CT fluoroscopic guided insertion of inferior vena cava filters

Inferior vena cava filter placement at bedside using computed tomography scan information: a new technique for accurate deployment

BACKGROUND

An inferior vena cava filter (IVCF) is indicated for the prophylaxis of pulmonary embolism where anticoagulation is contraindicated. The majority of these filters are placed using fluoroscopy and venogram. We hypothesized that a computed tomography (CT) scan of the abdomen and pelvis provides sufficient information for successful deployment of an IVCF at bedside without the need for any further imaging during the procedure.

METHODS

A retrospective review of prospectively collected data of a bedside IVCF placement technique using measurements from abdominal/pelvic CT scans without additional intraoperative imaging in 38 patients at a level 1 trauma center was conducted.

RESULTS

The most common indication for IVCF placement was high-risk patients without deep venous thrombosis. All these procedures were performed at bedside. Nonretrievable (TrapEase) and retrievable (OptEase) type filters were used. All these IVCFs were placed below the renal veins without any complications.

CONCLUSIONS

IVCFs can be placed based on measurements from abdominal CT scans without the need for further imaging such as fluoroscopy or an inferior vena cava venogram. This technique is as simple as bedside femoral venous line placement.

Use of noncontrast computed tomography of the inferior vena cava for real-time imaging guidance for the placement of inferior vena cava filters

Appropriate placement of an inferior vena cava (IVC) filter necessitates imaging of the renal veins because when an IVC filter is deployed its tip should be at or below the inferior aspect of the inferiormost renal vein. Traditionally, imaging during placement of IVC filters has been with conventional cavography and fluoroscopy. Recently, intravascular ultrasound has been used for the same purpose but with additional expense. Morbidly obese patients often exceed the weight limit of fluoroscopy tables. In addition, short obese patients are at risk of falling from narrow fluoroscopy tables. For such patients, computed tomography (CT) guidance is a viable alternative to conventional fluoroscopic guidance. IVC placement was performed in the CT suite for two obese patients who exceeded the weight limits of the available fluoroscopy tables. In one case, a Vena-Tech filter (Braun Medical, Melsungen, Germany) was placed using CT fluoroscopy. In the second case, a Recovery (Bard, Murray Hill, NJ) filter was placed using intermittent limited z-axis scanning. In the first case, the filter was placed below the level of the renal veins and above the confluence of the iliac veins, which is acceptable placement. In the second case, with refinement of technique, the filter tip was placed less than 1 cm below the inferiormost renal vein, which is considered optimal placement. CT of the IVC precisely images the renal veins and can characterize their number and their confluence with the IVC. CT guidance is a viable alternative to fluoroscopic guidance for the placement of IVC filters in morbidly obese patients.

CT fluoroscopy-guided placement of inferior vena cava filters: feasibility study in pigs

PURPOSE

To evaluate the feasibility of computed tomography (CT)-guided placement of inferior vena cava (IVC) filters in a swine model.

MATERIALS AND METHODS

Five domestic pigs (60-70 kg) underwent transfemoral and transjugular IVC filter placement under real-time CT fluoroscopic guidance. Filter position was confirmed by contrast-enhanced CT and digital subtraction angiography. Filter tilt, distance to target position, and fluoroscopy time were analyzed.

RESULTS

A total of 10 filters were successfully implanted (five via transfemoral approach, five via transjugular approach) without complications. The mean distance to the target position was 0.3 cm ± 0.2. Mean filter tilt was 3.2° ± 2.3 (range, 0°-7°), without differences between deployment techniques (P = .8486). Average fluoroscopy time was 25.9 s ± 6.9 per procedure.

CONCLUSIONS

CT fluoroscopy-guided placement of IVC filters is safely feasible. Use of this technique may avoid the need to move critically ill patients.