Determination of the mean pressure gradient in aortic stenosis by Doppler echocardiography

1985 ◽  
Vol 6 (12) ◽  
pp. 999-1005 ◽  
Author(s):  
Y. ZHANG ◽  
S. NITTER-HAUGE
Keyword(s):  
Aortic Stenosis ◽  
Pressure Gradient ◽  
Doppler Echocardiography ◽  
Mean Pressure ◽  
The Mean

scholarly journals Use and success evaluation of percutaneous aortic balloon valvuloplasty in different hemodynamic entities of severe aortic stenosis in the TAVR era

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
K Piayda ◽  
A Wimmer ◽  
H Sievert ◽  
K Hellhammer ◽  
S Afzal ◽  
...  
Keyword(s):  
Heart Failure ◽  
Aortic Valve ◽  
Aortic Stenosis ◽  
Aortic Valve Replacement ◽  
Pressure Gradient ◽  
Severe Aortic Stenosis ◽  
Primary Treatment ◽  
Low Flow ◽  
Mean Pressure ◽  
The Mean

Abstract Background In the era of transcatheter aortic valve replacement (TAVR), there is renewed interest in percutaneous balloon aortic valvuloplasty (BAV), which may qualify as the primary treatment option of choice in special clinical situations. Success of BAV is commonly defined as a significant mean pressure gradient reduction after the procedure. Purpose To evaluate the correlation of the mean pressure gradient reduction and increase in the aortic valve area (AVA) in different flow and gradient patterns of severe aortic stenosis (AS). Methods Consecutive patients from 01/2010 to 03/2018 undergoing BAV were divided into normal-flow high-gradient (NFHG), low-flow low-gradient (LFLG) and paradoxical low-flow low-gradient (pLFLG) AS. Baseline characteristics, hemodynamic and clinical information were collected and compared. Additionally, the clinical pathway of patients (BAV as a stand-alone procedure or BAV as a bridge to aortic valve replacement) was followed-up. Results One-hundred-fifty-six patients were grouped into NFHG (n=68, 43.5%), LFLG (n=68, 43.5%) and pLFLG (n=20, 12.8%) AS. Underlying reasons for BAV and not TAVR/SAVR as the primary treatment option are displayed in Figure 1. Spearman correlation revealed that the mean pressure gradient reduction had a moderate correlation with the increase in the AVA in patients with NFHG AS (r: 0.529, p<0.001) but showed no association in patients with LFLG (r: 0.145, p=0.239) and pLFLG (r: 0.030, p=0.889) AS. Underlying reasons for patients to undergo BAV and not TAVR/SAVR varied between groups, however cardiogenic shock or refractory heart failure (overall 46.8%) were the most common ones. After the procedure, independent of the hemodynamic AS entity, patients showed a functional improvement, represented by substantially lower NYHA class levels (p<0.001), lower NT-pro BNP levels (p=0.003) and a numerical but non-significant improvement in other echocardiographic parameters like the left ventricular ejection fraction (p=0.163) and tricuspid annular plane systolic excursion (TAPSE, p=0.066). An unplanned cardiac re-admission due to heart failure was necessary in 23.7% patients. Less than half of the patients (44.2%) received BAV as a bridge to TAVR/SAVR (median time to bridge 64 days). Survival was significantly increased in patients having BAV as a staged procedure (log-rank p<0.001). Conclusion In daily clinical practice, the mean pressure gradient reduction might be an adequate surrogate of BAV success in patients with NFHG AS but is not suitable for patients with other hemodynamic entities of AS. In those patients, TTE should be directly performed in the catheter laboratory to correctly assess the increase of the AVA. BAV as a staged procedure in selected clinical scenarios increases survival and is a considerable option in all flow states of severe AS. (NCT04053192) Figure 1 Funding Acknowledgement Type of funding source: None

