Peripheral Arterial Disease: Pathophysiology, Risk Factors, and Role of Antithrombotic Therapy

Endovascular Interventions for Peripheral Arterial Disease in Saudi Patients: A Cross-Sectional Study Assessing Efficacy and Economic Impact

Introduction Peripheral Arterial Disease (PAD) is characterized by arterial narrowing or blockage, causing pain and reduced quality of life. Endovascular interventions, like angioplasty and stenting, offer less invasive treatment options with potential benefits. This study, conducted in the Al-Ahsa region of Saudi Arabia from January to August 2023, aims to assess the impact of these interventions on PAD management in Saudi patients. Specifically, we aim to evaluate their effectiveness in improving clinical outcomes, such as symptom relief and quality of life, and their cost-effectiveness in the Saudi healthcare system. By addressing these objectives, our research provides evidence to support informed clinical decisions and healthcare policy in Saudi Arabia, ultimately enhancing patient care. Methods In this study, a cross-sectional design was used to assess the impact of endovascular interventions on PAD management in Saudi patients in the Al-Ahsa region. Data collection took place from January to August 2023. The study focused on a sample of 385 or more Saudi patients who had undergone endovascular interventions. Inclusion criteria involved diagnosed PAD patients who had received these interventions, while non-Saudi patients and those without PAD or interventions were excluded. Data was collected through an online questionnaire distributed in hospitals. The study considered demographic and clinical/economic variables to evaluate intervention effectiveness and cost-effectiveness. Results The findings of this study emphasize the significance of variables such as gender, education level, employment status, and geographic location in shaping perceptions concerning the effectiveness and cost-effectiveness of endovascular interventions for the management of PAD. Participants in the study reported substantial improvements in symptom relief, quality of life, and daily activities following endovascular interventions. Moreover, the study revealed divergent perceptions regarding the cost-effectiveness of these interventions among participants. Conclusion This study highlights a positive association between the use of endovascular interventions and improved clinical outcomes in Saudi patients diagnosed with PAD. The results of this research indicate that endovascular interventions are not only more cost-effective when compared to alternative treatment modalities for PAD management but also lead to significant enhancements in symptom relief, quality of life, and daily activities among patients. The implications of these findings for the Saudi healthcare system are substantial, underscoring the importance of evidence-based decisions in the adoption of endovascular interventions for PAD management.

Antithrombotic Treatment Patterns of Patients with Symptomatic Peripheral Arterial Occlusive Disease in Germany: Evidence from Health Insurance Claims Data

Objectives: Patients with peripheral arterial occlusive disease (PAOD) are at risk of worsening limb symptoms, major adverse cardiovascular events and exhibit an impaired life expectancy. There is a lack of evidence on the extent of pharmacological secondary prevention in PAOD patients. This study assesses treatment patterns of antithrombotic agents in symptomatic PAOD patients. Methods: This is a retrospective cohort study using data from the second largest insurance fund in Germany, BARMER. We included symptomatic PAOD patients undergoing in-hospital treatment with an index admission between 1 January 2010 and 31 December 2017. Outcomes were proportions of single antiplatelets (SAPT), dual antiplatelets (DAPT), vitamin-K antagonists (VKA), or direct oral anticoagulants (DOAC) in the 12 months prior and 6 months after the index hospitalization. Non-parametric cumulative incidence for competing risks was estimated to account for censoring and death after discharge from hospital stay. Patient flows were visualised by alluvial diagrams. All analyses were stratified by intermittent claudication (IC) and chronic limb-threatening ischaemia (CLTI). The protocol was registered to ClinicalTrials.gov (NCT03909022). Results: A total of 80,426 unique patient encounters were identified. Mean age was 72.7 (46.3% female). Amongst all patients, 25.6% were on SAPT, 4.1% on DAPT, 9.1% on VKA, 3.9% on DOAC, 3.9% on both antiplatelets and oral anticoagulation, and 53.3% without any antithrombotic therapy during the 12 months before index stay. The estimated cumulative incidence was 37.9% SAPT, 14.8% DAPT, 7.5% VKA, 4.3% DOAC, 7.4% both, and 28.1% without any antithrombotic therapy during the 6 months after index stay. The considerable increases in antiplatelet therapy were mainly driven by the group of patients without antithrombotics before index stay. As compared with IC, patients who suffered from CLTI received less often antiplatelets but more often anticoagulants both before and after index stay. Conclusions: Utilisation rates of antithrombotic therapy increased considerably after in-hospital treatment for PAOD. Yet, remarkably high rates of symptomatic patients without any blood-thinning therapy constitute a major concern with respect to adequate secondary prevention of PAOD patients.

