Determination of inferior vena cava diameter in the angiography suite: Comparison of three common methods

PURPOSE: Significant inferior vena cava (IVC) filter migration has been ass ociated with deployment of some filter types in IVCs measuring more than 28 mm in diameter at inferior vena cavography, The purposes of this study wer e to (a) determine if significant differences exist between IVC measurement s obtained using a gold standard technique and two other widely accepted me thods, and (b) if differences exist, how often do these differences cause i ncorrect IVC sizing around a diameter of 28 mm, with its associated filter migration issues. MATERIALS AND METHODS: One hundred thirteen consecutive inferior vena cavog rams were retrospectively reviewed, The transverse diameter of the infraren al IVC was determined by using a calibrated intravascular catheter (the gol d standard), subtraction of 20% from the measured transverse IVC diameter o n a cut-film radiograph, and a radiopaque ruler placed immediately posterio r to the patient, RESULTS: The concordance correlation of the 20% magnification method versus internal calibration was 0.94. Kappa analysis to determine agreement at a diameter of 28 mm yielded a Kappa coefficient of 0.490, The concordance cor relation of an external ruler versus internal calibration was 0.43, with a Kappa coefficient of 0. CONCLUSION: The poor Kappa correlations for both methods demonstrate that t hey are unreliable in identifying megacava, Inferior vena cavography prior to IVC filter placement should be performed with a calibrated intravascular catheter.