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A lumped parameter model of the coronary circulation incorporating time-varying resistance, intramyocardial pressure and vascular compliance

Yong, Enhui ; Latief, Javeria ; Wang, Yufei ; Erlinge, David LU orcid ; Dahlgren, Axel LU ; Kotecha, Tushar ; Muthurangu, Vivek and Torii, Ryo (2025) In Journal of Biomechanics 189.
Abstract

Conventional lumped parameter models (LPMs) simulate coronary flow incorporating intramyocardial pressure and vascular compliance, but assuming constant resistance despite its dynamic changes during myocardial contraction. We developed a coronary LPM incorporating time-varying resistance, intramyocardial pressure and vascular compliance to simulate phasic flow, critically evaluating key contributing factors. A closed-loop LPM with coronary tree was constructed. For each of Left Anterior Descending (LAD), left circumflex and Right Coronary (RCA) territories, time-varying microvascular resistance Rmicrot and intramyocardial pressure (IMP) Pimt were defined additionally to standard components. Scenarios of normal... (More)

Conventional lumped parameter models (LPMs) simulate coronary flow incorporating intramyocardial pressure and vascular compliance, but assuming constant resistance despite its dynamic changes during myocardial contraction. We developed a coronary LPM incorporating time-varying resistance, intramyocardial pressure and vascular compliance to simulate phasic flow, critically evaluating key contributing factors. A closed-loop LPM with coronary tree was constructed. For each of Left Anterior Descending (LAD), left circumflex and Right Coronary (RCA) territories, time-varying microvascular resistance Rmicrot and intramyocardial pressure (IMP) Pimt were defined additionally to standard components. Scenarios of normal physiology and Pulmonary Hypertension (PH) were studied. Model output was assessed against in vivo measurement in the literature. The mean diastolic-systolic flow ratio (mDSFR) in LAD was underestimated by the conventional model only considering IMP (mDSFR = 1.70, vs 1.95 for in vivo measurement). Inclusion of time-varying resistance in the LPM raised mDSFR to 2.65. In the RCA, mDSFR was raised from 1.00 to 1.50 by introduction of time-varying resistance, markedly closer to 1.76 that was measured in vivo. In PH, modelled RCA flow became more diastolic dominant, represented by mDSFR of 5.35 that is closer to in vivo value of 5.83 than 2.17 which was obtained by the conventional model. The intramyocardial pressure component remained essential for regional arterial phasic changes and venous systolic-dominant flow. The simple-to-implement method of time-varying vascular resistance, developed in this study to better reflect the myocardial contraction in coronary flow analysis, facilitated an improved physiological representation compared to conventional methods, notably in the RCA especially in PH.

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author
; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Computational modelling, Coronary haemodynamics, Coronary mechanics, Lumped parameter model, Time-varying resistance
in
Journal of Biomechanics
volume
189
article number
112679
publisher
Elsevier
external identifiers
  • scopus:105007135962
ISSN
0021-9290
DOI
10.1016/j.jbiomech.2025.112679
language
English
LU publication?
yes
id
0f018ae1-17f1-4a5c-8402-7284b2d42cc3
date added to LUP
2025-07-17 09:58:45
date last changed
2025-07-17 10:00:00
@article{0f018ae1-17f1-4a5c-8402-7284b2d42cc3,
  abstract     = {{<p>Conventional lumped parameter models (LPMs) simulate coronary flow incorporating intramyocardial pressure and vascular compliance, but assuming constant resistance despite its dynamic changes during myocardial contraction. We developed a coronary LPM incorporating time-varying resistance, intramyocardial pressure and vascular compliance to simulate phasic flow, critically evaluating key contributing factors. A closed-loop LPM with coronary tree was constructed. For each of Left Anterior Descending (LAD), left circumflex and Right Coronary (RCA) territories, time-varying microvascular resistance R<sub>micro</sub>t and intramyocardial pressure (IMP) P<sub>im</sub>t were defined additionally to standard components. Scenarios of normal physiology and Pulmonary Hypertension (PH) were studied. Model output was assessed against in vivo measurement in the literature. The mean diastolic-systolic flow ratio (mDSFR) in LAD was underestimated by the conventional model only considering IMP (mDSFR = 1.70, vs 1.95 for in vivo measurement). Inclusion of time-varying resistance in the LPM raised mDSFR to 2.65. In the RCA, mDSFR was raised from 1.00 to 1.50 by introduction of time-varying resistance, markedly closer to 1.76 that was measured in vivo. In PH, modelled RCA flow became more diastolic dominant, represented by mDSFR of 5.35 that is closer to in vivo value of 5.83 than 2.17 which was obtained by the conventional model. The intramyocardial pressure component remained essential for regional arterial phasic changes and venous systolic-dominant flow. The simple-to-implement method of time-varying vascular resistance, developed in this study to better reflect the myocardial contraction in coronary flow analysis, facilitated an improved physiological representation compared to conventional methods, notably in the RCA especially in PH.</p>}},
  author       = {{Yong, Enhui and Latief, Javeria and Wang, Yufei and Erlinge, David and Dahlgren, Axel and Kotecha, Tushar and Muthurangu, Vivek and Torii, Ryo}},
  issn         = {{0021-9290}},
  keywords     = {{Computational modelling; Coronary haemodynamics; Coronary mechanics; Lumped parameter model; Time-varying resistance}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Journal of Biomechanics}},
  title        = {{A lumped parameter model of the coronary circulation incorporating time-varying resistance, intramyocardial pressure and vascular compliance}},
  url          = {{http://dx.doi.org/10.1016/j.jbiomech.2025.112679}},
  doi          = {{10.1016/j.jbiomech.2025.112679}},
  volume       = {{189}},
  year         = {{2025}},
}