Analysis of blood flow characteristics of intimal rupture in intramural hematoma using computational fluid dynamics.

Intramural hematoma (IMH) is frequently accompanied by intimal tear, presenting as penetrating atherosclerotic ulcer (PAU) or ulcer-like projection (ULP) in aortic computed tomography angiography (CTA) examination, and usually requires clinical intervention. To analyze potential hemodynamic risk factors for intimal rupture in IMH, computational fluid dynamics (CFD) methods were used. CTA images from IMH patients were collected to establish three-dimensional models. The models with ULP removed served as the morphological representation before IMH formed. The three-dimensional models were discretized into grids, and simulations were conducted using the CFD method. No extensive regions of high oscillatory shear index (OSI) and endothelial cell activation potential (ECAP) occurred in the normal aortic arch. The ulcer-like projections or intimal tear sites in IMH exhibit significantly elevated OSI and ECAP. Following repair of the intimal rupture site in the IMH models, hemodynamic parameters demonstrated significant differences between pre-IMH and normal cases. Statistically significant differences were identified in segmented aortic ECAP and OSI between the IMH pre-model and normal aortas. The average ECAPmax was significantly lower in the intimal rupture of pre-IMH cases compared to corresponding normal cases (0.73 vs. 0.84, P = 0.04). Similarly, the average ECAPave showed a higher value in the intimal rupture of pre-IMH cases compared to corresponding normal cases (0.0027 vs 0.0021 with P = 0.03). Notably, the average OSIave was markedly elevated in the intimal rupture of pre-IMH cases compared to corresponding normal controls (0.0038 vs 0.0024 with P = 0.001). This indicates that intimal rupture in IMH was associated with high OSI and ECAP regions in the aorta.