Beyond Pressure Gradients: The Effects of Intervention on Heart Power in Aortic Coarctation

Fernandes, João Filipe; Goubergrits, Leonid; Brüning, Jan; Hellmeier, Florian; Nordmeyer, Sarah; Silva, Tiago Ferreira da; Schubert, Stephan; Berger, Felix; Küehne, Titus; Kelm, Marcus

doi:10.1371/journal.pone.0168487

Cited by 15 publications

(33 citation statements)

References 25 publications

(27 reference statements)

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“…Following Fernandes et al, this is feasible by assuming that

{\overset{P}{true}}_{int}

occurs at the instant of peak pressure,

t_{\overset{p}{true}}

. Consistent with expectations based on Laplace law, this was not the case in any of our LV models.…”

Section: Discussionsupporting

confidence: 82%

“…Mechanical heart power P int and cardiac power efficiency P eff defined as the ratio between peak mechanical power expended by the LV,

{\overset{P}{true}}_{int}

, and the mean hydrodynamic power delivered to the arterial system, EHP, have been proposed recently as a diagnostic marker . On grounds of conservation of energy the global mechanical power P int expended by the LV and the hydrodynamic power transferred to the LV blood pool, P ext , must be equal.…”

Section: Discussionmentioning

confidence: 99%

“…Alternatively, the simpler P eff,clin marker can be used as in Fernandes et al, which relies on IHP and does not require an estimation of

\overset{ε}{true}

. While simpler, its use brings about a number of drawbacks.…”

Section: Discussionmentioning

confidence: 99%

“…Following Fernandes et al, we define external hydrodynamic heart power, EHP, as

EHP = {\overset{P}{true}}_{ext,ao} = \frac{1}{T_{sys}} true \int_{t_{ED}}^{t_{ES}} p_{ao} q normald t \approx MAP \cdot CO,

where MAP and CO are mean arterial pressure and cardiac output, respectively, and p ao = p LV − Δ p is the pressure in the aorta ascendens. Power efficiency, P eff , has been defined previously in Fernandes et al as the ratio

P_{eff,clin} = \frac{EHP}{IHP} .

Since P eff essentially relates the mean hydrodynamic power delivered to the arterial system to the peak biomechanical power generated by the LV myocardium during systole, P eff can be expressed as

P_{eff} = \frac{{\overset{P}{true}}_{ext,ao}}{{\overset{P}{true}}_{int}} \approx \frac{{\overset{P}{true}}_{ext,ao}}{{\overset{P}{true}}_{ext}} .

where

{\overset{P}{true}}_{int}

{\overset{P}{true}}_{ext}

, and

{\overset{P}{true}}_{ext,ao}

are determined based on Equations , and , respectively. That is, P eff can be estimated from hemodynamic data using

{\overset{P}{true}}_{ext}

or from LV deformation analysis using

{\overset{P}{true}}_{int}

.…”

Section: Methodsmentioning

confidence: 99%

“…As a direct measurement of energy metabolism, positron emission tomography (PET) was used(); however, the method is limited due to its complexity, including the need for tracers involving ionizing radiation. More recently, a concept of biomechanical internal myocardial heart power (IHP), necessary to maintain adequate cardiac output ( external heart power [EHP]), has been introduced in patients with aortic coarctation . Findings in this cohort suggest that the ratio EHP/IHP, referred to as power efficiency, improved mostly in those cases with elevated IHP.…”

Section: Introductionmentioning

confidence: 99%

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Assessment of wall stresses and mechanical heart power in the left ventricle: Finite element modeling versus Laplace analysis

Gsell

Augustin

Prassl

et al. 2018

Numer Methods Biomed Eng

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Laplace estimates of LV wall stress are able to provide a rough approximation of global mean stress in the circumferential-longitudinal plane of the LV. However, according to FE results, spatial heterogeneity of stresses in the LV wall is significant, leading to major discrepancies between local stresses and global mean stress. Assessment of mechanical power with Laplace methods is feasible, but these are inferior in accuracy compared with FE models. The accurate assessment of stress and power density distribution in the LV wall is only feasible based on patient-specific FE modeling.

