Hybrid model analysis of intra-aortic balloon pump performance as a function of ventricular and circulatory parameters

Gianfranco Ferrari*, Ashraf W. Khir, Libera Fresiello, Arianna di Molfetta, Maciej Kozarski

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

15 Citations (Scopus)

Abstract

We investigated the effects of the intra-aortic balloon pump (IABP) on endocardial viability ratio (EVR), cardiac output (CO), end-systolic (Ves) and end-diastolic (Ved) ventricular volumes, total coronary blood flow (TCBF), and ventricular energetics (external work [EW], pressure-volume area [PVA]) under different ventricular (Emax and diastolic stiffness) and circulatory (arterial compliance) parameters. We derived a hybrid model from a computational model, which is based on merging computational and hydraulic submodels. The lumped parameter computational submodel consists of left and right hearts and systemic, pulmonary, and coronary circulations. The hydraulic submodel includes part of the systemic arterial circulation, essentially a silicone rubber tube representing the aorta, which contains a 40-mL IAB. EVR, CO, Ves, and Ved, TCBF and ventricular energetics (EW, PVA) were analyzed against the ranges of left ventricular Emax (0.3-0.5-1mmHg/cm3) and diastolic stiffness Vstiffness (≈0.08 and ≈0.3mmHg/cm3, obtained by changing diastolic stiffness constant) and systemic arterial compliance (1.8-2.5cm3/mmHg). All experiments were performed comparing the selected variables before and during IABP assistance. Increasing Emaxl from 0.5 to 2mmHg/cm3 resulted in IABP assistance producing lower percentage changes in the selected variables. The changes in ventricular diastolic stiffness strongly influence both absolute value of EVR and its variations during IABP (71 and 65% for lower and higher arterial compliance, respectively). Ved and Ves changes are rather small but higher for lower Emax and higher Vstiffness. Lower Emax and higher Vstiffness resulted in higher TCBF and CO during IABP assistance (~35 and 10%, respectively). The use of this hybrid model allows for testing real devices in realistic, stable, and repeatable circulatory conditions. Specifically, the presented results show that IABP performance is dependent, at least in part, on left ventricular filling, ejection characteristics, and arterial compliance. It is possible in this way to simulate patient-specific conditions and predict the IABP performance at different values of the circulatory or ventricular parameters. Further work is required to study the conditions for heart recovery modeling, baroreceptor controls, and physiological feedbacks.

Original languageEnglish
Pages (from-to)902-911
Number of pages10
JournalArtificial organs
Volume35
Issue number9
DOIs
Publication statusPublished - Sept 2011
Externally publishedYes

Keywords

  • Comprehensive model
  • Computational model
  • Endocardial viability ratio
  • Hybrid model
  • Intra-aortic balloon pump
  • Variable elastance model
  • Ventricular energetics

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