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Peripheral Arteries (peripheral + artery)
Terms modified by Peripheral Arteries Selected AbstractsInsulin resistance and endothelial dysfunction: the road map to cardiovascular diseasesDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 6 2006Eugenio Cersosimo Abstract Cardiovascular disease affects approximately 60% of the adult population over the age of 65 and represents the number one cause of death in the United States. Coronary atherosclerosis is responsible for the vast majority of the cardiovascular events, and a number of cardiovascular risk factors have been identified. In recent years, it has become clear that insulin resistance and endothelial dysfunction play a central role in the pathogenesis of atherosclerosis. Much evidence supports the presence of insulin resistance as the fundamental pathophysiologic disturbance responsible for the cluster of metabolic and cardiovascular disorders, known collectively as the metabolic syndrome. Endothelial dysfunction is an important component of the metabolic or insulin resistance syndrome and this is demonstrated by inadequate vasodilation and/or paradoxical vasoconstriction in coronary and peripheral arteries in response to stimuli that release nitric oxide (NO). Deficiency of endothelial-derived NO is believed to be the primary defect that links insulin resistance and endothelial dysfunction. NO deficiency results from decreased synthesis and/or release, in combination with exaggerated consumption in tissues by high levels of reactive oxygen (ROS) and nitrogen (RNS) species, which are produced by cellular disturbances in glucose and lipid metabolism. Endothelial dysfunction contributes to impaired insulin action, by altering the transcapillary passage of insulin to target tissues. Reduced expansion of the capillary network, with attenuation of microcirculatory blood flow to metabolically active tissues, contributes to the impairment of insulin-stimulated glucose and lipid metabolism. This establishes a reverberating negative feedback cycle in which progressive endothelial dysfunction and disturbances in glucose and lipid metabolism develop secondary to the insulin resistance. Vascular damage, which results from lipid deposition and oxidative stress to the vessel wall, triggers an inflammatory reaction, and the release of chemoattractants and cytokines worsens the insulin resistance and endothelial dysfunction. From the clinical standpoint, much experimental evidence supports the concept that therapies that improve insulin resistance and endothelial dysfunction reduce cardiovascular morbidity and mortality. Moreover, interventional strategies that reduce insulin resistance ameliorate endothelial dysfunction, while interventions that improve tissue sensitivity to insulin enhance vascular endothelial function. There is general agreement that aggressive therapy aimed simultaneously at improving insulin-mediated glucose/lipid metabolism and endothelial dysfunction represents an important strategy in preventing/delaying the appearance of atherosclerosis. Interventions that 1 correct carbohydrate and lipid metabolism, 2 improve insulin resistance, 3 reduce blood pressure and restore vascular reactivity, and 4 attenuate procoagulant and inflammatory responses in adults with a high risk of developing cardiovascular disease reduce cardiovascular morbidity and mortality. Whether these benefits hold when the same prevention strategies are applied to younger, high-risk individuals remains to be determined. Copyright © 2006 John Wiley & Sons, Ltd. [source] Doppler ultrasound assessment of posterior tibial artery size in humansJOURNAL OF CLINICAL ULTRASOUND, Issue 5 2006Manning J. Sabatier PhD Abstract Purpose. The difference between structural remodeling and changes in tone of peripheral arteries in the lower extremities has not been evaluated. The purpose of this study was to (1) evaluate the day-to-day reproducibility and interobserver reliability (IOR) of posterior tibial artery (PTA) diameter measurements and (2) evaluate the effect of posture on PTA diameter at rest (Drest), during 10 minutes of proximal cuff occlusion (Dmin), and after the release of cuff occlusion (Dmax), as well as range (Dmax , Dmin) and constriction [(Dmax , Drest)/(Dmax , Dmin) × 100] in vivo. Methods. We used B-mode sonography to image the PTA during each condition. Results. Day-to-day reliability was good for Drest (intraclass correlation coefficient [ICC] 0.95; mean difference 4.2%), Dmin (ICC 0.93; mean difference 5.4%), and Dmax (ICC 0.99; mean difference 2.2%). The coefficient of repeatability for IOR was 70.5 ,m, with a mean interobserver error of 4.7 ,m. The seated position decreased Drest (2.6 ± 0.2 to 2.4 ± 0.3 mm; p = 0.002), increased Dmin (2.1 ± 0.2 to 2.4 ± 0.2 mm; p = 0.001), and decreased Dmax (3.1 ± 