Unlike the posterior leaflet, which has broad annular attachment and can be immobilized and forced to act as an abutment for the functioning anterior leaflet, the anterior leaflet has narrow annular attachment and a broad occlusive surface area that must function properly for mitral competency. Therefore, repair of the anterior leaflet requires more imagination, often requires a combination of repair techniques, and is considered more prone to failure on long-term follow-up. However, this assumption is contraindicated by Grossi et al. who found, after reviewing 588 consecutive repairs, that the requirement for anterior leaflet repair did not increase the risk for reoperation (1).
General principles of anterior leaflet repair include elimination of redundancy and excess tissue, elimination of prolapse, and maintenance of pliability. The leaflet's motion must allow adequate diastolic flow avoiding stenosis yet adequately occlude the mitral orifice during systole, eliminating regurgitation. Leaflet interventions must be durable and resistant to functional alterations related to healing.
This chapter will deal specifically with techniques used to alter the leaflet shape and size; chordal repair techniques are detailed in Chapter 11.
Early in the history of valve repair concern was expressed regarding the longevity of anterior triangular resection (2), however, Grossi et al. reported excellent results and advocate appropriate application of this procedure (1,3). Separately described recently by Fasol (4) (Fig. 8.1) and Spencer et al. (5), the technique involves the resection of a narrow isosceles triangle of tissue, excising no more than 1.5 cm of prolapsing leaflet tissue. The excision is made to a strong chord on each side. Spencer et al. (5) routinely apply this technique for focal anterior leaflet prolapse, preferring it to shortening or transferring chords.
Most recently Fasol and Mahdjoobian described a combined anterior triangular resection and posterior quadrangular resection with folding plasty (see Chapter 9) for Barlow's disease with good short-term results in 37 patients (Fig. 8.2) (6).
Shortening of the anterior leaflet by excision of an ellipse of tissue (elliptoid excision) has been described (7), however no series detailing the success of this technique were found. A refined description of this technique was made by Duran (8) (Fig. 8.3). The upper incision is made 5 mm from the annulus. Tissue is removed to create a final leaflet height of
between 25 and 30 mm. Major basal chords attached to the removed leaflet tissue are repositioned to maintain ventricular function. The use of this procedure to correct SAM (systolic anterior motion) was reported by Raney et al. who called it the Pomeroy Procedure (9).
Figure 8.1 Anterior triangular resection. (From Fasol R, Joubert-Hubner E. Triangular resection of the anterior leaflet for repair of the mitral valve. Ann Thorac Surg. 2001; 71:381-383.)
Figure 8.2 Anterior triangular resection and posterior quadrangular resection and folding plasty for Barlow's disease. (From Fasol R, Mahdjoobian K. Repair of mitral valve billowing and prolapse (Barlow): the surgical technique. Ann Thorac Surg. 2002;74:602-605.)
Figure 8.3 Anterior leaflet shortening. (From Duran CMG. Surgical techniques for the repair of anterior mitral leaflet prolapse. J Card Surg. 1999;14;471-481.)
Figure 8.4 Technique of free edge remodeling. (From Fundaro P, Moneta A, Villa E, et al. Chordal plication and free edge remodeling for mitral anterior leaflet prolapse repair: 8-year follow-up. Ann Thorac Surg. 2001;72:1515-1519.)
Figure 8.5 Technique of free edge remodeling. (From Fundaro P, Moneta A, Villa E, et al. Chordal plication and free edge remodeling for mitral anterior leaflet prolapse repair: 8-year follow-up. Ann Thorac Surg. 2001;72:1515-1519.)
FREE EDGE REMODELING
Demonstrated in Figures 8.4 and 8.5 are techniques described by Fundaro et al. as chordal suture plication and free edge remodeling (10). Reviewing 61 patients, they noted postoperative mitral regurgitation fell to 0.4 ± 0.7 from 3.7 ± 0.4. With mean follow-up of 40.5 months he reported 3 late deaths and 3 reoperations and actuarial overall survival, freedom from cardiac death, and freedom from mitral reoperation at 92 months of 85.1% ± 7.9%, 88.9% ± 7.7%, and 94.6% ± 3.0%. This technique can be used for focal or extensive prolapse. It is particularly useful for a focal area of prolapse or thickening on the anterior leaflet that prevents occlusive coaptation. The edge is pulled under to present a smooth portion of the anterior leaflet for apposition against the posterior leaflet.
OTHER METHODS TO DEAL WITH LEAFLET PROLAPSE
See Chapter 12.
See Chapter 12.