Abstract
Some clinicians use endograft to cover half the left subclavian artery (LSA) ostium to cure some cases with insufficient landing area in thoracic endovascular aortic repair(TEVAR) treatment. So we used computational fluid dynamics (CFD) to study the hemodynamic changes on LSA, because they may cause acute thrombosis or arteriosclerosis of LSA.
Methods
The digital model of the aortic arch was established and named model A, which only included supraarch branch the LSA. By directly covering half of the LSA ostiumto simulate half cover LSA ostium as model B. All established models were imported into the Gambit grid division software for grid division and were subsequently imported into the Fluent software for hemodynamic numerical simulation and calculation. The related changes for hemodynamic parameters of LSA were analyzed and compared.
Results
Under the same aortic inlet flow, in model B, the local blood flow velocity of LSA ostium increased and whole blood flow velocity at the distal end decreased. The average wall shear stress(WSS) of the LSA was significantly decreased. Meanwhile there was an obvious turbulent flow in the LSA lumen, and the related blood flow state was disordered.
Conclusion
CFD research confirmed that the implantation of an endograft covering half the LSA ostium can cause obvious hemodynamic changes, which is likely to cause a long-term hardening or an acute thrombosis of the LSA, finally increased the risk of stroke. Once this operation is performed in some specific clinical cases for simplicityand economy, we should actively anticoagulate and follow up regularly.