Evaluating the feasibility and acceptability of an exercise and behaviour change intervention in socioeconomically deprived patients with peripheral arterial disease: The textpad study protocol

This pilot randomised controlled trial aims to assess the feasibility and acceptability of a 12-week home-based telehealth exercise and behavioural intervention delivered in socioeconomically deprived patients with peripheral artery disease (PAD). The study will also determine the preliminary effectiveness of the intervention for improving clinical and health outcomes. Sixty patients with PAD who meet the inclusion criteria will be recruited from outpatient clinic at the Freeman Hospital, United Kingdom. The intervention group will undergo telehealth behaviour intervention performed 3 times per week over 3 months. This program will comprise a home-based exercise (twice a week) and an individual lifestyle program (once per week). The control group will receive general health recommendations and advice to perform unsupervised walking training. The primary outcome will be feasibility and acceptability outcomes. The secondary outcomes will be objective and subjective function capacity, quality of life, dietary quality, physical activity levels, sleep pattern, alcohol and tobacco use, mental wellbeing, and patients’ activation. This pilot study will provide preliminary evidence of the feasibility, acceptability and effectiveness of home-based telehealth exercise and behavioural intervention delivered in socioeconomically deprived patients with PAD. In addition, the variance of the key health outcomes of this pilot study will be used to inform the sample size calculation for a future fully powered, multicentre randomized clinical trial.

Effects of arm-crank exercise on cardiovascular function, functional capacity, cognition and quality of life in patients with peripheral artery disease: Study protocol for a randomized controlled trial

Background

Arm-crank exercise training (ACT) is an alternative exercise strategy for patients with symptomatic peripheral artery disease (PAD) due to the attenuation of pain symptoms during the exercise, as well as the benefits to functional capacity.

Purpose

The aim of this study is to describe the study protocol to analyze the effects of ACT exercise on cardiovascular function, functional capacity, cognition and quality of life in patients with symptomatic PAD.

Methods

This is a three-armed randomized, prospective, single-blind data collection, single-center, controlled study enrolling 45 patients with symptomatic PAD who will be randomized into 3 intervention groups: walking training (WT), ACT and control group. The WT and ACT will perform 2 sessions/week, 15 to 10 sets of 2 to 5 minutes at values of 13 to 15 on the Borg scale. Before and after 12 weeks of intervention, cardiovascular function (ambulatory blood pressure, office blood pressure, central blood pressure, heart rate variability, arterial stiffness and vascular function), functional capacity (six-minute walk test, 2 minute step test, handgrip test, Walking impairment questionnaire, Walking estimated limitation calculated by history, Baltimore activity scale for intermittent claudication, and short physical performance battery), cognition (executive function and memory), and quality of life (vascular quality of life questionnaire and World Health Organization Quality of Life) will be assessed.

Results

This is the first trial to evaluate the effects of ACT on regulatory mechanisms of the cardiovascular system in PAD patients. If the results are as expected, they will provide evidence the ability of ACT to promote cardiovascular benefits in the symptomatic PAD population.

Burden of Peripheral Artery Disease and Its Attributable Risk Factors in 204 Countries and Territories From 1990 to 2019

Background

Data on burden of peripheral artery disease (PAD) and its attributable risk factors are valuable for policymaking. We aimed to estimate the burden and risk factors for PAD from 1990 to 2019.

Methods

We extracted the data on prevalence, incidence, death, years lived with disability (YLDs), and years of life lost (YLLs) from the Global Burden of Disease Study 2019 to measure PAD burden. Moreover, the attributable burden to PAD risk factors was also estimated.

Results

Globally, in 2019, 113,443,017 people lived with PAD and 10,504,092 new cases occurred, resulting in 74,063 deaths, 500,893 YLDs, and 1,035,487 YLLs. The absolute numbers of PAD prevalent and incident cases significantly increased between 1990 and 2019, contrasting with the decline trends in age-standardized prevalence and incidence rates. However, no statistically significant changes were detected in the global age-standardized death or YLL rates. The burden of PAD and its temporal trends varied significantly by location, gender, age group, and social-demographic status. Among all potentially modifiable risk factors, age-standardized PAD deaths worldwide were primarily attributable to high fasting plasma glucose, followed by high systolic blood pressure, tobacco, kidney dysfunction, diet high in sodium, and lead exposure.

