Carbon Dioxide Angiography in Endovascular Aneurysm Repair May Overestimate the Presence of Type II Endoleak

To evaluate the utility of carbon dioxide (CO₂) angiography in the detection of type II endoleak (T2EL) during endovascular treatment of infrarenal abdominal aortic aneurysms (AAAs).

A retrospective analysis was conducted on a prospectively enrolled 20 consecutive patients with infrarenal AAAs treated with endovascular aneurysm repair (EVAR) and intraoperative completion imaging using both contrast media and CO2. The primary end points were the early intraoperative detection of T2EL and 30-day reintervention and mortality. The secondary end points were the confirmatory diagnosis of T2EL on the first postoperative and follow-up computed tomography (CT) scans, follow-up reinterventions, follow-up mortality, and safety of CO₂ angiography.

Twenty male patients (median age 71 years) were included. Intraoperative CO₂ angiography identified a higher detection rate of T2EL in 9 patients, while iodinated contrast detected T2EL in 2 patients (45% vs. 10%, P 0.189). No T2EL was confirmed on the postoperative and follow-up CT scans. No adverse events related to CO₂ angiography were observed. Subgroup analysis revealed patients with CO₂-detected T2EL had larger inferior mesenteric artery (IMA) diameters (3.2 mm vs. 2.3 mm, P = 0.030) and more patent lumbar arteries (median 4 vs. 3, P = 0.04), while IMA patency and preoperative largest aortic sac diameter were similar. Thirty-day outcomes were recorded as 3 reinterventions and no mortality. A median follow-up period of 47 months resulted in no newly formed endoleaks, no reinterventions, and 1 mortality.

CO₂ angiography demonstrated a higher intraoperative detection rate of T2ELs during EVAR compared to iodinated contrast. However, none were confirmed on postoperative imaging or led to adverse outcomes during long-term follow-up. These findings suggest that many CO₂-detected T2ELs may represent transient, hemodynamically insignificant flow lacking clinical consequence, but may have a future role in evaluating occult or type V endoleaks. Future prospective studies are needed to clarify their clinical relevance.