Premature atherosclerotic peripheral artery disease: An underrecognized and undertreated disorder with a rising global prevalence

Development and evaluation of a prediction model for peripheral artery disease-related major adverse limb events using novel biomarker data

OBJECTIVE

Prognostic tools for individuals with peripheral artery disease (PAD) remain limited. We developed prediction models for 3-year PAD-related major adverse limb events (MALE) using demographic, clinical, and biomarker data previously validated by our group.

METHODS

We performed a prognostic study using a prospectively recruited cohort of patients with PAD (n = 569). Demographic/clinical data were recorded including sex, age, comorbidities, previous procedures, and medications. Plasma concentrations of three biomarkers (N-terminal pro-B-type natriuretic peptide [NT-proBNP], fatty acid binding protein 3 [FABP3], and FABP4) were measured at baseline. The cohort was followed for 3 years. MALE was the primary outcome (composite of open/endovascular vascular intervention or major amputation). We trained three machine learning models with 10-fold cross-validation using demographic, clinical, and biomarker data (random forest, decision trees, and Extreme Gradient Boosting [XGBoost]) to predict 3-year MALE in patients. Area under the receiver operating characteristic curve (AUROC) was the primary model evaluation metric.

RESULTS

Three-year MALE was observed in 162 patients (29%). XGBoost was the top-performing predictive model for 3-year MALE, achieving the following performance metrics: AUROC = 0.88 (95% confidence interval [CI], 0.84-0.94); sensitivity, 88%; specificity, 84%; positive predictive value, 83%; and negative predictive value, 91% on test set data. On an independent validation cohort of patients with PAD, XGBoost attained an AUROC of 0.87 (95% CI, 0.82-0.90). The 10 most important predictors of 3-year MALE consisted of: (1) FABP3; (2) FABP4; (3) age; (4) NT-proBNP; (5) active smoking; (6) diabetes; (7) hypertension; (8) dyslipidemia; (9) coronary artery disease; and (10) sex.

CONCLUSIONS

We built robust machine learning algorithms that accurately predict 3-year MALE in patients with PAD using demographic, clinical, and novel biomarker data. Our algorithms can support risk stratification of patients with PAD for additional vascular evaluation and early aggressive medical management, thereby improving outcomes. Further validation of our models for clinical implementation is warranted.

Outcomes of open and endovascular infra-inguinal revascularization are poor in young patients with atherosclerotic peripheral artery disease but do not differ between genders

OBJECTIVES

The effect of gender on the outcomes of revascularization procedures in young patients with premature atherosclerotic peripheral arterial disease (PAD) is not known. The objective of this study was to compare short-term and long-term outcomes between young males and females undergoing infra-inguinal revascularization procedures.

METHODS

We examined postoperative outcomes of male and female PAD patients under the age of 55 who underwent infra-inguinal revascularization procedures at a single tertiary institution from 2011 to 2019. Primary outcomes included 30-day morbidity, patency of the revascularization procedures, and major adverse limb events (MALE). Secondary outcomes included survival, amputation rate, reintervention rate, improvement of ankle-brachial index (ABI), and number of reinterventions.

RESULTS

Eighty-one infra-inguinal revascularization procedures (46 endovascular and 35 open procedures) were reviewed including 45 procedures in 37 males and 36 procedures in 31 females. Fifty-three (65.4%) of the procedures were performed in patients with chronic limb-threatening ischemia symptoms. The rest were treated for life-disabling claudication. The female patients were younger, had higher body mass index, and were more likely to have diabetes, hyperlipidemia, or chronic obstructive pulmonary disease in comparison to males. Thirty-day major adverse cardiovascular event was 0.0% and MALE was 16.0%. Mean follow-up was 806.2 days. At 1 year, primary patency was 34.4 ± 6.2%, primary assisted patency was 52.7 ± 6.5%, secondary patency was 61.8 ± 6.3%, and MALE-free rate was 47.0 ± 6.4%. For secondary outcomes at 1 year, amputation-free rate was 92.5 ± 3.2%, reintervention-free rate was 50.2 ± 6.4%, and survival was 96.2 ± 2.6%. By the end of the study, overall mortality rate was 14.8% and major amputation rate was 13.6%. No major differences were observed between males and females among these outcomes. A smaller improvement in ABI after revascularization was noted in females compared to males (female 0.2 ± 0.2 vs male 0.4 ± 0.2, p = .04). Among patients who required reintervention, females required a higher number of reinterventions than males (female 1.7 ± 2.5 vs male 0.8 ± 1.1, p = .03).

