Purpose: To report emergent transcatheter aortic valve implantation (TAVI) to treat acute severe aortic regurgitation caused by valve cusp dysfunction following proximal migration of an endograft implanted in the ascending aorta during endovascular arch repair. Case Report: A 65-year-old man had been previously treated with thoracic and fenestrated endografts in a 2-stage procedure for a chronic type B dissection. At 2-year follow-up, aneurysmal evolution of the distal arch led to development of a proximal type Ia endoleak. The patient was deemed unfit for open repair because of severe nonrevascularizable coronary artery disease. A custom-made endograft was designed consisting of a double inner branch arch endograft with a proximal component to reline the ascending aorta to avoid iatrogenic type A dissection. The first component was successfully deployed. However, this device migrated toward the aortic valve when the delivery system of the branch device was advanced through the aortic valve. Aortography and transesophageal echography showed acute aortic regurgitation due to obstruction of the left coronary valve cusp. An emergency bailout TAVI procedure was performed to successfully treat the aortic regurgitation. Conclusion: TAVI can be used as a bailout procedure for acute aortic valve dysfunction during endovascular arch or ascending aorta repair.