Conclusion

PAD remained a serious public health problem worldwide. More strategies aimed at implementing cost-effective interventions and addressing modifiable risk factors should be carried out, especially in regions with high or increasing burden.

Health economic evaluation of rivaroxaban in the treatment of patients with chronic coronary artery disease or peripheral artery disease

Aims

In the COMPASS trial, rivaroxaban 2.5 mg twice daily (bid) plus acetylsalicylic acid (ASA) 100 mg once daily (od) performed better than ASA 100 mg od alone in reducing the rate of cardiovascular disease, stroke, or myocardial infarction (MI) in patients with coronary artery disease (CAD) and peripheral artery disease (PAD). A Markov model was developed to assess the cost-effectiveness of rivaroxaban plus ASA vs. ASA alone over a lifetime horizon, from the UK National Health System perspective.

Methods and results

The base case analysis assumed that patients entered the model in the event-free health state, with the possibility to experience ≤2 events, transitioning every three-month cycle, through acute and post-acute health states of MI, ischaemic stroke (IS), or intracranial haemorrhage (ICH), and death. Costs, quality-adjusted life-years (QALYs), life years—all discounted at 3.5%—and incremental cost-effectiveness ratios (ICERs) were calculated. Deterministic and probabilistic sensitivity analyses were conducted, as well as scenario analyses. In the model, patients on rivaroxaban plus ASA lived for an average of 14.0 years with no IS/MI/ICH, and gained 9.7 QALYs at a cost of £13 947, while those receiving ASA alone lived for an average of 12.7 years and gained 9.3 QALYs at a cost of £8126. The ICER was £16 360 per QALY. This treatment was cost-effective in 98% of 5000 iterations at a willingness-to-pay threshold of £30 000 per QALY.

Conclusion

This Markov model suggests that rivaroxaban 2.5 mg bid plus ASA is a cost-effective alternative to ASA alone in patients with chronic CAD or PAD.

A Targeted Literature Review of the Disease Burden in Patients With Symptomatic Peripheral Artery Disease

Patients with peripheral artery disease (PAD) have an increased risk of cardiovascular (CV) and limb events, but the disease is frequently underdiagnosed and treatment options are limited. This review examines the disease burden of symptomatic PAD as well as key guideline recommendations. Publications were identified using the ProQuest portal to access the Medline, Medline In-Process, and Embase databases. Search terms for symptomatic PAD were combined with terms relevant to epidemiology, burden, treatment practice, and physiopathology. Articles in English published between January 2001 and September 2016 were screened according to the population, interventions, comparator, outcomes, and study design criteria. Relevant publications (n = 200) were identified. The reported incidence and prevalence of PAD varied depending on the definitions used and the study populations. Patients generally had a poor prognosis, with an increased risk of mortality, CV, and limb events and decreased quality of life. Guideline recommendations included ankle–brachial index measurements, exercise testing, and angiography for diagnosis and risk factor modification, antiplatelets, cilostazol, exercise therapy, or surgical interventions for treatment, depending on the patient profile. The clinical, humanistic, and economic burden of disease in patients with symptomatic PAD is substantial and needs to be reduced through improved PAD management.

Influence of Mild Peripheral Arterial Obstructive Disease in the Functional Capacity

