Search results for "velocity"
showing 10 items of 881 documents
Computational fluid dynamics of the ascending aorta before the onset of type A aortic dissection.
2016
We performed a pre-dissection computational fluid analysis of an ascending aortic aneurysm associated with unicuspid aortic valve. The analysis showed an abnormal helical flow pattern inside the aneurysm and an increased wall stress on the right postero-lateral wall of the ascending aorta. These values were largely higher than the theoretical cut-off for aortic wall dissection, their topographic distribution followed the intimal tear site as subsequently diagnosed by computed tomography scan and confirmed during the operation for dissection repair.
Anatomic and flow dynamic considerations for safe right axillary artery cannulation.
2013
Objectives Neuroprotection is of paramount interest in cardiac surgery. Right axillary artery cannulation is well established in aortic surgery because it significantly improves survival and outcome, but malperfusion of the right brain after direct cannulation has been reported. Anatomically, 4 vessel segments are potentially amenable for cannulation of the subclavian and axillary arteries. Clinical studies vary widely in dissection sites and cannulation techniques. We investigated critical flow dynamics in the right brain caused by arterial inflow after direct cannulation and specified cannulation positions that provide optimal cerebral perfusion. Methods Distances from the lateral margin …
Arterial stiffness in symptomatic smokers with normal lung function
2017
Chronic obstructive pulmonary disease (COPD) is associated with cardiovascular morbidity and mortality. Arterial stiffness and endothelial dysfunction index are validated surrogate cardiovascular markers and are increased in subjects with COPD. We tested whether increased arterial stiffness and endothelial dysfunction occur in symptomatic smokers with no evidence of bronchial obstruction. Clinical and lung functional assessments were conducted in smoker subjects with chronic respiratory symptoms and in COPD patients. Pulse wave velocity (PWV), aortic augmentation index (AIx) and reactive hyperaemia index (RHI) were measured to estimate the cardiovascular risk. 48 smokers (male n=37, female …
RELATIONSHIP BETWEEN SERUM URIC ACID AND AORTIC STIFFNESS IN UNTREATED HYPERTENSIVE SUBJECTS
2013
Recent studies have reported an association between serum uric acid (SUA) and reduced arterial elasticity. However, in these studies arterial elastic properties have been assessed chiefly by measuring brachial-ankle pulse wave velocity (PWV) or peripheral PWV and only sometimes by using aortic PWV. Moreover, the relationships between SUA and arterial stiffness have never been statistically adjusted for albuminuria. Furthermore, the studies exploring the influence of uric acid on aortic distensibility in subjects with arterial hypertension yielded conflicting results. The aim of our study was to evaluate the relationships between SUA and aortic stiffness in a group of essential hypertensive …
ASSOCIATION OF RENAL RESISTIVE INDEX WITH AORTIC PULSE WAVE VELOCITY IN HYPERTENSIVE PATIENTS.
2013
The assessment of renal hemodynamic parameters by duplex Doppler sonography has been used for many years as a diagnostic tool in the daily work-up of kidney diseases. Recent data suggest that these parameters, especially the intrarenal resistive index (RI) may be also associated with systemic vascular changes and with an enhanced cardiovascular risk. However, conflicting data exist in literature about the independent association of aortic stiffness with RI. The aim of this study was to evaluate the relationship between RI and arterial stiffness, assessed by aortic pulse wave velocity (PWV), in the hypertensive subjects consecutively attending our hypertension centre. We enrolled 264 subject…
Correlations between non ivasive renal index and markers of atherosclerosis in lupus patients
2014
Recent data suggest that renal hemodynamic parameters obtained by duplex Doppler sonography, especially the intrarenal resistive index (RI), may be associated with systemic vascular changes in some groups of patients. However, conflicting data exist about the relationship between aortic stiffness and RI in autoimmune disease, like systemic lupus erythematosus, characterized by high and early incidence of atherosclerotic disease. The aim of this study was to evaluate the relationship between RI and arterial stiffness, assessed by aortic pulse wave velocity (aPWV), and carotid atherosclerosis, evaluated by intimal medial thickness measurement (IMT) in patients with SLE. DESIGN: Cross-sectiona…
Early vascular aging in normotensive subjects with systemic lupus erythematous. Comparison with young hypertensive patients
2014
early vascular aging
RELATIONSHIP BETWEEN AORTIC PULSE WAVE VELOCITY AND RENAL RESISTIVE INDEX IN HYPERTENSIVE PATIENTS.
2013
INTRODUCTION: The assessment of renal hemodynamic parameters by duplex Doppler sonography has been used for many years as a diagnostic tool in the daily workup of kidney diseases. Recent data suggest that these parameters, especially the intrarenal resistive index (RI), may be also associated with systemic vascular changes and cardiovascular risk. However, conflicting data exist about the independent association of aortic stiffness with RI. AIM: The aim was to evaluate the relationship between RI and arterial stiffness, assessed by aortic pulse wave velocity (PWV), in the hypertensive subjects consecutively attending our hypertension centre. METHODS: We enrolled 264 subjects, aged between 3…
Vascular health assessment of the hypertensive patients (VASOTENS) Registry: rationale, design and methods of an international registry for ambulator…
2015
Ambulatory (A) blood pressure (BP), central BP and pulse wave velocity (PWV) are parameters recommended by hypertension guidelines for estimating BP control and vascular impairment. Recent advances in technology made available devices allowing combined non-invasive estimation of these parameters over the 24-h during ABP monitoring (ABPM). However, at present, there is limited evidence on the usefulness of such an approach for routine hypertension managementWe recently launched an investigator-initiated, international, multicenter, observational, prospective study with the following objectives: • The evaluation of non-invasive ambulatory blood pressure and arterial stiffness estimates (throu…
Expansions of the solutions of the confluent Heun equation in terms of the incomplete Beta and the Appell generalized hypergeometric functions
2015
We construct several expansions of the solutions of the confluent Heun equation in terms of the incomplete Beta functions and the Appell generalized hypergeometric functions of two variables of the first kind. The coefficients of different expansions obey four-, five-, or six-term recurrence relations that are reduced to ones involving less number of terms only in a few exceptional cases. The conditions for deriving finite-sum solutions via termination of the series are discussed.