Impact of surgical ventricular restoration on intracardiac hemodynamics: An in silico study using CCT data

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.