Transcatheter Aortic Valve-in-Mechanical Valve Replacement: A First-in-Human Study 

In this article, the authors present a bench-to-animal-to-human proof of concept for valve-in-mechanical (ViMech) transcatheter aortic valve implantation (TAVI) in patients with failed bileaflet mechanical aortic valves. Bench testing showed disc dislodgement with balloon inflation at pressures of 2 to 4 atm, while snaring failed. In pigs weighing 60 to 80 kg with heterotopic and orthotopic bileaflet valves, disc fracture with an ascending aortic filter plus balloon was followed by immediate TAVI using the sewing ring as a landmark. Three first-in-human cases then underwent ViMech TAVI (ages 75, 79, 67) using balloon-expandable valves (21.5 to 24.5 mm) with disc trapping or en bloc retrieval. At six months, all patients were alive, asymptomatic, CT-negative for leaflet thrombosis, and without bleeding or ischemic events.