First-generation prosthetic heart valves commonly caused sufficient red blood cell (RBC) injury to induce hemolytic anemia. Although multiple studies have shown that new-generation valves are not associated with anemia, the extent to which these valves are injurious to RBCs is not known, because RBC survival not has not been measured ...

BACKGROUND AND AIM OF THE STUDY: Native pulmonary valve leaflets (PVL) are exposed to lower pressures compared to aortic valve leaflets. Knowledge of the biology of PVL exposed to aortic pressures is limited. Hence, the study's aim was to investigate the biological properties of PVL subjected to normal aortic pressures. ...

In previous studies, we investigated the cavitation phenomenon in a mechanical heart valve using an electro-hydraulic total artificial heart. With this system, a 50% glycerin solution kept at 37 degrees C was used as the working fluid. We reported that most of the cavitation bubbles were observed near the valve ...

This study compares the implantation characteristics and the hemodynamic performance of the new Carpentier-Edwards Perimount Magna (CEPM) xenograft with those of the standard Perimount (CEPS) valve in the aortic position. Eighty consecutive patients surviving an aortic valve replacement with either the CEPS valve (n=40) or the CEPM prosthesis (n=40) in ...

OBJECTIVE: New pericardial aortic bioprostheses (3F Therapeutics and temporarily stented autologous pericardial valve prosthesis) were developed recently. These valves are designed with commissures connected to the aortic wall at only three single points (single point attached commissures (SPAC)). The aim of this study was to investigate the forces acting on ...

BACKGROUND: Chronic mitral regurgitation imparts a volume load on the left atrium (LA). Because this chamber may dilate asymmetrically, changes in left atrial size may be underestimated using standard two-dimensional or M-mode techniques. METHODS: The effect of lisinopril therapy in the setting of chronic organic mitral regurgitation on LA dimension ...

PURPOSE: To investigate the pressure gradient and degree of flow reduction associated with embolus protection filters for carotid stenting in an in vitro experiment. METHODS: Three filter devices with a perforated membrane design and one wire mesh type filter were tested. At a pressure of 70 mmHg, the flow reduction ...

BACKGROUND AND AIM OF THE STUDY: Cardiovascular risk factors are believed to play a role in the pathogenesis of aortic valve disease. In the present study the hypothesis was proposed that elevated pressure would cause a change in the expression of prototypical pro-inflammatory genes. Hence, the expression of MCP-1, osteopontin ...

BACKGROUND: The prosthesis used for aortic valve replacement in patients with small aortic root can be too small in relation to body size, thus showing high transvalvular gradients at rest and/or under stress conditions. This study was carried out to evaluate rest and Dobutamine stress echocardiography (DSE) hemodynamic response of ...

Does the opening pressure of hydrostatic shunts influence the clinical outcome for patients suffering from idiopathic normal-pressure hydrocephalus (NPH)? Between September 1997 and January 2003, 123 patients with idiopathic NPH were surgically treated by implanting a hydrostatic shunt at the Departments of Neurosurgery of the Unfallkrankenhaus Berlin and the University ...

Mitral inflow filling pattern usually consists of 2 forward flow velocities in sinus rhythm: early rapid filling (E) and late filling with atrial contraction (A). However, additional mid-diastolic flow velocity may be present resulting in triphasic mitral inflow filling pattern. When mitral inflow is triphasic, mitral annulus velocity recorded by ...

A better course of the disease after implantation of a low-pressure valve in patients with idiopathic normal pressure hydrocephalus normally comes at the cost of a distinctly higher rate of overdrainage. Can combining an adjustable valve with a gravity unit produce optimization of treatment results? In a prospective observation of ...

The early mitral filling velocity (E)/early diastolic mitral annular velocity (E') ratio is increasingly being used as a simplified approach to estimate left ventricular (LV) filling pressure. The validity of applying this Doppler parameter to patients with severe mitral regurgitation is unknown. We retrospectively identified 20 patients in sinus rhythm ...