Doppler Echocardiographic Evaluation of Prosthetic Valves in Tricuspid Position

2003 ◽  
Vol 11 (3) ◽  
pp. 193-197 ◽  
Author(s):  
Shigeaki Aoyagi ◽  
Hiroshi Tomoeda ◽  
Hiroshi Kawano ◽  
Shogo Yokose ◽  
Shuji Fukunaga
Keyword(s):  
Pressure Gradient ◽  
Doppler Echocardiography ◽  
Peak Velocity ◽  
Half Time ◽  
Prosthetic Valves ◽  
Echocardiographic Evaluation ◽  
Mechanical Prostheses ◽  
Doppler Data ◽  
Mean Pressure ◽  
The Mean

Doppler echocardiographic characteristics of 29 normally functioning prosthetic valves (23 mechanical, 6 biological) and 8 obstructed mechanical prostheses in the tricuspid position are reported. In normally functioning prostheses, peak velocity, mean pressure gradient, and pressure-half time were 1.25 ± 0.18 m·sec−1, 2.6 ± 1.1 mm Hg, and 122.6 ± 30.7 msec, respectively. Although no significant differences were seen in peak velocity and mean pressure gradient between mechanical and biological valves, the pressure half-time was significantly greater in biological valves. All normally functioning prostheses had a mean pressure gradient ⩽5.5 mm Hg and pressure half-time < 200 msec. In obstructed bileaflet valves, peak velocity was 1.66 ± 0.28 m·sec−1, mean pressure gradient was 6.1 ± 2.8 mm Hg, and pressure half-time was 265.8 ± 171.7 msec. These Doppler data were significantly greater than those in normally functioning valves where the mean pressure gradient was ⩽5.1 mm Hg and the pressure half-time was ⩽156 msec in all except one patient. Pathological obstruction of a tricuspid prosthesis can be strongly suspected in patients with a mean pressure gradient > 5.5 mm Hg and a pressure half-time > 200 msec on Doppler echocardiography.

An Analytical Model of the Instantaneous Transvalvular Pressure Gradient Through an Aortic Stenosis

2010 ◽  
Author(s):  
Zahra Keshavarz-Motamed ◽  
Nima Maftoon ◽  
Lyes Kadem
Keyword(s):  
Experimental Data ◽  
Aortic Stenosis ◽  
Pressure Gradient ◽  
Cardiac Catheterization ◽  
Doppler Echocardiography ◽  
Pressure Difference ◽  
Accurate Determination ◽  
Before And After ◽  
Analytical Result

Diagnosis and treatment of aortic stenosis largely depends on accurate determination of the pressure difference before and after the valve, known as transvalvular pressure gradient (TPG). Clinically, TPG is obtained using Doppler echocardiography though sometimes invasive cardiac catheterization has to be used to confirm Doppler echocardiography findings. By solving analytically coupled fluid and solid domain equations, we suggest a formulation that with a good degree of accuracy can be used to calculate TPG. Analytical result is validated using experimental data from literature. The suggested methodology is an alternative to cardiac catheterization and helps to prevent its risks.

SIMULATION OF A CLOSED LOOP MODEL EQUIVALENT ELECTRONIC OF NORMAL CARDIOVASCULAR SYSTEM AND VALVULAR AORTIC STENOSIS

2020 ◽  
Vol 20 (01) ◽  
pp. 1950074
Author(s):  
AMINA HALAIMI ◽  
BOUALEM CHETTI ◽  
BOUALEM LARIBI ◽  
OMAR LABBADLIA
Keyword(s):  
Aortic Stenosis ◽  
Pressure Gradient ◽  
Effective Orifice Area ◽  
Loop Model ◽  
Orifice Area ◽  
Electrical Analogy ◽  
Mean Pressure ◽  
Valvular Aortic Stenosis ◽  
The Mean ◽  
Good Agreement

