There was no significant difference in baseline characteristics between the AFX2 and Endurant II groups (Table 1). Table 2 shows that the duration of AFX2 procedure was significantly shorter (87.2 vs. 140 minutes) and that the AFX2 required less contrast medium (48.3 vs. 119.3 mL).
1) Narrow distal aorta
Three patients in the AFX2 group and one in the Endurant II group had narrow distal aorta. Patients A, B, and C were treated using AFX2 graft system, whereas patient 1 was treated using the Endurant II graft. The narrow distal aorta diameters of these patients were as follows: patient A, 13.6 mm; patient B, 12.8 mm; patient C, 8.9 mm; patient 1, 13.5 mm. The follow-up CT images showed patency of the stent lumen, even in these patients with narrow distal aorta. All patients achieved technical success (Fig. 1).
2) Reversed tapered neck
One patient (patient D) in the AFX2 group and one (patient 2) in the Endurant II group had reversed tapered neck (Fig. 2A). Technical success was achieved in patient D, and no complications occurred in the 1 month follow-up period. This patient also had severe beta angulation, which was overcome using the telescopic technique. The main body and distal graft were first placed at the aortic bifurcation; followed by proximal extensions that could be manipulated to be placed exactly under the renal arteries.
However, with the Endurant II graft, the proximal main body had to be placed first—directly below the renal arteries—to prevent type Ia endoleak and migration. This resulted in a partial overlap of the orifice of the right renal artery, which was revealed on the final angiography. Therefore, the surgeon placed a renal stent to prevent stenosis or occlusion. However, this additional stent insertion resulted in occlusion of the access site (branchial artery).
3) Iliac artery aneurysm
Patient E had an aneurysm of the right common iliac aorta (CIA) measuring 43 mm and of the left internal iliac artery (IIA) measuring 66 mm (Fig. 2B). Patient F had a right CIA aneurysm of 39 mm. Both patients were treated using the AFX2 graft. Patient E had the left IIA embolized and the right CIA bypassed. Patient F had the right IIA embolized.
In contrast, patient 3 had a bilateral CIA aneurysm of 22.95 mm on the right side and 20 mm on the left, with a growing AAA. In both groups, technical success was achieved. However, the procedure time was more than double with patient 3 with 200 minutes, compared to patient E with 60 minutes and patient F with 95 minutes.
4) Dose of contrast medium
The mean preoperative and postoperative creatinine levels of both groups are shown in Table 2. The AFX2 patient group showed no significant change in serum creatinine level (1.34 mg/dL before surgery, 1.24 mg/dL afterwards), whereas the Endurant II patient group showed an increase from 1.29 to 1.59 mg/dL.
In both groups, patients with chronic renal failure (patients G, H, 4, and 5) were noted and the amount of contrast medium was reduced as much as possible. Preoperative serum creatinine levels of patients in the AFX group (patients G and H) were 2.2 and 1.6 mg/dL, respectively, whereas postoperative levels were 2.0 and 1.6 mg/dL (Fig. 3A). Preoperative serum creatinine levels of patients in the Endurant II group (patients 4 and 5) were 1.64 and 2.78 mg/dL, respectively, whereas postoperative levels were 3.49 and 2.99 mg/dL, showing mild elevation.
5) Impending rupture
Patient I, who was treated using the AFX2 graft, had shown a sudden increase in aneurysm diameter of 26 mm over 2 months (Fig. 3B). Patients 6 and 7, who were treated using the Endurant II, both had an aneurysm size of >86.6 mm. The procedure time of patient I was 100 minutes, whereas that of patients 6 and 7 was 200 and 205 minutes, respectively. Patients I and 7 had technical success, but patient 6 experienced intra- and postoperative bleeding, resulting in multi-organ failure and death.
Patient outcomes up to July 31, 2019, were further reviewed. On average, the first follow-up visit occurred 6 to 8 months after surgery, while follow-up CT was taken annually after the first postoperative CT. Of the nine patients in the AFX2 group, one had a type II endoleak in the 1-year follow-up CT, one did not show up to the outpatient clinic after discharge, and one died during follow-up due to advancement of their underlying cancer. No other endoleaks, occlusions, or complications related to EVAR were found in the other patients. In comparison, of the seven patients in the Endurant II group, four showed type II endoleak in the 1-year follow-up CT and two did not attend follow-up.