CONCLUSIONS

There were no significant differences in short-term and long-term outcomes between males and females under the age of 55 after infra-inguinal revascularization. Poor patency, high MALE rate, and high mid-term mortality, and amputation rates after revascularization in young PAD patients highlight the need for improved strategies to treat premature PAD.

A machine learning algorithm for peripheral artery disease prognosis using biomarker data

Peripheral artery disease (PAD) biomarkers have been studied in isolation; however, an algorithm that considers a protein panel to inform PAD prognosis may improve predictive accuracy. Biomarker-based prediction models were developed and evaluated using a model development (n = 270) and prospective validation cohort (n = 277). Plasma concentrations of 37 proteins were measured at baseline and the patients were followed for 2 years. The primary outcome was 2-year major adverse limb event (MALE; composite of vascular intervention or major amputation). Of the 37 proteins tested, 6 were differentially expressed in patients with vs. without PAD (ADAMTS13, ICAM-1, ANGPTL3, Alpha 1-microglobulin, GDF15, and endostatin). Using 10-fold cross-validation, we developed a random forest machine learning model that accurately predicts 2-year MALE in a prospective validation cohort of PAD patients using a 6-protein panel (AUROC 0.84). This algorithm can support PAD risk stratification, informing clinical decisions on further vascular evaluation and management.

Peripheral artery disease: an underdiagnosed condition in familial hypercholesterolemia? A systematic review

PURPOSE

Familial hypercholesterolemia (FH) is one of the most common inherited diseases characterized by elevated LDL-cholesterol levels, leading to early-onset atherosclerosis. While the association between FH and coronary and carotid artery disease is well-established, its association with peripheral artery disease (PAD) is less robust. This systematic review aims at exploring existing evidence on PAD prevalence and incidence in FH individuals.

METHODS

A comprehensive search was conducted on MEDLINE and Embase databases, for studies published between January 2013 and December 2023, evaluating prevalence and incidence of PAD in FH patients. Literature reviews, case reports, responses to editors and non-English language articles were excluded.

RESULTS

The initial research provided 53 results. After article screening, 28 articles were fully reviewed and 24 were finally included in the analysis. Among these, 19 reported PAD prevalence, while 5 PAD incidence over a mean follow-up time of 8.7 years. PAD prevalence and incidence ranged from 0.3 to 60% and from 0.5 to 4.2% respectively, probably reflecting the heterogeneity in PAD definition criteria.

CONCLUSION

This systematic review sheds light on the limited number of studies on PAD in FH patients. Particularly, considering the potential positive effects of newly available lipid-lowering strategies on PAD outcomes, addressing this research gap is pivotal for a more comprehensive understanding of peripheral vascular manifestations in FH patients and for optimal management of this population.

A Scoping Review of Measurement Tools Evaluating Awareness and Disease-Related Knowledge in Peripheral Arterial Disease Patients

BACKGROUND

Peripheral arterial disease (PAD) is the third leading cause of atherosclerotic cardiovascular morbidity worldwide, with high prevalence and associated complications, and is often overlooked and undertreated. Research has shown that there is a profound lack of PAD-related knowledge and awareness; additionally, information sources are not often reliable and accessible. The objective of this scoping review was: (1) to identify and critically appraise instruments that measure patients' disease-related knowledge/awareness about PAD, and (2) to characterize the current state of knowledge/awareness levels among these patients.

METHODS

This systematic review was conducted and reported in accordance with the PRISMA statement. Six databases (APA PsycInfo, CINAHL Ultimate, Embase, Emcare Nursing, Medline ALL and Web of Science Core Collection) were searched, and search strategies were developed utilizing the PICO framework. Potential studies of any methodological design were considered for inclusion through a snowball hand search. Data from the included articles were extracted by a reviewer, and the extraction accuracy was independently cross-checked by another author.

