Impact of surgical ventricular restoration on intracardiac hemodynamics: An in silico study using CCT data
Lukas Obermeier1, Moritz Wiegand1, Titus Kuehne2
1Deutsches Herzzentrum der Charité, Institute of Computer-assisted Cardiovascular Medicine, Augustenburger Platz 1, 13353, Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany.
Insights
Surgical ventricular restoration (SVR) improves heart function by reshaping the left ventricle (LV). Digital models show SVR enhances blood flow dynamics and efficiency, leading to better heart performance post-surgery.
Area of Science:
- Cardiovascular Surgery
- Biomedical Engineering
- Computational Fluid Dynamics
Background:
- Myocardial infarction can lead to dilated, aneurysmal left ventricles (LVs), impairing cardiac function.
- Surgical ventricular restoration (SVR) aims to restore LV shape and contractility by excluding scarred myocardium.
- Intracardiac hemodynamic changes after SVR require detailed investigation.
Purpose of the Study:
- To investigate the hemodynamic impact of successful SVR using patient-specific digital replicas.
- To analyze changes in LV morphology, dynamics, and intracardiac blood flow post-SVR.
Main Methods:
- Creation of digital LV replicas from pre- and post-operative cardiac CT data of nine patients.
- Application of image-based computational fluid dynamics (CFD) to calculate LV morphology, dynamics, and hemodynamics.
- Analysis of morphological parameters (wall thickness, sphericity) and hemodynamic metrics (kinetic energy, washout, vortex strength, energy loss).
Main Results:
- SVR successfully reduced LV volumes and restored myocardial wall thickness in aneurysmal regions.
- Post-operative analysis revealed increased end-diastolic sphericity and higher kinetic energy levels.
- Improved global washout, increased vortex strength, and decreased energy loss indicated enhanced flow efficiency and diastolic filling.
- Hemodynamic filling forces aligned with the LV long axis and correlated with LV contractility.
Conclusions:
- Digital patient replicas are valuable tools for detailed hemodynamic analysis after SVR.
- Successful SVR leads to favorable intracardiac flow changes, improving LV function and efficiency.
- The study demonstrates significant hemodynamic benefits of SVR beyond morphological restoration.
Abstract:
Surgical ventricular restoration (SVR) excludes scarred myocardium after myocardial infarction to restore shape and contractility of dilated, aneurysmal left ventricles (LVs). Detailed changes in intracardiac hemodynamics following the surgery are not fully investigated. In this study, digital replicas of the patient's LV were used to study the hemodynamic impact of successful SVR. The digital replicas were built based on pre-operative and post-operative cardiac computed tomography data of nine patients (3females, 60 ± 13years) who underwent successful SVR (significant reduction in heart failure symptoms). The computational framework was used to calculate LV morphology, dynamics, and intracardiac hemodynamics using image-based computational fluid dynamics (CFD). SVR successfully reduced the LV volumes. Morphological analysis showed restoration of myocardial wall thickness in aneurysmal regions (5.5 ± 2.0 vs. 8.6 ± 3.0 mm) and an increased end-diastolic sphericity (sphericity index 0.39 ± 0.07 vs. 0.46 ± 0.07). No distinct flow alterations could be linked thereto. CFD revealed a higher post-operative kinetic energy level (diastolic maximum 10.0 ± 7.6 vs. 16.8 ± 9.1mJ) and an improved global washout (29.5 ± 9.7 vs. 10.3 ± 6.4% after five cycles), which correlated to increases in volume-curve-derived diastolic energy gain and ejection fraction, respectively. Flow efficiency improved by means of an increased end-diastolic surface-averaged vortex strength (16.2 ± 5.1 vs. 30.0 ± 15.01/s) and a decreased normed diastolic energy loss (18.9 ± 3.9 vs. 15.0 ± 3.7%). The hemodynamic filling forces in diastole were aligned with the LV long axis before and after surgery and correlated with LV contractility. In summary, the digital patient replicas facilitated a detailed analysis and showed favorable flow changes with successful SVR.
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