Transapical aortic valve implantation with a self-expanding anatomically oriented valve

The Medtronic Engager™ aortic valve bioprosthesis is a self-expanding valve with support arms facilitating anatomically correct positioning and axial fixation. Valve leaflets, made of bovine pericardium, are mounted on a Nitinol frame. Here, we report the first in man study with this new implant (Trial Identifier NCT00677638).

Thirty patients (mean age 83.4 ± 3.8 years; 83% female) with tricuspid aortic valve stenosis were included in the study. Mean logistic EuroSCORE was 23.4 ± 11.9. Mean aortic annulus diameter was 21.8 ± 1.4 mm. For this study, the Engager was available in only one size (23 mm), to fit aortic annuli of 19-23 mm. Standard transapical valve implantation was performed using pre-dilation of the aortic valve and rapid ventricular pacing during balloon valvuloplasty and most valve deployments. Accurate valve placement was achieved in 29/30 cases (97%). Post-implant peak-to-peak gradient was 13.3 ± 9.3 mmHg. In 80% of the patients, no more than grade I paravalvular leakage was observed, in 13% grades I-II and in 3% grade II. Three patients (10%) required permanent pacemaker implantation for higher-degree or complete atrioventricular block. Four dissections (13%) occurred during positioning of the valve and were treated surgically in three cases. Thirty-day and in-hospital mortality were 20% and 23%, respectively, and 6-month survival was 56.7%. No structural failure occurred for up to 1 year.

This series established the feasibility of implanting a novel self-expanding transapical aortic valve prosthesis predictably into an anatomically correct position. Observed complications led to complete redesign of the delivery system for upcoming clinical studies with the goal of establishing safety and performance.