Anatomic and hemodynamic changes in the inferior vena cava associated with prevention of pulmonary thromboembolism.

This paper analyzes the results of a multimodality instrumental study of the structural and functional properties of the inferior vena cava (IVC) in 173 patients with acute venous thrombosis, who underwent different interventions aimed at pulmonary thromboembolism (PTE) prevention. Of these, 63% of patients were examined in the long-term period, within the time 2 to 36 months. 26% of patients were found to have variants of the anatomic structure of the IVC system, such as the doubling of the renal veins, ring-shaped structure or entry to the IVC at a distance exceeding 5 cm from each other. The paper also provides a detailed analysis of the hemodynamic parameters (maximal and minimal linear flow velocities in the IVC, time-averaged maximal linear flow velocities and their different indices) and of their changes as dependent on the type of interventions on the IVC. It has been established on the basis of the data obtained that endovascular catheter thrombectomy is the method for PTE prevention because it restores the IVC lumen and refines the regional hemodynamics. Cava filter implantation induces a rounded deformation and expansion of the infrarenal IVC up to 40.9% of the area of its cross section but exerts a minimal adverse effect on the flow. IVC plication leads to a slit-like deformation and a 12.9% stenosis of its lumen as well as to deceleration of the flow acquiring a turbulent character.