A new self-convertible inferior vena cava filter:in vivo experimental evaluation / 中国组织工程研究

ABSTRACT

BACKGROUND:An inferior vena cava filter is an effective tool to prevent fatal pulmonary embolism. The existing filters have some shortcomings that limit their clinical application. OBJECTIVE:To evaluate the feasibility and capture efficiency of a new self-convertible inferior vena cava filter (SCF)in vivo. METHODS:L-lactide and ε-caprolactone were fused and polymerized to act as a degradable deformable switch of the filter. Medical stainless steel wire as the metal structure of the filter was combined with the degradable deformable switch to make the SCF. Eight SCFs were implanted into the inferior vena cava of eight adult Beagle dogs. The inferior vena cava angiography was performed to evaluate the release process, morphology and location of the filter. Venous angiography was performed 2 weeks later to evaluate the morphology and location of the filter and inferior vena cava patency. Detection of pulmonary embolism or other complications was performed at autopsy. RESULTS AND CONCLUSION:Eight SCFs were successfully implanted and positioned accurately with no tilt, and they were converted successfully at 2 weeks after the implantation, as assessed by the venous angiography. One of the eight SCFs migrated to the orifice of the right atrium, and caused asymptomatic inferior vena cava obstruction. The remaining SCFs were normally positioned with no tilt and local lesion or obstruction after deformation. No marked filling defect in the trunk of the pulmonary artery was shown by the pulmonary artery angiography. The autopsy report revealed that the filter arm had been endothelialized, and the inferior vena cava that was in contact with the filter arm had no obvious stenosis. Mild intimal hyperplasia, less than 1 mm in thickness, was found in the bottom of the filter arm, but it did not cause a stenosis in the lumen. No vena cava perforation, retroperitoneal hemorrhage, and injury of the surrounding viscera were found. Overall, the design of the SCF is feasible.