AbstractThe peripheral arterial obstructive disease (PAOD) is a chronic illnes that has as main symptom intermittent claudication and causes a progressive functional impairment of the patient. The literature is still inconclusive when it addresses the relationship among functional capacity, endurance, muscle contraction speed, and degree of blood flow impairment in patients with PAOD. The objective of this study was to evaluate the physical fitness individuals with bilateral PAOD, claudication and ankle-brachial index between 0.8 and 0.9, to verify the impact of the disease in this outcome and to analyze the association among the tests. Forty individuals, with mean age 56 years were divided in: group PAOD (n=20) and control group (n=20) were subjected to the following tests: Five-Times-Sit-to-Stand Test (FTSST), Heel-rise test (HRT), test of gait speed usual (UV) and maximum (MV), shuttle walking test (SWT). There was a significant difference among the variables obtained through HRT, UV, MV and SWT, showing a worse performance of the group with PAOD compared to the control. The FTSST test showed no differences among the groups. Analyzing the whole sample, the presence of PAOD is an indicator of poor performance in TDBP. This study suggests that people with mild PAOD present reduced performance in functional endurance tests of the lower limbs and that there is a direct relationship between walking speed and patency of local arterial flow, demonstrating in an unprecedented way the need for evaluation of this public, considering the possibility of initial identification of the symptoms and giving greater efficiency in the therapeutic planning of maintenance of the functionality.Keywords: Physical Fitness. Intermittent Claudication. Peripheral Vascular Diseases.ResumoA doença arterial obstrutiva periférica (DAOP) é uma doença crônica que tem como sintoma principal a claudicação intermitente e causa um progressivo comprometimento funcional do paciente. A literatura ainda é inconclusiva quando aborda a relação entre a capacidade funcional, endurance, velocidade de contração muscular e grau de comprometimento de fluxo sanguíneo em pacientes com DAOP. O objetivo deste estudo foi avaliar a aptidão física de indivíduos com DAOP bilateral, claudicantes e Índice tornozelo-braço entre 0,8 e 0,9, verificar o impacto da doença neste desfecho e analisar a associação entre os testes. Quarenta indivíduos, com faixa etária média de 56 anos, divididos em grupo DAOP (n=20) e grupo controle (n=20), foram submetidos aos testes: Teste senta-levanta (TSL), teste ponta de pé (TPP), testes de velocidade usual (VU) e máxima (VM), teste de deslocamento bidirecional progressivo (TDBP). Houve diferença significativa entre as variáveis do TPP, VU, VM e TDBP, mostrando pior performance do grupo com DAOP comparado ao controle. O teste TSL não apresentou diferença entre os grupos. Analisando os grupos em conjunto a presença de DAOP foi indicadora de pior desempenho no TDBP. Este estudo sugere que pacientes com DAOP leve apresentam redução da performance nos testes funcionais de endurance dos membros inferiores e que existe uma relação direta entre a velocidade da marcha e a patência do fluxo arterial local, demonstrando de forma inédita, a necessidade de avaliação deste público, considerando a possibilidade de identificação inicial dos sintomas e conferindo maior eficiência no planejamento terapêutico de manutenção da funcionalidade.Palavras-chave: Aptidão Física. Claudicação Intermitente. Doenças Vasculares Periféricas.

Cardiac Autonomic Modulation Is Associated with Arterial Stiffness in Patients with Symptomatic Peripheral Artery Disease

BACKGROUND

The objective of this study was to analyze the association between cardiac autonomic modulation and arterial stiffness in patients with peripheral artery disease (PAD).

METHODS

This cross-sectional study included one hundred fourteen patients with symptomatic PAD (67.5% men; 65 ± 7 years; body mass index: 26.8 ± 4.5 kg/m²). Heart rate variability (HRV) was measured within time (standard deviation of all RR intervals [beat to beat heart interval] [SDNN], root mean square of the successive differences between adjacent normal RR intervals [RMSSD], and the proportion of successive RR intervals that differed by more than 50 msec [pNN50]) and frequency (low frequency [LF] and high frequency [HF]) domains. Arterial stiffness was assessed by carotid-femoral pulse wave velocity (cfPWV). Crude and adjusted linear regression analyses examined the relationship between HRV and cfPWV.

RESULTS

Nonsignificant crude associations were identified among cfPWV and RMSSD (P = 0.181), SDNN (P = 0.105), pNN50 (P = 0.087), LF (P = 0.376), HF (P = 0.175), and LF/HF ratio (P = 0.426). After adjustments for age, sex, smoking, body mass index, ankle-brachial index, and use of beta-blockers, significant associations were identified among cfPWV and RMSSD (P = 0.037), SDNN (P = 0.049), and pNN50 (P = 0.049).

CONCLUSIONS

Cardiac autonomic modulation was significantly associated with arterial stiffness in patients with PAD after adjustment for confounding factors. This relationship may contribute to the enhanced cardiovascular disease risk for PAD patients and provides a target for strategies to improve patient clinical outcomes.