RESULTS

The initial database search yielded 9832 records, of which sixteen studies (thirteen quantitative and three qualitative) were included. Only three questionnaires had their psychometric properties assessed. Questionnaire items focused on the following topics: definition/characteristics, risk factors/causes, treatment, complications, and personal issues regarding the perception/management of the disease. Overall, knowledge/awareness about PAD was low among patients.

CONCLUSIONS

This study identified major gaps in PAD education, including the lack of availability of a validated measurement tool addressing all educational topics relevant to care and low knowledge/awareness of patients about their condition.

Fatty acid binding protein 4 has prognostic value in peripheral artery disease

OBJECTIVE

Peripheral artery disease (PAD) remains undertreated, despite its association with major amputation and mortality. This is partly due to a lack of available disease biomarkers. The intracellular protein fatty acid binding protein 4 (FABP4) is implicated in diabetes, obesity, and metabolic syndrome. Given that these risk factors are strong contributors to vascular disease, we assessed the prognostic ability of FABP4 in predicting PAD-related adverse limb events.

METHODS

This was a prospective case-control study with 3 years of follow-up. Baseline serum FABP4 concentrations were measured in patients with PAD (n = 569) and without PAD (n = 279). The primary outcome was major adverse limb event (MALE; defined as a composite of vascular intervention or major amputation). The secondary outcome was worsening PAD status (drop in ankle-brachial index ≥0.15). Kaplan-Meier and Cox proportional hazards analyses adjusted for baseline characteristics were conducted to assess the ability of FABP4 to predict MALE and worsening PAD status.

RESULTS

Patients with PAD were older and more likely to have cardiovascular risk factors compared with those without PAD. Over the study period, MALE and worsening PAD status occurred in 162 (19%) and 92 (11%) patients, respectively. Higher FABP4 levels were significantly associated with 3-year MALE (unadjusted hazard ratio [HR], 1.19; 95% confidence interval [CI], 1.04-1.27; adjusted HR, 1.18; 95% CI, 1.03-1.27; P = .022) and worsening PAD status (unadjusted HR, 1.18; 95% CI, 1.13-1.31; adjusted HR, 1.17; 95% CI, 1.12-1.28; P < .001). Three-year Kaplan-Meier survival analysis demonstrated that patients with high FABP4 levels had a decreased freedom from MALE (75% vs 88%; log rank = 22.6; P < .001), vascular intervention (77% vs 89%; log rank = 20.8; P < .001), and worsening PAD status (87% vs 91%; log rank = 6.16; P = .013).

CONCLUSIONS

Individuals with higher serum concentrations of FABP4 are more likely to develop PAD-related adverse limb events. FABP4 has prognostic value in risk-stratifying patients for further vascular evaluation and management.

Association between dietary magnesium intake and peripheral arterial disease: Results from NHANES 1999-2004

BACKGROUND

Magnesium has been found to have a strong association with peripheral arterial disease (PAD), and dietary magnesium intake shows promise as a predictor of the condition. However, the relationship between low dietary magnesium intake and an increased risk of PAD remains uncertain, and further research is needed to clarify this relationship.

METHODS

This study analyzed data from 5969 participants in the National Health and Nutrition Examination Survey (NHANES) of the United States from 1999 to 2004. Multifactorial logistic regression models were used to investigate the association between dietary magnesium intake and PAD.

RESULTS

Participants with PAD had lower dietary magnesium intake compared to those without PAD. After adjusting for all covariates, dietary magnesium intake remained negatively associated with PAD (OR: 0.999, 95% CI: 0.998, 1.000). When dietary magnesium intake was divided into quartiles, compared with the fourth quantile, the first quartile is associated with a higher incidence rate of PAD (OR: 1.560, 95%CI: 1.019, 2.386). Subgroup analysis revealed that the link between dietary magnesium intake and PAD remained significant among specific subgroups, including non-white, never or former smokers, and non-hypertensive, non-diabetic individuals (P < 0.05).

CONCLUSION

Our study provides evidence that dietary magnesium intake is negatively associated with the incidence of PAD. Therefore, people with inadequate dietary magnesium intake, particularly those with excessively low intake, should increase their magnesium intake to reduce the risk of PAD.

Increasing Awareness for Peripheral Artery Disease through the Identification of Novel Biomarkers

Peripheral artery disease (PAD) is a chronic atherosclerotic disorder that involves the lower extremity arteries, manifesting in claudication, rest pain, and tissue loss [...].

