arXiv subjects

Karoline-Marie Bornemann

Publications and source records attributed to Karoline-Marie Bornemann.

2 recordsLinked to original sources

arXiv2026

The Fluid Mechanics of Truncus Arteriosus

Truncus arteriosus (TA) is a rare, severe congenital heart disease in which the two main arteries exiting the heart fail to separate in utero resulting in one truncus and truncal valve, carrying mixed oxygenated and deoxygenated blood. About 25% of patients have a quadricuspid valve, which is prone to regurgitation and re-intervention. Despite its relevance for valve performance and mixing, fluid mechanics in TA are poorly understood. Patient-specific fluid-structure interaction simulations were performed based on CT imaging before and after TA repair. The quadricuspid valve was constructed using elasticity-based design with the patient's free edge length and geometric height extracted from echocardiography. Interaction between blood and valve was simulated with the Immersed Boundary Method. Boundary conditions were tuned to the patient's data. Mixing of oxygenated and deoxygenated blood and streaming were assessed via Lagrangian Coherent Structures (LCS) and Lagrangian Particle Tracing (LPT). Low pressures, forward flow and streamwise vortices in the one-sided pulmonary arteries (PAs) throughout the cardiac cycle affected leaflet motion, leading to asymmetric closure and regurgitation. Holodiastolic aortic flow reversal supplied PA flow and the regurgitant jet. LCS and LPT indicated favorable streaming of oxygenated blood from the LV to the aorta and deoxygenated blood from the RV to the PAs. After truncal surgery, normal hemodynamics were restored. This is the first study of fluid mechanics of TA. Using qualitative and quantitative flow analysis, we identified disrupted preoperative hemodynamics caused by one-sided PAs and showed how normal hemodynamics were re-established after repair. Favorable streaming was demonstrated aligned with patient reports. Thus, favorable streaming is plausible in total mixing lesions and patient-specific modeling may aid in its detection.

q-bio.TO↗

arXiv2026

Simulations Predict Improved Valve Performance Without Direct Leaflet Intervention After Neonatal Truncus Arteriosus Repair

Truncus arteriosus (TA) is a rare and severe congenital heart disease. Quadricuspid valve morphology occurs in 25% of all TA patients and is linked to regurgitation and increased risk of re-operation. It remains unclear how hemodynamic changes after TA repair alter valve performance. This study simulated pre- and postoperative conditions in a neonatal TA patient to investigate valve performance without direct intervention. We hypothesize that valve performance before and after truncal repair can be predicted in-silico, matching in-vivo imaging and identifying mechanisms how hemodynamic changes after repair will reduce valve regurgitation without direct intervention. Pre- and postoperative CT images of a neonatal patient with quadricuspid valve were segmented. Free edge length and geometric height from the patient's echocardiogram were used to model the valve. For the preoperative condition, ventricular pressures were set equal modeling an unrestricted ventricular septal defect. Systemic and pulmonary resistances were tuned based on the patient's Qp:Qs ratio. For the postoperative condition, boundary conditions were modified to mimic patient-specific hemodynamics after TA repair. The preoperative simulation confirmed mild valve regurgitation seen in-vivo. Interaction between asymmetric flow and surrounding vessel resulted in asymmetric opening and closing. Poor central coaptation led to a central regurgitant jet toward the septum. Altered postoperative hemodynamics improved coaptation and eliminated regurgitation, as seen in-vivo. This modeling approach reproduced in-vivo pre- and postoperative valve performance and identified mechanisms improving coaptation after TA repair. TA repair led to elimination of regurgitation due to enhanced central coaptation. Thus, altered postoperative hemodynamic conditions after TA repair may improve valve performance without direct leaflet intervention.

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