This work presents a developed zero-dimensional cardiovascular (CV) system model, based on an electrical analogy, with a detailed compartmental description of the heart and the main vascular circulation which is able to simulate normal and diseased conditions of CV system, especially the stenosis valvular aortic. To know the effect of each parameter on hemodynamics, the number of parameters is increased by adding more segments. The developed model consists of 14 compartments. The results show that the severity of aortic stenosis (AS) effect varies with the effective orifice area and the mean pressure gradient for the case of no AS; the effective orifice area is 4[Formula: see text]cm2 and the mean pressure gradient is 0[Formula: see text]mmHg, while for the case of mild AS, the effective orifice area is 1.5[Formula: see text]cm2 and the mean pressure gradient is 27.24[Formula: see text]mmHg. For the case of moderate AS, the effective orifice area is 1.0[Formula: see text]cm2 and the mean pressure gradient is 44.68[Formula: see text]mmHg. For the case of the severe AS, the effective orifice area is 0.61[Formula: see text]cm2 and the mean pressure gradient is 77.51[Formula: see text]mmHg. It is found that the developed model can estimate an accurate value of the effective orifice area for any value of mean pressure gradient in AS. The results obtained for the CV system under normal and diseased conditions show a good agreement compared to published results.

A theoretical study of viscous effects in peristaltic pumping

1994 ◽  
Vol 279 ◽  
pp. 177-195 ◽  
Author(s):  
Alden M. Provost ◽  
W. H. Schwarz
Keyword(s):  
Wave Propagation ◽  
Pressure Gradient ◽  
Flow Rate ◽  
Mean Flow ◽  
Viscous Effects ◽  
Transverse Waves ◽  
Peristaltic Pumping ◽  
Mean Pressure ◽  
Flow Through ◽  
The Mean

Intuition and previous results suggest that a peristaltic wave tends to drive the mean flow in the direction of wave propagation. New theoretical results indicate that, when the viscosity of the transported fluid is shear-dependent, the direction of mean flow can oppose the direction of wave propagation even in the presence of a zero or favourable mean pressure gradient. The theory is based on an analysis of lubrication-type flow through an infinitely long, axisymmetric tube subjected to a periodic train of transverse waves. Sample calculations for a shear-thinning fluid illustrate that, for a given waveform, the sense of the mean flow can depend on the rheology of the fluid, and that the mean flow rate need not increase monotonically with wave speed and occlusion. We also show that, in the absence of a mean pressure gradient, positive mean flow is assured only for Newtonian fluids; any deviation from Newtonian behaviour allows one to find at least one non-trivial waveform for which the mean flow rate is zero or negative. Introduction of a class of waves dominated by long, straight sections facilitates the proof of this result and provides a simple tool for understanding viscous effects in peristaltic pumping.

scholarly journals Non-Invasive Determination of Left Ventricular Workload in Patients with Aortic Stenosis Using Magnetic Resonance Imaging and Doppler Echocardiography

PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e86793 ◽  
Author(s):  
Zahra Keshavarz-Motamed ◽  
Julio Garcia ◽  
Emmanuel Gaillard ◽  
Romain Capoulade ◽  
Florent Le Ven ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Aortic Stenosis ◽  
Doppler Echocardiography ◽  
Left Ventricular ◽  
Resonance Imaging ◽  
Non Invasive

Oscillatory forcing of flow through porous media. Part 2. Unsteady flow

2002 ◽  
Vol 465 ◽  
pp. 237-260 ◽  
Author(s):  
D. R. GRAHAM ◽  
J. J. L. HIGDON
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Pressure Gradient ◽  
Flow Rate ◽  
Flow Through Porous Media ◽  
Mean Flow ◽  
Two Fluids ◽  
Mean Pressure ◽  
Flow Through ◽  
The Mean

