Impact of implant depth on hydrodynamic function with the ACURATE neo transcatheter heart valve following valve-in-valve transcatheter aortic valve replacement in Mitroflow bioprosthetic valves: an ex-vivo bench study.

AIMS: We assessed impact of implant depth on hydrodynamic function following valve-in-valve(VIV) transcatheter aortic valve replacement(TAVR) using the ACURATE neo (Boston Scientific Corporation, Natick, MA) transcatheter heart valve(THV) through an ex-vivo bench study.

METHODS AND RESULTS: Multiple implantation depths were tested at incremental depths of 2mm using a small size ACURATE neo valve for VIV TAVR in 19mm, 21mm, 23mm, and 25mm Mitroflow(Sorin Group Canada Inc, Burnaby, BC) bioprosthetic valves. Multimodality imaging and hydrodynamic evaluation was performed at each implantation depth. A low implantation was associated with higher transvalvular gradients. The highest transvalvular gradient was observed at -10mm depth for 19mm(40.0±0.5mmHg), -8mm for 21mm(15.3±0.2mmHg), -6mm for 23mm(14.7±0.3mmHg) and -8mm for 25mm(8.4±0.2mmHg) surgical valves. The lowest transvalvular gradient was observed at 0mm depth for the 19mm(14.9±0.2mmHg)/21mm(7.2±0.1mmHg), and +2mm depth for the 23mm(5.7±0.1mmHg)/25mm(5.8±0.1mmHg) surgical valves. At low implantation there was worse leaflet pin-wheeling and also evidence of THV leaflet interaction with those of the surgical valve that impaired leaflet coaptation resulting in a high regurgitant fraction(42.5% in the 21mm and 83.3% in the 23mm surgical valve at -10mm depths).

CONCLUSIONS: A high implant is desirable to facilitate favourable hydrodynamic function when performing VIV TAVR using the ACURATE neo THV for Mitroflow aortic bioprosthesis sized ≤ 25mm. In a 19mm Mitroflow valve, positioning the upper crown of the ACURATE neo above the posts of the surgical valve facilitates favourable transvalvular gradients. Low implantation results in higher transvalvular gradients, worse pin-wheeling and THV leaflet dysfunction can be severe due to interaction with the surgical valve.