Background and Clinical Significance: Complex abdominal aortic aneurysms (AAAc) involving visceral and renal vessels can be treated via open surgery or less invasive fenestrated endovascular aneurysm repair (FEVAR). Intravascular ultrasound (IVUS) minimizes contrast and radiation while improving placement accuracy, though its specific role in FEVAR remains understudied. This CARE-compliant article reports a FEVAR case guided by IVUS. Case Presentation: A 75-year-old male with multiple comorbidities presented with an enlarging AAAc extending to the renal artery ostia, lacking an adequate neck. Anatomical variants included a left renal artery with a caudal origin (pelvic left kidney), a left renal polar artery originating from the right common iliac artery, and a patent inferior mesenteric artery (<3 mm). Following multidisciplinary evaluation, the patient successfully underwent simultaneous FEVAR and coronary angiography. Guided by IVUS, the fenestrated endograft was deployed with preserved visceral patency. The patient recovered uneventfully and was discharged on postoperative day two. A 30-day CT angiogram detected a stable inferior mesenteric artery endoleak, managed conservatively through a 6-month follow-up. Conclusions: IVUS-guided FEVAR may offer a promising alternative to traditional angiography, reducing radiation and contrast exposure. Further large-scale studies are needed to confirm these findings and establish clinical and economic benefits.