The effects of combining fusion imaging, low-frequency pulsed fluoroscopy, and low-concentration contrast agent during endovascular aneurysm repair

OBJECTIVE: This study evaluated the effects of a combined imaging protocol using low-frequency pulsed fluoroscopy, fusion imaging, and low-concentration iodine contrast for endovascular aneurysm repair (EVAR) of aortic aneurysms of varying complexity.

METHODS: The study retrospectively reviewed the data of 103 patients treated between May 2013 and November 2014 with the combined imaging protocol (group A) with low-dose fluoroscopy at 3.75 frames/s, fusion imaging, and iodine contrast of 140 mg iodine/mL. A control group (group B) consisted of 123 consecutive patients who underwent EVAR before the combined imaging protocol was introduced by matching the type of procedure. In group B, low-dose 7.5 frames/s fluoroscopy, no fusion imaging, and 200 mg iodine/mL contrast were used. All patients were reviewed for preoperative, intraoperative, and postoperative variables, with emphasis on intraoperative radiation (dose area product) and iodine exposure, fluoroscopy, and operation times, as well as technical success. Values are presented as median and interquartile range (IQR) when not stated otherwise.

RESULTS: Group A included 22 infrarenal EVARs, 17 iliac branch devices, 10 thoracic endovascular aortic repairs, 21 fenestrated EVARs, and 33 thoracoabdominal branched/fenestrated EVARs. Groups A and B were similar in types of procedure, body mass index (P > .05), and intraoperative technical success (92% and 92%, respectively; P > .05). Operation time (230 [IQR, 138-331] minutes vs 235 [IQR, 158-364] minutes) and fluoroscopy time (66 [IQR, 33-101] minutes vs 72 [IQR, 42-102] minutes) were similar in both groups (P > .05), but radiation exposure (19,934 [IQR, 11,340-30,615] μGym(2) vs 32,856 [IQR, 19,562-55,677] μGym(2); P < .0001), contrast volume usage (63 [IQR, 103-145] mL vs 215 [IQR, 166-280] mL; P < .0001), and iodine dose (14.5 [IQR, 8.8-20.4] g iodine vs 43.0 [IQR, 32.2-56.0] g iodine; P < .0001) were lower in group A than in group B. The differences were uniform throughout the different procedure types, with the exception of fenestrated grafts, where radiation exposure was similar between group A and B; however, group A had a much higher involvement of the superior mesenteric artery in the repairs (81% vs 17%; P < .0001) explaining this finding. Fluoroscopic frame rate reduction contributed to a median reduction of the dose area product by 22%. Only four of the group A patients (3.9%) showed a decrease in the glomerular filtration rate ≥30% after EVAR, although 32% of the entire group had at least moderately impaired renal function preoperatively.

CONCLUSIONS: Combining low-frequency pulsed fluoroscopy, fusion imaging, low-concentration, and iodine contrast medium during EVAR reduces the exposure to radiation and iodine.