Retrievable IVC filter: preliminary in vitro and in vivo evaluation.
OBJECTIVE
To develop an inferior vena cava (IVC) filter that is retrievable even after neointimal formation and incorporation into the caval wall.


METHODS
Eight filters were placed percutaneously in the infrarenal IVC of eight dogs. Four weeks after placement, percutaneous retrieval of the filters was attempted. Vena cavograms were obtained before and immediately after retrieval. Three dogs were killed immediately after the retrieval procedure was completed. In the other five dogs, follow-up vena cavography was performed 4-14 weeks after retrieval, and autopsy was performed.


RESULTS
The filters were placed and retrieved successfully in all eight dogs. No migration, caval penetration, or tilting occurred. The IVCs were completely patent both before and immediately after retrieval in all eight dogs. In the three dogs killed immediately after retrieval, neointimal hyperplasia was seen around the struts, but there was no detachment. Delayed stenosis was not seen in any of the five dogs that were followed up, and the inner surface of the caval wall was smooth.


CONCLUSIONS
This IVC filter can be easily placed and safely retrieved percutaneously, even after neointimal formation.
Irie
T
T
Department of Radiology, National Defense Medical College, Saitama, Japan.
Yamauchi
T
T
Makita
K
K
Kusano
S
S
D000818:Animals; D002405:Catheterization, Central Venous / Q000295:instrumentation; D004285:Dogs; D004867:Equipment Design; D005500:Follow-Up Studies; D006965:Hyperplasia; D011859:Radiography; D015642:Radiology, Interventional; D012834:Silver; D013193:Stainless Steel; D013499:Surface Properties; D013927:Thrombosis / Q000517:prevention & control; D017539:Tunica Intima / Q000473:pathology; D014654:Vascular Patency; D016306:Vena Cava Filters; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging / Q000473:pathology
D013193:Stainless Steel; D012834:Silver