Vena cavography with CO2 versus with iodinated contrast material for inferior vena cava filter placement: A prospective evaluation

PURPOSE: To determine whether carbon dioxide (CO2) vena cavography can safe ly guide the placement of inferior vena cava (IVC) filters. MATERIALS AND METHODS: One hundred nineteen patients were prospectively enr olled in this study. CO2 cavograms were obtained and evaluated for IVC diam eter, location of renal veins, and presence of thrombus and venous anomalie s. If CO2 cavography was judged to be adequate, an IVC filter was deployed. After filter placement, cavography was performed with iodinated contrast m aterial; these images were compared with the CO2 cavograms. RESULTS: Two patients experienced mild side effects related to venous CO2 i njection. Comparison of cavograms obtained with CO2 and iodinated contrast- enhanced material showed the caval size to be within 3 mm in ail 119 patien ts. in 116 patients (97.5%), CO2 cavography was judged to be adequate, and in 115 patients, filters were placed. In three (2.5%) patients, it was nece ssary to perform iodinated contrast-enhanced cavography before filter deplo yment. All six cases of venous anomaly and 11 (78.6%) of 14 cases of thromb osis were clearly identified with CO2 cavography, One filter was maldeploye d owing to misinterpretation of the CO2 cavogram. CONCLUSION: CO2 cavography is well tolerated, safe, and adequate for identi fication of the parameters necessary for filter deployment. It is especiall y valuable in patients with a history of reaction to iodinated contrast mat erial or renal insufficiency.