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Eric Dumont – One of the best experts on this subject based on the ideXlab platform.

  • transcatheter aortic valve implantation in patients with severe aortic stenosis and small aortic Annulus
    Journal of the American College of Cardiology, 2011
    Co-Authors: Dimitri Kalavrouziotis, Josep Rodescabau, Rodrigo Bagur, Daniel Doyle, Robert De Larochelliere, Philippe Pibarot, Eric Dumont

    Abstract:

    Objectives Valve hemodynamics and clinical outcomes among patients with a small aortic Annulus who underwent transcatheter aortic valve implantation (TAVI) were examined. Background The presence of a small aortic Annulus may complicate the surgical management of patients with severe aortic stenosis (AS). TAVI is an alternative to aortic valve replacement (AVR) in high-risk patients, but few data exist on the results of TAVI in patients with a small aortic Annulus. Methods Between 2007 and 2010, 35 patients (mean age 79.2 ± 9.4 years) with severe AS and an aortic Annulus diameter Results Procedural success was achieved in 34 patients (97.1%). There was 1 in-hospital death. Peak and mean transaortic gradients decreased from 76.3 ± 33.0 mm Hg and 45.2 ± 20.6 mm Hg at baseline to 21.8 ± 8.4 mm Hg and 11.7 ± 4.8 mm Hg post-procedure, respectively, both p Conclusions In high-risk patients with severe AS and a small aortic Annulus, TAVI is associated with good post-procedural valve hemodynamics and clinical outcomes. TAVI may provide a reasonable alternative to conventional AVR in elderly patients with a small aortic Annulus.

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Yunshik Choi – One of the best experts on this subject based on the ideXlab platform.

  • assessment of mitral Annulus velocity by doppler tissue imaging in the evaluation of left ventricular diastolic function
    Journal of the American College of Cardiology, 1997
    Co-Authors: Daewon Sohn, Inho Chai, Byunghee Oh, Youngbae Park, Yunshik Choi

    Abstract:

    Objectives. This study assessed the clinical utility of mitral Annulus velocity in the evaluation of left ventricular diastolic function.

    Background. Mitral inflow velocity recorded by Doppler echocardiography has been widely used to evaluate left ventricular diastolic function but is affected by other factors. The mitral Annulus velocity profile during diastole may provide additional information about left ventricular diastolic function.

    Methods. Mitral Annulus velocity during diastole was measured by Doppler tissue imaging (DTI) 1) in 59 normal volunteers (group 1); 2) in 20 patients with a relaxation abnormality as assessed by Doppler mitral inflow variables (group 2) at baseline and after saline loading; 3) in 11 patients (group 3) with normal diastolic function before and after intravenous nitroglycerin infusion; and 4) in 38 consecutive patients (group 4) undergoing cardiac catheterization in whom mitral inflow velocity and tau as well as mitral Annulus velocity were measured simultaneously.

    Results. In group 1, mean ± SD peak early and late diastolic mitral Annulus velocity was 10.0 ± 1.3 and 9.5 ± 1.5 cm/s, respectively. In group 2, mitral inflow velocity profile changed toward the pseudonormalization pattern with saline loading (deceleration time 311 ± 84 ms before to 216 ± 40 ms after intervention, p < 0.001), whereas peak early diastolic mitral Annulus velocity did not change significantly (5.3 ± 1.2 cm/s to 5.7 ± 1.4 cm/s, p = NS). In group 3, despite a significant change in mitral inflow velocity profile after nitroglycerin, peak early diastolic mitral Annulus velocity did not change significantly (9.5 ± 2.2 cm/s to 9.2 ± 1.7 cm/s, p = NS). In group 4, peak early diastolic mitral Annulus velocity (r = −0.56, p < 0.01) and the early/late ratio (r = −0.46, p < 0.01) correlated with tau. When the combination of normal mitral inflow variables with prolonged tau (≥50 ms) was classified as pseudonormalization, peak early diastolic mitral Annulus velocity <8.5 cm/s and the early/late ratio <1 could identify the pseudonormalization with a sensitivity of 88% and specificity of 67%. Conclusions. Mitral Annulus velocity determined by DTI is a relatively preload-independent variable in evaluating diastolic function.

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  • Assessment of Mitral Annulus Velocity by Doppler Tissue Imaging in the Evaluation of Left Ventricular Diastolic Function
    Journal of the American College of Cardiology, 1997
    Co-Authors: Daewon Sohn, Inho Chai, Byunghee Oh, Youngbae Park, Yunshik Choi

    Abstract:

    Objectives. This study assessed the clinical utility of mitral Annulus velocity in the evaluation of left ventricular diastolic function.

