Abstract
Transapical off-pump mitral valve repair with neochord implantation has been approved for patients presenting with severe mitral regurgitation due to leaflet prolapse or flail. The procedure is performed under real-time 2D and 3D transoesophageal echocardiography for both implantation and neochordae tension adjustment allowing real-time monitoring of haemodynamic recovery.
INTRODUCTION
Mitral valve (MV) repair techniques that ‘respect rather than resect’ the diseased portion of the MV have been associated with good clinical and physiological outcomes. Transapical off-pump echo-guided MV repair with neochordae implantation was recently introduced as an innovative minimally invasive option to treat degenerative mitral regurgitation due to prolapse or flail [1–4]. The procedure employs the NeoChord DS1000 system (NeoChord, Inc., Eden Prairie, MN, USA) that allows implantation of commercially available expanded polytetrafluoroethylene sutures (CV-4) under 2D and 3D transoesophageal echocardiography guidance to correct leaflet prolapse/flail [5] (Fig. 1).
(A) Preoperative 2D TOE with and without colour Doppler, (B) preoperative 3D TOE, (C) preoperative 3D TOE colour Doppler, (D) postoperative 2D TOE with and without colour Doppler, (E) postoperative 3D TOE and (F) postoperative 3D TOE with colour Doppler. TOE: transoesophageal echocardiography.
TECHNIQUE
The procedure is performed in a conventional operating theatre under general anaesthesia. A left lateral minithoracotomy is performed (Video 1), generally at the 5th intercostal space, using a 30° right-side rotation of the thorax for better exposure of the lateral left ventricle (LV). Access site location is contingent on avoiding potential interference with the subvalvular apparatus. We employ a ‘finger test’ to identify the site by gently pushing on the LV under 2D transoesophageal echocardiography monitoring (biplane view of mid-oesophageal long-axis and commissural images). The access site is generally located 2–3 cm cranial from the true apex on the posterolateral LV wall, just below the diagonal branch.
Selected clips from full neochordae implantation procedure.
Two pledgeted crown-like purse strings are prepared and a ventriculotomy is performed, either using the Seldinger technique or with an 11-blade scalpel. The device is introduced into the LV, and the distal tip is moved towards the MV under 2D transoesophageal echocardiography guidance (long axis 120–140°). Once the prolapsing leaflet is reached, the device tail is simultaneously lowered and pushed, providing smooth entry over the opposing leaflet. Visualization is then switched to a 3D surgical view to observe the interaction of the device with the leaflets. If anomalous leaflet movement or resistance is observed, then MV crossing must be repeated.
Once positioned above the diseased segment, the device jaws are opened and maintained orthogonal to the leaflet. The device is slowly retrieved until the leaflet is properly situated. The jaws are closed and capture is confirmed using the fibre-optic monitor. The needle is advanced to puncture the leaflet and then retrieved, bringing the loop tip and the suture double tail out of the ventricle. The entire device is then removed, and the apical purse strings are temporarily tightened. A girth hitch knot is made, locking one end of the suture on the valve. Tension is applied to the neochordae until a significant reduction in mitral regurgitation is observed.
Additional neochordae are implanted to achieve maximal valve competence. At least 3 sutures are required to balance the tension and avoid excessive mechanical stress, which could result in early suture dehiscence. After all chordae are deployed, the apical purse strings are tied. A French-eye needle is used to pass through all neochordae as well as a large round pledget, which is then fixed to the epicardial LV surface using a 4-0 prolene suture. Each neochordae is passed through a paediatric tourniquet and independently tensioned to achieve maximal leaflet coaptation as evaluated in real time with 2D and 3D colour Doppler. During this phase, observation of the acute influence of neochordae tensioning on haemodynamic recovery is possible (Video 1).
DISCUSSION
We have performed this minimally invasive MVR procedure with positive results on >150 cases, improved upon with learnings from the early experience. Patient selection was found to be a crucial factor in obtaining optimal postoperative results [6]. Proper access site identification was also refined to target posterolateral ventricular access [7]. This location provides alignment with the MV, reducing the risk of interference with the subvalvular apparatus. Moreover, anchoring the neochordae at this location provides a more physiological axis orientation and restores the natural posterior leaflet hemiarch shape. Finally, the introduction of 2D and 3D simultaneous ‘biview’ has significantly improved the quality and precision of the MV crossing manoeuvre.
Conflict of interest: Andrea Colli, Eleonora Bizzotto and Gino Gerosa received travel grants from Neochord, Inc. Andrea Colli and Demetrio Pittarello performed proctoring for Neochord, Inc.
