Valve in Valve: Breaking New Ground…
Herein, we present 3 important studies concerning the use of transcatheter aortic valve implantation (TAVI) within small degenerated surgical bioprosthetic valves. In such cases, left main coronary occlusion and high post-implant gradients are not infrequently encountered, increasing mortality and curtailing symptomatic improvement.
In the first manuscript, Andersen and colleagues from Aarhus University Hospital in Denmark publish bench tests detailing the high-pressure balloon fracturing of four small (19-21mm) surgical bioprostheses (Mitroflow, Mosaic, Trifecta, Magna Ease). The authors recorded the pressure at which the non-compliant balloon (1mm larger than the index valve size; eg. 20mm balloon for the 19mm valve) induced bioprosthesis fracture. Importantly, these authors observed that valves with a polymer frame (Mitroflow and Mosaic) fractured at a much lower pressure (8–10atm) than those with a metal frame (Trifecta and Magna; 19– 26atm), which were, on occasion, impossible to break.
The second study, from the same authors group, details their first clinical experience of balloon-fracturing among 10 patients undergoing valve-in-valve procedures for failing Mitroflow surgical valves. In vivo, the required fracture pressures (13-15atm), were higher than on the bench, and following implantation with the Edwards Sapien 3, the mean transvalvular gradient was 17mmHg.
Finally, Adamo and colleagues from Brescia report the outcome of 15 patients undergoing VIV with the Medtronic CoreValve Evolut R within small (19, 21, 23) Mitroflow prostheses. The authors experienced 3 cases of left main coronary artery occlusion and report a mean gradient of 17mmHg post implant.
Deputy Editor, EuroIntervention