Deep venous thrombosis after percutaneous insertion of vena caval filters

Purpose: A large multicenter study has recently questioned the overall clin ical efficacy of vena caval filters, especially when inserted prophylactica lly, because of the subsequent development of deep venous thrombosis (DVT) at the insertion site. We examined the incidence of this complication with newer, smaller diameter percutaneous devices. Methods: We reviewed our vascular surgery and interventional radiology clin ical registries to identify patients in whom a femoral percutaneous vena ca val filter had been placed from 1993 to 1998. This list was cross reference d with patients who had undergone lower extremity venous ultrasound scan ex aminations for the diagnosis of DVT in the vascular laboratory within a 60- day period before and after the insertion of the filter device. Results: A total of 35 patients during this 5-year period had timely follow -up venous duplex scan studies performed. The indications for filter placem ent were DVT in 16 patients (46%), pulmonary embolus in 13 patients (37%), DVT and pulmonary embolus in three patients (9%), and prophylactically in t hree patients (9%) at high risk for thromboembolization. Of the patients wi th documented thromboembolic events, 91% (29 of 32) had contraindications t o anticoagulation therapy, and the remaining 9% (3 of 32) represented failu re of anticoagulation therapy. A Greenfield filter was used in 13 patients (37%), a Simon Nitinol filter was used in 11 patients (31%), and a VenaTech filter was used in nine patients (26%). The other two patients (6%) had a Bird's Nest filter. inserted. At a mean follow-up period of 12 +/- 2 days ( median, 6 days), there was a 40% (14 of 35) incidence of proximal DVT in ve nous segments without evidence of thrombus before filter insertion. The maj ority (71%; 10 of 14) occurred in the common femoral vein, with three locat ed in the superficial femoral vein and one in the external iliac vein. The lowest incidence of DVT was seen with the Greenfield and Bird's Nest filter s as compared with the smaller Simon Nitinol and VenaTech filters (20% vs 5 5%; P <.05). The highest incidence of thrombosis occurred in patients with pre-insertion pulmonary emboli (50%; 8 of 16) as compared with those patien ts with DVT (38%; 6 of 16) and prophylactic insertion (0%; 0 of 3). However , the subgroups were too small to attain statistical significance. Conclusion: There is a continuing and significant incidence of new DVT deve lopment ipsilateral to the percutaneous femoral insertion site of vena cava l filters. The smaller diameter filters are not associated with a lower inc idence of femoral thrombosis.