A computational fluid study on hemodynamics in visceral arteries in a complicated type B aortic dissection after thoracic endovascular repair

To report a numerical research on the effect of a renal artery arising from false lumen (FL) on the treatment outcome of thoracic endovascular repair (TEVAR) for complicated type B aortic dissection (TBAD). The original patient-specific model with the right renal artery (RRA) partially supplied by the FL (TFM) was reconstructed from its postoperative computed tomography images. Two additional models were reconstructed by artificially modifying the RRA either fully arising from the FL(CFM) or true lumen (CTM). Computational fluid dynamics (CFD) simulations were performed. First, for all the models, the flow splits to all the visceral arteries were much less than those of a healthy aorta. Second, the flow split to RRA in the CFM and in CTM was the least and largest respectively. Third, in TFM, the pressure gradient between the true lumen (TL) and FL was negative at the proximal FL and the entire FL was full of active blood flow. In the contrast, in CTM and CFM, the pressure differences between the two lumens remained positive and little flow was present in FL. Finally, both TL and proximal FL of this particular patient expanded and the diameters of all visceral arteries decreased at one-year follow-up. Compared to a healthy aorta, a renal artery arising from FL following TEVAR would result in severe visceral ischemia including RA and superior mesenteric artery (SMA). In addition, our numerical simulation of the postoperative hemodynamics of this particular patient perfectly matched with its TL remodeling, FL expansion and contraction of the visceral arteries at one-year follow-up, and a patient-specific CFD simulation may be adopted to obtain information on visceral perfusion after endovascular repair for TBAD patients.