PURPOSE: To investigate retrospectively the use of catheter-based intraaccess blood flow measurements as an adjunct to physical examination and fistulography in hemodialysis access interventions. MATERIALS AND METHODS: Among 1,540 dialysis interventions performed at a single institution in a 2.5-year period, 104 qualifying catheter-based flow measurements were made in 70 mature ...

OBJECTIVES: Left ventricular assist devices (LVADs) have become an important treatment option for heart failure patients. However, altered blood flow patterns are suspected to affect perfusion in the aorta or cause structural changes to the aortic root, leading to regurgitation and valve dysfunction or thrombus formation. The purpose of this ...

Trifurcated arch grafts (3-branch grafts) are now being used to repair the thoracic aorta in addition to conventional arch grafts (4-branch grafts). The anatomical shape of the 3-branch graft is different from the original vessel, so it is necessary for clinical application to evaluate blood flow distribution in the graft ...

BACKGROUND: Intracranial aneurysm flow diverting stents are a new endovascular treatment option for wide neck and large/giant aneurysms. Since August 2011, our center has integrated flow diverting stents into aneurysm treatment management. To further understand the effects of flow diverting stents, we developed the intracranial stent flow mapping program, which ...

Type B aortic dissection can be acutely complicated by rapid expansion, rupture, and malperfusion syndromes. Short-term adverse outcomes are associated with failure of the false lumen to thrombose. The reasons behind false lumen patency are poorly understood, and the objective of this pilot study was to use computational fluid dynamics ...

Studies have reported a correlation between blood flow dynamics in the cardiac cycle and vascular diseases, but research to analyze the dynamic changes of flow in cerebral aneurysms is limited. This quantitative study investigates the temporal changes in flow during a cardiac cycle (flow waveform) in different regions of aneurysms ...

Numerical simulations are performed on patient-specific basilar aneurysms that are treated with shape memory polymer (SMP) foam. In order to assess the post-treatment hemodynamics, two modeling approaches are employed. In the first, the foam geometry is obtained from a micro-CT scan and the pulsatile blood flow within the foam is ...

The development of an engineering transitional turbulence model and its subsequent evaluation and validation for some diseased cardiovascular flows have been suggestive of its likely utility in normal aortas. The existence of experimental data from human aortas, acquired in the early 1970s with catheter-mounted hot film velocimeters, provided the opportunity ...

This study experimentally investigated the instability of flow impingement in a cerebral aneurysm, which was speculated to promote the degradation of aneurysmal wall. A patient-specific, full-scale and elastic-wall replica of cerebral artery was fabricated from transparent silicone rubber. The geometry of the aneurysm corresponded to that found at 9 days ...

The occlusional performance of sole endoluminal stenting of intracranial aneurysms is controversially discussed in the literature. Simulation of blood flow has been studied to shed light on possible causal attributions. The outcome, however, largely depends on the numerical method and various free parameters. The present study is therefore conducted to ...

BACKGROUND: Ascending aortic aneurysm is a life threatening conditions leading to surgery in many cases. Demonstrating risk factors for this disease is essential for development of screening strategies for high-risk populations. Blood group although described as a potential risk factor for abdominal aortic aneurysm, has not been addressed in patients ...

Although coil embolization is one of the most effective treatments for intracranial aneurysms (ICAs), the procedure is often unsuccessful. For example, an ICA may persist after coil embolization if deployed coils fail to block the flow of blood into the aneurysm. Unfortunately, the specific flow changes that are effected by ...

BACKGROUND AND PURPOSE:Flow-diverter stents modify intra-aneurysmal blood flow and induce the progressive thrombosis of intracranial aneurysms followed by stable vascular reconstruction. The aim of this study was to report a new method for the appraisal of intracranial blood flow from DSA performed during endovascular treatment procedures.MATERIALS AND METHODS:A cohort of ...

Computer-based simulation is necessary to clarify the hemodynamics in brain aneurysm. Specifically for endovascular treatments, the effects of indwelling intravascular devices on blood stream need to be considered. The most recent technology used for cerebral aneurysm treatment is related to the use of flow diverters to reduce the amount of ...

An in vitro dynamics set-up of the flow in a compliant abdominal aortic aneurysm (AAA) model with an anterior posterior asymmetry, aorto-iliac bifurcation, and physiological inlet flow rate and outlet pressure waveforms was developed. The aims were first to show that the structural mechanical behavior of the used material to ...

Earlier studies have indicated an association between blood group non-O and atherosclerosis related vascular diseases. Abdominal aortic aneurysm (AAA) is traditionally regarded as a consequence of atherosclerosis. The aim of the present study was to investigate the association between ABO blood groups and AAA with special regard to a relation ...

The flow in a cerebral aneurysm on the Anterior Communicating Artery is simulated based on patient medical imaging. The sensitivity of the flow pattern is assessed with respect to variation of outflow split and geometric parameters. A comparison is made between the results from unsteady pulsatile computations and steady-state computations. ...

