Search results for "HEMODYNAMICS"
showing 10 items of 511 documents
Ticlopidine in the Treatment of Multiple Atherosclerotic Arteriopathy: a Strain Gauge Plethysmography and Döppler Spectrum Analysis Evaluation
1987
The effect of ticlopidine was compared with flunarizine in patients with iliac–femoral and / or femoral–popliteal arteriosclerotic arteriopathy accompanied by lesions of the cervical arteries of no haemodynamic significance. In the lower limbs, plethysmography (strain gauge measurements) and Döppler ultrasonography integrated by spectral analysis of the cervical arteries showed qualitative and quantitative improvements of the regional haematic flow. Side-effects were negligible which suggests that ticlopidine is useful in the treatment of multiple arteriosclerotic arteriopathy.
Impact of Aortic Stenosis on Myofiber Stress: Translational Application of Left Ventricle-Aortic Coupling Simulation
2020
The severity of aortic stenosis (AS) has traditionally been graded by measuring hemodynamic parameters of transvalvular pressure gradient, ejection jet velocity, or estimating valve orifice area. Recent research has highlighted limitations of these criteria at effectively grading AS in presence of left ventricle (LV) dysfunction. We hypothesized that simulations coupling the aorta and LV could provide meaningful insight into myocardial biomechanical derangements that accompany AS. A realistic finite element model of the human heart with a coupled lumped-parameter circulatory system was used to simulate AS. Finite element analysis was performed with Abaqus FEA. An anisotropic hyperelastic mo…
Coronary venous therapy to improve microvascular dysfunction.
2021
The coronary circulation is a complex system in which vascular resistances are determined by an interplay of forces in at least three compartments: the epicardial, the microvascular, and the venous district. Cardiologists, and particularly interventional cardiologists, normallly place the focus of their attention on diseases of the epicardial coronary circulation as possible causes of coronary syndromes and neglect the importance of the other two compartments of coronary circulation. The study of the coronary microcirculation, an increasingly recognized source of ischemia, has long been disregarded, but is witnessing a revival since the (re-)introduction of diagnostic tools in the better eq…
Causal linear parametric model for baroreflex gain assessment in patients with recent myocardial infarction
2001
Spectral and cross-spectral analysis of R-R interval and systolic arterial pressure (SAP) spontaneous fluctuations have been proposed for noninvasive evaluation of baroreflex sensitivity (BRS). However, results are not in good agreement with clinical measurements. In this study, a bivariate parametric autoregressive model with exogenous input (ARXAR model), able to divide the R-R variability into SAP-related and -unrelated parts, was used to quantify the gain (αARXAR) of the baroreflex regulatory mechanism. For performance assessing, two traditional noninvasive methods based on frequency domain analysis [spectral, baroreflex gain by autogressive model (αAR); cross-spectral, baroreflex gain…
Low target birth weight or growth retardation? Umbilical Doppler flow velocity waveforms and histometric analysis of fetoplacental vascular tree
1993
Objective: The placental vascular architecture of small-for-gestatonal-age fetuses seems to have an impact on the flow patterns in the umbilical arteries. Study Design: Blood flow velocity waveforms of the umbilical arteries were measured by Doppler ultrasonography in nine small-for-gestational-age fetuses with elevated systolic/diastolic ratios of the umbilical arteries, seven small-for-gestational-age fetuses with normal flow patterns, and 14 appropriate-for-gestational-age fetuses with normal flow patterns. After delivery histomorphometric placental investigations were performed. Results: Reduced end-diastolic flow velocities were significantly associated with both a reduction of vascula…
Surgical treatment of chronic thromboembolic pulmonary hypertension
1999
Background: Chronic thromboembolic pulmonary artery obstruction from unresolved pulmonary emboli is characterized by persistent elevation of pulmonary vascular resistance and progressive right heart dysfunction and failure. The diagnosis of chronic thromboembolic pulmonary hypertension is difficult and often missed. Medical therapy is ineffective in these patients. The prognosis is poor and depends on the degree of pulmonary hypertension. Pulmonary thromboendarterectomy has proven to be an effective and potentially curative surgical therapy for this clinical entity although less than 1000 cases have been reported in the surgical literature. Methods: The current principles of diagnosis, pati…
Septic cardiomyopathy: evidence for a reduced force-generating capacity of human atrial myocardium in acute infective endocarditis
2017
AbstractBackground:This study analyzes the myocardial force-generating capacity in infective endocarditis (IE) using an experimental model of isolated human atrial myocardium. In vivo, it is difficult to decide whether or not alterations in myocardial contractile behavior are due to secondary effects associated with infection such as an altered heart rate, alterations of preload and afterload resulting from valvular defects, and altered humoral processes. Our in vitro model using isolated human myocardium, in contrast, guarantees exactly defined experimental conditions with respect to preload, afterload, and contraction frequency, thus not only preventing confounding by in vivo determinants…
The "Renocentric Theory" of Renal Resistive Index: Is It Time for a Copernican Revolution?
2020
Ultrasound (US) with duplex Doppler scanning has spread to the capillary level, becoming an irreplaceable tool in daily clinical practice thanks to its characteristics: low cost, repeatability, and noninvasiveness. Moreover, US has become over time more sensitive and accurate; it can be considered an extension of the clinician’s hand. For this reason, it currently represents the ideal tool for first-level diagnostic use in several fields, and is the simplest and most flexible instrument for obtaining morphological and functional information on different organs, including the kidneys. In this issue of The Journal , Gigante, et al 1 propose to assess renal involvement in patients with systemi…
An Exploratory Look at Bicuspid Aortic Valve (Bav) Aortopathy: Focus on Molecular and Cellular Mechanisms
2019
Bicuspid aortic valve (BAV) is the most common congenital heart malformation. BAV patients are at increased risk for aortic valve disease (stenosis/regurgitation), infective endocarditis, thrombi formation and, in particular, aortic dilatation, aneurysm and dissection. This review aims at exploring the possible interplay among genetics, extracellular matrix remodeling, abnormal signaling pathways, oxidative stress and inflammation in contributing to BAV-associated aortopathy (BAV-A-A). Novel circulating biomarkers have been proposed as diagnostic tools able to improve risk stratification in BAV-A-A. However, to date, the precise molecular and cellular mechanisms that lead to BAV-A-A remain …
Hemodynamic Monitoring in Patients With Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis
2020
Aneurysmal subarachnoid hemorrhage (aSAH) often causes cardiopulmonary dysfunction. Therapeutic strategies can be guided by standard (invasive arterial/central venous pressure measurements, fluid balance assessment), and/or advanced (pulse index continuous cardiac output, pulse dye densitometry, pulmonary artery catheterization) hemodynamic monitoring. We conducted a systematic review and meta-analysis of the literature to determine whether standard compared with advanced hemodynamic monitoring can improve patient management and clinical outcomes after aSAH. A literature search was performed for articles published between January 1, 2000 and January 1, 2019. Studies involving aSAH patients …