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

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.

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

Romanian Journal of Internal Medicine ◽

10.1515/rjim-2017-0005 ◽

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.

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Determination of pressure gradient in mitral stenosis with Doppler echocardiography.

Heart ◽

10.1136/hrt.41.5.529 ◽

1979 ◽

Vol 41 (5) ◽

pp. 529-535 ◽

Cited By ~ 61

Author(s):

J Holen ◽

S Simonsen

Keyword(s):

Pressure Gradient ◽

Doppler Echocardiography ◽

Mitral Stenosis

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

European Heart Journal ◽

10.1093/ehjci/ehaa946.1934 ◽

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

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A theoretical study of viscous effects in peristaltic pumping

Journal of Fluid Mechanics ◽

10.1017/s0022112094003873 ◽

1994 ◽

Vol 279 ◽

pp. 177-195 ◽

Cited By ~ 36

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.

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

Journal of Fluid Mechanics ◽

10.1017/s0022112002001143 ◽

2002 ◽

Vol 465 ◽

pp. 237-260 ◽

Cited By ~ 12

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.

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SEVERE MITRAL STENOSIS;

The Professional Medical Journal ◽

10.29309/tpmj/2017.24.06.1114 ◽

2017 ◽

Vol 24 (06) ◽

pp. 850-854

Author(s):

Haroon Aziz Khan Babar ◽

Abubakr Ali Saad ◽

Zahid Rafique Butt ◽

Zainab Khan ◽

Saima Dastgeer ◽

...

Keyword(s):

Mitral Valve ◽

Pressure Gradient ◽

Mitral Stenosis ◽

Cross Sectional Study ◽

P Value ◽

Cross Sectional ◽

Mitral Valve Area ◽

Mean Pressure ◽

Procedural Outcomes ◽

Valve Area

Objectives: To evaluate the immediate outcomes of PTMC in patients with severemitral valve stenosis. Study Design: Cross-sectional study. Setting: Ninety (90) subjects whounderwent PTMC in Cardiac Catheterization Department of CPE Institute of Cardiology. Period:June 2008 to June 2011. Methods: Patients with severe MS having mitral valve (MV) area <1.0cm2 and having morphology suitable for PTMC in the absence of regurgitation and left atrial clotwere included in this study. An increase in mitral valve area more than 50% of the baseline areawithout the development of moderate to severe MR was considered as the procedural success.Data were analyzed using SPSS V19. Pre and post procedural outcomes were measured usingpaired sample t-test. Results: There were a total number of ninety (90) patients in this study.Mean age of subjects was 28.08+9.61 years. There were more females 59 (65.5%) as comparedto only 31 (34.5%) males. There was significant increase in mitral valve area, 1.83+0.36 cm2post-PTMC versus 0.63+0.17 cm2 pre-PTMC (p-value <0.001). There was significant decreasein Peak pressure gradient (PPG) from 28.31+6.01 mmHg to 12.85+3.20 mmHg after PTMC(p-value <0.001). There were also significant reductions in mean pressure gradient andpulmonary artery systolic pressures after PTMC with p-value <0.001 and <0.001 respectively.PTMC was successful in 87 (97.7%) patients and it failed in only 3 (3.3%) patients. Conclusion:PTMC is an excellent treatment option regarding optimal outcomes and success rate in patientsof severe mitral stenosis especially when performed by experienced interventionists.

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Balloon dilation of stenosed systemic venous pathways following the Mustard operation

Cardiology in the Young ◽

10.1017/s1047951100003000 ◽

1995 ◽

Vol 5 (3) ◽

pp. 238-242 ◽

Cited By ~ 3

Author(s):

Narayanswami Sreeram ◽

Venkateswararao Dikkala ◽

Robert Arnold

Keyword(s):

Pressure Gradient ◽

Balloon Dilation ◽

Mustard Operation ◽

Mean Pressure ◽

Angiographic Data ◽

Alternative Measures ◽

The Mean ◽

Term Management

SummaryStenoses of the systemic venous pathways are a potentially dangerous complication after the Mustard operation. The acute and intermediate-term efficacy of balloon dilation of these stenoses has not previously been studied in a large group of patients. A retrospective analysis of clinical and angiographic data, with prospective clinical and echocardiographic follow-up, was performed in a consecutive group of 25 patients (17 male, 8 female) who underwent balloon dilation of the superior or inferior caval venous pathways. For 17 dilations of stenoses in the superior pathway, the mean pressure gradient decreased from 9.1±5.7 to 3.4±2.3 mm Hg (p<0.01), while the diameter of the stenosis increased from 5.9±2.9 to 11.2±3.0 mm (p<0.01). For 25 dilations of the inferior pathway, the mean gradient decreased from 4.3±1.8 to 1.4±1.1 mm Hg (p<0.01), while the diameter of the stenosis increased from 7.3±1.5 to 10.6±2.3 mm (p<0.01). Over a median follow-up of 3.5 years, 16 patients have been without symptoms or signs suggestive of recurrence of stenoses. In the remaining nine patients, 11 further procedures were performed at a median of 3.1 years after initial dilation. In five patients who had previously undergone dilation of the superior (3), inferior (1) or both (1) pathways, further dilations of the same pathway(s) and/or stent implantations were performed. Three patients, including one in whom superior caval venous stenosis had recurred, had developed a new stenosis of a previously undilated pathway, while in two patients no further dilations were required. Balloon dilation offers an alternative to reoperation for stenoses of the systemic venous pathways after the Mustard operation, and appears to provide satisfactory intermediate-term palliation. Recurrences of stenoses in previously dilated pathways, and new stenoses in previously unobstructed pathways, are commonly seen at follow-up. Alternative measures, such as placement of stents, need to be considered in the long-term management of these patients.

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

ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting: Volume 1, Symposia – Parts A, B, and C ◽

10.1115/fedsm-icnmm2010-31099 ◽

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.

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