Prevalence and predictors of lower extremity atherosclerotic disease amongst high-risk patients using ankle brachial index

INTRODUCTION

The prevalence of lower extremity artery disease (LEAD) continues to increase worldwide. This is expected to translate into logarithmic rise in lower-limb amputations especially in the developing world. Majority of patients suffering from LEAD remain asymptomatic until late and are vulnerable to limb-threatening complications unless actively screened and treated.

METHODS

This was a prospective, single-center, observational study to determine the prevalence and predictors of LEAD. Patients with known atherosclerotic vascular disease (but not known LEAD) or those at risk were enrolled. All underwent ABI measurement as per the standard protocol. A threshold of ABI ≤ 0.90 was taken to diagnose LEAD.

RESULTS

A total of 1000 patients were enrolled. The mean age of the group was 61.4±10.0 years and the prevalence of LEAD was 10.2%. Amongst those who had LEAD, the majority of patients (69.6%) had no symptoms. The prevalence of LEAD in diabetic population in our study was 13.2% and in coronary artery disease patients it was 30.9%. Factors independently linked to LEAD on regression analysis included advanced age, presence of diabetes, smoking history, lower serum HDL and a lower ejection fraction.

CONCLUSIONS

The vast majority of patients suffering from LEAD are asymptomatic. Early diagnoses and institution of appropriate medical and physical therapy can prevent excess morbidity and mortality due to LEAD. Factors independently linked to LEAD are advanced age, presence of diabetes, smoking history, lower serum HDL and a lower ejection fraction. The presence of either of these should signal undertaking of appropriate steps to unmask underlying LEAD.

Monitoring antiplatelet therapy: where are we now?

Single antiplatelet therapy represents the cornerstone of thrombosis prevention in atherosclerotic cardiovascular disease. Dual antiplatelet therapy (DAPT), consisting of aspirin plus a P2Y12 inhibitor, is the standard of care for patients with acute coronary syndrome or undergoing both coronary and peripheral percutaneous interventions. Recent data suggest the efficacy of DAPT also after minor stroke. In this setting, a large body of evidence has documented that genetic and acquired patients' characteristics may affect the magnitude of platelet inhibition induced by antiplatelet agents. The implementation of tools allowing the identification and prediction of platelet inhibition has recently been shown to improve outcomes, leading to an optimal balance between antithrombotic efficacy and bleeding risk. We are therefore clearly moving towards tailored antiplatelet therapy. The aim of this paper is to summarize the available evidence on the evaluation of platelet inhibition in patients with coronary, peripheral, or cerebrovascular atherosclerosis. We will here focus on antiplatelet therapy based on both aspirin and P2Y12 inhibitors. In addition, we provide practical insights into the clinical settings in which it appears reasonable to implement antiplatelet therapy monitoring.

Association Between Atherosclerosis-Related Cardiovascular Disease and Uveitis: A Systematic Review and Meta-Analysis

BACKGROUND

Uveitis is not only an intraocular inflammatory disease, but also an indicator of systemic inflammation. It is unclear whether uveitis can increase the risk of cardiovascular disease (CVD) through the atherosclerotic pathway.

METHODS

PubMed and Embase databases were searched until 5 September, 2022. Original studies investigating uveitis and cardiovascular events were selected. The random-effects model was used to calculate the difference of groups in pooled estimates.

RESULTS

A total of six observational studies that included mainly ankylosing spondylitis (AS) patients were included. Of these, three studies reported data on carotid plaques and carotid intima-media thickness (cIMT) and the other three studies provided data on atherosclerosis-related CVD. No significant difference was found in cIMT between uveitis and controls (MD = 0.01, 95% CI = -0.03-0.04, p = 0.66), consistent with the findings of carotid plaque incidence (OR = 1.30, 95% CI = 0.71-2.41, p = 0.39). However, uveitis was associated with a 1.49-fold increase in atherosclerosis-related CVD (HR = 1.49, 95% CI = 1.20-1.84, p = 0.0002).

CONCLUSIONS

Uveitis is a predictor of atherosclerosis-related CVD in AS patients. For autoimmune disease patients with uveitis, earlier screening of cardiovascular risk factors and the implementation of corresponding prevention strategies may be associated with a better prognosis.

