Sex differences in the prevalence of peripheral artery disease in patients undergoing coronary catheterization

Focus on Prevention: Peripheral Arterial Disease and the Central Role of the Cardiologist

Peripheral artery disease (PAD) is a manifestation of systemic atherosclerotic disease. PAD patients have a poor prognosis with an increased risk of cardiovascular (CV) events, including myocardial infarction (MI), stroke, limb ischemia and CV death; therefore, it is important to detect and treat PAD early. PAD and coronary artery disease (CAD) share a common pathogenesis and risk factors for development; therefore, cardiologists are in a unique position to screen, diagnosis and treat PAD. Moreover, PAD and CAD also share some treatment goals, including an aggressive modification of risk factors to reduce the risk of CV events. However, PAD remains an underdiagnosed and undertreated disease with medico-legal implications. As the role of cardiologists is expanding, the purpose of this review was to awaken the clinicians to the significance of PAD.

Socioeconomic characteristics of those with peripheral artery disease in the chronic renal insufficiency cohort

BACKGROUND

The association between socioeconomic factors and peripheral arterial disease (PAD) has not been as well characterized as other cardiovascular conditions. We sought to define how annual income and education level are associated with PAD in a well-characterized diverse set of adults with chronic kidney disease (CKD).

METHODS

The Chronic Renal Insufficiency Cohort Study (CRIC) is a multi-center, prospective cohort study designed to examine risk factors for progression of CKD and cardiovascular disease. Demographic, income, and education-level data, as well as clinical data including ankle-brachial index (ABI) were collected at baseline. Annual income was categorized as < $25,000, $25,000-50,000, $50,000-100,000, or above $100,000; educational level was categorized as some high school, high school graduate, some college, or college graduate. Participants with missing income data or incompressible ABI (>1.4) were excluded from initial analysis. Logistic regression was used to estimate the association of income and/or education level with PAD, defined as an enrollment ABI of <0.90, history of PAD, or history of PAD intervention.

RESULTS

A total of 4122 were included, mean age of participants was 59.5 years, 56% were male, and 44% were Black. There were 763 CRIC participants with PAD at study enrollment (18.5%). In the final multivariable logistic regression model, Black race (OR = 1.3, 95% CI 1.1-1.6, p = 0.004) and level of annual household income remained independently associated with PAD at the time of enrollment (income <$25,000 OR = 1.9, 95% CI 1.3-2.8, p < 0.001; income $25,000-50,000 OR = 1.6, 95% CI 1.1-2.3, p = 0.011; income $50,000-100,000 OR = 1.2, 95% CI 0.9-1.8, p = 0.246), relative to a baseline annual income of >$100,000 (overall p-value <0.001). Decreasing level of educational attainment was not independently associated with increased PAD at enrollment, but lower level of educational attainment was associated with increased PAD when income data was not adjusted for (p = 0.001). Interestingly, Black race (OR = 0.7, 95% CI 0.6-0.8, p < 0.001), female gender (OR = 0.8, 95% CI 0.7-0.9, p = 0.007), and income <$25,000 (OR = 0.7, 95% CI 0.5-0.9, p = 0.008) were significantly associated with decreased statin use even after controlling for cardiovascular conditions.

CONCLUSIONS

In this prospectively followed CKD cohort, lower annual household income and Black race were significantly associated with increased PAD at study enrollment. In contrast, educational level was not associated with PAD when adjusted for patient income data. Black race, female gender, and low income were independently associated with decreased statin use, populations which could be targets of future public health programs.

Women benefit from endovenous ablation with fewer complications: Analysis of the Vascular Quality Initiative Varicose Vein Registry

OBJECTIVE

To evaluate the association between gender and long-term clinician-reported and patient-reported outcomes after endovenous ablation procedures.

METHODS

This retrospective cohort study of prospectively collected data from the Vascular Quality Initiative's Varicose Vein Registry included patients undergoing endovenous ablation procedures on truncal veins with or without treatment of perforating veins between 2015 and 2019. A univariate analysis included comparisons of preprocedural, postprocedural, and periprocedural change in Venous Clinical Severity Score (VCSS) and total symptom score by gender. Rates of complications including deep vein thrombosis, endovenous heat-induced thrombosis, leg pigmentation, blistering, paresthesia, incisional infection, and any postprocedural complications were reported by gender. Multivariable analysis leveraged linear regression to examine how gender affected the relationships between patient characteristics, complication rates, and periprocedural change in VCSS score and total symptom score.

