Noninvasive calculation of the aortic blood pressure waveform from the flow velocity waveform: a proof of concept

Samuel Vennin; Alexia Mayer; Ye Li; Henry Fok; Brian Clapp; Jordi Alastruey; Phil Chowienczyk

doi:10.1152/ajpheart.00152.2015

Noninvasive calculation of the aortic blood pressure waveform from the flow velocity waveform: a proof of concept

Samuel Vennin, Alexia Mayer, Ye Li, Henry Fok, Brian Clapp, Jordi Alastruey, Phil Chowienczyk

Biomedical Engineering Department

Research output: Contribution to journal › Article › peer-review

22 Citations (Scopus)

Abstract

Estimation of aortic and left ventricular (LV) pressure usually requires measurements that are difficult to obtain during the imaging required to obtain concurrent LV dimensions essential for determination of LV mechanical properties. We describe a novel method for deriving aortic pressure from the aortic flow velocity. The target pressure waveform is divided into an early systolic upstroke, determined by the water hammer equation, and a diastolic decay equal to that in the peripheral arterial tree, interposed by a late systolic portion described by a second-order polynomial constrained by conditions of continuity and conservation of mean arterial pressure. Pulse wave velocity (PWV, obtainable during imaging), mean arterial pressure, diastolic pressure and diastolic decay are required inputs for the algorithm. Pressure and flow velocities were simulated using a simplified 1-D tube model and experimental data were acquired through a pressure/Doppler flow velocity transducer placed in the ascending aorta in 18 patients (mean±SD, age: 61.8±10.3 years, aortic BP: 136±23/73±13 mmHg). PWV, mean and diastolic pressures and diastolic decay were taken from model parameters or calculated from reference pressures/flows (i.e. were assumed to be known). Estimated pressure waveforms showed excellent agreement with reference pressures for both the simulated and experimental data (mean±SD root mean square error, 0.7±0.1 mmHg and 2.4±1.0 mmHg for numerically simulated and experimental data respectively; peak systolic pressure, mean±SD, 0.4±0.6 mmHg and 1.4±2.0 mmHg for numerically simulated and experimental data respectively). This is the first non-invasive derivation of aortic pressure based on phenomenon occurring directly in the ascending aorta.

Original language	English
Pages (from-to)	H969–H976
Number of pages	8
Journal	AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
Volume	309
Issue number	5
DOIs	https://doi.org/10.1152/ajpheart.00152.2015
Publication status	Published - 1 Sept 2015

Keywords

central blood pressure
aortic flow velocity
pulse wave velocity
hypertension;
left ventricle

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title = "Noninvasive calculation of the aortic blood pressure waveform from the flow velocity waveform: a proof of concept",

abstract = "Estimation of aortic and left ventricular (LV) pressure usually requires measurements that are difficult to obtain during the imaging required to obtain concurrent LV dimensions essential for determination of LV mechanical properties. We describe a novel method for deriving aortic pressure from the aortic flow velocity. The target pressure waveform is divided into an early systolic upstroke, determined by the water hammer equation, and a diastolic decay equal to that in the peripheral arterial tree, interposed by a late systolic portion described by a second-order polynomial constrained by conditions of continuity and conservation of mean arterial pressure. Pulse wave velocity (PWV, obtainable during imaging), mean arterial pressure, diastolic pressure and diastolic decay are required inputs for the algorithm. Pressure and flow velocities were simulated using a simplified 1-D tube model and experimental data were acquired through a pressure/Doppler flow velocity transducer placed in the ascending aorta in 18 patients (mean±SD, age: 61.8±10.3 years, aortic BP: 136±23/73±13 mmHg). PWV, mean and diastolic pressures and diastolic decay were taken from model parameters or calculated from reference pressures/flows (i.e. were assumed to be known). Estimated pressure waveforms showed excellent agreement with reference pressures for both the simulated and experimental data (mean±SD root mean square error, 0.7±0.1 mmHg and 2.4±1.0 mmHg for numerically simulated and experimental data respectively; peak systolic pressure, mean±SD, 0.4±0.6 mmHg and 1.4±2.0 mmHg for numerically simulated and experimental data respectively). This is the first non-invasive derivation of aortic pressure based on phenomenon occurring directly in the ascending aorta.",

keywords = "central blood pressure, aortic flow velocity, pulse wave velocity, hypertension;, left ventricle",

author = "Samuel Vennin and Alexia Mayer and Ye Li and Henry Fok and Brian Clapp and Jordi Alastruey and Phil Chowienczyk",

