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Influence of Offset on Hemodynamics of Intra-atrial Conduit Fontan's Procedure and Its Clinical Implications
Jie Hu1, Qian Wang2, Zhirong Tong3
1Department of Pediatric Cardio-Thoracic Surgery, Shanghai Children's Medical Center, Shanghai, China.
Insights
Optimizing the offset distance in intra-atrial conduit Fontan procedures is crucial. A 33% offset demonstrated superior hemodynamic performance, improving blood flow and energy efficiency for better patient outcomes.
Area of Science:
- Cardiovascular Surgery
- Medical Imaging
- Computational Fluid Dynamics
Background:
- The optimal offset distance for the superior vena cava (SVC) and intra-atrial conduit (IAC) in Fontan procedures was previously undefined.
- This study aimed to evaluate hemodynamic performance with varying offset designs using virtual surgical models.
Observation:
- Three-dimensional models of IAC Fontan procedures were created from patient MRI data.
- Four offset variations (100%, 67%, 33%, 0% IVC diameter) were simulated for each patient.
- Computational fluid dynamics (CFD) analyzed blood flow, wall shear stress (WSS), energy loss (EL), and hepatic flow distribution (HFD).
Findings:
- A 33% offset consistently yielded the best overall hemodynamic performance across all modeled patients.
- Specific benefits included improved HFD ratios (e.g., 35/65% and 60/40%) and reduced energy loss.
- The 33% offset offered the best balance between hemorheology, pulmonary perfusion, and energy efficiency.
Implications:
- The offset distance significantly impacts hemodynamic performance in IAC Fontan procedures.
- A 33% offset is recommended for surgical planning to optimize hemorheology, pulmonary perfusion, and energy efficiency.
- Further optimization of this distance can enhance surgical outcomes for patients undergoing IAC Fontan procedures.
Background:
The desirable distance, defined as offset, between the central line of the superior vena cava (SVC) and the intra-atrial conduit after an intra-atrial conduit (IAC) Fontan's procedure remained unclear. We compared the hemodynamic features using virtual surgery with different offset designs in our study.
Methods:
Three-dimensional models of IAC Fontan's procedure were reconstructed according to the magnetic resonance imagings (MRIs) of three patients, then four models for each patient with different offsets equaling 100, 67, 33, and 0% of the diameter of the IVC were reconstructed. Computational fluid dynamics (CFD) were performed in each model to predict the best hemodynamic features, including streamlines of blood flow, wall shear stress (WSS), energy loss (EL), and the hepatic flow distribution (HFD) ratio.
Results:
Comprehensive evaluation of WSS, EL, and HFD revealed than an offset of 33% presents the best hemodynamic performance among the three patients modeled. In patient A, an offset of 33% resulted in the best HFD (left pulmonary artery/right pulmonary artery [LPA/RPA] = 35/65%). In patient B, the best trade-off between HFD (35/65%), and WSS was achieved with an offset of 33%. In patient C, EL peaked at an offset of 0% and significantly dropped at an offset of 33% with a desirable HFD (60/40%).
Conclusions:
We verified that the offset distance influences hemodynamic performance in IAC Fontan's procedure. Considering several hemodynamic parameters, the best trade-offs between hemorheology, pulmonary perfusion, and energy efficiency were achieved at an offset of 33%. This distance should be taken into consideration and optimized during the surgical planning for the IAC Fontan's procedure.
