: Approach to venous leg ulcers

Leg ulcerations are a common problem, with an estimated prevalence of 1% to 2% in the adult population. Venous leg ulcers are primarily treated in outpatient settings and often are managed by dermatologists. Recent advances in the diagnosis and treatment of leg ulcers combined with available evidence-based data will provide an update on this topic. A systematized approach and the judicious use of expensive advanced therapeutics are critical. Specialized arterial and venous studies are most commonly noninvasive. The ankle brachial pressure index can be performed with a handheld Doppler unit at the bedside by most clinicians. The vascular laboratory results and duplex Doppler findings are used to identify segmental defects and potential operative candidates. Studies of the venous system can also predict a subset of patients who may benefit from surgery. Successful leg ulcer management requires an interdisciplinary team to make the correct diagnosis, assess the vascular supply, and identify other modifiable factors to optimize healing. The aim of this continuing medical education article is to provide an update on the management of venous leg ulcers. Part I is focused on the approach to venous ulcer diagnostic testing.

Ankle Brachial Index and Subsequent Cardiovascular Disease Risk in Patients With Chronic Kidney Disease

BACKGROUND

The clinical implications of ankle-brachial index (ABI) cutpoints are not well defined in patients with chronic kidney disease (CKD) despite increased prevalence of high ABI attributed to arterial stiffness. We examined the relationship of ABI with cardiovascular disease (CVD) and all-cause mortality among CKD patients.

METHODS AND RESULTS

Three thousand six hundred twenty-seven participants without clinical peripheral artery disease (PAD) at baseline from the Chronic Renal Insufficiency Cohort Study were included. ABI was obtained per standard protocol and CVD events were confirmed by medical record adjudication. A U-shaped association of ABI with PAD, myocardial infarction (MI), composite CVD, and all-cause mortality was observed. Individuals with an ABI between 1.0 and <1.4 had the lowest risk of outcomes. Compared to participants with an ABI between 1.0 and <1.4, multiple-adjusted hazard ratios (95% confidence intervals) for those with an ABI of <0.9, 0.9 to <1.0, and ≥1.4 were 5.78 (3.57, 9.35), 2.76 (1.56, 4.88), and 4.85 (2.05, 11.50) for PAD; 1.67 (1.23, 2.29), 1.85 (1.33, 2.57), and 2.08 (1.10, 3.93) for MI; 1.51 (1.27, 1.79), 1.39 (1.15, 1.68), and 1.23 (0.82, 1.84) for composite CVD; and 1.55 (1.28, 1.89), 1.36 (1.10, 1.69), and 1.00 (0.62, 1.62) for all-cause mortality, respectively.

CONCLUSIONS

This study indicates that ABI <1.0 was related to risk of PAD, MI, composite CVD, and all-cause mortality whereas ABI ≥1.4 was related to clinical PAD. These findings suggest that ABI cutpoints of <1.0 or ≥1.4 for diagnosing PAD and ABI <1.0 for CVD risk stratification should be further evaluated among CKD patients.

Vascular structure and function and their relationship with health-related quality of life in the MARK study

Background

There is limited evidence concerning the relationship between vascular disease and health-related quality of life (HRQL). We investigated the relationship between vascular structure and function with health-related quality of life in a population with intermediate cardiovascular risk.

Methods

This study analyzed 303 subjects with ankle-brachial index (ABI) values ranging from 0.9 to 1.4 who were included in the MARK study (age 35 to 74 years; mean:60.5 ± 8.5), of which 50.2 % were women. Measurements included: ABI, brachial-ankle pulse wave velocity (ba-PWV), and cardio-ankle vascular index (CAVI), all measured using the VaSera device. The central augmentation index was adjusted to 75 lpm (AIx_75) using the Mobil-O-Graph device. HRQL was assessed by the Spanish version of the SF-12, version2. The highest obtained CAVI and ba-PWV values and the lowest ABI values were considered for the study.

Results

The cohort was composed of21 % smokers, 76 % hypertensive patients, and 24 % diabetic patients. The ABI mean was 1.09 ± 0.07,the ba-PWV mean was 14.64 ± 2.55 m/s with a 12.9 % of subjects higher than 17.5 m/s, AIx_75 26.46 ± 14.05, and CAVI 8.61 ± 1.08 with a 36.6 % of subjects higher than 9. Men scored higher than women in the HRQL measurements for physical (PSC-12; 49.9 vs. 46.9, p = 0.004) and mental (MSC-12) domains (51.2 vs. 47.7, p = 0.003). Age was positively correlated with CAVI (r = 0.547), ba-PWV (r = 0.469), AIx_75 (r = 0.255, p < 0.01), and the MSC-12 (r = 0.147, p < 0.05), but not the PSC-12. In the adjusted multiple linear regression analysis, the positive association of ABI and CAVI with the PSC-12 was maintained.

