Abstract 12056: Computational Fluid Dynamics Description of Blood Flow in a Bidirectional Glenn Shunt Supplemented With a Modified Blalock-Taussig Shunt: Relevance to Thrombosis and Power Loss
Introduction: A bidirectional Glenn shunt (BGS) has been supplemented with a modified Blalock-Taussig shunt (BTS), to enhance growth of the pulmonary arteries (PAs). However, the hemodynamics is incompletely understood.
Hypothesis: High velocity BTS flow imposed on low velocity BGS flow can create secondary currents (vortices) in the PAs conducive to clot deposition and power dissipation.
Methods: We employed a computational model (Fluent) of pulsatile flow (viscosity 5 cPa-s), using the finite volume method, and a schematic representation of a BGS with a BTS, to determine velocity field, wall shear stress (WSS) and power (W) efficiency (PE). The region studied included the internal jugular, subclavian and innominate veins, BGS (12.5 mm), BTS (4 mm) and PAs (9 mm). Vessel sizes and flow rates were derived from reported values. Flow rates were fixed at the inlet of the veins, and in the BGS was 1L/min. Aortic pressure (82/42 mmHg) was used at the inlet to the BTS, and a mean pressure (12 mmHg) at the outlets of the PAs.
Results: Fig 1 shows velocity magnitude at peak systole. The BTS jet (red) enters the LPA, where it gives rise to dissipative counter-rotating velocity fields, which augment local WSS. Fig (2) shows the velocity fields (arrows) in cross-sectional planes where the BGS and BTS connect to the PAs. The high WSS (350 Pa) is sufficient (> 100 Pa) to initiate platelet aggregation leading to thrombus formation. PE (1-Wloss /Win) for the BGS alone was 97%; whereas, with the BTS it decreased to 29%. The BTS increased BGS pressure, 12.3 to 14.0 mmHg.
Conclusion: Supplementing a BGS with a BTS can: 1) elevate BGS pressure, 2) create regions at risk for thrombus formation and 3) worsen power loss.
Author Disclosures: S. Aslan: None. N. Ross-Ascuitto: None. M. Guillot: None. R. Ascuitto: None.
- © 2016 by American Heart Association, Inc.