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Circ Cardiovasc Imaging. 2017 Jan;10(1). pii: e005207. doi: 10.1161/CIRCIMAGING.116.005207.

Beyond Bernoulli: Improving the Accuracy and Precision of Noninvasive Estimation of Peak Pressure Drops.

Author information

1
From the King's College London, Division of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, The Rayne Institute, United Kingdom (F.D., N.P.S., D.A.N., P.L.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom (S.M., M.M.B., S.N.); University of Auckland, New Zealand (N.P.S.); and Department of Non Invasive Cardiology, King's College Hospital, London, United Kingdom (M.J.M.).
2
From the King's College London, Division of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, The Rayne Institute, United Kingdom (F.D., N.P.S., D.A.N., P.L.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom (S.M., M.M.B., S.N.); University of Auckland, New Zealand (N.P.S.); and Department of Non Invasive Cardiology, King's College Hospital, London, United Kingdom (M.J.M.). Pablo.Lamata@kcl.ac.uk.

Abstract

BACKGROUND:

Transvalvular peak pressure drops are routinely assessed noninvasively by echocardiography using the Bernoulli principle. However, the Bernoulli principle relies on several approximations that may not be appropriate, including that the majority of the pressure drop is because of the spatial acceleration of the blood flow, and the ejection jet is a single streamline (single peak velocity value).

METHODS AND RESULTS:

We assessed the accuracy of the Bernoulli principle to estimate the peak pressure drop at the aortic valve using 3-dimensional cardiovascular magnetic resonance flow data in 32 subjects. Reference pressure drops were computed from the flow field, accounting for the principles of physics (ie, the Navier-Stokes equations). Analysis of the pressure components confirmed that the spatial acceleration of the blood jet through the valve is most significant (accounting for 99% of the total drop in stenotic subjects). However, the Bernoulli formulation demonstrated a consistent overestimation of the transvalvular pressure (average of 54%, range 5%-136%) resulting from the use of a single peak velocity value, which neglects the velocity distribution across the aortic valve plane. This assumption was a source of uncontrolled variability.

CONCLUSIONS:

The application of the Bernoulli formulation results in a clinically significant overestimation of peak pressure drops because of approximation of blood flow as a single streamline. A corrected formulation that accounts for the cross-sectional profile of the blood flow is proposed and adapted to both cardiovascular magnetic resonance and echocardiographic data.

KEYWORDS:

Bernoulli principle; biomarker; blood pressure; hemodynamics; stenosis; valve

PMID:
28093412
PMCID:
PMC5265685
DOI:
10.1161/CIRCIMAGING.116.005207
[Indexed for MEDLINE]
Free PMC Article

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