A word of caution using self-expanding transcatheter aortic valve-frame infolding.

Transcatheter aortic valve replacement has become a mainstay alternative to surgical aortic valve replacement in patients with severe aortic stenosis at high and intermediate surgical risk. Two commercially approved valves are available in the United States: balloon-expandable and self-expanding. We report here a rare complication of a self-expanding Evolut PRO (Medtronic, Minneapolis, Minnesota) valve failing to expand due to nitinol frame infolding. This results in a malopposed valve with a severe paravalvular leak, even though treated successfully with balloon valvuloplasty. It is important to recognize the characteristic angiographic signature of this complication-the "straight line" sign-and how to avoid this potentially serious complication by balloon valvuloplasty or by recapture and deployment of a new valve.