The purpose of this study was to establish a method for estimating mechanical in vitro heart valve cavitation in an electro-hydraulic total artificial heart (EHTAH). The variations in the left driving pressure (LDP) slope of the EHTAH were used as an index of the cavitation intensity. The LDP slope was ...

OBJECTIVE: Improved clinical outcomes after implantation of a low pressure valve in patients with idiopathic normal-pressure hydrocephalus is usually achieved at the expense of a higher overdrainage rate. Can an adjustable valve with a gravitational unit provide optimal results? METHOD: In a prospective clinical outcome study conducted in the Unfallkrankenhaus ...

BACKGROUND AND AIM OF THE STUDY: The study aim was to compare the effects of dobutamine stress and exercise on prosthetic mitral valve hemodynamics. METHODS: Twenty-three patients who had recently (3 +/- 1 months) undergone mechanical mitral valve implantation were studied. Hemodynamic variables, two-dimensional echocardiographic and Doppler mitral/aortic flows were ...

A method has been developed for applying water pressure to a closed mitral valve on the side corresponding to the heart's left ventricle. The pressure is increased until fluid flows through the valve, i.e. until it fails. A specific dissection technique has been developed to produce a specimen with two ...

AIM: The right atrium pressure load is increased in pulmonary stenosis (PS) that is a congenital anomaly and this changes the electrophysiological characteristics of the atria. However, there is not enough data on the issue of P wave dispersion (PWD) in PS. METHODS: Forty-two patients diagnosed as having valvular PS ...

OBJECTIVE: We sought to assess the hemodynamic significance of mitral stenosis (MS) using a new index. METHODS: We studied 88 patients with MS. Maximum separation of mitral leaflet tips in diastole in parasternal long-axis and apical 4-chamber views was measured. These two parameters were averaged to yield the mitral leaflet ...

INTRODUCTIONThis protocol describes a method for constant-flow microinjection using the Pneumatic PicoPump (World Precision Instruments). This type of system is very simple and can be assembled on a relatively low budget. In this method, a constant flow of sample is delivered from the tip of the pipette, and the amount ...

BACKGROUND: In aortic stenosis, natriuretic peptides have recently been shown to correlate with ventricular function and to predict symptom-free survival and outcome. Elevated big endothelin-1 (bigET) is associated with poor prognosis in chronic heart failure, but little is known about its role in severe aortic stenosis. METHODS: In 61 patients ...

OBJECTIVE: To evaluate the differences between non-circular shape of FloWatch-PAB and conventional pulmonary artery (PA) banding. METHODS: Geometrical analysis. Conventional banding and FloWatch-PAB perimeters were plotted against cross-sections. Computational fluid dynamics (CFD) model. CFD compared non-circular FloWatch-PAB cross-sections with conventional banding regarding pressure gradients. Clinical data. Seven children, median age ...

OBJECTIVE: This study investigated the change in new diastolic indexes in patients with uremia who undergo regular hemodialysis (H/D). METHODS: We studied 81 patients with uremia (41 men and 40 women) receiving regular H/D. All patients were in sinus rhythm before H/D. They had normal left ventricular systolic performance without ...

AIM: To assess the effect of short-term pressure overload on left atrial (LA) mechanical function in pre-eclampsia. METHODS: Twenty women with pre-eclampsia and 17 age-matched healthy pregnant women were included. LA volumes were measured echocardiographically at the time of mitral valve opening (Vmax), onset of atrial systole (p-wave at the ...

In presence of aortic stenosis, a jet is produced downstream of the aortic valve annulus during systole. The vena contracta corresponds to the location where the cross-sectional area of the flow jet is minimal. The maximal transvalvular pressure gradient (TPG(max)) is the difference between the static pressure in the left ...

The increased interest in HPLC at elevated pressures, beyond the conventional 6000 psi (400 bar), has created a demand for injection systems capable of withstanding pressures beyond the 20,000 psi (1380 bar). To achieve high-resolution separations, an appropriate length of columns packed with sub 2-microm packing materials, a 30,000-40,000 psi ...

