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Techniques for Repairing Posterior Leaflet Prolapse of the Mitral Valve

2011; Elsevier BV; Volume: 16; Issue: 4 Linguagem: Inglês

10.1053/j.optechstcvs.2011.11.001

1532-8627

Robin Varghese, David Adams,

Cardiac Structural Anomalies and Repair

Posterior leaflet prolapse is the most common lesion seen in degenerative mitral valve disease. The spectrum of degenerative disease can range from isolated chordal rupture/elongation of a posterior leaflet scallop (usually the P2 segment) with minimal leaflet tissue to complex Barlow's disease with bileaflet prolapse and giant excess tissue and annular dilation.1Anyanwu A.C. Adams D.H. Etiologic classification of degenerative mitral valve disease: Barlow's disease and fibroelastic deficiency.SeminThorac Cardiovasc Surg. 2007; 19: 90-96PubMed Scopus (196) Google Scholar In between these 2 ends of the spectrum lies forme fruste, which is similar to Barlow's disease but exhibits less tissue and a smaller annular diameter. There are a number of approaches to repairing posterior leaflet prolapse including resectional and nonresectional techniques. We employ a lesion-specific approach with the aim of returning the valve to its normal anatomical shape.2Anyanwu A.C. Adams D.H. Bileaflet repair for Barlow syndrome.Semin Thorac Cardiovasc Surg. 2010; 22: 179-183Abstract Full Text Full Text PDF PubMed Scopus (6) Google Scholar Here we illustrate 3 approaches to repairing posterior leaflet prolapse in 3 different forms of degenerative disease. All these techniques can be done via a small incision (8-10 cm) full-sternotomy approach (Fig. 1). We illustrate a case of fibroeleastic deficiency with isolated P2 chordal rupture is a nonresection technique using polytetrafluoroethylene (PTFE) sutures to construct neochordae (Figure 2, Figure 3, Figure 4, Figure 5).Figure 3The first step is to place some or all the annular sutures. This provides additional exposure of the valve, by pulling it up toward the surgeon. Once saline testing is done and reveals isolated chordal rupture of P2 with no further undiagnosed lesions, leaflet work can commence. First, identify the postermedial papillary muscle head providing chordal support to the posterior leaflet. A 5-0 PTFE suture is then passed through the head of the papillary muscle, ensuring that an adequate purchase of the fibrous head is taken. The suture can be placed with a single pass through the head or with 2 passes in a figure-of-8 fashion as illustrated. Both suture ends are then passed through the prolapsing and unsupported portion of the leaflet scallop approximately 2 mm from the edge.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 4(A) This next step illustrates our approach to adjusting the height of the neochordae. Notice the annuloplasty ring was sized and then tied in place before the final height adjustment of the neochordae. We employ a functional height adjustment that does not involve any direct measurements of native chordal height. Two slipknots are placed in the PTFE neochordae and the knots are loosely tied down approximately to the height of normal leaflet segments, erring on the side of having the knot tied slightly looser than one estimates. Saline testing is done to assess the height of this segment with the neochordae. The regurgitation should be markedly better. Now, the final PTFE chordal height can be adjusted based on the saline test and the coaptation line. If the slipknot needs to be loosened, this can be done with a nerve hook. Once the valve coaptation looks appropriate and the leaflet scallop is no longer prolapsing with saline testing, the saline is suctioned out and the remaining 6 to 8 knots are placed in the neochord, being careful to avoid the knots slipping further down and hence inadvertently shortening the neochord. (B) A final saline test is performed to confirm the valve competency and closure line.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 5An alternative approach to addressing this case is illustrated. (A) A very limited triangular resection is performed of the ruptured chord. (B) This is then closed using a 4-0 polypropylene suture. As mentioned earlier, notice how the ruptured chord is slightly to the right of the midline of the P2 scallop. (C) In the absence of excess tissue, as the leaflet edges are reapproximated, slight tension may result in a leak between the P2 and P3 scallop over time. As a result, we would recommend closing the gap between the P2 and P3 scallop using a figure-of-8 magic suture. The magic suture technique is described in a subsequent case. The normal anatomical gap between P1 and P2 is left alone as to allow for normal valve opening during diastole.View Large Image Figure ViewerDownload Hi-res image Download (PPT) In this case a forme fruste valve with P2 prolapse is repaired using a triangular resection and placement of neochordae (Figure 6, Figure 7, Figure 8, Figure 9).Figure 7Again, the repair is started by first placing the annuloplasty sutures around the valve to improve visualization and facilitate leaflet work. Leaflet retraction sutures are placed to mark the edges of the resection. The area of greatest prolapse is marked and then resected with a limited triangular resection. Notice that the apex of the triangle stops a few millimeters from the annulus.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 8The leaflet edges are then reapproximated using a 4-0 prolene suture either in a double layer running fashion (illustrated) or by using interrupted sutures.