RESULTS

Of 9743 patients who met the inclusion criteria, 3090 (31.7%) were men and 6653 (68.2%) were women. The perioperative change in VCSS score was greater for men than women (average -4.46 for men vs -4.13 for women; P < .0001). Perioperative change in total symptom score was greater for women than for men (average -10.64 for women vs -9.64 for men; P < .0001). Women had lower incidence of any leg complication (6.1% vs 8.6%; P = .001) endovenous heat-induced thrombosis (1.1% vs 2.2%; P = .002), and infection (0.4% vs 0.7%; P = .001). In multivariable analysis, among patients with a body mass index of more than 40, presence of deep reflux, and preoperative Clinical, Etiologic, Anatomic, and Physiologic classification of 2, women had a greater periprocedural change in VCSS score than men.

CONCLUSIONS

Women benefited from endovenous ablation similarly as men, with a lower incidence of postprocedural complications. Gender may be useful for patient selection and counseling for endovenous ablation, with particular usefulness among patients with a high body mass index, presence of deep reflux, and preoperative Clinical, Etiologic, Anatomic, and Physiologic classification of 2.

Below-the-ankle arterial disease: a new marker of coronary artery disease in patients with diabetes and foot ulcers

AIM

The aim of the current study is to evaluate the association between below-the-ankle (BTA) arterial disease and coronary artery disease (CAD) in patients with diabetic foot ulcers (DFUs).

METHODS

The study group was composed of patients with an active neuro-ischaemic DFUs managed in a tertiary care diabetic foot clinic. All patients received a pre-set limb salvage protocol including lower limb revascularization. By a retrospective analysis of individual angiograms, patients were divided in two groups: below-the-ankle (BTA) and above-the-ankle (ATA) arterial disease groups. The rate of CAD at baseline assessment and the new events of acute myocardial ischaemia (AMI) during 1-year of follow-up were evaluated and compared between the two groups.

RESULTS

Two hundreds seventy-two (272) patients were included, 120 (44.1%) showed BTA arterial disease while 152 (55.9%) ATA arterial disease. The mean age was 68.9 ± 9.6 years, 198 (72.8%) were male, 246 (90.4%) had type 2 diabetes, the mean diabetes duration was 20.7 ± 11.6 years, the mean HbA1c was 7.8 ± 4.2% (62 ± 22 mmmol/mol). The whole population reported CAD in 172 cases (63.4%), and the rate in the BTA group was significantly higher than in ATA group, respectively, 90 (75.4%) vs 82 (54.1%), p < 0.0001. During the follow-up, BTA group had 5% of new cases of AMI in comparison to 1.3% in ATA group (p < 0.001). At the multivariate analysis BTA resulted an independent marker of CAD [OR 1.9 CI 9 5% (1.3-4.5) p = 0.0001].

CONCLUSION

The current study shows a significant association between BTA arterial disease and CAD. A close cardiovascular screen should be required in patients with DFUs.

The Association Between Socioeconomic Factors and Incident Peripheral Artery Disease in the Chronic Renal Insufficiency Cohort (CRIC)

BACKGROUND

The association between socioeconomic factors and development of peripheral artery disease (PAD) has not been as well characterized compared to other cardiovascular diseases. We sought to define how annual income, sex, race, and education level are associated with newly diagnosed PAD in a well-characterized, diverse set of adults with CKD.

METHODS

The Chronic Renal Insufficiency Cohort Study (CRIC) is a multicenter, prospective cohort study designed to examine risk factors for progression of CKD and cardiovascular disease. Demographic and clinical data including ankle brachial index (ABI) and interventions were collected at baseline, as well as yearly during follow-up visits. Annual income was categorized as: <$25,000, $25,000-50,000, $50,000-100,000, or above $100,000. We excluded those with pre-existing PAD, defined as enrollment ABI of <0.9 or >1.4, or missing income data. Cox proportional hazards regression was used to estimate the risk for incident PAD during CRIC enrollment, defined as a drop in ABI to <0.90 or a confirmed PAD intervention, including revascularization or amputation.

RESULTS

A total of 3,313 patients met inclusion criteria, the mean age was 58.7 years, 56% were male, and 42% were Black. Over a median follow-up of 10.1 years, 639 participants (19%) were newly diagnosed with PAD. After adjusting for cardiovascular risk factors, all lower levels of annual household income were associated with increased incidence of PAD (income <$25,000 HR 1.7, 95% CI 1.1-2.4, P = 0.008; income $25,000-50,000 HR 1.5, 95% CI 1.1-2.3, P = 0.009; income $50,000-100,000 HR 1.6, 95% CI 1.2-2.4, P = 0.004), relative to a baseline annual income of >$100,000 (overall P-value = 0.02). In the multivariable model, there was no association between education level and PAD incidence (P = 0.80). Black race (HR 1.2, 95% CI 1.0-1.5, P = 0.023) and female sex (HR 1.7, 95% CI 1.4-2.0, P < 0.001) were independently associated with PAD incidence. Multiple imputation analysis provided similar results.

