Hemodynamics of type B aortic dissection with structural chirality

Abnormal morphologies of blood vessels may cause severe clinical complications. The true lumens (TLs) of type B aortic dissection (TBAD) patients exhibit different levels of spiral configurations. It remains unclear how the true lumen chirality (TLC) influences, e.g., vascular remodeling and disease progression. In this paper, we investigate, through a combination of experimental measurements and numerical simulations, the hemodynamics of TBAD with structural chirality. A fluid–structure interaction (FSI) model integrating the support effect of lateral aortic branches is applied to analyze the complex hemodynamic process in spirally curved, flexible luminal structures. The FSI results are supported by the four-dimensional flow magnetic resonance imaging measurements. We find that the entire dissected aortas with more notable TLC are featured by higher time-averaged wall shear stress, larger averaged von Mises stresses, more prominent deformation, and greater time-averaged luminal blood pressure. The TLC shortens the relative residence time of the blood, and accelerates the blood flow in the false lumens (FLs). The postoperative follow-up results demonstrate that the helical TL can be effectively straightened and well remodeled when long stent graft repair is adopted. It is revealed that the TLC in TBAD may promote aortic rupture, progression of the dissection, and FL dilation. It is suggested that the TLC should be accounted for in the surgical planning when the helical angle of TBADs exceeds 180°. This work may help understand the biomechanical and biomedical effects of the structural chirality in TBAD, and holds potential applications in the treatment of TBAD and other aortic diseases.