ultrasound-assessment-endothelial-dependent-flow-mediated

Ultrasound Assessment of Endothelial-Dependent Flow-Mediated Vasodilation of the Brachial Artery in Clinical Research

The vascular endothelium is a monolayer of cells that cover the interior of blood vessels and provide both structural and functional roles. The ...

University of California, San Francisco

Veterans Affairs Medical Center, San Francisco

Peripheral artery disease (PAD) is an understudied chronic illness most prevalent in elderly individuals. PAD patients experience substantial walking impairment due to symptoms of limb ischemia that significantly diminishes quality of life (QOL). Cardiovascular disease (CVD) morbidity and mortality is increased in this population because of aggressive atherosclerosis resulting from untreated CVD risk factors. Despite current national guidelines recommending intensive CVD risk factor management for PAD patients, untreated CVD risk factors are common. Interventions that bridge this gap are imperative. The Vascular Insufficiency - Goals for Optimal Risk Reduction (VIGOR(2)) study is a randomized controlled trial (RCT) that examines the effectiveness of a long-term multifactor CVD risk reduction program on walking and quality of life in patients with PAD. The purpose of this article is to provide a detailed description of the design and methods of VIGOR(2). Clinical Trial Registration - URL: http://clinicaltrials.gov/ct2/show/NCT00537225.

Efficacy of optimal long-term management of multiple cardiovascular risk factors (CVD) on walking and quality of life in patients with peripheral artery disease (PAD): protocol for randomized controlled trial.

To determine the feasibility of using ferumoxytol-enhanced magnetic resonance (MR) angiography to depict the vasculature of hemodialysis fistulas and improve image quality compared with nonenhanced time-of-flight (TOF) MR angiography.

USPIO-enhanced MR angiography of arteriovenous fistulas in patients with renal failure.

Peripheral Arterial Disease (PAD) is most prevalent in the elderly and associated with increased cardio vascular disease (CVD) morbidity and mortality. Treatment focuses on improving functional capacity and reducing CVD risk factors. To date, little is understood about dietary habits and weight in this patient population. Nutritional and weight recommendations are based on heart health, and little is known about the unique needs of elderly PAD patients with multiple comorbidities. This prospective study compared 1) the dietary intake of nonobese PAD patients in comparison with those who were obese and; 2) dietary intake of those patients with the Estimated Average Requirement (EAR) based on age, gender and BMI. Nutritional intake was assessed with the Block 98 Food Frequency Questionnaire. Body mass index (BMI) was calculated in accordance with the National Heart, Lung, and Blood Institute (NHLBI) guidelines.The study population was divided into obese (BMI ≥ 30) and nonobese (NO) groups. Comparisons between groups were performed using the Mann-Whitney U test for continuous variables and the Chi-square test for ordinal variables. All tests were two-tailed and P < 0.05 was considered significant. The Estimated Average Requirement (EAR) cut-point method was used to compare nutritional variables with Dietary Reference Intakes (DRI). The study population included 189 NO (BMI < 30) and 111 obese (BMI > 30) individuals. Obese participants reported greater intake of foods containing cholesterol and trans-fatty acids and more frequent intake of B vitamins in comparison with the NO BMI group. Additionally, the nutrient intake of all participants by age, gender and BMI was lower than the EAR for magnesium, folate, and Vitamin E. These results suggest that the nutritional intake of PAD patients differs based on gender and BMI. Additionally, EAR was lower for specific nutrients than recommended. Further investigation is needed to examine the association between nutritional intake and nutrition-related deficits.

Differences in nutrition status by body mass index in patients with peripheral artery disease.

Hemodynamic parameters play an important role in regulating vascular remodeling in arterio-venous fistula (AVF) maturation. Investigating the changes in hemodynamic parameters during AVF maturation is expected to improve our understanding of fistula failure, but very little data on actual temporal changes in human AVFs is available. The present study aimed to assess the feasibility of using a noncontrast-enhanced MRI protocol combined with CFD modeling to relate hemodynamic changes to vascular remodeling following native AVF placement. MR angiography (MRA) and MR velocimetry (MRV) data was acquired peri-operatively, 1 month, and 3 months later in three patients. Vascular geometries were obtained by segmentation of the MRA images. Pulsatile flow simulations were performed in the patient specific vascular geometries with time-dependent boundary conditions prescribed from MRV measurements. A principal result of the study is the description of WSS changes over time in the same patients. The disturbed flow observed in the venous segments resulted in a variability of the WSS distribution and could be responsible for the non-uniform remodeling of the vessel. The artery did not show regions of disturbed flow upstream from the anastomosis, which would be consistent with the uniform remodeling. MRI use demonstrated the ability to provide a comprehensive evaluation of clinically relevant information for the investigation of upper extremity AVFs. 3D geometry from MRA in combination with MRV provides the opportunity to perform detailed CFD analysis of local hemodynamics in order to determine flow descriptors affecting fistula maturation.

Vascular remodeling in autogenous arterio-venous fistulas by MRI and CFD.