CONCLUSIONS

In the CRIC, a multi-center cohort of prospectively followed CKD patients undergoing yearly CVD surveillance, lower annual household income, female sex, and Black race were significantly associated with the PAD incidence. In contrast, level of education was not independently associated with incident PAD.

Peripheral Artery Disease as a Predictor of Coronary Artery Disease in Patients Undergoing Coronary Angiography

Background

Peripheral artery disease (PAD) may be a useful tool to predict coronary artery disease (CAD) in patients undergoing coronary angiography. If proven that PAD can be a good predictor of CAD, it can help in early and cost-effective diagnosis of CAD.

Methodology

This observational study was conducted from January 2020 to February 2021 in the cardiology unit of a tertiary care hospital. Participants older than 40 years, with a history of uncontrolled hypertension and unstable angina, who warranted the need of angiography were enrolled in study. After enrollment and recording history, these cases were assessed for the presence of PAD based on ankle brachial index (ABI). ABI values less than 0.9 were labelled as participants with PAD. Then these cases underwent coronary angiography at the same institute, and the presence of greater than 50% stenosis of any coronary vessel on angiography was taken as positive CAD.

Results

In this study, PAD was identified in 152 (62.8%) participants. A total of 165 (68.1%) participants had greater than 50% stenosis on angiography. Out of 152 participants with ABI less than 0.9, 140 had greater than 50% stenosis on angiography. In total, 90 participants had ABI more than 0.9, of which 35 participants had greater than 50% stenosis. Sensitivity of PAD in predicting coronary artery stenosis was 80.0% (95% confidence interval [CI]: 73.30%-85.66%), specificity was 82.09% (95% CI: 70.80%-90.39%), and accuracy was 80.58% (95% CI: 75.02%-85.37%).

Conclusions

Our study demonstrated that the sensitivity, specificity, and accuracy of PAD in predicting coronary artery stenosis were significant. Hence, we conclude that PAD can be an excellent predictor of CAD by helping in early and cost-effective diagnosis of CAD.

Risk of peripheral artery disease according to race and sex: The Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND AIMS

Previous community-based studies have demonstrated sex and race-based disparities in the risk of cardiovascular disease. We sought to examine the association of sex and race with incident peripheral artery disease (PAD-) and critical limb ischemia (CLI-) related hospitalizations.

METHODS

In 13,451 Black and White ARIC participants without prevalent PAD at baseline (1987-89), we estimated the cumulative incidence of PAD- and CLI-related hospitalization over a median follow-up of 26 years. We quantified hazard ratios (HRs) using Cox models across four sex- and race-groups. PAD and CLI were defined by hospitalization discharge codes.

RESULTS

The cumulative incidence of PAD-related hospitalization was higher in males than females in Whites (5.1% vs. 2.7%; p<0.001) but not in Blacks (5.7% vs. 5.0%; p=0.39). The cumulative incidence of CLI-related hospitalization differed significantly by race more than sex, occurring in 3.1% Black males, 3.1% Black females, 1.4% White males, and 0.8% White females (p<0.001). After risk factor adjustment, the risk of incident PAD-related hospitalization was similar for White males vs. White females [HR 1.14, 95%CI 0.90-1.45], and slightly higher for Black males [HR 1.26, 95%CI 0.92-1.72] and Black females [HR 1.39, 95%CI 1.03-1.87] compared to White females. The adjusted risk of incident CLI-related hospitalization was similar for White males vs. White females [HR 1.15, 95%CI 0.75-1.76], and significantly higher for Black males [HR 1.96, 95%CI 1.22-3.16] and Black females [HR 2.06, 95%CI 1.31-3.24] compared to White females.

CONCLUSIONS

These data suggest that there are both sex- and race-specific patterns of PAD-related hospitalization that lead to differences in clinical disease risk and presentation.

Burden of Coronary Artery Disease and Peripheral Artery Disease: A Literature Review

BACKGROUND

Atherothrombotic disease, including coronary artery disease (CAD) and peripheral artery disease (PAD), can lead to cardiovascular (CV) events, such as myocardial infarction, stroke, limb ischemia, heart failure, and CV death.

AIM

Evaluate the humanistic and economic burden of CAD and PAD and identify unmet needs through a comprehensive literature review.

METHODS

Relevant search terms were applied across online publication databases. Studies published between January 2010 and August 2017 meeting the inclusion/exclusion criteria were selected; guidelines were also included. Two rounds of screening were applied to select studies of relevance.

