Invited commentary

Abstract

Although in use for digital subtraction angiography (DSA) since about the 1970s,1Hawkins I.F. Carbon dioxide digital subtraction arteriography.AJR Am J Roentgenol. 1982; 139: 19-24Crossref PubMed Scopus (158) Google Scholar carbon dioxide remains a very useful contrast medium in our ever-growing population of patients with renal insufficiency and/or significant iodinated-contrast sensitivity. With the present report, Criado et al add to the existing support for use of CO2 DSA in endovascular aortic aneurysm repair (EVAR). Providing support for alternate imaging methods to deliver endovascular therapy safely is particularly important, considering improving technologies will extend therapy to more patients who are at risk of renal compromise. As others have,2Chao A. Major K. Kumar S.R. Patel K. Trujillo I. Hood D.B. et al.Carbon dioxide digital subtraction angiography-assisted endovascular aortic aneurysm repair in the azotemic patient.J Vasc Surg. 2007; 45: 451-458Abstract Full Text Full Text PDF PubMed Scopus (66) Google Scholar, 3Bush R.L. Lin P.H. Bianco C.C. Lumsden A.B. Gunnoud A.B. Terramani T.T. et al.Endovascular aortic aneurysm repair in patients with renal dysfunction or severe contrast allergy: utility of imaging modalities without iodinated contrast.Ann Vasc Surg. 2002; 16: 537-544Abstract Full Text PDF PubMed Scopus (39) Google Scholar, 4Lee A.D. Hall R.G. An evaluation of the use of carbon dioxide angiography in endovascular aortic aneurysm repair.Vasc Endovasc Surg. 2010; 44: 341-344Crossref PubMed Scopus (19) Google Scholar Criado et al demonstrate that CO2 DSA is safe, and results are comparable with procedures performed with iodinated contrast. The single element that sets this paper apart from previous ones is that radiation times were shorter for CO2 than iodinated contrast; this is inexplicable based even on our own experience. Furthermore, settings are modified for CO2 DSA by increasing the frame rate, a maneuver that tends to increase the radiation dose. In their paper, the authors conclude with a rhetorical question; why should procedures be performed with iodinated contrast if results are equivalent? There are multiple reasons for this: 1) as CO2 is delivered by hand injection, there is significant potential for increased radiation exposure as the interventionalist is always at the table, and this becomes even more relevant if indeed the radiation times are longer as described by previous authors. 2) The potential for complications with air emboli is also increased by the fact that no system is completely sealed; the plastic bag system (AngioFlush 111, AngioDynamics, Queensbury, NY) is being discontinued due to a Food and Drug Administration mandate following a serious complication, where the bag was filled with O2 rather than CO2.5Cho K.J. Hawkins Jr, I.F. Discontinuation of the plastic bag delivery system for carbon dioxide angiography will increase radiocontrast nephropathy and life-threatening complications.AJR Am J Roentgenol. 2011; 197: W940-W941Crossref PubMed Scopus (4) Google Scholar There is some instruction and expertise required to avoid potentially serious complications. 3) In order to prevent overestimating disease, when injecting in the aorta a bolus of 40 to 60 mL of CO2 is required, which can lead to “trapping” of CO2 within a branch, ultimately leading to ischemic insult. This can be somewhat mitigated by patient positioning, but only experience or adequate instruction will prompt such maneuvers.6Spinosa D.J. Matsumoto A.H. Angle J.F. Hagspiel K.D. Hooper T.N. Transient mesenteric ischemia: a complication of carbon dioxide angiography.J Vasc Interv Radiol. 1998; 9: 561-564Abstract Full Text PDF PubMed Scopus (39) Google Scholar In a larger review of cases, complication rates were minor in 7% and major in 1.1% of cases.7Rundback J.H. Shah P.M. Wong J. Babu S.C. Rozenblit G. Poplausky M.R. Livedo reticularis, rhabdomyolysis, massive intestinal infarction, and death after carbon dioxide arteriography.J Vasc Surg. 1997; 26: 337-340Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar The authors briefly described alternate imaging modalities such as intravascular ultrasound (IVUS), but did not include another very valuable way of avoiding contrast, by performing preoperative magnetic resonance angiography (MRA). This MRA can be imported into a system capable of c-arm computed tomography (CT) image acquisition (dynaCT, XperCT). The imported image is thereafter fused with the c-arm CT acquisition and can then serve as a 3D overlay, which can precisely guide the EVAR. Furthermore, it is important to consider that the operative phase is only a small segment of what is a lifetime of imaging for patients with EVAR. In the pre- and postoperative phase, it is imperative that we continue to keep the patients from iodinated contrast exposure and perform studies either with MR (depending on stent), noncontrast CT, or by ultrasound either with or without contrast enhancement. Endovascular aortic aneurysm repair with carbon dioxide-guided angiography in patients with renal insufficiencyJournal of Vascular SurgeryVol. 55Issue 6PreviewRenal dysfunction following endovascular abdominal aortic aneurysm repair (EVAR) remains a significant source of morbidity and mortality. We studied the use of carbon dioxide (CO2) as a non-nephrotoxic contrast agent for EVAR. Full-Text PDF Open Archive