Rivaroxaban: searching the integral vascular protection

INTRODUCTION

Residual cardiovascular risk remains high in patients with atherosclerotic cardiovascular disease despite current antithrombotic therapy. On the other hand, patients with atrial fibrillation have an increased risk of myocardial infarction and cardiovascular death. As a result, a new antithrombotic approach appears necessary to reduce this risk. Areas covered: In this article, the role of rivaroxaban on vascular protection in patients with cardiovascular disease and/or atrial fibrillation was reviewed, with a particular focus, but not limited, on clinical trials. Expert commentary: Previous data have shown that factor Xa plays a key role in the etiopathogenesis of atherothrombosis. Experimental data suggest that rivaroxaban exhibits antiinflammatory and antioxidative stress properties, and may improve endothelial dysfunction. The COMPASS trial showed that among patients with stable atherosclerotic vascular disease, the addition of rivaroxaban 2.5 mg twice daily (vascular dose) to aspirin provided a higher cardiovascular protection than aspirin alone. In ROCKET-AF trial, compared with warfarin, rivaroxaban 20 mg once daily (15 mg if moderate renal dysfunction) (anticoagulant dose) was, at least, as effective as warfarin for the prevention of stroke or systemic embolism among patients with nonvalvular atrial fibrillation, with a trend toward a reduction in the risk of cardiovascular outcomes. All these data suggest that rivaroxaban might have a vascular protective effect beyond its stroke/systemic embolism preventive activity.

Peripheral vascular insufficiency impairs functional capacity in patients with heart failure

INTRODUCTION: Heart failure (HF) is a complex syndrome in which effort limitation is associated with deterioration of peripheral musculature. Improving survival rates among these patients have led to the appearance of cases in which other pathologies are associated with HF, such as peripheral vascular insufficiency (PVI). The combination of these two pathologies is common, with significant repercussions for affected patients. OBJECTIVE: To compare functional limitations and quality of life between patients with HF in isolation or HF + PVI. METHOD: Twelve patients with HF+PVI were paired to 12 patients with HF in isolation. All had ejection fraction <40%. The following were conducted: 6 minute walk test (6MWT), chair test (CT), step test (ST), one repetition maximum test (1RM) and quality of life questionnaire. RESULTS: The results for the 6MWT (311±27 vs. 447±29), ST (49±3 vs. 81±10) and CT (17±1 vs. 21±1) were lower in the HF+PVI group than in the HF group (p<0.05). The HF+PVI group exhibited a reduction in the number of steps taken from the first to the second minute of the ST, in relation to the HF group. The HF group exhibited better HR recovery than the HF+PVI group (50±4 vs. 26±3; p<0.05). No differences were found in results for the Borg scale, the peripheral muscle strength test (1RM) or the questionnaires (p>0.05). CONCLUSIONS: The study participants who had mixed disease exhibited a greater degree of functional impairment than the group with HF, without reporting worsened quality of life.

Novel anticoagulants in the therapy of peripheral arterial and coronary artery disease

Anticoagulant and antiplatelet drugs are used and studied in numerous trials for primary and secondary prevention of atherothrombosis since decades. The annual rate for cardiovascular morbidity and mortality is high in patients following an acute coronary syndrome and in patients with peripheral arterial disease (PAD) due to concomitant cardiac and cerebrovascular diseases. Plaque rupture and subsequent thrombosis involves activation of both platelets and coagulation factors. Therefore the combination of aspirin and warfarin to improve prevention of atherothrombosis compared to antiplatelet therapy alone was studied but could not be established due to significantly increased risk of major bleeding compared to a nonsignificant reduction in ischemic events. During the past two decades, clinical trials focused on combined antiplatelet therapies for the prevention of secondary events following acute coronary syndromes and very recently on the new oral anticoagulants in combination with antiplatelet therapy. This review discusses the role of the new oral anticoagulants such as Factor IIa (thrombin) and Factor Xa inhibitors in atherothrombosis, their pharmacological properties and recently published clinical data in secondary prevention of atherothrombotic events and potential implications for patients with PAD.

Reliability of the Baltimore Activity Scale Questionnaire for Intermittent Claudication

We assessed the reliability of the Baltimore Activity Scale for Intermittent Claudication (BASIC) for the evaluation of physical activity levels in individuals with intermittent claudication. We also identify the characteristics of the patients that influence the reliability of this questionnaire. A total of 38 men and women with peripheral artery disease and symptoms of intermittent claudication participated in the study. BASIC was administered to patients by the same evaluator at 2 different visits, separated by 7 days. The concordance coefficient ranged from .43 (How often do you walk at a fast pace?) to .85 (What happens when you feel pain while you walk?). The concordance coefficient of BASIC total score was .60. Higher concordance coefficients were observed in women (.66 vs .55), in younger patients (.63 vs .56), and in patients with lower ankle-brachial index (.64 vs .55). The reliability of BASIC questionnaire ranged from moderate to good in patients with claudication.

