Search results for "Flow velocity"
showing 10 items of 227 documents
Significance of resting and stimulated cerebral blood flow for predicting the risk of hemodynamic cerebral ischemia in a model of chronic hemodynamic…
2000
OBJECTIVE: It has been postulated that patients with a compromised cerebrovascular reserve capacity (RC), defined as cerebral blood flow (CBF) response to acetazolamide (ACZ) (by percent), are at higher risk for ischemic stroke. The value of CBF and RC for predicting the risk of hemodynamically induced impairment of cerebral function is examined. METHODS: Both common carotid arteries were occluded in 22 Wistar-Kyoto rats. Thirty-one days later, mean arterial blood pressure was reduced to 40 mm Hg for 30 minutes. Laser Doppler scanning of CBF at resting conditions and after intraperitoneal administration of ACZ (0.1 mg/g body weight) was performed 30 minutes and 28 days after occlusion as we…
Deep vein thrombus formation induced by flow reduction in mice is determined by venous side branches.
2013
Interaction between vascular wall abnormalities, inflammatory leukocytes, platelets, coagulation factors and hemorheology in the pathogenesis of deep vein thrombosis (DVT) is incompletely understood, requiring well defined animal models of human disease. METHODS AND RESULTS: We subjected male C57BL/6 mice to ligation of the inferior vena cava (IVC) as a flow reduction model to induce DVT. Thrombus size and weight were analyzed macroscopically and sonographically by B-mode, pulse wave (pw) Doppler and power Doppler imaging (PDI) using high frequency ultrasound. Thrombus size varied substantially between individual procedures and mice, irrespective of the flow reduction achieved by the ligatu…
Endovascular treatment options for complex abdominal aortic aneurysms
2015
Abstract Purpose To report short-term and midterm outcomes of endovascular aneurysm repair (EVAR) of complex aneurysms requiring revascularization of visceral arteries. Materials and Methods Prospective data were collected from patients deemed unsuitable for conventional EVAR and conventional surgery who were treated with different endovascular approaches according to the clinical presentation of the aneurysm. Custom-made fenestrated endovascular aneurysm repair (CM f-EVAR) was used in the elective setting, homemade fenestrated endovascular aneurysm repair (HM f-EVAR) or HM f-EVAR combined with chimney endovascular aneurysm repair (ch-EVAR) was used in the emergent setting in patients with …
Low-Frequency Electrical Stimulation Increases Muscle Strength and Improves Blood Supply in Patients With Chronic Heart Failure
2005
This study was designed to evaluate the effects of low-frequency electrical stimulation (LFES) on muscle strength and blood flow in patients with advanced chronic heart failure (CHF).Patients with CHF (n=15; age 56.5 +/- 5.2 years; New York Heart Association III - IV; ejection fraction 18.7 +/- 3.3%) were examined before and after 6 weeks of LFES (10 Hz) of the quadriceps and calf muscles of both legs (1 h/day, 7 days/week). Dynamometry was performed weekly to determine maximal muscle strength (F(max); N) and isokinetic peak torque (PT(max); Nm); blood flow velocity (BFV) was measured at baseline and after 6 weeks of LFES using pulsed-wave Doppler velocimetry of the right femoral artery. Si…
Detection of Left Ventricular Systolic Dysfunction in Cardiac Amyloidosis with Strain Rate Echocardiography .
2006
Background We examined the potential role of Doppler myocardial imaging including tissue velocity imaging, strain imaging, and strain rate imaging for detection of left ventricular systolic dysfunction in cardiac amyloidosis (CA) and determined the minimum dataset required to make the diagnosis. Methods and Results Doppler myocardial imaging was performed in 103 patients with amyloidosis (AL). Peak longitudinal systolic tissue velocity, systolic strain rate (sSR), and systolic strain (sS) were determined for 16 left ventricular segments. Radial and circumferential sSR and sS were also measured. Patients with increased left ventricular wall thickness were classified with advanced-CA, and the…
Mean velocity of the pulmonary artery estimated by cardiac magnetic resonance as an early prognostic predictor in heart failure.
2018
Background and objective: To identify early, non-invasive prognostic indicators in heart failure (HF), with and without associated pulmonary hypertension, by means of cardiac magnetic resonance, and oxidative stress and anti-inflammatory biomarkers such as Trolox (TM) (antioxidant status) and IL-10 (anti-inflammatory cytokine). Patients and methods: We prospectively included 70 patients admitted for new-onset HF. During index admission, mean velocity of the pulmonary artery (mvPA) was measured, and blood Trolox (TM) and IL-10 determined. The study sample was divided in two groups according to the optimal cut-off value for event prediction calculated by the ROC curve (mvPA = 8 cm/s), conside…
Impaired Cerebrovascular Autoregulation in Large Vessel Occlusive Stroke after Successful Mechanical Thrombectomy: A Prospective Cohort Study
2020
Abstract Introduction: Successful thrombectomy improves morbidity and mortality after stroke. The present prospective, observational cohort study investigated a potential correlation between the successful restoration of tissue perfusion by mechanical thrombectomy and intact cerebrovascular autoregulation (CA). Objective: Status of CA in patients with large vessel occlusive stroke after thrombectomy. Methods: After thrombectomy CA was measured using transcranial Doppler ultrasound. For this purpose a moving correlation index (Mxa) based on spontaneous arterial blood pressure fluctuations and corresponding cerebral blood flow velocity changes was calculated. CA impairment was defined by Mxa …
Arterial and Venous Cerebral Blood Flow Velocities and Their Correlation in Healthy Volunteers and Traumatic Brain Injury Patients.
2020
Few studies have explored the cerebral venous compartment or the correlation between venous and arterial cerebral blood flows. We aimed to correlate cerebral blood flow velocities in the arterial (middle cerebral artery) and venous (straight sinus) compartments in healthy volunteers and traumatic brain injury (TBI) patients. In addition, we determined the normative range of these parameters.A total of 122 healthy volunteers and 95 severe TBI patients of both sexes were included and stratified into 3 age groups as follows: group 1 (aged, 18 to 44 y); group 2 (aged, 45 to 64 y); group 3 (older than 65 y). Transcranial Doppler systolic cerebral blood flow velocity, diastolic cerebral blood flo…
Photoreactive flow changes in the posterior cerebral artery in control subjects and patients with occipital lobe infarction.
1995
Background and Purpose Photoreactive flow changes of the posterior cerebral artery (PCA) in control subjects and patients with unilateral occipital lobe infarction were investigated to study the hypothesis that occipital lobe infarction of varying extent leads to a reduced visually activated flow increase in the ipsilateral PCA. Methods Maximum mean flow velocity (MFV) of the PCA was investigated by transcranial Doppler sonography after photic stimulation of the retina. Results In 25 control subjects MFV was increased by 30.6±9.7%. In 13 patients with unilateral occipital lobe infarction the ipsilateral MFV increase was significantly lower than in control subjects. Nine patients with homon…
Color Doppler Imaging of the Ocular Ischemic Syndrome
1992
Purpose: This study describes hemodynamic characteristics of the ophthalmic, central retinal, and posterior ciliary arteries in 16 eyes of 11 patients with the ocular ischemic syndrome. Understanding the hemodynamic characteristics of the retrobulbar circulation may elucidate the natural history and pathophysiology of the ocular ischemic syndrome and perhaps form the basis for rational treatment of this condition. Methods: Color Doppler imaging, a procedure that permits rapid noninvasive imaging of the ophthalmic, central retinal, and posterior ciliary arteries, was used to quantitate peak systolic blood flow velocities and vascular resistance (pulsatility index) within these vessels in stu…