OBJECTIVE: We sought to determine the safety, success and accuracy of using a pressure wire through a 4 French catheter with single arterial access to determine the aortic valve area in patients with aortic stenosis. BACKGROUND: Conventional invasive techniques to assess aortic stenosis are associated with procedural risks secondary to ...

BACKGROUND AND AIM OF THE STUDY: The study aim was to compare the hemodynamic profiles of the aortic standard porcine Carpentier-Edwards (C-E) and Ultracor (tilting-disc) valve using exercise and dobutamine stress. METHODS: A total of 36 patients was examined, 18 for each valve type. When analyzing the data, valve types ...

Transmitral Doppler echocardiography is the preferred method of noninvasive diastolic function assessment. Correlations between catheterization-based measures of isovolumic relaxation (IVR) and transmitral, early rapid filling (Doppler E-wave)-derived parameters have been observed, but no model-based, causal explanation has been offered. IVR has also been characterized in terms of its duration as ...

The biological response of valves to mechanical forces is not well understood. The aim of this study was to design a pulsatile system to enable the ex vivo study of aortic valves when subjected to various hemodynamic conditions. A bioreactor was designed to subject porcine aortic valves to physiological and ...

The Ahmed glaucoma valve (AGV) is a popular glaucoma drainage device, allowing maintenance of normal intraocular pressure in patients with reduced trabecular outflow facility. The uniquely attractive feature of the AGV, in contrast to other available drainage devices, is its variable resistance in response to changes in flow rate. As ...

BACKGROUND: The comparative impact of percutaneous alcohol septal reduction (ASR) and surgical myectomy on the left ventricular outflow tract (LVOT) area in patients with obstructive hypertrophic cardiomyopathy (HC) is not well defined. Real-time 3-dimensional echocardiography (RT3DE) provides accurate information about the LVOT geometry and shape. We aimed to analyze the ...

OBJECTIVE: Preserving aortic valve cusps during operations for aortic root pathology theoretically offers several advantages over alternative prosthetic valve-bearing conduits. Functional properties of different valve-sparing techniques under defined conditions are not well studied. METHODS: Fresh porcine aortic roots were investigated in a pulsatile flow simulator, either native root or after ...

Glycosaminoglycans (GAGs) are important structural and functional components in native aortic heart valves and in glutaraldehyde (Glut)-fixed bioprosthetic heart valves (BHVs). However, very little is known about the fate of GAGs within the extracellular matrix of BHVs and their contribution to BHV longevity. BHVs used in heart valve replacement surgery ...

Diagnosing constrictive pericarditis (CP) remains a clinical challenge. Ventricular interdependence and dissociation of intrathoracic and intracardiac pressures are hallmark features that are readily recognized by invasive and noninvasive hemodynamics. The Doppler echocardiographic signal from pulmonic valve regurgitation depends on the relationship between pulmonary artery (intrathoracic) and right ventricular (intracardiac) pressure. ...

Echocardiograms routinely sample pulmonary regurgitation signals from which it is possible to measure end diastolic gradients; these correlate with pulmonary artery diastolic pressures. We performed echocardiograms in 741 ambulatory adults with coronary artery disease who were recruited for the Heart and Soul Study. We compared indicators of cardiac status among ...

BACKGROUND: This study sought to investigate the relative load dependence of left atrial appendage (LAA) tissue Doppler velocities in patients with mitral stenosis after percutaneous mechanical mitral commissurotomy (PMMC). METHODS: LAA tissue Doppler velocities were obtained in 34 patients with mitral stenosis (20 with sinus rhythm and 14 with atrial ...

OBJECTIVE: It is widely accepted that both valve and cardiac functions are closely correlated. In order to investigate the relationship between the valve and cardiac functions, we developed a model of an isolated working heart with crystalloid perfusate in swine. We investigated the feasibility of this model to evaluate the ...

