Eur J Cardiothorac Surg 2003;24:650-652
© 2003 Elsevier Science NL
Chordal-sparing mitral valve replacement: pitfalls and techniques to prevent complications
Hideki Sasaki*,
Kenji Ihashi
Department of Cardiovascular Surgery, Hoshi General Hospital, 2-1-16, Omachi, Koriyama City, Fukushima 963-8501, Japan
Received 4 May 2003;
received in revised form 9 July 2003;
accepted 14 July 2003.
* Corresponding author. Tel.: +81-24-923-3711; fax: +81-24-939-3141
e-mail: h-sasaki{at}hoshipital.or.jp
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Abstract
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When feasible, mitral valve repair is the usual treatment of choice for correction of chronic mitral insufficiency. When valve replacement is required, chordal sparing is the preferred technique. Many investigators have pointed out the merits of preserving the subvalvular apparatus during mitral valve replacement. However, many surgeons hesitate to perform chordal-sparing mitral valve replacement because of its technical complexity and potential interference with mechanical valve leaflet motion. We present a modified technique of chordal-sparing mitral valve replacement to avoid these problems.
Key Words: Chordal-sparing mitral valve replacement
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1. Introduction
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Mitral valve repair is the usual treatment of choice, when feasible, for correction of chronic mitral insufficiency. We usually perform mitral valve repair for degenerative mitral regurgitation. However, when the mitral valve proves to be unrepairable, we convert the procedure to mitral valve replacement. When valve replacement is required, chordal sparing is the preferred technique. The importance of maintaining mitral annular-papillary muscle continuity has been described in many studies [1–6]. We have performed the technique of mitral valve replacement described by Sintek and associates that retains the subvalvular apparatus [1], but in some cases we experienced size mismatch between the annulus and strip of leaflet with attached chordae tendineae. Therefore, we devised a modified technique of chordal-sparing mitral valve replacement and have performed it on 17 patients.
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2. Technique
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Through a median sternotomy, cardiopulmonary bypass is established with standard bicaval cannulation. Mitral valve is inspected through a left atriotomy or transatrial incision. When mitral valve repair is considered to be difficult because of more complex lesion involving anterior leaflet, we convert to mitral valve replacement. A semi-elliptical-shaped piece of tissue is excised from the annulus of the anterior leaflet, leaving a 5-–10-mm long rim of leaflet whose free edge remains attached to the primary and secondary chordae tendineae (Fig. 1A)
[1]. If this strip of anterior leaflet proves to be smaller than the annulus, the annulus may deform during mitral valve replacement when reattaching the strip to the annulus. Therefore, we detach the strip only from the annulus at the anterolateral commissure and reattach it to the annulus beginning at the posteromedial commissure in a counterclockwise fashion with pledgeted mattress sutures that will also be used for the valve replacement (Fig. 1B). We use an everting mattress technique with pledgeted mattress sutures for both mechanical and bioprosthetic valves. Because the strip is not detached from the annulus at the posteromedial commissure, no additional sutures are placed in the annulus (Fig. 2)
. The strip is usually shorter than the annulus, so it rotates in a posteromedial direction as it is sutured and, as a result, does not protrude into the left ventricular outflow tract. If the posterior leaflet is not diseased, it is preserved completely without excision.
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Fig. 1. (A) Schematic of mitral valve. In detaching the ellipsoid of tissue from the anterior leaflet, incision B is nearly straight and shorter than incision A. (AL=anterolateral commissure, PM=posteromedial commissure). (B) We reattached the strip to the annulus beginning at the posteromedial commissure in a counterclockwise direction with pledgeted mattress sutures that will also be used for the valve replacement.
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Fig. 2. Intraoperative photograph. The strip is not detached from the annulus at the posteromedial commissure.
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3. Results
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Since April 2001, we have used this modification on 17 patients. The mitral valve disease was myxomatous in 15 patients, ischemic in 1, and rheumatic in 1. Mechanical bileaflet valves (St. Jude Medical prosthesis; St. Jude Medical, Inc., St. Paul, MN) were implanted in 15 patients and bioprostheses were implanted in two patients. Fourteen patients underwent isolated mitral valve replacement, two patients had combined mitral valve and aortic valve replacement, and one patient underwent mitral valve replacement and coronary artery bypass grafting. All patients are currently alive and are New York Heart Association classes I or II. No patient has required reoperation. Postoperative low output syndrome was not observed in this series of patients, nor was left ventricular outflow tract obstruction detected by postoperative echocardiography. A decrease between echocardiographic measurements made preoperatively and at discharge was noted in left ventricular end-diastolic dimension (61±7 versus 50±4 mm) and left ventricular end-systolic dimension (39±6 versus 33±6 mm).
