Hemodynamic effects of blood clots trapped by an inferior vena cava filter

Abstract

The alteration of blood flow around an OPTEASE inferior vena cava filter with one or two blood clots attached was investigated by means of computational fluid dynamics. We used a patient‐specific vein wall geometry, and we generated different clot models with shapes adapted to the filter and vein wall geometries. A total of eight geometries, with one or two clots and a total clot volume of 0.5 or 1 cm3, were considered. A non‐Newtonian model for blood viscosity was adopted and the possible development of turbulence was accounted for by means of a three‐equation model. Two blood flow rates were considered for each case, representative for rest and exercise conditions. In exercise conditions, flow unsteadiness and even turbulence was detected in some cases. Pressure and wall shear stress (WSS) distributions were modified in all cases. Clots attached to the filter downstream basket considerably increased averaged WSS values by up to almost 50%. In all the cases a flow recirculation region appeared downstream of the clot. The degree of flow stagnation in these regions, an indicator of propensity to thrombogenesis, was estimated in terms of mean residence times and mean blood viscosity. High levels of flow stagnation were detected in rest conditions in the wake of those clots that were placed upstream from the filter. Our results suggest that one downstream placed big clot, showing a higher tendency to induce flow instabilities and turbulence, might be more harmful than two small clots placed in tandem.

Investigation of the Effects of an Inferior Vena Cava Filter and Captured Clot Size on the Hemodynamic Parameters in Non-Newtonian Turbulent Pulsatile Blood Flow

“…This study examines three types of blood clots: small, medium, and large blood clots with diameters of 30%, 50%, and 70% of the filter diameter. As mentioned in previous studies [3,4], the geometry of the clot tends to adapt to the filter geometry. The physiological pulses used as boundary conditions are shown in Figure 2.…”

“…The filter is carefully unfolded at the discretion of the practitioner to ensure proper contact with the IVC wall [44]. In this study, similar to previous research [4,44], we attempted to optimize filter placement by adjusting its angle and position to enhance contact with the vessel wall. Given the initial geometry derived from CT scan data, there was no location closely resembling an ideal cylindrical shape.…”

“…Implanting an IVC filter is a suitable option to catch emboli in the pulmonary circulation in particular situations, such as severe bleeding that prevents the use of anticoagulants [3]. IVC filters are metal devices that help prevent PE by trapping thrombi traveling through the blood flow and preventing them from entering the lungs [4].…”

“…In most CFD studies, simple models such as spherical models [14,21] or conical models with spherical ends [3,19,23] have been used to model clots. But it has been observed that clots tend to adapt to filter shape [4].…”

Study of the Influence of Plaque Growth and Hydrostatic Properties in an Atherosclerotic Artery, for the Prevention of Arterial Wall Damage: Application to Vascular Diseases

“…e atheroma plaque, nourished by fats circulating in the blood, gradually develops on the wall of the artery while causing a narrowing (stenosis) hampering the passage of blood and the supply of oxygen to the organ that it irrigates [40]. It also constitutes a real clot trap [41]. When passing through the stenosis, the blood flow slows down, tending to deposit clotting elements (platelet and fibrin) there.…”