Numerical computations are employed to study the phenomenon of oscillatory forcing of flow through porous media. The Galerkin finite element method is used to solve the time-dependent Navier–Stokes equations to determine the unsteady velocity field and the mean flow rate subject to the combined action of a mean pressure gradient and an oscillatory body force. With strong forcing in the form of sinusoidal oscillations, the mean flow rate may be reduced to 40% of its unforced steady-state value. The effectiveness of the oscillatory forcing is a strong function of the dimensionless forcing level, which is inversely proportional to the square of the fluid viscosity. For a porous medium occupied by two fluids with disparate viscosities, oscillatory forcing may be used to reduce the flow rate of the less viscous fluid, with negligible effect on the more viscous fluid. The temporal waveform of the oscillatory forcing function has a significant impact on the effectiveness of this technique. A spike/plateau waveform is found to be much more efficient than a simple sinusoidal profile. With strong forcing, the spike waveform can induce a mean axial flow in the absence of a mean pressure gradient. In the presence of a mean pressure gradient, the spike waveform may be employed to reverse the direction of flow and drive a fluid against the direction of the mean pressure gradient. Owing to the viscosity dependence of the dimensionless forcing level, this mechanism may be employed as an oscillatory filter to separate two fluids of different viscosities, driving them in opposite directions in the porous medium. Possible applications of these mechanisms in enhanced oil recovery processes are discussed.

scholarly journals The change in NT-pro-BNP and post-PTMC echocardiography parameters in patients with mitral stenosis. A pilot study

2017 ◽  
Vol 55 (2) ◽  
pp. 75-81
Author(s):  
Morteza Safi ◽  
Fariba Bayat ◽  
Zahra Ahmadi ◽  
Masood Shekarchizadeh ◽  
Isa Khaheshi ◽  
...  
Keyword(s):  
Sinus Rhythm ◽  
Pressure Gradient ◽  
Mitral Stenosis ◽  
Normal Sinus Rhythm ◽  
Left Atrial Volume ◽  
Normal Sinus ◽  
Mean Pressure ◽  
Percutaneous Transvenous Mitral Commissurotomy ◽  
Pulmonary Arterial ◽  
The Mean

Abstract Background. The change in the level of NT-pro-BNP (N-terminal-pro-Brain Natriuretic Peptide) is now considered as a reflection of the hemodynamic alterations and its circulatory reductions reported early after successful PTMC (percutaneous transvenous mitral commissurotomy). The present study aims to assess the change in the level of NT-pro BNP following PTMC in patients with mitral stenosis and also to determine the association between circulatory NT-pro-BNP reduction and post-PTMC echocardiography parameters. Methods. Twenty five symptomatic consecutive patients with severe MS undergoing elective PTMC were prospectively enrolled. All patients underwent echocardiography before and also 24 to 48 hours after PTMC. Peripheral blood samples were taken for measurement of NT-pro-BNP before as well as 24 to 48 hours after PTMC. The patients were also classified in group with normal sinus rhythm or having atrial fibrillation (AF) based on their 12-lead electrocardiogram. Results. It was shown a significant decrease in the parameters of PPG (Peak Pressure Gradient), MPG (Mean Pressure Gradient), PHT (Pressure Half Time), PAP (Pulmonary Arterial Pressure), LAV (Left Atrial Volume), and also a significant increase in MVA (Mitral Valve Area) RVS (Right Ventricular S velocity), and strains of lateral, septal, inferior and anterior walls of LA following PTMC. The mean LVEF remained unchanged after PTMC. The mean NT-pro-BNP before PTMC was 309.20 ± 17.97 pg/lit that significantly diminished after PTMC to 235.72 ± 22.46 pg/lit (p = 0.009). Among all echocardiography parameters, only MPG was positively associated with the change in NT-pro-BNP after PTMC. Comparing the change in echocardiography indices between the patients with normal rhythm and those with AF, lower change in PAP was shown in the group with AF. However, more change in the level of NT-pro-BNP after PTMC was shown in the patients with AF compared to those without this arrhythmia. Conclusion. PTMC procedure leads to reduce the level of NT-pro-BNP. The change in NT-pro-BNP is an indicator for change in MS severity indicated by decreasing MPG parameter. Lower change in PAP as well as higher change in NT-pro-BNP is predicted following PTMC in the group with AF compared to those with normal sinus rhythm.

Sign in / Sign up

Export Citation Format

Share Document