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R A Reed

Publications and source records attributed to R A Reed.

6 recordsLinked to original sources
PubMed1992

Comparison of filters in an oversized vena caval phantom: intracaval placement of a bird's nest filter versus biiliac placement of Greenfield, Vena Tech-LGM, and Simon nitinol filters.

For patients with an oversized inferior vena cava (IVC) (diameter greater than 28 mm, corrected for magnification) who require vena caval filtration for prophylaxis against pulmonary emboli, the accepted treatment has been the biiliac venous placement of Greenfield filters. Because of its wide strut span, the Bird's Nest filter (BNF) has been successfully placed in patients having an oversized IVC. However, the effects of the BNF on caval blood flow and its clot-capturing ability in an oversized IVC are not clearly understood. The authors created a flow phantom simulating an oversized IVC with "iliac" tributaries of normal inner diameter to analyze flow turbulence, pressure gradients, and the clot-capturing ability of the BNF, tested within the "caval" segment of the phantom, and the Greenfield, Vena Tech-LGM, and Simon nitinol filters, tested in the "iliac" segments. All filters were tested for flow disturbances before and after clot capture. The authors' results demonstrate that within an oversized IVC, the BNF creates less flow disturbance and is less occlusive with clot capture than biiliac filters. The BNF displayed a clot-capturing ability equal to that of biiliac filters. Thus, for patients with an oversized IVC, these results suggest that placement of a single intracaval BNF is preferable to biiliac placement of filters.

Humans↗
PubMed1991

Incomplete opening of LGM (Vena Tech) filters inserted via the transjugular approach.

Over a 12-month period, 216 LGM vena caval filters were placed in 216 patients at four institutions. The transjugular approach was used in 31 of 216 insertions (14%); 185 of 216 filters (86%) were inserted via the femoral route. Incomplete opening of filters was encountered in 13 of 31 transjugular insertions (41%) and none of 185 transfemoral insertions. Delayed spontaneous filter opening occurred in three of 12 cases (25%) of incomplete opening (in which follow-up was available) at 5 minutes, 4 days, and 2 months after insertion. One filter opened completely after catheter manipulations. Several mechanisms explaining this complication are proposed. In its present form, the LGM filter should not be inserted via the jugular route. Since the filtering capabilities of the incompletely opened LGM device have been shown to be diminished in vitro, it may be advisable to place a second filter cephalad to an incompletely opened LGM filter.

Equipment Failure↗
PubMed1991

Use of the Bird's Nest filter in oversized inferior venae cavae.

An inferior vena cava (IVC) diameter of greater than 28 mm has been considered a contraindication to the intracaval placement of Greenfield, LG-Medical (LGM), and Simon nitinol filters, necessitating biiliac placement of these devices. With the Bird's Nest filter (BNF), the maximum span of the struts, which immobilize the device, is 60 mm; this allows the placement of the BNF in an oversized IVC having a diameter of greater than 28 mm. Over a 44-month period, 799 IVC filters (547 BNF, 136 Greenfield filters, and 116 LGM filters) were inserted. BNFs were placed in 18 patients (2.3%) with an oversized IVC (diameter range, 29-42 mm); all filters were placed via the femoral route. Patient records were reviewed to determine if problems were associated with filter insertion (including insertion site femoral vein thrombosis) and to determine the prevalence of filter migration, caval thrombosis, and new or recurrent pulmonary emboli (PE) after insertion. No difficulties were encountered during insertion. There was no documented case of device migration, caval thrombosis, or clinically apparent new or recurrent PE. The data suggest that the BNF is the filtering device of choice in patients with an oversized IVC.

Adult↗