0.4 to 2.8 ± 0.3 mm; p < 0.001) compared with the supine position. The seated position also decreased arterial range (Dmax , Dmin) from 0.9 ± 0.2 to 0.5 ± 0.1 mm (p = 0.003) and increased basal arterial constriction from 57 ± 19% to 105 ± 27% (p = 0.007). Conclusions. The system employed for measuring PTA diameter yields unbiased and consistent estimates. Furthermore, lower extremity arterial constriction and range change with posture in a manner consistent with known changes in autonomic activity. © 2006 Wiley Periodicals, Inc. J Clin Ultrasound 34:223,230, 2006 [source] Peripheral Atherectomy: A Critical ReviewJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 6 2007TROY A. BUNTING M.D. Atherectomy is experiencing increased interest from endovascular specialists as a therapeutic treatment in the peripheral arteries. Long studied in the coronary vasculature, atherectomy has several theoretical advantages that make it uniquely suited for the peripheral circulation. In particular, infra-inguinal peripheral arterial disease experiences physiologic stresses and forces that have made traditional percutaneous coronary treatments such as angioplasty and stenting not as successful. Restenosis has been a major problem for angioplasty and stenting alone. The SilverHawk atherectomy device has favorable short-term data but important longer-term data are limited and need further study. Laser atherectomy also has favorable applications in niche patients but the number of studies is limited. Unfortunately, athero-ablative technologies for peripheral arterial disease require more definitive objective data regarding 12-month and longer-term outcomes in order to obtain widespread scientific acceptance. [source] Contrast-enhanced peripheral MR angiography at 3.0 Tesla: Initial experience with a whole-body scanner in healthy volunteersJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2003Tim Leiner MD Abstract Purpose To report preliminary experience with contrast-enhanced magnetic resonance angiography (CE-MRA) of the peripheral arteries on a 3.0 T whole-body scanner equipped with a prototype body coil. Materials and Methods Four healthy volunteers were imaged on the 3.0 T system and, for comparative purposes, two of the subjects were also imaged on a commercially available 1.5 T whole-body system. To investigate field strength influence on objective image quality, signal-to-noise (SN) and contrast-to-noise (CN) ratios were calculated for named vessels from the infrarenal aorta to the ankles at both field strengths. Comparable imaging protocols were used at both field strengths. In addition, two reviewers, blinded for field strength, gave subjective image quality scores (three-point scale). Results SN and CN ratios were approximately equal on both systems (variation ,9%) for the iliac and proximal upper leg stations. For the popliteal and lower leg stations SN ratios were 36% and 97% higher, and CN ratios were 44% and 127% higher, at 3.0 T. Subjective image quality at 3.0 T was substantially better for the distal upper and lower legs. Conclusion Contrast-enhanced peripheral MRA is possible at 3.0 T when an imaging protocol similar to a current state-of-the-art 1.5 T protocol is used. Objective and subjective image quality at 3.0 T is comparable for the iliac and upper legs but better for the popliteal and lower leg arteries. J. Magn. Reson. Imaging 2003;17:609,614. © 2003 Wiley-Liss, Inc. [source] A Comparative Study of Intraplacental Villous Arteries by Latex Cast Model in vitro and Color Doppler Flow Imaging in vivo,JOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 5 2001Junwu Mu Abstract Objective: The purpose of this study was to determine whether color Doppler sonogram can accurately depict the placental vascular structures using a latex cast model of the placental vessels, and to make a nomogram of several blood flow parameters according to the vascular structures. Methods: First, we made 9 latex cast models of placental arteries and performed morphologic observation and measurement. Second, the comparative anatomical observation of placental vessels by color flow mapping was performed for all 9 patients from whom the latex models were made. Third, a total of 102 uncomplicated pregnant women between 18 and 40 weeks gestation were examined by color Doppler imaging. The resistance indices (RI) and peak systolic velocity (PSV) were measured. Results: In the latex cast model of placentas, cotyledons could be differentiated by the presence of independent vascular structure units. First, second, third and fourth branches were noted in one cotyledon. Cotyledons were easily identified and counted by color Doppler imaging. Each cotyledon contained only one first branch of the intraplacental villous artery (IPVA). The number of IPVA-1 on color Doppler imaging was equal to the number of the cotyledon