The n-3 polyunsaturated fatty acids are dietary components derived from fish oil with beneficial cardiovascular effects that may relate in part to anti-inflammatory properties. Peripheral artery disease (PAD) is characterized by a marked proinflammatory state. We hypothesized that the n-3 polyunsaturated fatty acids content of red blood cells (omega-3 index) would be correlated with biomarkers of inflammation and vascular function in a PAD cohort.

Association between n-3 polyunsaturated fatty acid content of red blood cells and inflammatory biomarkers in patients with peripheral artery disease.

Despite current consensus guidelines recommending intensive cardiovascular risk factor management for peripheral artery disease (PAD), patients suffering from PAD continue to experience significant morbidity and mortality. This excess morbid burden is at least partially related to impaired vascular function and systemic inflammation. Interventions bridging this gap are critical. Dietary supplementation of n-3 polyunsaturated fatty acids (n-3 PUFA) has been shown to improve endothelial function and reduce inflammation in different cohorts, as well as to decrease cardiovascular events in secondary prevention trials in patients with coronary artery disease. Their effects in the PAD population are, however, less well understood. The OMEGA-PAD trial is a double-blinded, randomized, placebo-controlled trial that examines the impact of a high-dose, short-duration dietary oral supplementation of n-3 PUFA on vascular function and inflammation in patients with established PAD. The purpose of this article is to provide a detailed description of the design and methods of the OMEGA-PAD trial, and a summary of baseline characteristics of the cohort.

n-3 Polyunsaturated fatty acids supplementation in peripheral artery disease: the OMEGA-PAD trial.

Restenosis following endovascular treatment of the femoropopliteal segment is associated with the inflammatory response produced in the artery wall at the time of the procedure. Although local drug delivery to the superficial femoral and popliteal arteries promises improved patency, data are currently limited. We hypothesized that improved percutaneous delivery of an anti-inflammatory compound into the adventitia of the femoropopliteal at the time of endovascular treatment would be safe, feasible, and decrease the inflammatory response.

Safety and feasibility of adjunctive dexamethasone infusion into the adventitia of the femoropopliteal artery following endovascular revascularization.

Patients with peripheral artery disease (PAD) have varying degrees of walking disability that do not completely correlate with ankle-brachial index (ABI) or angiographic anatomy. We hypothesized that endothelial function (EF) is an independent predictor of symptom severity in PAD patients.

Walking disability in patients with peripheral artery disease is associated with arterial endothelial function.

Sedentarism, also termed physical inactivity, is an independent risk factor for cardiovascular diseases. Mechanisms thought to be involved include insulin resistance, dyslipidemia, hypertension, and increased inflammation. It is unknown whether changes in vascular and endothelial function also contribute to this excess risk. We hypothesized that short-term exposure to inactivity would lead to endothelial dysfunction, arterial stiffening, and increased vascular inflammation.

Short-term physical inactivity impairs vascular function.

Despite available medical therapies, patients with peripheral arterial disease (PAD) remain at high risk for cardiovascular events. The n-3 polyunsaturated fatty acids (PUFA), derived from marine sources, have been shown to improve cardiovascular mortality. The Omega-3 Index (O3I), a proportion of the n-3 PUFA eicosapentaenoic acid and docosahexaenoic acid in the red blood cell membrane, correlates with cardiovascular risk. Previous investigations have found that n-3 PUFA supplementation, fish consumption, older age, and smoking history affect the O3I in different patient populations, although similar correlations have never been explored in PAD. We hypothesized that in our PAD cohort, blood content of omega-3 fatty acids would directly and positively correlate with a history of fish oil supplementation and older age and inversely correlate with a smoking history and obesity.

Article	Year
Efficacy of optimal long-term management of multiple cardiovascular risk factors (CVD) on walking and quality of life in patients with peripheral artery disease (PAD): protocol for randomize... Vascular medicine (London, England)\| PubMed ID: 22363015	2012
USPIO-enhanced MR angiography of arteriovenous fistulas in patients with renal failure. Radiology\| PubMed ID: 22875796	2012
Differences in nutrition status by body mass index in patients with peripheral artery disease. Journal of vascular nursing : official publication of the Society for Peripheral Vascular Nursing\| PubMed ID: 22901446	2012
Vascular remodeling in autogenous arterio-venous fistulas by MRI and CFD. Annals of biomedical engineering\| PubMed ID: 23188560	2013
Association between n-3 polyunsaturated fatty acid content of red blood cells and inflammatory biomarkers in patients with peripheral artery disease. Journal of vascular surgery\| PubMed ID: 23830313	2013
n-3 Polyunsaturated fatty acids supplementation in peripheral artery disease: the OMEGA-PAD trial. Vascular medicine (London, England)\| PubMed ID: 24052491	2013
Safety and feasibility of adjunctive dexamethasone infusion into the adventitia of the femoropopliteal artery following endovascular revascularization. Journal of vascular surgery\| PubMed ID: 24423476	2014
Walking disability in patients with peripheral artery disease is associated with arterial endothelial function. Journal of vascular surgery\| PubMed ID: 24423479	2014
Short-term physical inactivity impairs vascular function. The Journal of surgical research\| PubMed ID: 24630521	2014
Clinical correlates of red blood cell omega-3 fatty acid content in male veterans with peripheral arterial disease. Journal of vascular surgery\| PubMed ID: 24953895	2014

Hugh Alley

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