## 4 Colonic Ischemia After Electrotive AAA Repair  
CI after elective AAA repair is a rare but significant complication, with a reported incidence of 1-3% in OSR and 0.5-3% in EVAR [28; 29]. [PERSON] et al. found no significant differences between the two surgical approaches [30; 31]. On the other hand, [PERSON] et al. and [PERSON] et al. observed variations in bowel ischemia rates between OSR and EVAR, with rates of 2% and 0.6% in EVAR-treated patients, respectively, compared to 2.6% and 2% in those undergoing open repair [32; 33]. However, these differences did not reach statistical significance due to small sample sizes. The most recent study by [PERSON] et al. analyzed a larger cohort and confirmed previous findings, reporting a similar risk of CI after EVAR at 0.5%, compared to 1.9% after OSR. This larger sample size reduced uncertainties associated with smaller series and identified the open surgical technique as an independent risk factor, with a 2.7-fold increased risk of ischemia compared to EVAR [34]. Regarding fenestrated endovascular aneurysm repair (FEVAR), ischemic complications involving the intestinal tract, though relatively uncommon, occur more frequently than with standard EVAR, as demonstrated by previous studies. This complication is mainly attributed to splanchhic hypoperfusion, rather than embolic events or direct vessel  
Figure 2: CI visualized with sigmoidoscopy. (Courtesy of the Gastroenterology Unit of Sant’Andrea Hospital of Rome, IT.) (**A**) Mucosal damage located at the transverse colon, characterized by edema, erythema, and petechial hemorrhagic lesions. (**B**) Ischemic changes involving the colic splenic flexure, showing more pronounced mucosal discoloration and loss of vascular pattern. injury, which are rare occurrences [35]. Effective management may include endovascular interventions or revascularization of the SMA, either via retrograde extra-anatomic bypass (e.g., from the common iliac artery to the SMA) or antegrade aorto-mesenteric bypass, particularly when the affected aortic segment lies outside the stent graft landing zone. The current literature lacks sufficient data on the incidence and risk factors of CI following FEVAR in an urgent setting. Further studies are needed to better characterize this complication in such a clinical setting. Despite the relatively low incidence, preventing this complication is essential due to its association with perioperative mortality, estimated to be approximately 50% even in elective treatment settings [36]. Careful preoperative assessment of splanchnic circulation is crucial to prevent colonic ischemia, particularly the evolution of SMA patency and the presence of a positive history for previous colonic surgery, which could compromise collateral blood flow. Regarding this topic, several studies in the literature have evaluated the consequences of intentional hypogastric artery interruption in both open and endovascular procedures. Earlier research, such as that by [PERSON] et al. and [PERSON] et al., found no significant differences in outcomes for patients who had at least one hypogastric artery sacrificed [37; 38]. However, more recent studies have identified hypogastric occlusion as an independent risk factor for ischemic complications, including intestinal ischemia [39; 40; 41]. In the study by [PERSON] et al., interruption of the hypogastric artery, whether by ligation or occlusion during open repair, or by embolization during EVAR, was significantly associated with an increased risk of postoperative intestinal ischemia (OR: 1.7, 95% CI: 1.0-2.8). Patients with bilateral occlusion exhibited an even higher risk [8]. A more recent analysis by [PERSON] et al. demonstrated significantly higher perioperative mortality in patients with compromised pelvic perfusion (5.5% vs. 3.1%; \(p<0.001\)). Bilateral interruption of blood flow was associated with greater perioperative mortality compared to unilateral interruption (7.1% vs. 4.7%; \(p=0.147\)) [42].