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4. Comment
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Mitral valve repair is recommended to correct mitral regurgitation. However, when the mitral valve proves to be unrepairable, the surgeon must quickly convert the procedure to that of mitral valve replacement. Many investigators have reported the importance of chordal preservation during mitral valve replacement [1–6]. This procedure improves early and late postoperative ventricular function compared to that of conventional mitral valve replacement with chordal resection and prevents catastrophic complications such as myocardial rupture by preserving annuloventricular continuity. But chordal-sparing mitral valve replacement is technically difficult and requires prolonged aortic cross-clamping time. In performing this procedure, we sometimes have experienced size mismatch between the remaining strip of anterior leaflet and the annulus. When we remove the ellipse-shaped tissue from the anterior leaflet, the first incision made is that marked by A in Fig. 1A. Then, while viewing the secondary chordae from the left ventricular side, incision B is made. Because the secondary chordae is attach at the belly of the leaflet, incision B is nearly straight to preserve these chordae. Line B is shorter than line A. Thus, when the strip of leaflet is reattached to the annulus and if an undersized artificial valve is inserted, the annulus has the potential to deform, resulting in perivalvular leakage. Before we introduced our modified technique, we experienced one case of hemolytic anemia because excess tissue protruded into the left ventricular outflow tract. In this patient in whom we applied the technique reported by Miki et al. [4], we split the remaining strip of anterior leaflet centrally and fixed the strips around the annulus of the two commissures, however, the anterior leaflet was redundant and excess tissue from the anterolateral commissure protruded into the left ventricular outflow tract, causing massive turbulence. Removal of this tissue was required postoperatively. In our modified suturing technique, the leaflet strip is fixed only at the posteromedial commissure and does not reach to the anterolateral commissure. By detaching the strip from one end of the annulus of the anterolateral commissure, tension between the two commissures is released, restriction of leaflet motion is prevented, and redundant tissue does not protrude into the left ventricular outflow tract. In this point, we believe our modified technique is superior to conventional techniques. When suturing the strip, line C is the desirable suture line to follow when penetrating the strip with the suture needle (Fig. 1A). The suture needle should penetrate from the left ventricular side to the left atrial side, taking care not to injure the primary or secondary chordae. If the needle penetrates the strip near line B or from the left atrial side at line C, the remaining strip and subvalvular apparatus will be bunched under the valve and will interfere with leaflet motion. Sintek and associates [1] recommended that this strip be divided into two to four segments and reattached in an anatomical position if the leaflet is thickened or calcified (Khonsari I technique). However, this technique is time-consuming, and we feel that it should not be used in patients with LV dysfunction or after a failed mitral valve repair because the procedure requires prolonged aortic clamping time. Thus, we developed our modified technique. We detach the strip of anterior leaflet only from the anterolateral commissure and preserve the posteromedial commissure attachment. This technique does not require any sutures other than those used for valve attachment and causes no annular deformation or leaflet restriction. Furthermore, because the strip is left attached at the annulus of posteromedial commissure, it is easy to begin attachment of the strip to the annulus. This modification is simple and effective in preventing complications associated with the technique of chordal-sparing mitral valve replacement.
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References
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- Sintek C.F., Pfeffer T.A., Kochamba G.S., Khonsari S. Mitral valve replacement: technique to preserve the subvalvular apparatus. Ann Thorac Surg 1995;59:1027-1029.[Abstract/Free Full Text]
- Yun K.L., Sintek C.F., Miller D.C., Schuyler G.T., Fletcher A.D., Pfeffer T.A., Kochamba G.S., Khonsari S., Zile M.R. Randomized trial of partial versus complete chordal preservation methods of mitral valve replacement: a preliminary report. Circulation 1999;100(Suppl.):II90-II94.
- Natsuaki M., Itoh T., Tomita S., Furukawa K., Yoshikai M., Suda H., Ohteki H. Importance of preserving the mitral subvalvular apparatus in mitral valve replacement. Ann Thorac Surg 1996;61:585-590.[Abstract/Free Full Text]
- Miki S., Kusuhara K., Ueda Y., Komeda M., Ohkita Y., Tahata T. Mitral valve replacement with preservation of chordae tendineae and papillary muscles. Ann Thorac Surg 1988;45:28-34.[Abstract]
- David T.E., Burns R.J., Bacchus C.M., Druck M.N. Mitral valve replacement for mitral regurgitation with and without preservation of chordae tendineae. J Thorac Cardiovasc Surg 1984;88:718-725.[Abstract]
- Komeda M., David T.E., Rao V., Sun Z., Weisel R.D., Burns R.J. Late hemodynamic effects of the preserved papillary muscles during mitral valve replacement. Circulation 1994;90(Suppl.):II190-II194.
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Abstract
1. Introduction