Major adverse limb events among patients with premature peripheral artery disease compared with those at the common age undergoing revascularization in the Vascular Quality Initiative

OBJECTIVES

Premature peripheral artery disease (PAD), defined as ≤ 50 years of age, is associated with poor outcomes following lower extremity revascularization (LER). However, the specific characteristics and outcomes of this group of patients compared to those at the common age undergoing revascularization have not been examined. The aim of this study is to compare patients with early versus late onset premature PAD undergoing LER focusing on major adverse limb events (MALEs).

METHODS

All LER procedures (open and endovascular) in the Vascular Quality Initiative (VQI) were reviewed. A histogram of patient age at the time of initial LER (no prior LER) was used to define the common age, which included all patients within one standard deviation of the mean. Characteristics and outcomes of patients with premature PAD were compared to patients treated at the common age of presentation undergoing LER.

RESULTS

A histogram of all patients undergoing LER was used to define 60 to 80 years as the common age. Patients with premature PAD were more likely to be female, African American, and Hispanic compared to patients at the common age. Patients with premature PAD were also more likely to have insulin-dependent diabetes, be current smokers, on dialysis, and be treated for claudication. Patients with premature PAD were less likely to have Transatlantic Intersociety Consensus (TASC II) C or D disease and were less likely to be on antiplatelets and statins. These differences were more pronounced in patients with chronic limb-threatening ischemia (CLTI). Cox proportional hazards regression demonstrated that premature PAD was independently associated with major adverse limb events (MALEs) at one-year for patients with claudication (HR:1.7, 95% CI:1.4-2.0) and CLTI (HR:1.3, 95% CI:1.2-1.5) compared to patients 60 to 80 years of age.

CONCLUSION

Patients with premature PAD have significant differences in characteristics compared to patients treated at the common age. Vascular providers should emphasize medical therapy prior to LER given the lower rates of medical optimization and worse one-year MALEs in patients with premature PAD.

Cardiac Rehabilitation in Patients with Peripheral Artery Disease-A Literature Review in COVID-19 Era

Cardiac rehabilitation (CR) is an integral part of the management of various cardiovascular disease such as coronary artery disease (CAD), peripheral artery disease (PAD), or chronic heart failure (CHF), with proven morbidity and mortality benefits. This article aims to review and summarize the scientific literature related to cardiac rehabilitation programs for patients with PAD and how they were adapted during the COVID-19 pandemic. The implementation of CR programs has been problematic since the COVID-19 pandemic due to social distancing and work-related restrictions. One of the main challenges for physicians and health systems alike has been the management of PAD patients. COVID-19 predisposes to coagulation disorders that can lead to severe thrombotic events. Home-based walking exercises are more accessible and easier to accept than supervised exercise programs. Cycling or other forms of exercise are more entertaining or challenging alternatives to exercise therapy. Besides treadmill exercises, upper- and lower-extremity ergometry also has great functional benefits, especially regarding walking endurance. Supervised exercise therapy has a positive impact on both functional capacity and also on the quality of life of such patients. The most effective manner to acquire this seems to be by combining revascularization therapy and supervised exercise. Rehabilitation programs proved to be a mandatory part of the integrative approach in these cases, increasing quality of life, and decreasing stress levels, depression, and anxiety.

Geographic Disparities in Readmissions for Peripheral Artery Disease in South Carolina

Readmissions constitute a major health care burden among peripheral artery disease (PAD) patients. This study aimed to 1) estimate the zip code tabulation area (ZCTA)-level prevalence of readmission among PAD patients and characterize the effect of covariates on readmissions; and (2) identify hotspots of PAD based on estimated prevalence of readmission. Thirty-day readmissions among PAD patients were identified from the South Carolina Revenue and Fiscal Affairs Office All Payers Database (2010-2018). Bayesian spatial hierarchical modeling was conducted to identify areas of high risk, while controlling for confounders. We mapped the estimated readmission rates and identified hotspots using local Getis Ord (G*) statistics. Of the 232,731 individuals admitted to a hospital or outpatient surgery facility with PAD diagnosis, 30,366 (13.1%) experienced an unplanned readmission to a hospital within 30 days. Fitted readmission rates ranged from 35.3 per 1000 patients to 370.7 per 1000 patients and the risk of having a readmission was significantly associated with the percentage of patients who are 65 and older (0.992, 95%CI: 0.985-0.999), have Medicare insurance (1.013, 1.005-1.020), and have hypertension (1.014, 1.005-1.023). Geographic analysis found significant variation in readmission rates across the state and identified priority areas for targeted interventions to reduce readmissions.

