Search results for "doppler"
showing 10 items of 637 documents
Impact of insulin resistance on cardiac and vascular function.
2016
Background Insulin resistance (IR), constitutes an important cardiovascular risk factor and can cause ischemic heart disease. It can lead to left ventricular dysfunction with a mechanism independent of ischemic heart disease and it is closely associated with impaired vascular function. The aim of our study was to explore the impact of IR on cardiac and vascular function, in patients with cardiovascular risk factors but angiographically undamaged coronary arteries. Methods We studied 32 patients (62.06 ± 11.19 years) with cardiovascular risk factors. All patients underwent coronary angiography, echocardiography, Doppler ultrasound of carotid arteries and laboratory tests. Exclusion criteria …
On the number of measurement sites required to assess regional cerebral blood flow by laser-Doppler scanning during cerebral ischemia and reperfusion.
2001
The aim of this study was to determine whether the number of measurement sites affected the precision of regional cerebral blood flow (CBF) assessment by Laser-Doppler (LD). A simulation study was applied based on data obtained by scanning the cortex in 25 rats during baseline conditions, 15 min global cerebral ischemia and reperfusion. Random samples were repeatedly collected from 1 to 100 locations and deviations from the median of the entire CBF data pool (800 locations) were determined. Single location CBF measurements missed the true median by 24.8+/-2.2 LD-units (baseline conditions, n=100 simulations, mean+/-SEM), 2.7+/-0.6 LD-units (ischemia), and 31.9+/-2.4 LD-units (30th min reper…
A genetic variant of the atrial natriuretic peptide gene is associated with cardiometabolic protection in the general community
2011
Objectives We sought to define the cardiometabolic phenotype associated with rs5068, a genetic variant of the atrial natriuretic peptide (ANP) gene. Background The ANP and B-type natriuretic peptide play an important role in cardiorenal homeostasis but also exert metabolic actions. Methods We genotyped 1,608 randomly selected residents from Olmsted County, Minnesota. Subjects were well-characterized. Results Genotype frequencies were: AA 89.9%, AG 9.7%, and GG 0.4%; all subsequent analyses were AA versus AG+GG. The G allele was associated with increased plasma levels of N-terminal pro-atrial natriuretic peptide (p = 0.002), after adjustment for age and sex. The minor allele was also associa…
Color Doppler ultrasonography in pediatric intussusception.
1994
CDU was used in 11 children with intussusception. Demonstration of vascular images within the "pseudokidney" mass was possible in none of 11 cases. Of them, eight could be treated by hydrostatic reduction. In the remaining case, marked edema of the bowel wall did not allow reduction, and surgery had to be performed: no necrosis was observed in the surgical specimen. Both patients in whom CDU failed to demonstrate vascular signals had necrosis at surgery, and bowel resection was performed. Because of the limited number of patients examined at this time, no firm conclusions can be drawn from our experience. However, CDU seems a promising technique in detecting vascular changes occurring in in…
Capillary flow and diameter changes during reperfusion after global cerebral ischemia studied by intravital video microscopy.
2004
The reaction of cerebral capillaries to ischemia is unclear. Based on Hossmann's observation of postischemic “delayed hypoperfusion,” we hypothesized that capillary flow is decreased during reperfusion because of increased precapillary flow resistance. To test this hypothesis, we measured cerebral capillary erythrocyte velocity and diameter changes by intravital microscopy in gerbils. A cranial window was prepared over the frontoparietal cortex in 26 gerbils anesthetized with halothane. The animals underwent either a sham operation or fifteen minutes of bilateral carotid artery occlusion causing global cerebral ischemia. Capillary flow velocities were measured by frame-to-frame tracking of…
Impaired cerebrovascular autoregulation in patients with severe sepsis and sepsis-associated delirium
2012
Introduction Sepsis-associated delirium (SAD) increases morbidity in septic patients and, therefore, factors contributing to SAD should be further characterized. One possible mechanism might be the impairment of cerebrovascular autoregulation (AR) by sepsis, leading to cerebral hypo- or hyperperfusion in these haemodynamically unstable patients. Therefore, the present study investigates the relationship between the incidence of SAD and the status of AR during sepsis. Methods Cerebral blood flow velocity was measured using transcranial Doppler sonography and was correlated with the invasive arterial blood pressure curve to calculate the index of AR Mx (Mx>0.3 indicates impaired AR). Mx was m…
Percutaneous angioplasty and stenting of left subclavian artery lesions for the treatment of patients with concomitant vertebral and coronary subclav…
2006
bjective: To evaluate the efficacy of subclavian stenosis percutaneous transfemoral angioplasty (PTA)-treatment in patients with intermittent or complete subclavian steal syndrome (SSS), and coronary-subclavian steal syndrome (C-SSS) after left internal mammary artery-interventricular anterior artery (LIMA-IVA) by pass graft. Methods: We studied 42 patients with coronary subclavian steal syndrome subdivided in two groups; the first group consisted of 15 patients who presented an intermittent vertebral-subclavian steal, while the second group consisted of 27 patients with a complete vertebral-subclavian steal. All patients were treated with angioplasty and stent application and were followed…
Effects of Cortical Spreading Depression on Cortical Blood Flow, Impedance, DC Potential, and Infarct Size in a Rat Venous Infarct Model
2000
A cortical venous infarction model has been evaluated as to the degree of regional flow reduction and by studying effects of cortical spreading depression (CSD). Two adjacent cortical veins were occluded photochemically with rose bengal and fiberoptic illumination. Seven rats served to demonstrate effects on regional cortical blood flow using laser Doppler scanning. In 36 rats local CBF, DC potential, and brain tissue impedance were measured continuously for 75 min after vein occlusion. No, 3, or 10 CSD waves were induced by potassium chloride injection during the initial 75 min. Rats were compared for spontaneous CSDs; baseline local CBF, CBF, and impedance response to CSD; and infarct vol…
Tissue optical perfusion pressure: a simplified, more reliable, and faster assessment of pedal microcirculation in peripheral artery disease
2020
Oscillometry is an alternative to continuous-wave Doppler (cw-Doppler) to determine peripheral artery disease (PAD) severity using the ankle-brachial index (ABI). cw-Doppler ABI differentiates systolic pressure of ATP and ADP where either one of both values in most patients is higher (high) and the other value is lower (low). In contrast, oscillometric ABI measures the strongest signal and hence misses the lower value. Both do not take pedal perfusion into consideration. Simultaneous determination of tissue microperfusion cares for pedal PAD. ABI was determined by cw-Doppler and oscillometry. Tissue optical perfusion pressure (TOPP) was taken from the first toe using photoplethysmography. 3…
Discrepancy between power-Doppler voiding urosonography and voiding cystourethrography is not relevant for the management of primary vesicoureteric r…
2006
The aim of this study was to assess if discrepancy between power-Doppler voiding urosonography (PD-VUS) and voiding cystourethrography (VCUG) affects the management of patients with primary vesicoureteric reflux (VUR).Fifty-six children with suspected or known VUR were assessed both by PD-VUS and VCUG. Two independent observers, both pediatric surgeons, each aware of the results of only one imaging modality, advised children's management according to present care standards. Agreement between diagnostic findings at the two imaging modalities and between therapeutic advice of the two observers was evaluated using kappa statistics.PD-VUS diagnosed VUR in 3 patients and 6 ureteral units more th…