Ann Thorac Surg 1999;68:2336-2338
© 1999 The Society of Thoracic Surgeons
Case Reports
Implantation of a mechanical valve within a flexible mitral annular ring
Yuzuru Sakakibara, MDa,
Yoshiharu Enomoto, MDa,
Akinobu Sasaki, MDa,
Motoo Osaka, MDa,
Toshio Mitsui, MDa
a Department of Surgery, Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Japan
Address reprint requests to Dr Sakakibara, Department of Surgery, Institute of Clinical Medicine, University of Tsukuba, Tsukuba Science City, 305-8575 Ibaraki, Japan
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Abstract
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The implantation of a mechanical valve within the orifice of a mitral Duran flexible annular ring is presented. Exact orifice matches of the former ring and the new mechanical valve prosthesis (Advancing The Standard [ATS]; ATS Medical Inc, Minneapolis, MN) can be obtained using a standard mitral type ATS valve, when the size of the former Duran ring is larger than 31 mm. If ring dehiscence is not noted at reoperation after mitral valve repair, this procedure can be simply performed in patients with late mitral valve dysfunction requiring valve replacement.
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Introduction
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Mitral valve plasty (MVP) with prosthetic ring annuloplasty has become a preferable alternative to mitral valve replacement (MVR) for patients with pure mitral insufficiency of non-rheumatic origin [1, 2]. Duran and Ubago developed a flexible annular ring capable of achieving greater physiological annuloplasty with an improvement of left ventricular function which is now widely used [2]. The number of patients who require reoperation for late valve failure after MVP has decreased due to improved surgical techniques and immediate assessment of operative results [1, 3]. However, reoperation is still required in a minority of patients due to late mitral valve failure.
Implantation of a mechanical valve within a flexible Duran ring was tried as a solution to various complications such as late perivalvular leakage in the reoperation after MVP. This procedure can be easily and safely performed and should allow for a shortening of operation time.
In a patient who was referred for MVR for late valve failure, which could not be revised with redo MVP, we used this surgical approach for reoperation.
Cardiac exposure is obtained via a redo median sternotomy. The patient is placed on cardiopulmonary bypass. After ascertaining the absence of ring dehiscence by inspection of the previously implanted Duran ring, only the native mitral leaflet is excised. A properly selected standard mitral Advancing The Standard (ATS) prosthesis (ATS Medical Inc, Minneapolis, MN) is sutured to the cloth cuff of the previously implanted Duran ring with mattress sutures (Fig 1). The ATS valve was selected for use because there is no radiographic marker on the St. Jude mechanical valve. Our experience in implanting mechanical valves within the orifice of the bioprosthesis has shown that only a standard mitral type ATS valve of less than 25 mm can be theoretically used, when the former ring size is smaller than 29 mm. A larger size (27 mm or 29 mm) aortic ATS valve could then be used in reverse fashion. Exact orifice matches are selected in consideration of both the inner diameter of the former ring and the annulus size or inner diameter of the new mechanical valve (Fig 2). The best choices of ATS valve types are shown in Table 1.
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Fig 1. Implantation of a mechanical valve within a Duran flexible ring. Only the mitral leaflet is excised and the posterior leaflet is not preserved. Mattress sutures were placed through the surrounding atrial tissue and the ring for fixing the mechanical valve prosthesis.
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Fig 2. Parameters for exact orfice matches in this technique: (left) internal diameter of the Duran flexible ring; (right) annulus size of the standard mitral mechanical (ATS) valve. (ATS = Advancing The Standard; ATS Medical Inc, Minneapolis, MN.)
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Comment
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A flexible annular ring was introduced by Duran and Ubago in 1976, and has been widely used for mitral annuloplasty because of good left ventricular perfor-mance in the early postoperative period [2]. On the other hand, intraoperative transesophageal echocardiography (TEE) provides direct visual information about the operative results of mitral valve repair. If an unsatisfactory surgical result is obtained, surgical revision is performed during the second run of cardiopulmonary bypass [3]. Consequently, a reduced number of patients have been requiring reoperation for early failure of mitral valve repair. However, there are patients with late valve failure which necessitates a second operative procedure due to failure of the anterior leaflet chordal shortening procedure, chordal elongation, or thickening of the repaired leaflet. Duran and Ubago reported their reoperation rate in which late surgical revision was required to be 3.7% of the total MVP patients with their flexible ring [2].
In reoperation for structural valve deterioration of a glutaraldehyde-preserved porcine bioprosthesis, the concept of implanting a reversed aortic mechanical valve within the orifice of the stent of a degenerated mitral bioprosthesis was introduced by Geha and Lee in 1995 [4]. For the implantation of a mechanical valve within the orifice of a mitral ring, an exact orifice match between the former ring and the new mechanical valve is a major concern. It is known that flexible ring sizes between 28 and 30 are appropriate for most female patients, and sizes 30 to 34 for most male patients with MVP [1, 5]. Bernal and his colleagues reported that more than half of the patients had large flexible rings implanted during the mitral valve repair operation [6]. If the previous ring size was 31 to 33, a 27 to 29 mm standard mitral type ATS valve could be implanted within the former Duran ring. When the smaller size Duran ring was used, total excision of the former ring or this new approach utilizing a reversed aortic ATS valve is recommended.
Although complete excision of the former flexible ring is the traditional approach, this (artificial valve in ring) approach seems to offer a good solution for shortening the reoperation time with simpler procedures and also for preventing complications associated with the traditional procedure.
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References
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Oury J.H., Grehl T.M., Lamberti J.J., Angell W.W. Mitral valve reconstruction for mitral regurgitation. J Cardiac Surg 1986;1:217-231.[Medline]
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Duran C.G., Ubago J.L.M. Clinical and hemodynamic performance of a totally flexible prosthetic ring for atrioventricular valve reconstruction. Ann Thorac Surg 1976;22:458-463.[Abstract]
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Loick H.M., Scheld H.H., Van Aken H. Impact of perioperative transesophageal echocardiography on cardiac surgery. Thorac Cardiovasc Surg 1997;45:321-325.[Medline]
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Geha A.S., Lee J.H. Evolution of the surgical approach for replacement of degenerated mitral bioprosthesis. Surgery 1995;118:662-668.[Medline]
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Duran C.G., Pomar J.L., Revuelta J.M., et al. Conservative operation for mitral insufficiency. Critical analysis supported by postoperative hemodynamic studies of 72 patients. J Thorac Cardiovasc Surg 1980;79:326-337.[Abstract]
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Bernal J.M., Rabasa J.M., Vilchez F.G., Cagigas J.C., Revuelta J.M. Mitral valve repair in rheumatic disease. The flexible solution. Circulation 1993;88(4 Part 1):1746-1753.[Abstract/Free Full Text]
Accepted for publication May 6, 1999.
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Abstract
Introduction