Identifying Gaps in Disease Knowledge among Patients with Peripheral Artery Disease

INTRODUCTION

An individual's understanding of disease risk factors and outcomes is important for the ability to make healthy lifestyle choices and decisions about disease treatment. Peripheral artery disease (PAD) is a condition with increasing global prevalence and high risk of adverse patient outcomes. This study seeks to understand the adequacy of disease understanding in patients with PAD.

METHODS

This was an observational study of patients with PAD recruited from vascular surgery outpatient clinic and PAD clinical studies at a single academic medical center over an 8-month period. A 44-item paper survey assessed demographic and socioeconomic information, knowledge of personal medical history, PAD risk factors, consequences of PAD, and health education preferences. Patients with documented presence of PAD were offered the survey. Patients unable to complete the survey or provide informed consent were not considered eligible. Disease "awareness" was defined as correct acknowledgement of the presence or absence of a disease, including PAD, in the personal medical history. "PAD knowledge score" was the percentage of correct responses to questions on general PAD risk factors and consequences. Of 126 eligible patients, 109 participated. Bivariate analysis was used to study factors associated with awareness of PAD diagnosis. Factors associated with the PAD knowledge score were studied using the Pearson correlation coefficient, two-sample T-test, or one-way ANOVA. P value < .05 was considered statistically significant.

RESULTS

Mean participant age was 69.4 ± 11.0 years and 39.4% (N=43) were female. Most participants (78.9%; N=86) had critical limb-threatening ischemia. Only 65.4% (N=70) of participants were aware of a diagnosis of PAD, which was less than their awareness of related comorbidities. Factors positively associated with PAD diagnosis awareness were female sex (81.4% vs. 54.7%; P=.004) and history of percutaneous leg revascularization (78.6% vs. 47.9%; p=.001). Among 17 patients who had undergone major leg amputation, 35% (N=6) were unaware of a diagnosis of PAD. PAD knowledge scores correlated positively with an awareness of PAD diagnosis (59.1% vs. 48.7%; P=.02) and negatively with a history of hypertension (53.4% vs. 68.1%; P=.001). Most participants (86.5%; N=90) expressed a desire to be further educated on PAD. The most popular education topics were dietary recommendations, causes, and treatment for PAD.

CONCLUSION

Patients with PAD have deficits in their awareness of this diagnosis and general knowledge about PAD. Future research priorities should further define these deficits and their causes in order to inform new strategies that foster information-seeking behavior and effective educational programs for PAD.

Under-Prescription of Medical Treatment for Peripheral Artery Disease in the Under 50s: A Retrospective Study

Peripheral artery disease (PAD) is a common cause of morbidity and mortality; however, data on its etiology and evolution in patients under 50 years old are scarce. Therefore, we performed a retrospective analysis of data from medical records, including cardiovascular risk factors, etiology, medical and surgical treatment, and follow-up. We included all patients with PAD aged between 18 and 50 years attending our university hospital between 2005 and 2015. Of the 87 patients included, 32 (36%) were women. Smoking was acknowledged by 81 patients (93%), and 37 had dyslipidemia (42.5%). Median follow-up was 24 months (10-59). Recurrence occurred in 41 patients (47.1%), all active smokers, with a median delay of 14 months (7-47). Acute limb ischemia at diagnosis was significantly associated with major amputation, odds ratio (OR) 5.95 (95%CI 1.41-40.90, P = .029), which was needed by 11 patients (12.6%). Treatments included antiplatelet therapy (76; 87.4%), statins (67; 77%), and anti-hypertensives (60; 69%), and 29 (32.1%) patients benefited from vascular rehabilitation. This cohort of relatively young patients with PAD showed a high level of symptom recurrence. Atherosclerosis was the most common etiology. Our study revealed that medical treatment is often under-prescribed in this age group and needs to be improved.