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doi = "10.1152/ajpheart.00152.2015",

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T1 - Noninvasive calculation of the aortic blood pressure waveform from the flow velocity waveform: a proof of concept

AU - Vennin, Samuel

AU - Mayer, Alexia

AU - Li, Ye

AU - Fok, Henry

AU - Clapp, Brian

AU - Alastruey, Jordi

AU - Chowienczyk, Phil

PY - 2015/9/1

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N2 - Estimation of aortic and left ventricular (LV) pressure usually requires measurements that are difficult to obtain during the imaging required to obtain concurrent LV dimensions essential for determination of LV mechanical properties. We describe a novel method for deriving aortic pressure from the aortic flow velocity. The target pressure waveform is divided into an early systolic upstroke, determined by the water hammer equation, and a diastolic decay equal to that in the peripheral arterial tree, interposed by a late systolic portion described by a second-order polynomial constrained by conditions of continuity and conservation of mean arterial pressure. Pulse wave velocity (PWV, obtainable during imaging), mean arterial pressure, diastolic pressure and diastolic decay are required inputs for the algorithm. Pressure and flow velocities were simulated using a simplified 1-D tube model and experimental data were acquired through a pressure/Doppler flow velocity transducer placed in the ascending aorta in 18 patients (mean±SD, age: 61.8±10.3 years, aortic BP: 136±23/73±13 mmHg). PWV, mean and diastolic pressures and diastolic decay were taken from model parameters or calculated from reference pressures/flows (i.e. were assumed to be known). Estimated pressure waveforms showed excellent agreement with reference pressures for both the simulated and experimental data (mean±SD root mean square error, 0.7±0.1 mmHg and 2.4±1.0 mmHg for numerically simulated and experimental data respectively; peak systolic pressure, mean±SD, 0.4±0.6 mmHg and 1.4±2.0 mmHg for numerically simulated and experimental data respectively). This is the first non-invasive derivation of aortic pressure based on phenomenon occurring directly in the ascending aorta.

AB - Estimation of aortic and left ventricular (LV) pressure usually requires measurements that are difficult to obtain during the imaging required to obtain concurrent LV dimensions essential for determination of LV mechanical properties. We describe a novel method for deriving aortic pressure from the aortic flow velocity. The target pressure waveform is divided into an early systolic upstroke, determined by the water hammer equation, and a diastolic decay equal to that in the peripheral arterial tree, interposed by a late systolic portion described by a second-order polynomial constrained by conditions of continuity and conservation of mean arterial pressure. Pulse wave velocity (PWV, obtainable during imaging), mean arterial pressure, diastolic pressure and diastolic decay are required inputs for the algorithm. Pressure and flow velocities were simulated using a simplified 1-D tube model and experimental data were acquired through a pressure/Doppler flow velocity transducer placed in the ascending aorta in 18 patients (mean±SD, age: 61.8±10.3 years, aortic BP: 136±23/73±13 mmHg). PWV, mean and diastolic pressures and diastolic decay were taken from model parameters or calculated from reference pressures/flows (i.e. were assumed to be known). Estimated pressure waveforms showed excellent agreement with reference pressures for both the simulated and experimental data (mean±SD root mean square error, 0.7±0.1 mmHg and 2.4±1.0 mmHg for numerically simulated and experimental data respectively; peak systolic pressure, mean±SD, 0.4±0.6 mmHg and 1.4±2.0 mmHg for numerically simulated and experimental data respectively). This is the first non-invasive derivation of aortic pressure based on phenomenon occurring directly in the ascending aorta.

KW - central blood pressure

KW - aortic flow velocity

KW - pulse wave velocity

KW - hypertension;

KW - left ventricle

UR - http://ajpheart.physiology.org/content/309/5/H969.abstract

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DO - 10.1152/ajpheart.00152.2015

M3 - Article

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SN - 0363-6135

VL - 309

SP - H969–H976

JO - AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY

JF - AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY

IS - 5

ER -

Noninvasive calculation of the aortic blood pressure waveform from the flow velocity waveform: a proof of concept

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