ADJUSTABLE TEMPORARY VENOUS SPRING FILTER - IN-VITRO ASSESSMENT

Rationale and Objectives. The authors performed an in vitro study to e valuate a temporary venous spring filter that can extend vessels of a wide range of diameters to a slit-shaped canal. Materials and Methods. Filters were placed in thin polyethylene tubes or in porcine inferior vena cava specimens (diameter, 10.0-16.0 mm). Physiologic saline was substituted for blood flow, and blood clots of three sizes (6 x 10, 6 x 20, and 9 x 20 mm) were funneled to the filter. Clot-trapping abilit y was assessed by the degree of luminal extension. Results. When the l uminal extension was increased from 2.6r to 2.8r (where r is the origi nal radius of the vein models), clot-trapping ability increased signif icantly (61.1%-87.5% in polyethylene tubes and 15.8%-77.5% in venous s pecimens; P < .001). When the luminal extension was increased to 3.0r, more than 90% of the clots were trapped in all tubes. After trapping the small, medium, and large clots, mean intraluminal pressure elevati on was 1.0, 1.0, and 17.0 cm of saline, respectively. Conclusion. Desp ite its simple design, the spring filter proved to be an efficient fil tering device.