PURPOSE: Erythropoiesis-stimulating agents can reduce red blood cell transfusion rates in patients developing anemia while receiving chemotherapy. We investigated potential cost savings from reduced transfusion rates in patients starting darbepoetin alfa (DA) at higher versus lower hemoglobin (Hb) levels. METHODS: Two systematic literature reviews were performed: transfusion outcomes in patients ...

In response to volume expansion, locally generated dopamine decreases proximal tubule reabsorption by reducing both Na/H-exchanger 3 (NHE3) and Na-K-ATPase activity. We have previously demonstrated that mouse proximal tubules in vitro respond to changes in luminal flow with proportional changes in Na(+) and HCO(3)(-) reabsorption and have suggested that this ...

Background:Dopamine is one of the most frequently used inotropic drugs in neonatal intensive care units; however, it apparently does not improve outcomes in premature infants. Given that the ultimate aim of cardiovascular management is to stabilize and maintain organ perfusion, an understanding of dopamine's effects on organ blood flow will ...

Aim:  Despite widespread use, effects of volume boluses and dopamine in hypotensive newborn infants remain controversial. We aimed to elucidate if hypovolemia alone impairs cerebral autoregulation (CA), and if dopamine affects cerebral vasculature. Methods:  In 12 piglets cerebral perfusion (laser-Doppler flux) and oxygenation (near-infrared spectroscopy) were examined during dopamine (20-50 ...

To characterize total retinal blood flow in a group of healthy subjects. Included in this study were 64 healthy volunteers. Retinal venous diameters were measured using a dynamic vessel analyzer. Retinal blood velocities were measured using bidirectional laser Doppler velocimetry. All vessels with a diameter of >60 μm entering the ...

This paper investigates the main characteristics of the magneto-hemodynamic (MHD) response for application as a biomarker of vascular blood flow. The induced surface potential changes of a volunteer exposed to a 3 T static B0 field of a magnetic resonance imaging (MRI) magnet were measured over time at multiple locations by ...

Systemic-pulmonary collateral (SPC) flow occurs commonly in single ventricle patients after superior cavo-pulmonary connection, with unclear clinical significance. We sought to evaluate the association between SPC flow and acute post-Fontan clinical outcomes using a novel method of quantifying SPC flow by cardiac magnetic resonance (CMR) imaging. All patients who had ...

AIM: We designed this study to investigate if immunoglobuline G-Pertussis toxin (IgG-PT) against Bordetella pertussis in umbilical cord blood can reliably be determined in dried blood spots on filter paper (Guthrie) cards. PATIENTS AND METHODS: We prospectively included 129 mothers and their newborns born in a general hospital in the ...

Intraoperative transfusion decisions generally are guided by blood loss estimation and periodic invasive hemoglobin measurement. Continuous hemoglobin measurement by pulse cooximetry (pulse hemoglobin; Rainbow® SET Pulse CO-Oximeter, Masimo Corporation, Irvine, CA) has good agreement with laboratory hemoglobin in healthy volunteers and could aid transfusion decision-making. Because intraoperative physiology may alter ...

BACKGROUND: New insights into potential adverse effects of banked blood and improved infectious surveillance have led to questions regarding the utility of preoperative autologous blood donation. METHODS: A retrospective chart review of 153 patients undergoing abdominal free flap breast reconstruction was performed with the goal of determining the effect of ...

PURPOSE: The aim of this study was to investigate the value of commonly examined laboratory measurements, including ammonia and lactate, in predicting neurologic outcome of out-of-hospital cardiac arrest (OHCA) patients treated with therapeutic hypothermia (TH). METHODS: This was a retrospective cohort study of patients with a return of spontaneous circulation ...

Neurocognition is impaired in chronic fatigue syndrome (CFS). We propose that the impairment relates to postural cerebral hemodynamics. Twenty-five CFS subjects and twenty control subjects underwent incremental upright tilt at 0, 15, 30, 45, 60, and 75° with continuous measurement of arterial blood pressure and cerebral blood flow velocity (CBFV). ...

The objective of this study was to determine whether changes in carboxyhaemoglobin (COHb) saturation following carbon monoxide (CO) rebreathing can be accurately detected by pulse CO-oximetry in order to determine blood volume. Noninvasive measurements of carboxyhaemoglobin saturation (SpCO) were continuously monitored by pulse CO-oximetry before, during and following 2 min ...

The Hall effect has been applied to electrolyte flow measurement. It has been proven that Hall voltage does not depend on electrolyte concentration; however, there is a linear relationship between Hall voltage and flow velocity. Obtained results for electrolyte allow us to suppose that Hall effect can be used to ...

The success of percutaneous interventions on stenotic hemodialysis prosthetic grafts and autogenous fistulas is assessed by comparing vessel diameter before and after treatment. These changes do not correlate with gold standard access blood flow (ABF) measurements obtained during hemodialysis. The AngioFlow (AngioDynamics, Inc, Queensbury, New York) calculates real-time blood flow ...

BackgroundPerfusion magnetic resonance imaging (MRI) is increasingly used in the evaluation of brain tumors. Relative cerebral blood volume (rCBV) is usually obtained by dynamic susceptibility contrast (DSC) MRI using normal appearing white matter as reference region. The emerging perfusion technique arterial spin labelling (ASL) presently provides measurement only of cerebral ...