RESULTS

Worldwide data showed approximately 5-8% prevalence of CAD and 10-20% prevalence of PAD, dependent on the study design, average age, gender, and geographical location. Data from the REACH registry indicated that 18-35% of patients with CAD and 46-68% of patients with PAD had disease in one or more vascular beds. Use of medication to control modifiable CV risk factors was variable by country (lower in France than in Canada); statins and aspirin were the most widely used therapies in patients with chronic disease. Survival rates have improved with medical advancements, but there is an additional need to improve the humanistic burden of disease (i.e., associated disability and quality of life). The economic burden of atherothrombotic disease is high and expected to increase with increased survival and the aging population.

CONCLUSION

CAD and PAD represent a substantial humanistic and economic burden worldwide, highlighting a need for new interventions to reduce the incidence of atherothrombotic disease.

Gender variation in symptomatic peripheral arterial occlusive disease among type-2 diabetic patients

Purpose:

Little is known about the existence of potential gender disparities in peripheral arterial occlusive disease. To our knowledge, this is the first study to analyze differences attributed to gender in type-2 diabetic patients with symptomatic peripheral arterial occlusive disease, with regard to clinical presentations, risk factors and anatomical distributions of atherosclerosis.

Patients and methods:

This study was conducted at King Abdullah University Hospital, Jordan. Medical records of all diabetic (type-2) patients who presented with symptomatic peripheral arterial occlusive disease in the period from January 2012 and November 2017 were reviewed, data were collected retrospectively. In all, 364 patients (282 males and 82 females) were involved. Criteria for diagnosis include the following Ankle-Brachial Index ⩽ 0.9 and intermittent claudication or critical limb ischemia. Risk factors for atherosclerosis (age, smoking and hypertension) and computed tomography-angiogram findings were analyzed using Statistical Package for the Social Sciences. p < 0.05 was considered statistically significant.

Results:

The mean age was higher in females than males (67.61 vs 62.61 years; p = 0.001). Females had greater prevalence of uncontrolled diabetes compared to males (HbA1c 9.07 in females vs 8.51 in males; p = 0.03). High density lipoprotein was higher in females than males (1.02 vs 0.935; p = 0.009). Females presented more with critical limb ischemia than intermittent claudication in comparison with males (p = 0.017). Involvement of superficial femoral artery, deep femoral artery and peroneal artery in hemodynamic relevant atherosclerotic lesion was significantly higher in females than males (p < 0.05). However, involvement of common iliac artery with hemodynamic relevant atherosclerotic lesion was significantly higher in males than females (p = 0.003).

Conclusions:

Clinical presentation, risk factors and anatomical distributions of atherosclerosis among type-2 diabetic patients with symptomatic peripheral arterial occlusive disease are different between males and females. When compared to males, female patients presented more with critical limb ischemia than intermittent claudication. Females showed higher age at presentation, poor control of diabetes mellitus and higher level of high density lipoprotein. Involvement of superficial femoral artery, deep femoral artery and peroneal artery in hemodynamic relevant atherosclerotic lesion were significantly higher in females than males. In contrast, common iliac artery involvement with hemodynamic relevant atherosclerotic lesion was significantly higher in males than females.

Searching for the Genetic Determinants of Peripheral Arterial Disease: A Review of the Literature and Future Directions

Peripheral arterial disease (PAD) is a significant but under-recognized disease that is poorly understood despite population-scale genetic studies. To address this morbid disease, clinicians need additional tools to identify, prevent, and treat patients at risk for PAD. Genetic studies of coronary artery disease have yielded promising results for clinical application, which have thus far been lacking in PAD. In this article, we review recent findings, discuss limitations, and propose future directions of genomic study and clinical application. However, despite many studies, we still lack definitive genetic markers for PAD. This can be attributed to the heterogeneity of PAD's pathogenesis and clinical manifestations, as well as inconsistencies in study methodologies, limitations of current genetic assessment techniques, incompletely comprehended molecular pathophysiology, and confounding generalized atherosclerotic risk factors. The goals of this review are to evaluate the limitations of our current genetic knowledge of PAD and to propose approaches to expedite the identification of valuable markers of PAD.

A risk score assessment tool for peripheral arterial disease in women: From the National Health and Nutrition Examination Survey

BACKGROUND

Peripheral arterial disease (PAD) carries a significant morbidity and mortality. Women are more commonly affected with this condition and are mostly asymptomatic, and undertreated. The objective of the study was to develop and validate a simple risk score to identify women with PAD.

HYPOTHESIS

Identifying those at early stage of the disease could help reduce the risk of complications.

