Key result
In a phantom model of an LVAD-supported patient, high wall shear stress was observed in the celiac trunk and mesenteric artery, suggesting a flow-mediated mechanism for gastrointestinal bleeding.
Computational and experimental flow analyses demonstrate that continuous-flow LVADs create high wall shear stress in the celiac trunk and mesenteric artery, providing a potential flow-mediated mechanism for gastrointestinal bleeding.
Supports flow-mediated GI bleeding mechanism in LVADs; leaves open whether anastomosis optimization alters clinical risk.
Whereas left ventricular assist device (LVAD) is the gold-standard therapy for patients with heart failure, gastrointestinal bleeding is one of the most common complications. LVAD implantation may remarkably impact aortic hemodynamics so that experimental and computational flow analyses can be used to study the disease mechanisms. Here we present an experimentally-calibrated computational model of the celiac trunk hemodynamic of a LVAD-supported patient who experienced bleeding after device implantation. Specifically, both particle image velocimetry (PIV) and echocardiography were used to measure and compare flow distributions in each branch of a phantom model of the patient abdominal aorta. Then, the distribution of wall shear stress (WSS) was estimated by computational flow analysis. At a cardiac output of 5 L/min, the highest flow division was found in the mesenteric artery (13.6% for PIV and 14.6% for echocardiography), while the left renal artery exhibited the lowest amount in the celiac trunk model (2.6% for PIV and 2.4% for echocardiography). Bland-Altman analysis demonstrated a high agreement between echocardiographic and PIV-related flow measurements, while computational flow analysis revealed that WSS was high in the LVAD graft anastomosis site and just after the ostia of both the celiac trunk and mesenteric artery. This altered shear stress distribution in the celiac trunk may lead to a flow-mediated mechanism of adverse remodeling of the von Willebrand factor and ultimately to gastrointestinal bleeding as seen clinically in this patient.
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Scardulla et al. (2017) studied Heart failure with LVAD and gastrointestinal bleeding (n=1). Continuous-flow left ventricular assist device was evaluated on Flow distributions and wall shear stress in the celiac trunk and branches. In a phantom model of an LVAD-supported patient, high wall shear stress was observed in the celiac trunk and mesenteric artery, suggesting a flow-mediated mechanism for gastrointestinal bleeding.
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