Conclusions

The ABI in the normal range has a positive association with the PSC-12 of HRQL evaluated with the SF-12. The CAVI also showed a positive association with the PSC-12 of HRQL.

Trial Registration

ClinicalTrials.gov Identifier: NCT01428934.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-016-0272-9) contains supplementary material, which is available to authorized users.

HIV infection and arterial stiffness among older-adults taking antiretroviral therapy in rural Uganda

HIV infection is associated with arterial stiffness, but no studies have assessed this relationship in sub-Saharan Africa. We enrolled 205 participants over 40 years old in Uganda: 105 on antiretroviral therapy for a median of 7 years, and a random sample of 100 age and sex-matched HIV-uninfected controls from the clinic catchment area. The prevalence of arterial stiffness (ankle brachial index  > 1.2) was 33%, 18%, 19% and 2% in HIV+ men, HIV- men, HIV+ women, and HIV- women. In multivariable models adjusted for cardiovascular risk factors, HIV+ individuals had over double the prevalence of arterial stiffness (adjusted prevalence ratio 2.86, 95% confidence interval 1.41-5.79, P = 0.003).

Increased Peripheral Arterial Calcification in Patients Receiving Warfarin

BACKGROUND

Matrix Gla protein is a vitamin K-dependent inhibitor of vascular calcification. Warfarin use is associated with increased breast arterial calcification, but whether this is reflective of other arteries or occurs in men is unclear. In this study, the prevalence of calcification in peripheral arteries was compared in patients with and without warfarin therapy.

METHODS AND RESULTS

This retrospective matched cohort study assessed 430 patients with radiographs performed during or after warfarin therapy who were identified by a computerized search of medical records. Each patient was matched to a patient without warfarin exposure based on age, sex, and diabetes status. Patients with warfarin exposure <1 month, history of end-stage renal disease, or serum creatinine >2.0 mg/dl were excluded. Radiographs were reviewed visually for arterial calcification. The prevalence of arterial calcification was 44% greater in patients with versus without warfarin use (30.2% versus 20.9%, P=0.0023) but not on radiographs performed before warfarin therapy (26.4% versus 22.4%, n=156) or prior to 5 years of warfarin therapy. The increase was noted only in the ankle and foot, was limited to a medial pattern of calcification, and was similar in men and women.

CONCLUSIONS

Warfarin use is associated with lower extremity arterial calcification in both men and women independent of age, sex, diabetes status, and other patient characteristics. This may have implications for the choice of therapies for long-term anticoagulation.

Physical Activity Improves Borderline Ankle-Brachial Index Values in a Cardiovascular Risk Population

BACKGROUND

Peripheral arterial disease (PAD) is an underdiagnosed and undertreated disease because it remains asymptomatic for so long. The ankle-brachial index (ABI) is a valid method for detecting PAD in lower extremities. ABI ≤0.90 indicates incident PAD. Recent studies have found that subjects with borderline ABI values (0.91-1.00) have increased mortality rates. The objective of our 7-year follow-up study was to investigate the progression of PAD in borderline ABI subjects, who underwent a multifactorial cardiovascular intervention.

METHODS

A total of 193 subjects with borderline ABI were examined in 2005-2006. None of them had previously diagnosed diabetes, cardiovascular or renal disease or intermittent claudication. They were given conventional treatment for multiple risk factors of cardiovascular diseases (hypertension, hypercholesterolemia, elevated blood glucose, smoking, and overweight). Sixty-four percent of these subjects (n = 123) attended a follow-up visit in 2012.

RESULTS

Of the 123 subjects with borderline ABI (mean age 59.0 ± 6.5 years, 62% female) at baseline, 18 (15%, 95% confidence intervals [CI]: 9%-22%) developed incident PAD during the follow-up. The mean ABI was 0.97 ± 0.03 at baseline and 1.01 ± 0.12 at 7-year follow-up visit. The change in mean ABI was +0.04 (95% CI: 0.03-0.07), P < 0.001. ABI improved significantly in 25 (20%) subjects. In multivariate ordered logistic regression analyses high and even moderate leisure-time physical activity (LTPA; odds ratio 6.15; 95% CI: 1.99-19.1) predicted a rise in ABI in comparison to low LTPA.

CONCLUSIONS

Physical activity seems to improve significantly ABI values among men and women with borderline ABI (0.91-1.00).

