Peripheral diagnostic and interventional procedures using an automated injection system for carbon dioxide (CO2): case series and learning curve.

INTRODUCTION: The administration of iodinated contrast media in doses sufficient for diagnosis and procedural guidance, when coincident with renal insufficiency, presents a considerable risk of exacerbating and hastening renal failure. Carbon dioxide has been proposed in the past as an alternative, but only recently dedicated injection systems have become available. We aimed to review our ongoing experience with an automated carbon dioxide injector for peripheral diagnostic and interventional procedures. METHODS: Details on 21 patients undergoing peripheral procedures with carbon dioxide angiography were systematically collected. An automated injector enabling customized and repeated carbon dioxide injections was used in all cases, with iodinated contrast media used only as bailout. RESULTS: No major or minor complications occurred in these patients, either during the procedure or up to discharge. Comparison according to phase of the learning curve showed that with accruing experience operators relied progressively more on carbon dioxide only, as there was a significantly reduced need for additional iodinated contrast media injections per procedure (from 2.5±2.1 to 0.6±2.1 injections per patient, p=0.005). Accordingly, in the second phase of our learning curve, iodinated contrast media were avoided in 91% of cases in comparison to 20% of procedures performed in the beginning of our experience (p=0.002). Concomitantly, no significant change in the duration of the procedure occurred. CONCLUSIONS: Carbon dioxide-based angiography using an automated injection system is feasible and safe in patients undergoing diagnostic or interventional procedures for infra-diaphragmatic conditions, especially for transcatheter renal sympathetic denervation.