Modifications of Transatrial Transcatheter Mitral Valve Replacement Technique

Mitral valve replacement (MVR) in patients with mitral annular calcification (MAC) poses a significant surgical challenge. A direct transatrial transcatheter mitral valve replacement (TMVR) approach with resection of the anterior leaflet of the mitral valve has been described (1, 2). Patients with MAC usually have small hypertrophic ventricles at risk of left ventricular outflow tract (LVOT) obstruction even with resection of the anterior mitral leaflet (2, 3). The authors present two modifications of this technique aimed to avoid LVOT obstruction and improve sealing against the calcified mitral annulus.

Severe MAC is often associated with small hypertrophic ventricles, increasing the risk of LVOT obstruction during TMVR (2, 3). A direct transatrial approach under cardiopulmonary bypass with an arrested heart allows for the resection of the anterior leaflet of the mitral valve, decreasing the risk of LVOT obstruction. In addition, a septal myectomy can also be performed to further decrease this risk. Improved sealing of the transcatheter prosthesis to the mitral annulus is achieved by sewing a felt strip to the outside of the stent frame. While having a felt strip of the same height as the expanded Sapien 3 valve may improve sealing, it can also obstruct the LVOT. In this report, the authors describe two modifications to minimize that risk:

1. A scalloped portion of the felt strip facing one of the leaflets of the prosthesis is created and oriented toward the anterior mitral annulus and the LVOT. It is not unusual for the open cells of the Sapien 3 stent to protrude into the LVOT and even touch the ventricular septum. The shorter felt strip in this area prevents LVOT obstruction. The longer felt strip facing the other two leaflets may improve sealing and prevent paravalvular regurgitation.
2. The placement of the guiding sutures through the mid-section of the stent allows for a more atrial position of the valve with less protrusion into the LVOT.

Conclusions:
The presented modified surgical technique improves sealing to minimize paravalvular regurgitation while decreasing the risk of LVOT obstruction.

References

1. El Sabbagh A, Eleid MF, Foley TA, Al-Hijji MA, Daly RC, Rihal CS et al. Direct transatrial implantation of balloon-expandable valve for mitral stenosis with severe annular calcifications: early experience and lessons learned. Eur J Cardiothorac Surg. 2018;53:162–169.
2. Russell HM, Guerrero ME, Salinger MH, Manzuk MA, Pursnani AK, Wang D, et al. Open atrial trancatheter mitral valve replacement in patients with mitral annular calcification. J Am Coll Cardiol. 2018;72(13):1437-1448.
3. Saran N, Greason KL, Schaff HV, Cicek SM, Daly RC, Maltais S, et al. Does mitral valve calcium in patients undergoing mitral valve replacement portend worse survival? Ann Thorac Surg. 2019;107(2):444-452.

Dr Guerrero has received research grant support from Edwards Lifesciences.
The use of a Sapien 3 transcatheter valve for this indication is an off-label use of this device and its implications in terms of outcomes, durability, and insurance coverage should be discussed with the patient.