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 9In this case, after the greatest area of prolapse is resected, there still remains areas of chordal elongation where the posterior leaflet requires additional support. The remaining elongated chordae are often thin and at risk for future rupture. Hence, we support this area of the leaflet with a PTFE neochord. As described earlier, the corresponding papillary muscle is identified and a 5-0 PTFE suture is placed through the fibrous portion of the papillary muscle head and brought through the remaining portion of P2 on either side of the leaflet reapproximation suture line. The neochord height is then again functionally adjusted based on saline testing and the line of coaptation. Note, additional neochordae may be required if saline testing illustrates remaining areas of prolapse or unsupported leaflet.View Large Image Figure ViewerDownload Hi-res image Download (PPT) This final case illustrates Barlow's valve disease where a limited quadrangular resection, horizontal annular plication, asymmetric sliding plasty, and magic suture placement technique are performed (Figure 10, Figure 11, Figure 12, Figure 13, Figure 14).Figure 11Notice here that annuloplasty sutures are first placed around the anterior annulus only as we plan on working mostly on the posterior annulus and so will place the posterior annuloplasty sutures in a later step. In this case, we have giant excess tissue with diffuse prolapse of almost all segments. Initially, a gap between the P2 and P3 scallop is closed, allowing this tissue to be treated as 1 segment. This is accomplished using 2 magic sutures.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 12The excess tissue is asymmetrically favored toward P2 and P3 with a relatively normal looking P1 scallop; we perform a targeted quadrangular resection of P2 with the aim of sliding the remaining portion of P2 and P3 toward P1, effectively shortening the height of these scallops. To mobilize and slide the P2/P3 segment, secondary chordae are cut to prevent leaflet restriction and allow for leaflet mobilization. Marginal/primary chordae are preserved where possible.Show full captionThe leaflet is quite tall (>20 mm), so a horizontal triangular resection is performed at the base of the free leaflet to shorten it further to approximately 15 mm. Note that the final height adjustment will be made as the leaflet is reattached to the annulus.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 13(A) Before sliding the leaflet, the posterior annuloplasty sutures are then placed as visualization is made easy without the leaflet in place. Subsequently, using a 4-0 polypropylene suture, the leaflet is then reapproximated to the annulus, keeping tension on the leaflet edge as illustrated to ensure that a "sliding plasty" is performed as opposed to just a leaflet reattachment. The height of the leaflet can be adjusted during this step by varying the depths of the sutures on the leaflet edge. Larger bites of tissue on the leaflet will result in a shorter overall leaflet height. (B) Once completed, the leaflet edges are reapproximated using a 4-0 polypropylene suture. We start the leaflet reapproximation by first placing 1 interrupted figure-of-8 suture at the base of the leaflets with 1 bite through the annulus to ensure no residual leaks at the base of the leaflets. Following this, the leaflets can then be reapproximated using a running 4-0 polypropylene suture.View Large Image Figure ViewerDownload Hi-res image Download (PPT) The leaflet is quite tall (>20 mm), so a horizontal triangular resection is performed at the base of the free leaflet to shorten it further to approximately 15 mm. Note that the final height adjustment will be made as the leaflet is reattached to the annulus. This technique (Fig. 14), described by Carpentier and colleagues,3Carpentier A. Adams D.H. Filsoufi F. Carpentier's Reconstructive Valve Surgery. MO Elsevier, Maryland Heights2010Google Scholar provides a method for closing gaps and indentations. The key benefit of this technique is its ability to imbricate the leaflet edges to provide approximately 5 mm of leaflet coaptation at the edges where the sutures are placed. The technique is performed using a 5-0 polypropylene suture. The suture is taken through the leaflet near its edge from atrium to ventricle and then is brought back through the same leaflet, this time closer to the leaflet edge. The same needle is then brought through the adjacent leaflet close to its edge from atrium to ventricle and then back through the leaflet one last time but slightly further back from the edge. When the suture is tied, the 2 edges of the leaflet will imbricate together, creating a normal surface of coaptation. This technique is most beneficial when addressing commissural prolapse. Posterior leaflet prolapse can present in a variety of forms and etiologies. A lesion-specific approach allows the surgeon the ability to employ a number of techniques to address the prolapse while attempting to return the valve to its normal anatomical configuration. The key elements of the above techniques involve 5 main components. The first technique is to understand the etiology and lesions associated with the prolapse, such as excess leaflet tissue, commissural prolapse, and anterior leaflet prolapse abnormal gaps/indentations. Second, address the primary lesion with a strategy to return the posterior leaflet toward a normal anatomical configuration. As we have illustrated, this may or may not require leaflet resection. Thirdly, adequate chordal support to the leaflet segments must be ensured. We believe this is important for long-term durability of the repair. Next, an appropriate ring annuloplasty is performed. Ring sizing is based on the anterior leaflet area. Finally, once the primary lesion has been addressed, saline testing may reveal additional lesions such as a prolapsing commissure. One should carefully analyze the saline test so as to target further repair toward areas of persistent regurgitation. Using a systematic approach will yield reliable results. Our results with these techniques have shown a 95% freedom from greater than 2+ mitral regurgitation at 5 years.