Relação entre aptidão física e os indicadores de qualidade de vida de indivíduos com claudicação intermitente

O objetivo deste estudo foi verificar a relação entre a aptidão física e os indicadores de qualidade de vida de indivíduos com claudicação intermitente (CI). Participaram do estudo 42 indivíduos (65,2 ± 8,3 anos) com CI, de ambos os gêneros. Para a avaliação da aptidão física, foram realizados teste de esforço em esteira, para obtenção da distância de claudicação (DC) e da distância total de marcha (DTM) e o teste de uma repetição máxima no exercício extensão de joelho. Os indicadores de qualidade de vida foram avaliados por meio do Medical Outcome Study Questionnaire Short Form 36, composto por oito domínios: capacidade funcional (CF), aspectos físicos (AF), dor, estado geral de saúde, vitalidade (VI), aspectos sociais (AS), aspectos emocionais (AE) e saúde mental. Para a análise estatística foi utilizado o coeficiente de correlação de Pearson, com p < 0,05. Foi observada correlação significante entre o domínio da CF com a DC e a DTM (r = 0,60, p < 0,01 e r = 0,49, p < 0,01, respectivamente), o domínio da AF com a DTM (r = 0,46, p < 0,01), o domínio da VI e dos AS com a DC (r = 0,34, p = 0,03 e r = 0,33, p = 0,04, respectivamente) e o domínio da AE com a DC e a DTM (r = 0,43, p = 0,01 e r = 0,44, p = 0,01, respectivamente). Como conclusão, os resultados deste estudo sugerem que os indicadores da qualidade de vida nos domínios da saúde física e da saúde emocional são relacionados com a capacidade de caminhada de indivíduos com CI

Addressing the common pathway underlying hypertension and diabetes in people who are obese by maximizing health: the ultimate knowledge translation gap

In accordance with the WHO definition of health, this article examines the alarming discord between the epidemiology of hypertension, type 2 diabetes mellitus (T2DM), and obesity and the low profile of noninvasive (nondrug) compared with invasive (drug) interventions with respect to their prevention, reversal and management. Herein lies the ultimate knowledge translation gap and challenge in 21st century health care. Although lifestyle modification has long appeared in guidelines for medically managing these conditions, this evidence-based strategy is seldom implemented as rigorously as drug prescription. Biomedicine focuses largely on reducing signs and symptoms; the effects of the problem rather than the problem. This article highlights the evidence-based rationale supporting prioritizing the underlying causes and contributing factors for hypertension and T2DM, and, in turn, obesity. We argue that a primary focus on maximizing health could eliminate all three conditions, at best, or, at worst, minimize their severity, complications, and medication needs. To enable such knowledge translation and maximizing health outcome, the health care community needs to practice as an integrated team, and address barriers to effecting maximal health in all patients. Addressing the ultimate knowledge translation gap, by aligning the health care paradigm to 21st century needs, would constitute a major advance.

Drug delivery by red blood cells: vascular carriers designed by mother nature

IMPORTANCE OF THE FIELD

Vascular delivery of several classes of therapeutic agents may benefit from carriage by red blood cells (RBC), for example, drugs that require delivery into phagocytic cells and those that must act within the vascular lumen. The fact that several protocols of infusion of RBC-encapsulated drugs are now being explored in patients illustrates a high biomedical importance for the field. AREAS COVERED BY THIS REVIEW: Two strategies for RBC drug delivery are discussed: encapsulation into isolated RBC ex vivo followed by infusion in compatible recipients and coupling therapeutics to the surface of RBC. Studies of pharmacokinetics and effects in animal models and in human studies of diverse therapeutic enzymes, antibiotics and other drugs encapsulated in RBC are described and critically analyzed. Coupling to RBC surface of compounds regulating immune response and complement, affinity ligands, polyethylene glycol alleviating immune response to donor RBC and fibrinolytic plasminogen activators are described. Also described is a new, translation-prone approach for RBC drug delivery by injection of therapeutics conjugated with fragments of antibodies providing safe anchoring of cargoes to circulating RBC, without need for ex vivo modification and infusion of RBC.

WHAT THE READER WILL GAIN

Readers will gain historical perspective, current status, challenges and perspectives of medical applications of RBC for drug delivery.

TAKE HOME MESSAGE

RBC represent naturally designed carriers for intravascular drug delivery, characterized by unique longevity in the bloodstream, biocompatibility and safe physiological mechanisms for metabolism. New approaches for encapsulating drugs into RBC and coupling to RBC surface provide promising avenues for safe and widely useful improvement of drug delivery in the vascular system.