METHODS

Using data from the National Health and Nutrition Examination Survey 1999-2004, we identified women who had data on ankle brachial index. The cohort was divided into development (70%) and validation (30%) groups. Using variables that are self-reported or measured without laboratory data, we developed a multivariable logistic regression to predict PAD, which was evaluated in the validation cohort.

RESULTS

A total of 150.6 million women were included. A diagnosis of PAD was reported in 13.7%. Age, body mass index, hypertension, diabetes mellitus, smoking, non-oral contraceptive pill usage, and parity were all independently associated with PAD. The C-statistics was 0.74, with good calibration. The model showed good stability in the validation cohort (C-statistics 0.73).

CONCLUSION

This parsimonious risk model is a valid tool for risk prediction of PAD in women, and could be easily applied in routine clinical practice.

Undetected Peripheral Arterial Disease Among Older Adults With Alzheimer's Disease and Other Dementias

BACKGROUND

Peripheral arterial disease (PAD) was reported to increase the risk of dementia(s) even more than stroke. We assessed the prevalence of PAD in a group with definite diagnosis of dementia.

METHODS

Patients aged 65 years or older with Alzheimer's disease (AD), vascular dementia (VaD), or AD-VaD were enrolled (n = 162, mean age: 78.87 [6.05] years). An age- and gender-matched control group was also included (n = 190). Peripheral arterial disease was diagnosed by the ankle-brachial index.

RESULTS

Frequency of PAD among patients with and without dementia was 35.2% and 16.3%, respectively ( P < .001), being similar among different types of dementia. After adjustment for covariates, dementia (odds ratio: 2.41, 95% confidence interval: 1.34-4.32; P = .003) was among the predictors of PAD diagnosis along with older age, female gender, and diabetes.

CONCLUSIONS

The prevalence of PAD was more than double in patients with dementia, with no difference among AD, VaD, and AD-VaD types.

Sex-Specific Characteristics of the Microcirculation

The requirements of metabolizing tissue are both continuous and variable; accordingly, the microvasculature serving that tissue must be similarly dynamic. Just as it is recognized that males and females of the same species have differing metabolic requirements, is it not likely that the microvasculature serving these tissues will differ by sex? This section focusing on the constituents of the microcirculation identifies what is known presently about the role sex plays in matching metabolic demand with microvascular function and areas requiring additional study. Many of the identified sex differences are subtle and easily ignored. In the aggregate, though, they can profoundly alter phenotype, especially under stressful conditions including pregnancy, exercise, and disease states ranging from diabetes to heart failure. Although the features presently identified to "have sex" range from differences in growth, morphology, protein expression, and intracellular signaling, males and females alike achieve homeostasis, likely by different means. Studies of microvascular sexual dimorphism are also identifying age as an independent but interacting factor requiring additional attention. Overall, attempting to ignore either sex and/or age is inappropriate and will prevent the design and implementation of appropriate interventions to present, ameliorate, or correct microvascular dysfunction.

The use of machine learning for the identification of peripheral artery disease and future mortality risk

OBJECTIVE

A key aspect of the precision medicine effort is the development of informatics tools that can analyze and interpret "big data" sets in an automated and adaptive fashion while providing accurate and actionable clinical information. The aims of this study were to develop machine learning algorithms for the identification of disease and the prognostication of mortality risk and to determine whether such models perform better than classical statistical analyses.

METHODS

Focusing on peripheral artery disease (PAD), patient data were derived from a prospective, observational study of 1755 patients who presented for elective coronary angiography. We employed multiple supervised machine learning algorithms and used diverse clinical, demographic, imaging, and genomic information in a hypothesis-free manner to build models that could identify patients with PAD and predict future mortality. Comparison was made to standard stepwise linear regression models.

RESULTS

Our machine-learned models outperformed stepwise logistic regression models both for the identification of patients with PAD (area under the curve, 0.87 vs 0.76, respectively; P = .03) and for the prediction of future mortality (area under the curve, 0.76 vs 0.65, respectively; P = .10). Both machine-learned models were markedly better calibrated than the stepwise logistic regression models, thus providing more accurate disease and mortality risk estimates.

CONCLUSIONS

Machine learning approaches can produce more accurate disease classification and prediction models. These tools may prove clinically useful for the automated identification of patients with highly morbid diseases for which aggressive risk factor management can improve outcomes.

Effect of physical activity assessment on prognostication for peripheral artery disease and mortality

OBJECTIVE

To examine whether a simple question about the performance of regular vigorous activity is associated with peripheral artery disease (PAD) and mortality.

METHODS

A total of 1288 individuals undergoing nonemergency coronary angiography were assessed for participation in regular vigorous activity by questionnaire. Data on demographic characteristics, ankle-brachial indexes, and cardiovascular outcomes were prospectively collected.

