Teitelbaum G P, Jones D L, van Breda A, Matsumoto A H, Fellmeth B D, Chespak L W, Barth K H
Department of Radiology, Georgetown University Hospital, Washington, DC.
Radiology. 1989 Dec;173(3):809-14. doi: 10.1148/radiology.173.3.2813790.
Significant structural and mechanical differences exist between the titanium and stainless steel versions of the Greenfield filter (GF). The titanium GF has a longer leg length (49 mm vs 43 mm), a greater span (38.5 mm vs 28.0 mm), and a larger hook angle (41 degrees vs 23.5 degrees). In vitro tests demonstrated approximately sevenfold greater filter length shortening (a measure of filter splaying) for the titanium GF in response to a given applied load. These differences resulted in marked filter splaying and inferior vena cava (IVC) perforation in three patients in whom a titanium GF had been inserted. The aorta was penetrated by a filter leg in one patient, and abdominal or back pain was present in all three patients. In vitro tests involving thrombosis within a latex balloon revealed that the titanium GF, but not the stainless steel GF, remained splayed even in the face of clot retraction. Design modifications, possibly using shorter, thicker filter legs and using reduced hook angles, should be made in the titanium GF to decrease the risk of filter splaying and IVC perforation before widespread use of this device.
格林菲尔德滤器（GF）的钛制版本和不锈钢版本之间存在显著的结构和力学差异。钛制GF的腿长更长（49毫米对43毫米），跨度更大（38.5毫米对28.0毫米），钩角更大（41度对23.5度）。体外测试表明，在给定的外加负荷下，钛制GF的滤器长度缩短（滤器展开的一种度量）约为不锈钢GF的七倍。这些差异导致在三名植入钛制GF的患者中出现明显的滤器展开和下腔静脉（IVC）穿孔。一名患者的滤器腿穿透了主动脉，所有三名患者均出现腹痛或背痛。涉及乳胶气球内血栓形成的体外测试显示，即使面对血块收缩，钛制GF仍会展开，而不锈钢GF则不会。在广泛使用该装置之前，应在钛制GF上进行设计改进，可能采用更短、更粗的滤器腿并减小钩角，以降低滤器展开和IVC穿孔的风险。
