Search

Aim: a 7 F percutaneous cava filter was achieved, developed and tested in a goat. Thanks to its double-spiral original form, it is possible to place and remove it atraumaticaly and percutaneously. PRINCIPLES OF THE FILTER: its diameter, larger than the lower vena cava's (LVC) leads to a flattening of the venous lumen whose flow is intersected by the filter turns, thus creating a netting effect., Case-Report: during 28 months, 40 filters were introduced under fluorscopy in 20 goats. Thanks to 16 embolizations, it was possible to test the effectiveness of the filter against small emboli, with simultaneous cavography and pulmonary angiography in 4 cases. 29 filters were removed by jugular and femoral track, from D0 to D14. 12 goats were sacrificed to investigate histologicaly and macroscopicaly the LVC and control the biocompatibility from the 8th to the 385th day. Clinical and radiological supervision lasted more than one year for 3 goats., Results: the size of the filter (30, 35, 40 mm) is chosen from the LVC diameter measured by cavography. 30 filters were introduced via jugular vein, 10 via femoral vein. These filters were introduced by catheter 7F thanks to an applicator and placed in correct position in the LVC. RELIABILITY OF THE FILTER: easy percutaneous introduction 7F. Once installed, the filters flatten the LVC; this process is automatically confirmed by cavography, and by scanning in 4 cases. EFFECTIVENESS AGAINST EMBOLI: out of 16 cases, 2 partial failures were observed at the beginning of the experiment (one spiral-fitted filter). Its effectiveness was optimized thanks to the addition of a second spiral which allowed the blocking of over-2 mm clots. PERCUTANEOUS REMOVAL: during the initial removals, partial failures were due to the fragility of the filter and the inflexibility of the extracting material. Successive changes of the shape and the alloy of the filter as well as the development of catheters and extracting materials have led to a sufficient reliability to remove (D0 to D14) the filter in security, by percutaneous tract (9 jugular, 9 femoral) before its clamping on the LVC, on the 15th day. INNOCUOUSNESS: both biological supervision and anatomo-pathological investigation have showed the good tolerance of the filter. In local areas, this atraumatic filter does not wound nor perforate the LVC wall. Histologically, a thickening of the intima is observed. The positive results of this experiment led us to start clinical trials of "DM" filter in human beings.

Healthcare professionals increasingly are using vena cava filters to prevent pulmonary emboli (PE) in patients with cancer. Patients with cancer are predisposed to developing thrombosis and subsequent PE for a variety of reasons. These patients commonly have contraindications to anticoagulant therapy because of their disease or cancer treatment; therefore, vena cava filters are an appealing option for managing potential emboli. This article describes the etiologies of thrombosis in patients with cancer; problems associated with conventional anticoagulant therapy; vena cava filters and placement procedures; complications associated with filter placement; and related nursing implications pre- and postinsertion and during long-term follow-up.

Digital subtraction venacavography (DSV) as a follow-up examination was performed in 46 patients after placement of a standard stainless steel Greenfield vena caval filter (SGF). DSV is an exact method of visualizing the lumen of the inferior vena cava as well as intraluminal or captured thrombi. Eccentric filters with an angulation of more than 15 degrees were found in 8 patients causing a higher risk of pulmonary embolism from smaller emboli and propagating thrombi. Penetration of the caval wall by filter struts was however frequent (41%), without any damage to adjacent structures as demonstrated by CT scans. The long-term caval patency rate was 90%, with 4 cases of caval thrombosis. Two patients with an occluded inferior vena cava showed no venostasis. Although changes of the filter position usually remain asymptomatic, regular follow-up examinations seem necessary to recognize any impairment of the filter's clot trapping efficiency. Filters should only be used in patients with a risk of recurrent pulmonary embolism despite anticoagulation and patients with contraindications to anticoagulation therapy.

This study comprises a series of 35 patients with pelvic or lower extremity fractures requiring surgery who also had a documented significant acute deep venous thrombosis (DVT). The authors treated these with low-dose Coumadin and 36 vena caval filters, which were used prophylactically prior to surgery. The patients received low-dose warfarin after placement of the vena caval filters and were maintained at 1.3-1.5 times the prothrombin control value for 6 weeks to 3 months. In this group of patients, there were no fatal pulmonary emboli and no clinically significant complications from filter placement. There were nine asymptomatic filter complications demonstrated radiographically in eight patients. Additionally, one patient with a tilted vena caval filter required placement of another filter. The combination of vena caval filters and low-dose warfarin appears to be a successful and relatively safe method of managing those patients who have acute DVT and require surgery for their pelvic or lower extremity fractures.

Pulmonary embolism is a potentially lethal complication among patients with acetabular fractures requiring surgery. The reliability, safety, and extent of efficacy of pharmacologic as well as existing nonpharmacologic anticoagulation prophylaxis in this patient group has not been determined. A careful analysis of the myriad factors acting on these patients who have had major trauma and have undergone a major surgical procedure about the hip prompted a change in our approach to prophylaxis in this patient group. In the period from March 1984 through October 1987, 51 patients having 52 acetabular fractures underwent osteosynthesis at the Wake Forest University Medical Center. Twenty-four patients had two or more identifiable risk factors and underwent insertion of a Greenfield filter for prevention of pulmonary emboli. Filters were inserted at the time of acetabular surgery with C-arm guidance via the internal jugular vein approach. The average time for insertion was 57 min. Placements were verified by plain roentgenograms. There were no complications during filter insertion. Four patients with filters (17%) developed leg edema; in three the edema was minor, and in one the filter trapped what could have been a fatal embolus but caused lower extremity venous stasis severe enough to result in peripheral lower extremity tissue loss. There were no pulmonary emboli (by clinical criteria). The remaining 27 patients had routine medical prophylaxis and no filters. In this group, two patients had a clinically evident pulmonary embolus (7%), and one of these patients died. Two other patients (7%) had minor chronic leg edema. In one of them, a proximal deep venous thrombosis in the lower extremity was documented with venography, requiring rehospitalization and anticoagulant therapy.(ABSTRACT TRUNCATED AT 250 WORDS)