Standardization of a Carbon Dioxide Automated System for Endovascular Aortic Aneurysm Repair.

BACKGROUND: Endovascular aortic repair (EVAR) is presently the preferred treatment for abdominal aortic aneurysm; however, it requires the injection of a contrast medium, which can hamper the renal function. Other nontoxic agents such as carbon dioxide (CO2 ) have been sporadically tested in this setting with uncertain results. The aim of the study is to investigate the efficacy of a new standardized CO2 injection method in standard EVAR procedures.

METHODS: Between August and October 2016, 31 consecutive patients (median age 76.1 [interquartile range {IQR}: 7.4] years) were submitted to standard EVAR. Proximal and distal endograft landing zones were identified by the injection of 100 mL of CO2 at 300 mm Hg, through an 11 cm 10F femoral sheath by a specifically manufactured automated injection device (Angiodroid Srl, San Lazzaro, Bologna, Italy). Before EVAR deployment, a confirmative injection with a conventional contrast medium was accomplished. The possibility of precisely visualizing the proximal and distal landing zones by CO2 digital subtraction angiography (DSA) was evaluated considering the contrast medium injection obtained in the same procedure as a gold standard. Similarly, the possible presence of endoleak was assessed at the end of the procedure by the 2 techniques.

RESULTS: CO2 DSA allowed to identify the juxtarenal landing zone of the endograft in 19/31 cases (61%) and the distal one in 31/31 (100%). In 12 (39%) cases, CO2 injection failed to visualize at least the lowest renal artery. This occurred in large aneurysms with scarce thrombotic apposition and a luminal volume greater than 95.9 (IQR: 25.2) mm3 . Completion CO2 DSA detected type II endoleaks (ELIIs) in 10 cases compared with 2 of conventional contrast media.

CONCLUSIONS: The injection of nontoxic CO2 through an automated device allowed to perform EVAR procedures effectively, in the majority of cases. In some cases, a single injection of a minimum amount of conventional contrast medium can be used to overcome the lack of renal artery visualization by CO2 . ELIIs are more frequently visualized with CO2 compared with standard contrast medium. Although the CO2 injection technique needs further amelioration particularly in the renal arteries detection, this technique appears promising and possibly substitutive of the standard contrast medium, with significant benefit for the renal function.