calculated from the latex model. RI exhibited a negative, and PSV a positive correlation with gestational age (p < 0.05 in both cases). At any given gestational age, both RI and PSV in the peripheral arteries were significantly lower (p < 0.01) than those in the upstream arteries. Conclusions: Color Doppler flow sonography is a valuable tool for detecting the blood flow of intraplacental villous arteries in vivo and the images agree with the vascular anatomy of placenta in vitro. These results may also provide the basic parameters for future studies of some complicated pregnancies. [source] The effect of rizatriptan, ergotamine, and their combination on human peripheral arteries: a double-blind, placebo-controlled, crossover study in normal subjectsBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 1 2002Peer Tfelt-Hansen Aims, To compare the peripheral vasoconstrictor effects of ergotamine, rizatriptan, and their combination, in normal subjects. Methods, This was a double-blind, four-way, crossover study. Sixteen young male volunteers, selected as responders to the vasoconstrictor effect of 0.5 mg ergotamine i.v., were administered 10 mg oral rizatriptan, 0.25 mg i.v. ergotamine, 10 mg oral rizatriptan+0.25 mg i.v. ergotamine, and placebo. The vasoconstrictor effect on peripheral arteries was measured with strain gauge plethysmography up to 8 h after dosing. The 8 h assessment period was divided into two 4 h intervals to assess the immediate (0,4 h) vs sustained effect (4,8 h) of treatment. Results, For the 0,4 h interval, the decreases in peripheral systolic blood pressure gradients were: placebo (,1 mmHg [95% CI: ,3, 1]) Beyond peripheral arteries in Buerger's disease: Angiographic considerations in thromboangiitis obliteransCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 3 2002Bobbi Hoppe MD Abstract Thromboangiitis obliterans is an inflammatory peripheral vascular disease that is strongly associated with smoking. It predominantly affects distal small- and medium-sized blood vessels of both the upper and lower extremities. We present histological evidence of this disease process affecting the internal mammary arteries. This can be of paramount clinical significance for patients with Buerger's disease who present with obstructive coronary artery disease and require coronary artery bypass grafting surgery (CABG). Internal mammary arteries involved with thromboangiitis obliterans cannot be utilized as arterial conduits during CABG and other alternatives have to be used. Therefore, we recommend preoperative angiography of both internal mammary arteries in patients with Buerger's disease requiring CABG to prevent extensive intraoperative dissection of diseased internal mammary arteries. Cathet Cardiovasc Intervent 2002;57:363,366. © 2002 Wiley-Liss, Inc. [source] Experimental and clinical study of the combined effect of arterial stiffness and heart rate on pulse pressure: Differences between central and peripheral arteriesCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 3 2005Theodoros G Papaioannou SUMMARY 1.,Pulse pressure (PP) constitutes an independent predictor of cardiovascular events and mortality in various populations. Heart rate (HR) and arterial stiffness, in addition to their independent predictive value for cardiovascular complications, seem to interact with regard to the modification of PP. The aim of the present study was to investigate the association of PP with HR under different levels of arterial compliance (AC), revealing their synergistic effects. 2.,Seventy-one normotensive and untreated hypertensive subjects were examined. Arterial compliance was measured by the ,area' method, whereas central blood pressures and wave reflections were evaluated using the Sphygmocor® system (AtCor Medical, Sydney, NSW, Australia). A hydraulic Windkessel model was also used to evaluate the independent effect of HR and AC on PP. Peripheral PP was associated only with mean pressure and AC. In contrast, central PP was further related to HR (20 b.p.m. decrease in HR resulted in central PP augmentation by 5.6 mmHg) regardless of mean pressure, stroke volume, age and gender. However, this association was statistically significant only for subjects with lower AC (< 1.1 mL/mmHg) and not for those with more compliant arteries. These findings are also in accordance with the experimental data. 3.,Aortic PP is affected to a greater degree by HR changes compared with peripheral PP. This response was observed only at high levels of arterial stiffness. 