Embolus Migration and Capture from Different Cross-sectional Release Positions

Open Access
Author:
Pulenthiran, Arichanah Annam
Area of Honors:
Biomedical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Keefe B Manning, Thesis Supervisor
  • William O Hancock, Honors Advisor
  • Peter J Butler, Faculty Reader
Keywords:
  • Filter
  • vena cava
  • IVC
  • embolus
  • imaging
Abstract:
Deep vein thrombosis occurs in one out of one thousand people and can eventually produce pulmonary embolisms by dislodging and traveling to the lungs. Anti-coagulation therapy is currently the primary treatment for venous thromboembolism, but vena cava filters are now being used as an alternative in up to fifteen percent of patients. Filters are not more prevalent because they have several problems including perforation of vessels, travel within the vessel, and breakage of struts that may travel into the heart. This study experimentally examined embolus migration through the inferior vena cava (IVC) and capture by an IVC filter. A flow loop containing an acrylic IVC model was constructed containing a Bard G2 Express IVC filter placed within the inferior vena cava. Resting (1.2 L/min) and exercise (3.5 L/min) flow rates were used in the loop to simulate physiological conditions with 1/4", 1/8”, and 3/16” sized emboli. High speed imaging was used to obtain two planes of video of the embolus trajectory in the model, which allowed for a three-dimensional construction of the embolus trajectory. To account for the mirror displacement, data were obtained by correlating the Y values for both views which created a calibration curve to combine both two-dimensional views into a three-dimensional plot. The three-dimensional embolus trajectories showed that there is a small recirculation zone on the right side of the IVC model. In addition, when entering from the right iliac vein, emboli followed very similar paths for all three embolus sizes. In general, the emboli that entered from the right iliac vein had a higher percentage of being captured at both flow rates and emboli traveling at a higher flow rate had a higher chance of being captured. These results are important for vertical and angular placement of the IVC filter.