Mitral valve replacement with a calcified annulus

1 The leaflets and annular calcification are inspected. In this case, the calcium is localized to the annulus and both the anterior and posterior leaflet edges are thickened but not calcified (inset).

2 The anterior leaflet is detached from the annulus and two small areas or pods of the leaflet are retained that contain the chordae to the anterior and posterior papillary muscles. At this point the size of the orifice is determined and must be capable of fitting at least a 25-mm prosthesis. Plegeted sutures are placed with the pledgets on the ventricular side. Although more difficult to do, this approach has the advantages of being theoretically stronger, reduces the chance of wrapping the sutures around the struts of the biologic valve when the valve is lowered into position, and allows direct tissue to sewing ring apposition without eversion of tissue.⁴

3 The pods of the anterior leaflet are usually secured at the 2-to-3 and 9-to-10 o'clock positions. These sites keep the tissue away from the left ventricular outflow tract and avoids too much heaping of the tissue on top of the posterior leaflet.

4 Any thickening or calcification of the posterior leaflet must be removed. Sutures are then placed with the needle going first through the free edge of the posterior leaflet and then through the body of the leaflet above the annular calcification. This creates a neoannulus above the calcification. Another technique is to place the sutures from the atrial side under the annular calcification, then through the free edge of the leaflet, and finally through the sewing ring of the valve. I am concerned, however, that this approach increases the risk of circumflex artery injury or kinking and paravalvular leaks.

5 The aortic valve is inspected with a mirror and the commissure between the left and non-coronary cusp is identified. This is a good approximation of the middle of the left ventricular outflow tract and the suture beneath this commissure is placed in the middle of the pericardial valve. This orients the valve in such a way as to keep the valve struts out of the middle of the outflow tract.

1 In this case, the leaflet tissue is too rigid and the orifice too small to allow direct placement of a valve prosthesis. Note that all or portions of the anterior leaflet are often spared and can be used later to support the posterior annular reconstruction and maintain ventricular annular continuity.

2 Sometimes the posterior leaflet can be detached and used to support the repair, but in this case the valve is too thickened and calcified to be saved. The posterior leaflet is removed, exposing the underlying annular and ventricular calcification.

3 If one chooses to completely remove the calcium, care must be taken to avoid injury to the ventricular myocardium and coronary vessels. Often there is a fibrous capsule beneath the calcium and I try to stay above this plane (inset). All calcium fragments must be diligently aspirated from the field.

4 In cases where the exposed subannular trough is narrow it is closed directly. Pledgeted mattress sutures pass first through the ventricular myocardium, then through the atrial tissue. The anterior leaflet is brought posterior such that the annular edge of the anterior leaflet is apposed to atrial tissue. This is a modification of the technique described by Casselman.⁵ In theory, when the ventricle contracts the anterior leaflet will pull the valve and atrial tissue toward the ventricle and reduce the risk of atrioventricular disruption.

5 For calcification that extends deeply into or completely through the atrioventricular groove, the calcium is reduced in height or “leveled” to facilitate valve insertion. The defect is covered with a bovine pericardial patch using a running prolene suture.⁶ Exposure within the depths of the ventricle can be limited and interrupted pledgeted sutures may be easier for patch placement.

6 Valve sutures are placed through the center of the patch.

7 The anterior leaflet is then used to support the patch or can be separated into smaller sections and attached to the annulus, as described above. Bileaflet valves are inserted with the leaflets in an antianatomic position.