RESULTS

Compared with those who denied participation in regular vigorous activity, those who reported participation were less likely to have PAD (odds ratio, 0.58; 95% CI, 0.39-0.86), had higher ankle-brachial indexes, had better Walking Impairment Questionnaire scores (P<.001), and experienced reduced all-cause mortality rates (hazard ratio, 0.48; 95% CI, 0.31-0.74). When added to the Framingham Risk Score, the response improved the net reclassification index for all-cause (32.6%) and cardiovascular (32.0%) mortality.

CONCLUSION

Among at-risk individuals, regular vigorous activity is associated with decreased PAD and all-cause mortality. Simple and readily available, a single yes/no query about participation in regular vigorous exercise could be used to improve risk stratification.

Task force on: 'Early markers of atherosclerosis: influence of age and sex'

Atherosclerosis and its complications are the most important causes of death all over the world, especially in Western countries. Diet habits, modern stress life, smoking, sedentary way of life and an involvement of genetic pattern of individuals lead to a sure degeneration of quality of life increasing the risk of atherosclerosis development. For this reason, the main purpose of actual medicine is to identify all the markers that could allow the physicians to evaluate the first moments of the development of this dangerous pathological process. The aim is to reduce the speed of its evolution, trying to delay indefinitely the risk coming from the morphological alterations of the vessels. 'Endothelium function' could allow physicians to detect the first moment of the natural history of atherosclerosis process. Its impairment is the first step in the degeneration of vascular structures. Many methods [flow-mediated vasodilatation (FMD); antero-posterior abdominal aorta diameter (APAO); intima-media thickness of the common carotid artery (CCA-IMT); arterial stiffness; and so on] try to evaluate its function, but many limitations come from general population characteristics. A standardization of the methods should take into account individuals' peculiarities. Two elements, not modifiable, should be taken into account for vascular evaluation: age and sex. The aim of this review is to outline the linkage among age, sex and instrumental evaluation of patients considered for a noninvasive assessment of their cardiovascular risk profile.

Clinical and socioeconomic factors associated with unrecognized peripheral artery disease

Peripheral artery disease (PAD) is a highly prevalent condition that frequently goes undetected and untreated. Socioeconomic factors associated with unrecognized PAD are not known. The ankle-brachial index (ABI) was calculated in 1656 study participants undergoing non-emergent coronary angiography with PAD defined as an ABI <0.9. Subjects were followed for mortality and cardiovascular outcomes. Compared to those without PAD, those with unrecognized PAD at enrollment were older, had higher rates of cardiovascular comorbidities, and had higher major adverse cardiovascular events (MACE) (p<0.03 for all). Among those enrolling without a reported history of PAD, there was a higher prevalence of PAD with decreasing income (p=0.004), education level (p<0.001), social isolation (p=0.027) and depression (p=0.034); 50% of these individuals reported symptoms suggestive of claudication. In conclusion, the prevalence of unrecognized PAD is high amongst a cohort of high-risk individuals referred for coronary angiography. A profile of lower socioeconomic status is associated with unrecognized PAD. These subjects will report symptoms suggestive of claudication and impaired walking ability when directly queried.

Gender-specific risk factors for peripheral artery disease in a voluntary screening population

Background

Women have high rates of peripheral artery disease (PAD) despite fewer cardiovascular disease (CVD) risk factors, compared to men. We sought to determine the gender‐specific prevalence of low ankle brachial index (ABI) and the relationship to C‐reactive protein (CRP) levels and CVD risk factors in the Life Line Screening population.

Methods and Results

Between April 2005 and August 2011, 133 750 women and 71 996 men had ABI and CRP measured at a Life Line Screening Center. Women were slightly older than men, whereas men were more likely to be current smokers, have diabetes mellitus (DM), and coronary artery disease (CAD) (P<0.001 for each). Women were more likely to have ABI≤1.0, compared to men (26.6% versus 14.4%, respectively; P<0.001), as well as ABI≤0.9 (4.1% women versus 2.6% men; P<0.001). Women had higher median CRP levels (1.94 mg/L; interquartile range [IQR], 0.89, 4.44 mg/L), compared to men (1.35 mg/L; IQR, 0.73, 2.80 mg/L; P<0.001). Men and women shared similar risk factors for ABI≤0.9, including older age, black race, smoking, DM, hypertension, hypercholesterolemia, CAD, and elevated CRP levels. In an adjusted model, there were significant interactions between gender and age (P<0.001), CRP (P<0.001), CAD (P=0.03), and DM (P=0.06) with ABI as the outcome. The associations between age, CRP, CAD, and DM with ABI≤0.9 were stronger in men than in women.

