[CO2 angiography of transplanted kidneys]. / CO2-Angiographie von Transplantatnierenarterien.

PURPOSE: To compare image quality and diagnostic accuracy of carbon dioxide (CO2) and iodinated contrast medium as a contast medium in renal transplant artery angiography. MATERIAL AND METHODS: In this prospective, non-randomized, intra-individual study, we examined 17 patients. Digital subtraction angiography (DSA) was performed first with CO2 to find the optimal projection. Then at least one confirming run was performed with CM ("gold standard"). The quality of the angiographic studies with CO2 and CM and their diagnostic accuracy were compared. Blood creatinine levels were monitored during three days after angiography. RESULTS: Three of four renal transplant artery stenoses were diagnosed correctly with CO2. The false-negative CO2 angiography was due to poor contrast. There were no false-positive results with CO2. Regardless the inferior image quality of CO2 angiography, its positive predictive value was 100%. Renal function was not compromised. CONCLUSION: The primary use of CO2 as a contrast medium for the angiographic evaluation of renal transplant arteries is feasible and practical. It reduces the amount of CM needed. However, in order to confirm the diagnosis, at least one additional series with CM should be performed.

Efficacy of permanent and retrievable vena cava filters: experimental studies and evaluation of a new device.

PURPOSE: To evaluate the efficacy of vena cava filters and to compare them with the new TrapEase filter. METHODS: Thrombus capture rates of 10 permanent and retrievable vena cava filters were tested in vitro in vertical and horizontal positions with thrombus diameters of 3 and 5 mm (length 30 mm) and tube diameters of 21 and 28 mm. Testing included the new TrapEase filter. Results compared statistically using Fisher's exact test (capture rates) and the Kruskal-Wallis test (construction). RESULTS: Best-ranked filters were the Bird's Nest, the TrapEase and the Simon Nitinol filters. The Tempofilter, the Greenfield and the Keeper filter performed worst. Thrombus capture rates were significantly higher in the vertical position and also higher for large thrombi and in the small cava diameter. Conical filters performed worse than filters with two or more filtration levels. CONCLUSION: Filters with two or more filtration levels show the highest filtration efficiency in vitro and can be recommended, especially for the critically ill who will probably not tolerate even small emboli. The TrapEase filter is a promising device and should be evaluated clinically.