Mechanical Origins of Inferior Vena Cava Filter Tilt and Migration: The Interplay of Clot Burden and Exercise-Induced Pulsatility

Inferior vena cava (IVC) filters are prone to mechanical complications, including fracture, migration, tilt, and wall perforation; however, the underlying physiological mechanisms remain obscure. This paper employs computational fluid dynamics to investigate time-dependent hemodynamics of IVC filters under realistic clinical conditions. A patient-specific IVC geometry was subjected to physiologically pulsatile flow to evaluate flow-field dynamics, hemodynamic indices, and drag forces across varying clot burdens, heart rates, and device tilt angles. Results show that anatomical curvature inherently drives asymmetric, phase-dependent flow—an effect amplified by trapped clots and exercise-induced pulsatility. Filter tilting expands thrombogenic surfaces and spikes peak wall shear stress, raising the oscillatory shear index by up to 88%. While higher heart rates generally reduce extreme low-shear zones under mild occlusion, severe clot burdens generate new downstream stagnation regions characterized by elevated relative residence time, creating conditions favorable for secondary thrombosis. Force analysis reveals that clot burden governs force misalignment; large clots cause the resultant drag vector to deviate by approximately 60 ∘ from the filter axis, generating a substantial lateral moment that provides a mechanistic basis for progressive tilting and migration. Exercise heart rates further amplify pressure drop fluctuations, suggesting that patient activity level should be incorporated into post-implantation risk stratification. These findings demonstrate that the interplay between patient-specific geometry, pulsatile flow, and clot growth governs both local flow disturbances and mechanical stability, offering a pathway toward computational tools for individualized risk assessment and improved long-term management of IVC filters.