Conclusions

Women participating in the Life Line Screening had higher CRP levels and a higher prevalence of PAD, compared to men. Neither higher CRP levels nor conventional CVD risk factors explained the excess prevalence of PAD in women.

Self-reported history of childhood smoking is associated with an increased risk for peripheral arterial disease independent of lifetime smoking burden

Atherosclerotic disorders are well known to be associated with obesity, lipid profile, smoking, hypertension and other medical comorbidities, and large cohort studies have explored the childhood correlates to these adult risk factors. However, there has been little investigation into the childhood risk factors for peripheral arterial disease (PAD). We endeavored to better understand the role of smoking in childhood in the risk for PAD in a well described cohort of 1,537 adults at high risk for cardiovascular disease. In a multivariate regression model, we observed an increased risk of PAD among those who reported a history of smoking during childhood (OR = 2.86; 95% CI, 1.99-4.11; P<0.001), which remained statistically significant after controlling for lifetime smoking burden (OR = 1.55; 95% CI, 1.00-2.41; P = 0.049). Our novel observation of disproportionate risk of PAD conferred by a history of childhood smoking may reflect an unrecognized biological mechanism such as a unique susceptibility to vascular injury or an unaccounted for covariate such as secondhand smoke exposure in childhood. This observation suggests further investigation is required into the pathophysiology of smoking in the developing vasculature and the need for detailed clinical data about patterns of childhood smoking and smoke exposure.

The combination of 9p21.3 genotype and biomarker profile improves a peripheral artery disease risk prediction model

Peripheral artery disease (PAD) is a highly morbid condition affecting more than 8 million Americans. Frequently, PAD patients are unrecognized and therefore do not receive appropriate therapies. Therefore, new methods to identify PAD have been pursued, but have thus far had only modest success. Here we describe a new approach combining genomic and metabolic information to enhance the diagnosis of PAD. We measured the genotype of the chromosome 9p21 cardiovascular-risk polymorphism rs10757269 as well as the biomarkers C-reactive protein, cystatin C, β2-microglobulin, and plasma glucose in a study population of 393 patients undergoing coronary angiography. The rs10757269 allele was associated with PAD status (ankle-brachial index < 0.9) independent of biomarkers and traditional cardiovascular risk factors (odds ratio = 1.92; 95% confidence interval, 1.29-2.85). Importantly, compared to a previously validated risk factor-based PAD prediction model, the addition of biomarkers and rs10757269 significantly and incrementally improved PAD risk prediction as assessed by the net reclassification index (NRI = 33.5%; p = 0.001) and integrated discrimination improvement (IDI = 0.016; p = 0.017). In conclusion, a model including a panel of biomarkers, which includes both genomic information (which is reflective of heritable risk) and metabolic information (which integrates environmental exposures), predicts the presence or absence of PAD better than established risk models, suggesting clinical utility for the diagnosis of PAD.

Alternative ankle-brachial index method identifies additional at-risk individuals

OBJECTIVES

The aim of this study was to determine whether use of an alternative ankle-brachial index (ABI) calculation method improves mortality risk prediction compared with traditional methods.

BACKGROUND

The ABI is used to diagnose peripheral arterial disease (PAD) and to identify those at risk for cardiovascular events. Traditionally, the ABI is calculated with the higher of the dorsalis pedis and posterior tibial ankle arteries. Studies directly comparing calculation methods are limited.

METHODS

The ABI was calculated at baseline in 1,413 study participants undergoing non-emergent coronary angiography subsequently followed for all-cause and cardiovascular mortality. There were 224 individuals assigned to the traditional-PAD group (ABI <0.90) with the traditional ABI method. Of those remaining, an alternative ABI method using the lower of the 2 ankle pressures assigned 282 patients to the alternative-PAD group. The 862 individuals not assigned to PAD by either method were the no-PAD group.

RESULTS

There were 163 mortalities during a median follow-up of 5.0 years. Adjusted Cox regression models showed that the alternative-PAD group had an increased risk for all-cause (hazard ratio [HR]: 1.49; 95% confidence interval: 1.01 to 2.19) and cardiovascular mortality (HR: 3.21; 95% confidence interval: 1.53 to 6.37) versus the no-PAD group. Additionally, in the no-PAD group, there was an 11% (HR: 1.11; 95% confidence interval: 1.05 to 1.17) increased risk of all-cause mortality/1-mm Hg increased difference between the left and right brachial systolic pressures.

CONCLUSIONS

The implementation of an alternative ABI method and use of the brachial difference identifies individuals at an increased risk for mortality who are currently missed with traditional ABI methods. Current ABI protocols might need to be evaluated.

