Gluteal Blood Flow Monitoring in Endovascular Aneurysm Repair With Internal Iliac Artery Embolization

Background: When an internal iliac artery (IIA) has to be embolized during endovascular aneurysm repair (EVAR), buttock claudication sometimes poses problems. However, there is no established method to evaluate intraoperative blood flow to the gluteal muscles. Methods and Results: Gluteal regional oxygen saturation (rSO(2)) was monitored using near-infrared spectroscopy (NIRS) during surgery, and changes in rSO(2) were compared with treatment results. Twenty-seven patients who underwent EVAR and IIA embolization at our institution between April 2019 and May 2020 were included in this study. The association between intraoperative changes in rSO(2) and postoperative incidence of buttock claudication was analyzed. Furthermore, the presence or absence of communication between the superior and inferior gluteal arteries and the intraoperative changes in rSO(2) were compared to ascertain whether rSO(2) reflects blood flow change. Postoperative buttock claudication occurred in 4 of 19 patients (21%) with unilateral occlusion of IIA and in 4 of 8 patients (50%) with bilateral occlusion of IIAs. rSO(2) was found to decrease significantly further in patients with buttock claudication than in patients without buttock claudication (-15 +/- 12% vs. -4 +/- 16%, P<0.05). In addition, rSO(2) was predominantly lower in patients without the communication between the superior and inferior gluteal arteries than in those with the communication. Conclusions: Gluteal rSO(2) is useful as an indicator of intraoperative gluteal blood flow.