4.,The present study provides the first evidence regarding the combined effect of AC and HR on aortic PP, which may lead to larger clinical or epidemiological studies aiming to optimization of drug treatment and to a possible reduction of cardiovascular risk. [source] On the segmentation of vascular geometries from medical imagesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 1 2010A. G. Radaelli Abstract A comprehensive analysis of vascular morphology and the application of generic models of vascular biomechanics to specific patients require the ability of extracting a geometrical representation of the vascular anatomy from medical images. Owing to the wide range of clinical manifestations of vascular disease and associated imaging modalities and protocols, several segmentation methods have been proposed over the last 20 years and are available in the literature. In this paper, we review the methods of segmentation of angiographic medical images and identify major advantages and disadvantages of state-of-the-art techniques. We further discuss the performance of some of the most popular intensity-based and gradient-based methods using a set of images of peripheral by-pass grafts acquired with magnetic resonance angiography (MRA). We then propose a threshold front method for the segmentation of MRA images and assess its performance using two anatomic scale replica models, reproducing a normal and a stenotic peripheral artery. The threshold front algorithm is a simple, fast and parameter-free (still adaptive) method achieving segmentation errors below pixel resolution. Copyright © 2009 John Wiley & Sons, Ltd. [source] Cardiac Output Technologies with Special Reference to the HorseJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 3 2003Kevin T.T. Corley Critical illness, anesthesia, primary cardiovascular disease, and exercise may result in marked hemodynamic alterations. Measuring cardiac output (CO) is central to defining these alterations for both clinician and researcher. In the past 10 years, several new methods of measuring CO have been developed for the human medical market. Some of these methods are now validated in the horse and are in clinical use. The Fick method has been used in equine research for more than a century. It depends on simultaneous measurement of mixed venous (pulmonary arterial) and peripheral arterial oxygen content and oxygen uptake by the lungs. The technique is technically demanding, which restricts its clinical use. Indicator dilution techniques, with indocyanine green, cold (thermodilution), or lithium as the marker, have also been widely used in the horse. The indocyanine technique is cumbersome, and thermodilution requires right heart catheterization, which is not a benign procedure, making both of these methods less than ideal for clinical use. Lithium dilution requires catheterization of a peripheral artery and a jugular vein. It has recently been validated in anesthetized adult horses and neonatal foals. Doppler echocardiography is a noninvasive ultrasound-based technique. More accurate measurements are obtained with transesophageal than with transthoracic measurements; however, both methods require considerable technical expertise. Bioimpedance and pulse contour analysis are 2 new methods that have yet to be validated in the horse. With the currently available technology, lithium dilution appears to be the method of measuring CO best suited to the equine clinic. [source] A Novel Subcutaneous Counterpulsation Device: Acute Hemodynamic Efficacy During Pharmacologically Induced Hypertension, Hypotension, and Heart FailureARTIFICIAL ORGANS, Issue 7 2010Carlo R. Bartoli Abstract The miniaturization of mechanical assist devices and less invasive implantation techniques may lead to earlier intervention in patients with heart failure. As such, we evaluated the effectiveness of a novel, minimally invasive, implantable counterpulsation device (CPD) in augmenting cardiac function during impaired hemodynamics. We compared the efficacy of a 32-mL stroke volume CPD with a standard 40-mL intra-aortic balloon pump (IABP) over a range of clinically relevant pathophysiological conditions. Male calves were instrumented via thoracotomy, the CPD was anastomosed to the left carotid artery, and the IABP was positioned in the descending aorta. Hemodynamic conditions of hypertension, hypotension, and heart failure were pharmacologically simulated and data were recorded during CPD and IABP support (off, 1:2, 1:1 modes) for each condition. In all three pathophysiological conditions, the CPD and IABP produced similar and statistically significant (P < 0.05) increases in coronary artery blood flow normalized to the left ventricular (LV) workload. During hypotension and heart failure conditions, however, the CPD produced significantly greater reductions in LV workload and myocardial oxygen consumption as compared with the IABP. A novel 32-mL CPD connected to a peripheral artery produced equivalent or greater hemodynamic benefits than a standard 40-mL IABP during pharmacologically induced hypertension, hypotension, and heart failure conditions. [source]
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