Association of High Ankle Brachial Index With Incident Cardiovascular Disease and Mortality in a High-Risk Population

OBJECTIVE

The objective of this present study is to determine whether high ankle brachial index (ABI) as compared with ABIs within reference limits is associated with an increased incidence of cardiovascular disease (CVD) events and all-cause mortality in a high-risk population and whether this association is the same for patients with and without diabetes mellitus or prevalent CVD.

APPROACH AND RESULTS

Seven thousand five hundred and thirty-eight patients with ABI>0.9 and either prevalent CVD or a high risk for CVD were selected from the Second Manifestations of Arterial Disease (SMART) study. Three hundred and thirty-six participants (4.5%) had high ABI (≥1.4 or incompressible). Higher age, male sex, higher body mass index, and diabetes mellitus were associated with higher prevalences of high ABI; smoking and higher non-high-density lipoprotein levels were associated with lower prevalences of high ABI. Cox proportional hazards models were fitted assessing the association of high ABI (as compared with ABI 0.9-1.4) with the risk of myocardial infarction, stroke, cardiovascular death, the combined outcome of these 3, and total mortality (median follow-up 6.9 years). After multivariable adjustment, high ABI was associated with an increased risk of myocardial infarction (hazard ratio 1.83 [95% confidence interval 1.22-2.76]), but not with stroke (hazard ratio 0.86 [95% confidence interval 0.44-1.69]), cardiovascular (hazard ratio 1.14 [95% confidence interval 0.70-1.84]), or all-cause mortality (hazard ratio 0.95 [95% confidence interval 0.67-1.34]). Associations of high ABI with CVD outcomes tended to be stronger in patients with diabetes mellitus but without statistically significant interactions.

CONCLUSIONS

In a high-risk population, the presence of an ABI≥1.4 was associated with an increased risk for myocardial infarction, but not with stroke, all-cause, or vascular mortality.

Endothelial progenitor cells as a biological marker of peripheral artery disease

The role of endothelial progenitor cells (EPCs) in peripheral artery disease (PAD) remains unclear. We hypothesized that EPC mobilization and function play a central role in the development of endothelial dysfunction and directly influence the degree of atherosclerotic burden in peripheral artery vessels. The number of circulating EPCs, defined as CD34(+)/KDR(+) cells, were assessed by flow cytometry in 91 subjects classified according to a predefined sample size of 31 non-diabetic PAD patients, 30 diabetic PAD patients, and 30 healthy volunteers. Both PAD groups had undergone endovascular treatment in the past. As a functional parameter, EPC colony-forming units were determined ex vivo. Apart from a broad laboratory analysis, a series of clinical measures using the ankle-brachial index (ABI), flow-mediated dilatation (FMD) and carotid intima-media thickness (cIMT) were investigated. A significant reduction of EPC counts and proliferation indices in both PAD groups compared to healthy subjects were observed. Low EPC number and pathological findings in the clinical assessment were strongly correlated to the group allocation. Multivariate statistical analysis revealed these findings to be independent predictors of disease appearance. Linear regression analysis showed the ABI to be a predictor of circulating EPC number (p=0.02). Moreover, the functionality of EPCs was correlated by linear regression (p=0.017) to cIMT. The influence of diabetes mellitus on EPCs in our study has to be considered marginal in already disease-affected patients. This study demonstrated that EPCs could predict the prevalence and severity of symptomatic PAD, with ABI as the determinant of the state of EPC populations in disease-affected groups.

Effect of patient positioning on toe pressure measurement using noninvasive vascular testing

OBJECTIVE

Interpretation of digital pressure in the assessment of healing potential for diabetic foot disease has become common because of the potential for false elevation with the ankle-brachial index. However, the specific testing protocol for segmental Doppler examinations and photoplethysmography require patients to be in the supine position, with the lower limbs at heart level, in order to minimise the effect of hydrostatic pressure. This may be difficult in many patients with lower extremity pathology, particularly those who are nonambulatory, with painful wounds, or with orthopnea. In these situations, the noninvasive vascular test may be performed with the patient in a more comfortable position, which may include sitting in a wheelchair with the leg in a dependent position. The objective of this investigation was to evaluate the effect of patient positioning on measurement of the digital pressure.

METHOD

Hallux pressures were measured in 20 healthy volunteers in 3 variable positions of limb dependency.