Walking impairment questionnaire improves mortality risk prediction models in a high-risk cohort independent of peripheral arterial disease status

BACKGROUND

The Walking Impairment Questionnaire (WIQ) is a subjective measure of patient-reported walking performance developed for peripheral arterial disease. The purpose of this study is to examine whether this simple tool can improve the predictive capacity of established risk models and whether the WIQ can be used in patients without peripheral arterial disease.

METHODS AND RESULTS

At baseline we assessed the walking distance, stair-climbing, and walking speed WIQ category scores among individuals who were undergoing coronary angiography. During a median follow-up of 5.0 years, there were 172 mortalities among 1417 study participants. Adjusted Cox proportional hazards models showed that all 3 WIQ categories independently predicted future all-cause and cardiovascular mortality, including among individuals without peripheral arterial disease (P<0.001). Compared with the cardiovascular risk factors model, we observed significantly increased risk discrimination with a C-index of 0.741 (change in C-index, 0.040; 95% confidence interval, 0.011-0.068) and 0.832 (change in C-index, 0.080; 95% confidence interval, 0.034-0.126) for all-cause and cardiovascular mortality, respectively. Examination of risk reclassification using the net reclassification improvement index showed a 48.4% (P<0.001) improvement for all-cause mortality and a 77.4% (P<0.001) improvement for cardiovascular mortality compared with the cardiovascular risk factors model.

CONCLUSIONS

All 3 WIQ categories independently predicted future all-cause and cardiovascular mortality. Importantly, we found that this subjective measure of walking ability could be extended to patients without peripheral arterial disease. The addition of the WIQ scores to established cardiovascular risk models significantly improved risk discrimination and reclassification, suggesting broad clinical use for this simple, inexpensive test.

Usefulness of the addition of beta-2-microglobulin, cystatin C and C-reactive protein to an established risk factors model to improve mortality risk prediction in patients undergoing coronary angiography

Evidence-based therapies are available to reduce the risk for death from cardiovascular disease, yet many patients go untreated. Novel methods are needed to identify those at highest risk for cardiovascular death. In this study, the biomarkers β2-microglobulin, cystatin C, and C-reactive protein were measured at baseline in a cohort of participants who underwent coronary angiography. Adjusted Cox proportional-hazards models were used to determine whether the biomarkers predicted all-cause and cardiovascular mortality. Additionally, improvements in risk reclassification and discrimination were evaluated by calculating the net reclassification improvement, C-index, and integrated discrimination improvement with the addition of the biomarkers to a baseline model of risk factors for cardiovascular disease and death. During a median follow-up period of 5.6 years, there were 78 deaths among 470 participants. All biomarkers independently predicted future all-cause and cardiovascular mortality. A significant improvement in risk reclassification was observed for all-cause (net reclassification improvement 35.8%, p = 0.004) and cardiovascular (net reclassification improvement 61.9%, p = 0.008) mortality compared to the baseline risk factors model. Additionally, there was significantly increased risk discrimination with C-indexes of 0.777 (change in C-index 0.057, 95% confidence interval 0.016 to 0.097) and 0.826 (change in C-index 0.071, 95% confidence interval 0.010 to 0.133) for all-cause and cardiovascular mortality, respectively. Improvements in risk discrimination were further supported using the integrated discrimination improvement index. In conclusion, this study provides evidence that β2-microglobulin, cystatin C, and C-reactive protein predict mortality and improve risk reclassification and discrimination for a high-risk cohort of patients who undergo coronary angiography.

A Mechanism-Based Approach to Prevention of and Therapy for Fibromyalgia

Fibromyalgia syndrome (FMS) is characterized by pain referred to deep tissues. Diagnosis and treatment of FMS are complicated by a variable coexistence with regional pain, fatigue, sleep disruption, difficulty with mentation, and depression. The widespread, deep pain of FMS can be a consequence of chronic psychological stress with autonomic dysregulation. Stress acts centrally to facilitate pain and acts peripherally, via sympathetic vasoconstriction, to establish painful muscular ischemia. FMS pain, with or without a coexistent regional pain condition, is stressful, setting up a vicious circle of reciprocal interaction. Also, stress interacts reciprocally with systems of control over depression, mentation, and sleep, establishing FMS as a multiple-system disorder. Thus, stress and the ischemic pain it generates are fundamental to the multiple disorders of FMS, and a therapeutic procedure that attenuates stress and peripheral vasoconstriction should be highly beneficial for FMS. Physical exercise has been shown to counteract peripheral vasoconstriction and to attenuate stress, depression, and fatigue and improve mentation and sleep quality. Thus, exercise can interrupt the reciprocal interactions between psychological stress and each of the multiple-system disorders of FMS. The large literature supporting these conclusions indicates that exercise should be considered strongly as a first-line approach to FMS therapy.