We present a case of a 37-year-old woman diagnosed with Parkes-Weber syndrome characterized by high-flow arterio-venous malformations of the pelvic region with an estimated cardiac output of 7.2–8.5 l/min. Due to concomitant Marfan syndrome, the patient also presented an aortic root aneurysm needing surgical treatment under cardiopulmonary bypass. Concerns arose regarding the ability to maintain sufficient perfusion pressure during cardiopulmonary bypass due to the arterio-venous malformations. To address this, an intravascular balloon occlusion at the level of the aortic bifurcation was placed in order to limit arterial inflow into the arterio-venous malformations and achieve optimal perfusion pressure during cardiopulmonary bypass. The patient did not experience any complications and recovered completely after surgery.