Physical therapy in the 21st century (Part I): toward practice informed by epidemiology and the crisis of lifestyle conditions

Part I of this two-part introduction to this Special Issue on the practice of physical therapy in the 21st century outlines the epidemiological basis and rationale for evidence-informed physical therapy practice for addressing contemporary health priorities. This evidence emanates from the definition of health by the World Health Organization (WHO) and the International Classification of Functioning (ICF), and WHO and other international databases on the prevalence of lifestyle conditions. Lifestyle conditions include ischemic heart disease, smoking-related conditions, hypertension and stroke, obesity, diabetes, and cancer. Epidemiological data combined with evidence supporting the effectiveness of noninvasive interventions related to physical therapy to address these priorities (e.g., health education and exercise) are highly consistent with the promotion of health and wellness and the ICF. Given their commitment to exploiting effective noninvasive interventions, physical therapists are in a preeminent position to focus on prevention of these disabling and lethal conditions in every client or patient, their cure in some cases, as well as their management. Thus, a compelling argument can be made that clinical competencies in 21st century physical therapy need to include assessment of smoking and smoking cessation (or at least its initiation), basic nutritional assessment and counseling, recommendations for physical activity and exercise, stress assessment and basic stress reduction recommendations, and sleep assessment and basic sleep hygiene recommendations. The physical therapist can then make an informed clinical judgment regarding whether a client or patient needs to be referred to another professional related to one or more of these specialty areas. The prominence of physical therapy as an established health care profession and its unique pattern of practice (prolonged visits over prolonged periods of time) attest further to the fact that physical therapists are uniquely qualified to lead in the assault on lifestyle conditions. Evidence-based physical therapy practiced within the context of epidemiological indicators (i.e., evidence-informed practice) maximally empowers clinicians to promote lifelong health in every person and in turn, the health of communities. This vision of physical therapy's leading role in health promotion and health care in the 21st century holds the promise of reducing the need for invasive health interventions (drugs and surgery). Part II of this introduction describes evidence-based physical therapy practice within this context of evidence-informed practice.

Avaliação da reprodutibilidade de testes funcionais na doença arterial periférica

Este estudo visou avaliar a reprodutibilidade de dois testes funcionais de membros inferiores em pacientes com doença arterial periférica. Os testes senta-levanta da cadeira (TSL) e da ponta do pé (TPP) foram aplicados duas vezes em 14 voluntários com doença arterial periférica por três examinadores, com intervalo de 1 minuto entre os testes e de 15 minutos entre teste e reteste. A maioria dos participantes apresentou dificuldades no TPP, sendo realizadas adaptações. Os dados foram analisados estatisticamente; o grau de concordância entre examinadores foi estimado pelo coeficiente de correlação intraclasse (CCI), sendo ±<5% considerado significativo. Todas as correlações foram estatisticamente significativas. O TSL apresentou alta reprodutibilidade tanto inter-examinador (CCI=0,904 no teste e 0,857 no reteste) quanto intra- examinador. O mesmo ocorreu com o TPP (CCI=0,824 no teste e 0,941 no reteste, na avaliação inter-examinador). A correlação de Pearson entre as médias dos três examinadores no TSL e no TPP foi 0,651 no teste e 0,609 no reteste. Ambos os testes são pois reprodutíveis e viáveis na prática clínica, mas é necessário avaliar se são sensíveis a alterações que ocorram durante o processo natural da doença ou se podem ser instrumentos viáveis para acompanhamento desses pacientes.

Human complement receptor type 1-directed loading of tissue plasminogen activator on circulating erythrocytes for prophylactic fibrinolysis

Plasminogen activators (PAs) are not used for thromboprophylaxis due to rapid clearance, bleeding, and extravascular toxicity. We describe a novel strategy that overcomes these limitations. We conjugated tissue-type PA (tPA) to a monoclonal antibody (mAb) against complement receptor type 1 (CR1) expressed primarily on human RBCs. Anti-CR1/tPA conjugate, but not control conjugate (mIgG/tPA), bound to human RBCs (1.2 x 10(3) tPA molecules/cell at saturation), endowing them with fibrinolytic activity. In vitro, RBC-bound anti-CR1/tPA caused 90% clot lysis versus 20% by naive RBCs. In vivo, more than 40% of anti-CR1/(125)I-tPA remained within the circulation ( approximately 90% bound to RBCs) 3 hours after injection in transgenic mice expressing human CR1 (TgN-hCR1) versus less than 10% in wild-type (WT) mice, without RBC damage; approximately 90% of mIgG/(125)I-tPA was cleared from the circulation within 30 minutes in both WT and TgN-hCR1 mice. Anti-CR1/tPA accelerated lysis of pulmonary emboli and prevented stable occlusive carotid arterial thrombi from forming after injection in TgN-hCR1 mice, but not in WT mice, whereas soluble tPA and mIgG/tPA were ineffective. Anti-CR1/tPA caused 20-fold less rebleeding in TgN-hCR1 mice than the same dose of tPA. CR1-directed immunotargeting of PAs to circulating RBCs provides a safe and practical means to deliver fibrinolytics for thromboprophylaxis in settings characterized by a high imminent risk of thrombosis.

