DUPLEX-DIRECTED VENA-CAVAL FILTER PLACEMENT - REPORT OF INITIAL EXPERIENCE

Background. Fluoroscopy, cost, and patient transport contribute to dif ficulties occasionally associated with the placement of vena caval fil ters. Follow-up data in the literature document the use of duplex ultr asonography in visualizing the filter and determining caval patency. F ilter placement at the bedside or in the vascular laboratory with dupl ex ultrasonography may simplify this common procedure. We have attempt ed to define the feasibility of this method. Methods. Patients referre d to the vascular surgery service for vena caval interruption were eva luated for ability to visualize the renal veins and inferior vena cava . Location of renal veins, maximum diameter of the vena cava, and pres ence or absence of thrombus were documented. If visualization was adeq uate, placement was performed at the bedside for patients in intensive care or in the vascular laboratory for nonmonitored patients. The ini tial 10 patients and subsequent patients in whom there was a question of adequate deployment underwent completion abdominal roentgenography. Patient follow-up was difficult. Duplex ultrasonography was used to a ssess migration, thrombus adherent to the filter, and vena caval paten cy. Patients in whom filter placement was prophylactic were given anti coagulants at the discretion of the primary physician. Inadequate visu alization or vena caval size greater than 28 mm prompted fluoroscopic placement of the vena caval filter, because only Greenfield titanium f ilters were used in the study. Results. Twenty-nine patients were refe rred for vena caval interruption. Inadequate visualization occurred in four obese patients, and filters were placed by fluoroscopy. There we re no vena caval measurements greater than 24 mm. Twenty-five filters were placed without technical difficulty. One filter tilted into the r ight renal vein, requiring a suprarenal filter placed by fluoroscopy. Patient retrieval for follow-up has been difficult, but by ultrasonogr aphy there has been one vena caval thrombosis and no major filter migr ation. There have been no reported pulmonary emboli other than the one patient with initial tilt of the filter. Conclusions. Placement of ve na caval filters is feasible with duplex ultrasonography. Visualizatio n is the only limiting condition to placement and occurs rarely. Reduc ing the need for fluoroscopy, lowering costs, and not needing to trans port the critically ill patient support the use of this system. Intrav ascular ultrasonography in selected patients may eliminate the need fo r fluoroscopic placement of vena caval filters.