RESULTS

The mean±standard deviation of digital pressure for subjects while lying supine with the limb at heart level was 103.5±26.0 mmHg (the recommended position for performance of the test), while sitting upright with the limb level on the table was 130.6±27.9 mmHg (+26.2%, p<0.0001) and sitting upright with the limb in a dependent position was 169.8±30.8 mmHg (+64.1%, p<0.0001).

CONCLUSION

On the basis of these results, we conclude that patient positioning has a significant effect on measurement of digital pressure.

Complex nonlinear autonomic nervous system modulation link cardiac autonomic neuropathy and peripheral vascular disease

BACKGROUND

Physiological interactions are abundant within, and between, body systems. These interactions may evolve into discrete states during pathophysiological processes resulting from common mechanisms. An association between arterial stenosis, identified by low ankle-brachial pressure index (ABPI) and cardiovascular disease (CVD) as been reported. Whether an association between vascular calcification-characterized by high ABPI and a different pathophysiology-is similarly associated with CVD, has not been established. The current study aims to investigate the association between ABPI, and cardiac rhythm, as an indicator of cardiovascular health and functionality, utilizing heart rate variability (HRV).

METHODS AND RESULTS

Two hundred and thirty six patients underwent ABPI assessment. Standard time and frequency domain, and non-linear HRV measures were determined from 5-min electrocardiogram. ABPI data were divided into normal (n = 101), low (n = 67) and high (n = 66) and compared to HRV measures.(DFAα1 and SampEn were significantly different between the low ABPI, high ABPI and control groups (p < 0.05).

CONCLUSION

A possible coupling between arterial stenosis and vascular calcification with decreased and increased HRV respectively was observed. Our results suggest a model for interpreting the relationship between vascular pathophysiology and cardiac rhythm. The cardiovascular system may be viewed as a complex system comprising a number of interacting subsystems. These cardiac and vascular subsystems/networks may be coupled and undergo transitions in response to internal or external perturbations. From a clinical perspective, the significantly increased sample entropy compared to the normal ABPI group and the decreased and increased complex correlation properties measured by DFA for the low and high ABPI groups respectively, may be useful indicators that a more holistic treatment approach in line with this more complex clinical picture is required.

Plasma Levels of Advanced Glycation End Products Are Related to the Clinical Presentation and Angiographic Severity of Symptomatic Lower Extremity Peripheral Arterial Disease

Evidence implicates a role of advanced glycation end products (AGEs) in the development of atherosclerosis. The present study examined the relationship between plasma levels of AGEs and the clinical and angiographic characteristics of patients with symptomatic peripheral arterial disease (PAD). A total of 40 consecutive patients with symptomatic lower extremity PAD undergoing invasive evaluation were enrolled. Clinical history, angiographic data, and plasma levels of total AGE (tAGE), N'-carboxymethyllysine (CML), and high-sensitivity C-reactive protein were obtained. In multivariate analyses, there were independent relationships noted between tAGE levels and the presence of critical limb ischemia (CLI) (r (2) = 0.195, p = 0.003), Rutherford stage (r (2) = 0.351, p < 0.001), and the average below the knee (BTK) score (r (2) = 0.119, p = 0.006). Presence of CLI (r (2) = 0.154, p = 0.012) and the Rutherford stage (r (2) = 0.194, p = 0.003) were associated with CML levels. We demonstrate a relationship between tAGE and the symptom profile of patients with PAD and an association between tAGE and infrapopliteal angiographic disease severity. Both tAGE and CML levels were related to the presence of CLI. These data suggest that AGE levels may reflect the severity of PAD and may be of importance in CLI.

High Ankle-Brachial Index Indicates Cardiovascular and Peripheral Arterial Disease in Patients With Type 2 Diabetes

We assessed the association between high ankle-brachial index (ABI) and cardiovascular disease (CVD) and peripheral arterial disease (PAD) in Chinese patients with type 2 diabetes mellitus (T2DM). The ABI was measured, and foot inspection was performed in 2080 outpatients with T2DM. The clinical characters in different ABI levels were analyzed, and the diagnostic value of high ABI to CVD and PAD was determined. Compared with the normal ABI group, the high ABI (>1.3) group had a higher prevalence of CVD and PAD but less than the low ABI (≤0.9) group. High ABI was an independent risk factor for the development of CVD and PAD. Receiver-operating characteristic curve analysis showed that the optimal cutoff of high ABI to predict CVD and PAD was 1.43 and 1.45, respectively. The odds ratio of high ABI for CVD and PAD was 2.25 and 6.97, respectively, after adjusting for other confounding risk factors. In conclusion, high ABI indicated the risk of CVD and PAD in Chinese populations with T2DM.

