Comparison of thrombosis risk in an abdominal aortic dissection aneurysm with a double false lumen using computational fluid dynamic simulation method

Abstract

BACKGROUND:

Aneurysms are associated with a mortality rate of 81% or more in cases of rupture. Intraluminal thrombus (ILT) is a common complication of aneurysms, it can greatly increase the risk of rupture. Especially for some of the more complex aneurysms, physicians need to consider the risk of thrombosis or progression and precisely formulate a treatment plan. Therefore, it is particularly important to assess the level of thrombosis risk through haemodynamics.

OBJECTIVE:

To analyse the haemodynamic indices and compare the thrombosis risk in a double false lumen abdominal aortic dissection aneurysm using computational fluid dynamics (CFD).

METHODS:

Computer tomography angiography (CTA) imaging data were collected from a patient with a double false lumen abdominal aortic dissection aneurysm, and three different lesion morphology aneurysm models were established, double false lumen abdominal aortic dissection aneurysm, single false lumen abdominal aortic dissection aneurysm and saccular abdominal aortic aneurysm, in order to analyse the flow velocity, time-averaged shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT) of blood flow, and endothelial cell activation potential (ECAP).

RESULTS:

All three aneurysms were in a low-flow state within the body, and the low-flow velocity flow in the proximal vessel wall extended to the right common iliac artery; the vortex intensity was more intense in the abdominal aortic dissection aneurysm than in the saccular abdominal aortic aneurysm. The risk area for thrombosis was concentrated in the expansion part of the aneurysm and the false lumen. The RRT and ECAP maxima of the double false lumen abdominal aortic dissection aneurysm were much greater than those of the single false lumen dissection aneurysm and saccular aortic aneurysm.

CONCLUSION:

Low-velocity blood flow, high OSI, low TAWSS, high RRT, and high ECAP regions correlate with the risk of thrombosis. The double false lumen type of abdominal aortic dissection aneurysm had some specificity in this case. The risk of thrombosis in the patient was extremely high, and the largest risk zone was within the smaller false lumen, which could be because the smaller false lumen was connected to the true lumen by only one breach. The results of the study provide some guidance in the early screening and development of treatment plans.