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“…Following Fernandes et al, this is feasible by assuming that

{\overset{P}{true}}_{int}

occurs at the instant of peak pressure,

t_{\overset{p}{true}}

. Consistent with expectations based on Laplace law, this was not the case in any of our LV models.…”

Section: Discussionsupporting

confidence: 82%

“…Mechanical heart power P int and cardiac power efficiency P eff defined as the ratio between peak mechanical power expended by the LV,

{\overset{P}{true}}_{int}

Section: Discussionmentioning

confidence: 99%

“…Alternatively, the simpler P eff,clin marker can be used as in Fernandes et al, which relies on IHP and does not require an estimation of

\overset{ε}{true}

. While simpler, its use brings about a number of drawbacks.…”

Section: Discussionmentioning

confidence: 99%

“…Following Fernandes et al, we define external hydrodynamic heart power, EHP, as

EHP = {\overset{P}{true}}_{ext,ao} = \frac{1}{T_{sys}} true \int_{t_{ED}}^{t_{ES}} p_{ao} q normald t \approx MAP \cdot CO,

P_{eff,clin} = \frac{EHP}{IHP} .

Since P eff essentially relates the mean hydrodynamic power delivered to the arterial system to the peak biomechanical power generated by the LV myocardium during systole, P eff can be expressed as

P_{eff} = \frac{{\overset{P}{true}}_{ext,ao}}{{\overset{P}{true}}_{int}} \approx \frac{{\overset{P}{true}}_{ext,ao}}{{\overset{P}{true}}_{ext}} .

where

{\overset{P}{true}}_{int}

{\overset{P}{true}}_{ext}

, and

{\overset{P}{true}}_{ext,ao}

are determined based on Equations , and , respectively. That is, P eff can be estimated from hemodynamic data using

{\overset{P}{true}}_{ext}

or from LV deformation analysis using

{\overset{P}{true}}_{int}

.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Assessment of wall stresses and mechanical heart power in the left ventricle: Finite element modeling versus Laplace analysis

Gsell

Augustin

Prassl

et al. 2018

Numer Methods Biomed Eng

Self Cite

View full text Add to dashboard Cite

show abstract

Patient‐specific requirements and clinical validation of MRI‐based pressure mapping: A two‐center study in patients with aortic coarctation

Goubergrits

Hellmeier

Neumann

et al. 2018

Magnetic Resonance Imaging

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Background Invasive peak‐to‐peak pressure gradients are the current clinical reference standard for assessing aortic coarctation. To obtain them, patients need to undergo arterial heart catheterization. Unless an intervention is performed, the procedure remains purely diagnostic, while the concomitant risks remain. Purpose To validate MRI‐based pressure mapping against pressure drop derived from heart catheterization and to define minimal clinical requirements. Study Type Prospective clinical validation study. Population Twenty‐seven coarctation patients with an indicated heart catheterization were enrolled at two clinical centers. MRI Sequences 1.5T including 4D velocity‐encoded MRI and 3D anatomical imaging of the aorta. Assessment Pressure drop across the stenosis was calculated by pressure mapping based on the pressure Poisson equation. Calculated pressure drops were compared with catheter measured data. Spatial and temporal resolution were analyzed using in silico phantom‐based data as well as in vivo measurements. Statistics Pressure drop was compared to peak‐to‐peak measurements. A two‐sample paired mean equivalence test was used. Results In patients without imaging artifacts and a required spatial resolution ≥5 voxel/diameter, significant equivalence of pressure mapping compared to heart catheterization was found (17.5 ± 6.49 vs. 16.6 ± 6.53 mmHg, P < 0.001). Data Conclusion Pressure mapping provides equivalent accuracy to pressure drop obtained from heart catheterization in patients 1) without previous stenting and 2) with sufficient spatial image resolution (at least 5 voxels/diameter). In these patients the method can reliably be performed prior to the actual procedure, and thus allows safe noninvasive treatment planning based on MRI. Level of Evidence: 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019;49:81–89.

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Right ventricular energetics and power in pulmonary regurgitation vs. stenosis using four dimensional phase contrast magnetic resonance

Fernandes

Hammel

Zhou

et al. 2018

International Journal of Cardiology

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Beyond Pressure Gradients: The Effects of Intervention on Heart Power in Aortic Coarctation

Cited by 15 publications

References 25 publications

Assessment of wall stresses and mechanical heart power in the left ventricle: Finite element modeling versus Laplace analysis

Assessment of wall stresses and mechanical heart power in the left ventricle: Finite element modeling versus Laplace analysis

Patient‐specific requirements and clinical validation of MRI‐based pressure mapping: A two‐center study in patients with aortic coarctation

Right ventricular energetics and power in pulmonary regurgitation vs. stenosis using four dimensional phase contrast magnetic resonance

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