N-coumaroyldopamine and N-caffeoyldopamine increase cAMP via beta 2-adrenoceptors in myelocytic U937 cells

N-caffeoyldopamine is a phytochemical found in various plants, including cocoa (Theobroma cacao L.). N-caffeoyldopamine and its natural analogs (N-cinnamoyldopamine, N-coumaroyldopamine, N-feruloyldopamine, and N-sinapoyldopamine) were synthesized and investigated to determine their potency as beta-adrenoceptor agonists, because they have chemical structural moieties found in beta-adrenoceptor agonists. Among the compounds tested in this study, N-coumaroyldopamine and N-caffeoyldopamine were the two most potent compounds, able to increase cAMP at the concentrations < 0.05 microM in U937 cells. The decreasing order of potency was N-coumaroyldopamine > N-caffeoyldopamine > N-feruloyldopamine > N-sinapoyldopamine > N-cinnamoyldopamine. Using beta2-specific antagonists (butoxamine and ICI 118551), N-coumaroyldopamine and N-caffeoyldopamine were found to increase cAMP via beta2-adrenoceptors in U937 cells. In producing cAMP in U937 cells, N-coumaroyldopamine and N-caffeoyldopamine were as potent as several well-known beta2-adrenoceptor agonists (salbutamol, procaterol, and fenoterol). These results indicate that N-coumaroyldopamine and N-caffeoyldopamine are potent compounds able to increase cAMP via beta2-adrenoceptors in U937 cells, and may have potential effects on human health.

Pseudoclaudication as a manifestation of diabetic neuropathy

We present the case of a 64-year-old male Type 1 diabetic patient with painful diabetic neuropathy masquerading as intermittent claudication. Examination of the peripheral circulation (both arterial and venous) was normal. An MRI scan excluded lumbar spinal stenosis and nerve root compression as the cause of claudication. The case suggests that, in the absence of other identifiable causes and in the presence of peripheral diabetic neuropathy, "intermittent claudication" may be due to the neuropathy itself.

Blood coagulation and the risk of atherothrombosis: a complex relationship

The principles of Virchov's triad appear to be operational in atherothrombosis or arterial thrombosis: local flow changes and particularly vacular wall damage are the main pathophysiological elements. Furthermore, alterations in arterial blood composition are also involved although the specific role and importance of blood coagulation is an ongoing matter of debate. In this review we provide support for the hypothesis that activated blood coagulation is an essential determinant of the risk of atherothrombotic complications. We distinguish two phases in atherosclerosis: In the first phase, atherosclerosis develops under influence of "classical" risk factors, i.e. both genetic and acquired forces. While fibrinogen/fibrin molecules participate in early plaque lesions, increased activity of systemic coagulation is of no major influence on the risk of arterial thrombosis, except in rare cases where a number of specific procoagulant forces collide. Despite the presence of tissue factor – factor VII complex it is unlikely that all fibrin in the atherosclerotic plaque is the direct result from local clotting activity. The dominant effect of coagulation in this phase is anticoagulant, i.e. thrombin enhances protein C activation through its binding to endothelial thrombomodulin.

The second phase is characterized by advancing atherosclerosis, with greater impact of inflammation as indicated by an elevated level of plasma C-reactive protein, the result of increased production influenced by interleukin-6. Inflammation overwhelms protective anticoagulant forces, which in itself may have become less efficient due to down regulation of thrombomodulin and endothelial cell protein C receptor (EPCR) expression. In this phase, the inflammatory drive leads to recurrent induction of tissue factor and assembly of catalytic complexes on aggregated cells and on microparticles, maintaining a certain level of thrombin production and fibrin formation. In advanced atherosclerosis systemic and vascular wall driven coagulation becomes more important and elevated levels of D-dimer fragments should be interpreted as markers of this hypercoagulability.