Lower extremity amputation risk factors associated with elevated ankle brachial indices and radiographic arterial calcification

An elevated ankle brachial index (ABI) resulting from medial artery calcification, or Mönckeberg's arteriosclerosis, is commonly seen in patients with diabetes mellitus or end-stage renal disease. Recent data have found an association between elevated ABIs and cardiovascular morbidity and mortality. The purpose of the present study was to evaluate the prognostic significance of high ABIs, poorly compressible arteries, and radiographic artery calcification compared with low ABIs in predicting lower extremity amputation and morbidity. A retrospective review was conducted of patients who had undergone a lower extremity amputation from July 1, 2011 to August 31, 2012. A total of 129 patients (140 lower extremity amputations) were categorized into 3 groups: a low ABI (<0.9), a normal ABI (0.9 to 1.3), and a high ABI (>1.3) or poorly compressible arteries. Of the 129 patients, 31 (22.14%), 36 (25.71%), and 73 (52.14%) were in group 1, 2, and 3, respectively. The prevalence of diabetes was greatest in group 2 (p = .016). A high percentage of radiographic arterial calcification was found in all 3 groups (p = .003). Statistically significant differences were also found in groups 1 and 3 for peripheral arterial disease (p < .001), chronic kidney disease (p < .001), coronary artery disease (p = .021), revascularization history (p < .001), and tobacco use (p = .012). A U-shaped relationship between the ABI and comorbidity was found, suggesting an elevated ABI is as equally prognostic as a low index in predicting the need for amputation.

Relative value of the Ankle-Brachial Index of intermittent claudication

INTRODUCTION

The Ankle-Brachial Index (ABI) makes it possible to identify patients with peripheral artery disease (PAD). Intermittent claudication (IC) is the first major symptom of PAD, although many patients with an ABI ≤ 0.9 do not exhibit IC, and the range of ABI among those who do have IC is very variable. This study evaluates the correlation between ABI and the perception (symptomatology) of claudicant patients.

MATERIAL AND METHODS

An observational, cross-sectional and multicentre, study of 920 patients with IC. Clinical history, ABI, Walking Impairment Questionnaire (WIQ) and European Quality of Life Questionnaire (EQ-5D) were recorded. Associations were analysed using Spearman's correlation coefficient.

RESULTS

The mean ABI of the series was 0.63 (SD = 0.19). The mean WIQ-distance was 34.07 (SD = 26.77), values being smaller for lower ABI values (r = 0.343, p < 0.001). The mean EQ-5D score of the series was 0.58 (SD = 0.21), also showing lower values as the ABI decreased (r = 0.278, p < 0.001). The correlations of WIQ and EQ-5D with ABI were statistically significant in both cases, but always less than 0.400 (between 0.278 and 0.343).

CONCLUSIONS

The correlations of ABI with the questionnaires of walking capacity and quality of life are weak. For this reason, although in clinical practice the ABI of CI patients is commonly measured, decisions should not be taken during the development of IC exclusively on the basis of the ABI.

Peripheral arterial disease and risk of atrial fibrillation and stroke: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Peripheral arterial disease (PAD) shares several risk factors with atrial fibrillation (AF), and persons with PAD have an increased risk of stroke. It is unclear if PAD is associated with an increased risk for AF and whether this potential association explains the increased risk of stroke observed in those with PAD.

METHODS AND RESULTS

We examined the association between PAD, measured by ankle-brachial index (ABI), and incident AF and incident stroke, separately, in 6568 participants (mean age 62±10 years, 53% women, 62% nonwhite) from the Multi-Ethnic Study of Atherosclerosis (MESA). ABI values <1.0 or >1.4 defined PAD. AF was ascertained through review of hospital discharge records and from Medicare claims data until December 31, 2010. An independent adjudication committee ascertained stroke events. Cox regression was used to estimate hazard ratios and 95% CIs for the association between PAD and AF and stroke. Over a median follow-up of 8.5 years, 301 (4.6%) participants developed AF and 140 (2.1%) developed stroke. In a model adjusted for sociodemographics, cardiovascular risk factors, and potential confounders, PAD was associated with an increased risk of AF (hazard ratio 1.5, 95% CI 1.1 to 2.0). In a similar model, PAD was associated with incident stroke (hazard ratio 1.7, 95% CI 1.1 to 2.5), and the magnitude of risk was not different after inclusion of AF as a time-dependent covariate (hazard ratio 1.7, 95% CI 1.1 to 2.5).

CONCLUSIONS

PAD is associated with an increased risk of AF and stroke in MESA. Potentially, the relationship between PAD and stroke is not mediated by AF.