Hemodynamic Characterization of Spontaneous Isolated Superior Mesenteric Artery Dissection Revealed by Patient-Specific Computational Fluid Dynamics

Background Spontaneous isolated superior mesenteric artery dissection (SISMAD) is a rare but potentially lethal vascular emergency with unclear pathogenesis. While hemodynamic forces are implicated in its development, current understanding remains limited by the lack of patient-specific data. This study aimed to characterize the detailed hemodynamic environment in SISMAD using patient-specific computational fluid dynamics modeling. Results Analysis of a three-dimensional model reconstructed from computed tomography angiography of a Yun Type I SISMAD revealed complex flow patterns with marked hemodynamic differences between the true lumen (TL) and false lumen (FL). The TL exhibited high-velocity flow concentrated near the entry tear and significantly elevated wall shear stress along the intimal flap. In contrast, the FL demonstrated markedly lower velocities, regions of flow stasis, and low wall shear stress. A substantial pressure gradient existed across the intimal flap, with higher pressure in the TL compared to the FL. These findings provide quantitative confirmation of the theorized hemodynamic forces contributing to dissection progression and potential thrombosis formation. Conclusions Patient-specific computational modeling reveals a complex and heterogeneous hemodynamic environment within the dissected superior mesenteric artery. The high-velocity flow and elevated wall shear stress in the true lumen may contribute to flap instability and inflammation, while the low-flow, stagnant conditions in the false lumen likely promote thrombogenesis. This patient-specific approach provides valuable insights into SISMAD pathophysiology and demonstrates potential for personalized ris assessment and treatment planning in this rare but serious vascular condition.