BACKGROUND: A "saddle-shaped" mitral annulus with an optimal ratio between annular height and commissural diameter may reduce leaflet and chordal stress and is purported to be conserved across mammalian species. Whether annuloplasty rings maintain this relationship is unknown. METHODS AND RESULTS: Twenty-three adult sheep underwent implantation of radiopaque markers on ...

It has been speculated that heart valve interstitial cells (VICs) maintain valvular tissue homeostasis through regulated extracellular matrix (primarily collagen) biosynthesis. VICs appear to be phenotypically plastic, inasmuch as they transdifferentiate into myofibroblasts during valve development, disease, and remodeling. Under normal physiological conditions, transvalvular pressures (TVPs) on the right and ...

BACKGROUND: Complete supraannular placement and smaller stent design allow the implantation of a Perimount Magna bioprosthesis with a larger inner diameter than that of a standard Perimount. This study compares the hemodynamic performance and the incidence of patient-prosthesis mismatch (PPM) of both prostheses. METHODS: 128 patients underwent aortic valve replacement, ...

OBJECTIVE: The ratio of early transmitral pulsed Doppler velocity (E) to colour M-mode Doppler flow propagation velocity (Vp) has been reported to be a good predictor of pulmonary capillary wedge pressure (PCWP) and left ventricular end-diastolic pressure (LVEDP). It is unknown whether E/Vp can be used to reflect the instantaneous ...

OBJECTIVE: To determine survival times in dogs with severe subvalvular aortic stenosis (SAS) treated by means of balloon valvuloplasty or with atenolol, a beta-adrenoceptor blocking drug. DESIGN: Prospective study. ANIMALS: 38 dogs < 24 months old with severe SAS (peak systolic pressure gradient > or = 80 mm Hg). PROCEDURE: ...

BACKGROUND AND AIM OF THE STUDY: A sudden pressure drop and recovery can induce cavitation in liquids. Mechanical heart valves (MHVs) generate such a pressure drop at closure, and cavitation generation around MHVs has been demonstrated many times. Cavitation is suspected as being a cause of blood and valve material ...

Testicular-epididymal hemodynamics is studied by ultrasonographic color velocity imaging (CVI) in patients with primary, uncomplicated inguinal hernias. This procedure allows more precision than any other known Doppler system in measuring hemodynamic parameters such as peak systolic and diastolic velocity, resistance index and pulsatility index. The results of the exploration of ...

Dynamic arterial and venous pressures (PA, PV) are used as the simplest tools to assess vascular access quality (VAQ). An increased PV over three consecutive dialyses is believed to indicate a stenosis, a rule devised for synthetic grafts (AVG) but not adequately validated for AV fistulas (AVF). In this study ...

A 78-year-old woman was admitted to our hospital due to chest oppressive sensation. Admission electrocardiography revealed ST-segment elevation in I, II, III, aV(F) and V(2-6) leads. Left ventriculography showed apical akinesis and basal hyperkinesis with a pressure gradient of 60 mmHg between the left ventricular apex and the base. Right ...

Mucopolysaccharidosis I (MPS I, alpha-l-iduronidase deficiency disease) is a heritable lysosomal storage disorder involving multiple organs, including the heart. Malfunction of the heart is also a major manifestation in the mouse model of MPS I, progressing in severity from 6 to 10 months (of a 1 year life span). In ...

BACKGROUND: Conventional Doppler measurements have limitations in the prediction of left atrial pressure (LAP) in patients with mitral valve disease (MVD), given the confounding effect of valve area, left ventricular (LV) relaxation, and stiffness. However, the time interval between the onset of early diastolic mitral inflow velocity (E) and annular ...

BACKGROUND: The ratio of peak to mean pressure decrease is a new measure of transaortic continuous waveform shape that could be useful for grading aortic stenosis. METHODS: We retrospectively analyzed echocardiograms in 163 patients with all grades of aortic stenosis as assessed by the continuity equation. RESULTS: The peak to ...