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Quantitative assessment of right ventricular structure and flow dynamics in pulmonary homograft obstruction.

Chapron J, Aguib H, Theodoropoulos S, Kalantzi M, Yacoub M, Torii R - Glob Cardiol Sci Pract (2014)

View Article: PubMed Central - PubMed

Affiliation: Qatar Cardiovascular Research Centre, Doha, Qatar.

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The insertion of cryopreserved homograft conduit into the pulmonary outflow tract is an effective method of relieving severe pulmonary valve dysfunction... He remained asymptomatic, however, routine echocardiography six months after the operation showed a peak gradient of 25mmHg across the right ventricular outflow with evidence of diminution of right ventricular size and a competent pulmonary valve (homograft)... The cardiac output measured 4.55 L/min... Applying the jet shear layer detection method by Garcia et al. to the through-plane velocity map, effective orifice area (EOA) was also estimated to be 1.36 cm... Energy loss is in mmHg and was initially introduced to indicate the portion of the transvalvular pressure that is not recovered, in order to assess the severity of aortic stenosis... Indexed energy loss coefficient is an improved indicator which has been shown better correlated to clinical outcomes, i.e. mortality and reoperation... The diameter of the homograft in proportion to the dilated MPA was 57% and also due to relatively small orifice area equivalent to a moderate stenosis in case of the aorta (Bonow et al. ), the flow through the homograft became a high-speed jet... The jet flowing into the dilated MPA is accompanied by flow separation and recirculation (Figure 3) which are likely cause of disturbance in the flow, resulting in a significant energy loss that was estimated 26.6 mmHg... This means that the RV of this patient is required to provide extra 26.6 mmHg of pressure to overcome energy loss and ensure perfusion of the blood to the lungs... One of the limitations of this study is that we have used the energy loss equation for the pulmonary valve... However, the flow characteristics through the two semilunar valves is similar... Another limitation relates to the fact that we have not studied the effect of turbulence using computational fluid dynamics... This report illustrated the utility of multi-modality imaging analysis to fully characterize both the structural and functional changes at different times during follow-up of operations for complex heart disease... This has the potential to influence decision making regarding re-operation, and possibly optimise surgical techniques in the future.

No MeSH data available.


In-plane velocity map based on phase-contrast MR images (left: diastole, right: systole). The velocity is in head-foot direction that is the vertical direction in the figures.
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fig2: In-plane velocity map based on phase-contrast MR images (left: diastole, right: systole). The velocity is in head-foot direction that is the vertical direction in the figures.

Mentions: In-plane as well as through-plane, cine phase-contract MR images were acquired over the cardiac cycle in order to assess spatio-temporal flow characteristics. The in-plane images (Figure 2), encoding blood flow velocity in head-foot direction, were acquired in sagittal-oblique plane to depict the long-axis of the main pulmonary trunk with slice thickness 5 mm and encoding velocity (Venc) 3.5 m/s. The through-plane images were acquired immediately downstream to the pulmonary valve with same slice thickness and encoding velocity. The velocity map in Figure 2 illustrates a systolic jet through the homograft and regurgitation in diastole. The peak jet velocity was confirmed to be 2.87 m/s by the through-plane velocity map (Figure 3), equating to 33 mmHg of transvalvular pressure gradient. The regurgitant velocity was − 0.49 m/s. The cardiac output measured 4.55 L/min. Applying the jet shear layer detection method by Garcia et al.1 to the through-plane velocity map, effective orifice area (EOA) was also estimated to be 1.36 cm2.


Quantitative assessment of right ventricular structure and flow dynamics in pulmonary homograft obstruction.

Chapron J, Aguib H, Theodoropoulos S, Kalantzi M, Yacoub M, Torii R - Glob Cardiol Sci Pract (2014)

In-plane velocity map based on phase-contrast MR images (left: diastole, right: systole). The velocity is in head-foot direction that is the vertical direction in the figures.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4352686&req=5

fig2: In-plane velocity map based on phase-contrast MR images (left: diastole, right: systole). The velocity is in head-foot direction that is the vertical direction in the figures.
Mentions: In-plane as well as through-plane, cine phase-contract MR images were acquired over the cardiac cycle in order to assess spatio-temporal flow characteristics. The in-plane images (Figure 2), encoding blood flow velocity in head-foot direction, were acquired in sagittal-oblique plane to depict the long-axis of the main pulmonary trunk with slice thickness 5 mm and encoding velocity (Venc) 3.5 m/s. The through-plane images were acquired immediately downstream to the pulmonary valve with same slice thickness and encoding velocity. The velocity map in Figure 2 illustrates a systolic jet through the homograft and regurgitation in diastole. The peak jet velocity was confirmed to be 2.87 m/s by the through-plane velocity map (Figure 3), equating to 33 mmHg of transvalvular pressure gradient. The regurgitant velocity was − 0.49 m/s. The cardiac output measured 4.55 L/min. Applying the jet shear layer detection method by Garcia et al.1 to the through-plane velocity map, effective orifice area (EOA) was also estimated to be 1.36 cm2.

View Article: PubMed Central - PubMed

Affiliation: Qatar Cardiovascular Research Centre, Doha, Qatar.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

The insertion of cryopreserved homograft conduit into the pulmonary outflow tract is an effective method of relieving severe pulmonary valve dysfunction... He remained asymptomatic, however, routine echocardiography six months after the operation showed a peak gradient of 25mmHg across the right ventricular outflow with evidence of diminution of right ventricular size and a competent pulmonary valve (homograft)... The cardiac output measured 4.55 L/min... Applying the jet shear layer detection method by Garcia et al. to the through-plane velocity map, effective orifice area (EOA) was also estimated to be 1.36 cm... Energy loss is in mmHg and was initially introduced to indicate the portion of the transvalvular pressure that is not recovered, in order to assess the severity of aortic stenosis... Indexed energy loss coefficient is an improved indicator which has been shown better correlated to clinical outcomes, i.e. mortality and reoperation... The diameter of the homograft in proportion to the dilated MPA was 57% and also due to relatively small orifice area equivalent to a moderate stenosis in case of the aorta (Bonow et al. ), the flow through the homograft became a high-speed jet... The jet flowing into the dilated MPA is accompanied by flow separation and recirculation (Figure 3) which are likely cause of disturbance in the flow, resulting in a significant energy loss that was estimated 26.6 mmHg... This means that the RV of this patient is required to provide extra 26.6 mmHg of pressure to overcome energy loss and ensure perfusion of the blood to the lungs... One of the limitations of this study is that we have used the energy loss equation for the pulmonary valve... However, the flow characteristics through the two semilunar valves is similar... Another limitation relates to the fact that we have not studied the effect of turbulence using computational fluid dynamics... This report illustrated the utility of multi-modality imaging analysis to fully characterize both the structural and functional changes at different times during follow-up of operations for complex heart disease... This has the potential to influence decision making regarding re-operation, and possibly optimise surgical techniques in the future.

No MeSH data available.