Particle image velocimetry study of the celiac trunk hemodynamic induced by continuous-flow left ventricular assist...

Area of Science:

• Cardiovascular Engineering
• Biomedical Fluid Dynamics
• Medical Device Complications

Background:

• Gastrointestinal bleeding is a frequent complication in patients receiving left ventricular assist devices (LVADs).
• LVADs significantly alter aortic hemodynamics, potentially contributing to bleeding complications.
• Understanding these hemodynamic changes is crucial for patient management.

Purpose of the Study:

• To develop and validate a computational model of celiac trunk hemodynamics in an LVAD patient experiencing gastrointestinal bleeding.
• To investigate the relationship between altered blood flow, wall shear stress, and bleeding in the celiac trunk.
• To identify potential flow-mediated mechanisms contributing to gastrointestinal bleeding post-LVAD implantation.

Main Methods:

• An experimentally-calibrated computational fluid dynamics (CFD) model of the abdominal aorta was created.
• Particle image velocimetry (PIV) and echocardiography were used to measure and compare flow distributions in a phantom model.
• Wall shear stress (WSS) distribution was analyzed using CFD.

Main Results:

• Flow distribution analysis showed significant variations, with the mesenteric artery receiving the highest flow and the left renal artery the lowest.
• Bland-Altman analysis confirmed high agreement between PIV and echocardiography flow measurements.
• CFD revealed elevated WSS at the LVAD graft anastomosis and near the ostia of the celiac and mesenteric arteries.

Conclusions:

• Altered shear stress distribution in the celiac trunk may be a key factor in gastrointestinal bleeding after LVAD implantation.
• This hemodynamic alteration could lead to adverse remodeling of the von Willebrand factor, promoting bleeding.
• The developed model provides insights into the mechanisms of LVAD-related gastrointestinal bleeding.