Transcranial Doppler ultrasonography is the most commonly used method of cerebrovascular blood flow velocity measurement, but it is subject to certain technical and anatomic limitations. The Doppler velocity guidewire measures blood flow velocity within any vessel during cerebral angiography, overcoming these limitations. We report the first use of this guidewire ...

There is growing evidence supporting the role of inflammation in early brain injury and cerebral vasospasm following subarachnoid hemorrhage (SAH). Matrix metalloproteinases (MMPs) are released by inflammatory cells and can mediate early brain injury via disruption of the extracellular matrix and mediate vasospasm by cleaving endothelin-1 into vasoactive fragments. We ...

RATIONALE AND OBJECTIVES: To assess the effect of measurement time on blood flow (BF), blood volume (BV), and k-trans-values (flow extraction product) in patients undergoing volume perfusion computed tomography (VPCT) for lung cancer. MATERIALS AND METHODS: This prospective study was approved by our local Research Ethics Committee and informed consent was ...

Each year, more than 4 million patients receive a blood transfusion in the United States to control symptoms associated with anemia, coagulopathy, thrombocytopenia, or some combination thereof. In each of these cases, the physician and the patient must weigh the potential benefits of the transfusion along with the associated risks. ...

In 2005, The Joint Commission set about assessing the need for performance measures associated with the provision of blood products. Through a rigorous process, seven patient blood management performance measures were created. These measures incorporated a measure requiring transfusion consent; three measures requiring the combination of a laboratory value and ...

PURPOSE: To investigate blood flow and transit time measurement, using the pseudo-random arterial modulation (PRAM). MATERIALS AND METHODS: PRAM is based on a pseudo-random sequence of inversions and noninversions of the arterial blood at a labeling plane inferior to the imaging plane. To accomplish this, a pseudo-continuous tagging is used ...

Purpose:To determine whether flow velocity can be measured by using projection data from computed tomographic (CT) scans obtained during contrast material injection in a phantom model.Materials and Methods:The authors constructed a 12.7-mm-diameter single-channel flow phantom with constant water flow velocity settings of 25.3, 43.9, and 70.5 cm/sec. For each flow ...

WT1 levels may be a useful predictor of leukemia free survival (LFS) following treatment of acute myeloid leukemia (AML). We report a retrospective study in which levels of WT1 expression from patients with de novo AML were measured from bone marrow and peripheral blood at diagnosis, post-induction, post-consolidation and relapse. ...

Background:Monitoring hemoglobin levels in the operating room currently requires repeated blood draws, several steps, and a variable time delay to receive results. Consequently, blood transfusion management decisions may be delayed or made before hemoglobin results become available. The ability to measure hemoglobin continuously and noninvasively may enable a more rapid ...

Purpose:  To assess the agreement among three masked examiners on central retinal artery (CRA) and ophthalmic artery (OA) blood flow velocity measurements performed with colour Doppler imaging (CDI) in healthy volunteers. Methods:  The study included 30 eyes of 15 healthy volunteers. Prior to the study, all examiners underwent intensive CDI ...

Abstract Objetive: We studied intrauterine-growth-restricted (IUGR) fetuses with absent or reversed umbilical artery end-diastolic flow velocity (EDF) in order to evaluate the benefit of antenatal steroid therapy. Perinatal outcomes after betamethasone were evaluated where end diastolic flow returned (group I), compared with data from fetuses with persistent absent-reverse end diastolic ...

The primary objective of this investigation was to quantitatively identify which training variables result in the greatest strength and hypertrophy outcomes with lower body low intensity training with blood flow restriction (LI-BFR). Searches were performed for published studies with certain criteria. First, the primary focus of the study must have ...

We simultaneously measured respiratory, cerebrovascular and cardiovascular responses to 10-min of isoxic hypoxia at three constant CO(2) tensions in 15 subjects. We observed four response patterns, some novel, for ventilation, middle cerebral artery blood flow velocity, heart rate and mean arterial blood pressure. The occurrence of the response patterns was ...

The development of atherosclerosis has been shown to correlate with regions of low wall shear stress and seemingly reduced mass transport. The local tortuosity of the arteries and local secondary flow oscillation also seem to be negatively correlated with the local occurrence of the disease. However there is currently no ...

The radiocephalic arteriovenous fistula remains the method of choice for haemodialysis access. In order to assess their suitability for fistula formation, the radial arteries and cephalic veins were examined preoperatively by ultrasound colour flow scanner in conjunction with a pulse-generated run-off system. Intraoperative blood flow was measured after construction of ...

The degree of inflammation is the keystone of therapy management in rheumatoid arthritis and other arthritides. The assessment of synovial perfusion using power Doppler ultrasound is an important point in the quantification of the joint inflammation but it is limited by the subjectivity of the vascularization grading and incapacity to ...

Quantitative arterial spin labeling (ASL) estimates of cerebral blood flow (CBF) during oxygen inhalation are important in several contexts, including functional experiments calibrated with hyperoxia and studies investigating the effect of hyperoxia on regional CBF. However, ASL measurements of CBF during hyperoxia are confounded by the reduction in the longitudinal ...