    Background. Mitral inflow velocity recorded by Doppler echocardiography has been widely used to evaluate left ventricular diastolic function but is affected by other factors. The mitral Annulus velocity profile during diastole may provide additional information about left ventricular diastolic function.

    Methods. Mitral Annulus velocity during diastole was measured by Doppler tissue imaging (DTI) 1) in 59 normal volunteers (group 1); 2) in 20 patients with a relaxation abnormality as assessed by Doppler mitral inflow variables (group 2) at baseline and after saline loading; 3) in 11 patients (group 3) with normal diastolic function before and after intravenous nitroglycerin infusion; and 4) in 38 consecutive patients (group 4) undergoing cardiac catheterization in whom mitral inflow velocity and tau as well as mitral Annulus velocity were measured simultaneously.

    Results. In group 1, mean ± SD peak early and late diastolic mitral Annulus velocity was 10.0 ± 1.3 and 9.5 ± 1.5 cm/s, respectively. In group 2, mitral inflow velocity profile changed toward the pseudonormalization pattern with saline loading (deceleration time 311 ± 84 ms before to 216 ± 40 ms after intervention, p < 0.001), whereas peak early diastolic mitral Annulus velocity did not change significantly (5.3 ± 1.2 cm/s to 5.7 ± 1.4 cm/s, p = NS). In group 3, despite a significant change in mitral inflow velocity profile after nitroglycerin, peak early diastolic mitral Annulus velocity did not change significantly (9.5 ± 2.2 cm/s to 9.2 ± 1.7 cm/s, p = NS). In group 4, peak early diastolic mitral Annulus velocity (r = −0.56, p < 0.01) and the early/late ratio (r = −0.46, p < 0.01) correlated with tau. When the combination of normal mitral inflow variables with prolonged tau (≥50 ms) was classified as pseudonormalization, peak early diastolic mitral Annulus velocity

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Morteza Gharib – One of the best experts on this subject based on the ideXlab platform.

  • influence of ventricular pressure drop on mitral Annulus dynamics through the process of vortex ring formation
    Annals of Biomedical Engineering, 2007
    Co-Authors: Arash Kheradvar, Morteza Gharib

    Abstract:

    Several studies have suggested that the mitral Annulus displacement and velocity in early diastole can be used as indicators of diastolic performance. The peak velocity of the mitral Annulus away from the LV apex during early diastole, which indicates the rate of longitudinal expansion of the LV, is reduced in patients with impaired diastolic relaxation. With the intention of relating the trans-mitral flow to mitral Annulus plane dynamics, we measured mitral Annulus recoil force for different valve sizes, while applying an exponential pressure drop in a simplified model of the ventricle. The temporal changes in diameter of the valve during rapid filling phase were also considered. The process of ventricular vortex formation was studied together with the measurement of mitral Annulus recoil force within different pressure drop conditions. Matching the vorticity contour plots with the recoil force measurements resulted in the fact that the magnitude of recoil is maximal once the vortex ring is about to pinch off, regardless of the valve size or the characteristics of ventricular pressure drop. This study showed that the mitral Annulus recoil is maximal once occurs at the vortex formation time ranging from 3.5 to 4.5. It was also shown that the presence of leaflets would dissipate the Annulus recoil force.

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  • correlation between vortex ring formation and mitral Annulus dynamics during ventricular rapid filling
    Asaio Journal, 2007
    Co-Authors: Arash Kheradvar, Michele Milano, Morteza Gharib

    Abstract:

    One of the most important fluid phenomena observed in the
    left ventricle during diastole is the presence of vortex rings
    that develop with a strong jet entering through the mitral
    valve. The present study is focused on the rapid filling phase
    of diastole, during which the left ventricle expands and receives
    blood through the fully open mitral valve. The atrio-ventricular
    system during the rapid filling phase was emulated
    experimentally with a simplified mechanical model in
    which the relevant pressure decay and the dimension of
    mitral Annulus approximate the physiologic and pathologic
    values. Digital particle image velocimetry measurements
    were correlated with the force measurements on the mitral
    Annulus plane to analyze the relation between flow and the
    mitral Annulus motion. The recoil force on the displaced
    Annulus plane was computed on the basis of plane acceleration
    and plane velocity and correlated with the inflow jet.
    Measurements of the recoil force for different values of the
    mitral Annulus diameter showed that the recoil force was
    generated during fluid propulsion and that it is maximal for
    an Annulus diameter close to the normal adult value in a
    healthy left ventricle. We also tested Annulus diameters
    smaller and larger than the normal one. The smaller Annulus
    corresponds to the stenotic valves and the larger Annulus
    exists in dilated cardiomyopathy cases. In both conditions,
    the recoil force was found to be smaller than in the normal
    case. These observations are consistent with the previously
    reported results for dilated cardiomyopathy and mitral stenosis
    clinical conditions.

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