Ann Thorac Surg 2001;72:907-909
© 2001 The Society of Thoracic Surgeons
Case report
Prosthetic mitral valve replacement after atrioventricular septal defect repair: a technique for small children
Makoto Ando, MDa,
Charles D. Fraser, Jr, MDa
a Section of Congenital Heart Surgery, Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas, USA
Accepted for publication September 14, 2000.
Address reprint requests to Dr Fraser, Section of Congenital Heart Surgery, Texas Children’s Hospital, 6621 Fannin, MC1-2285, Houston, TX 77030
e-mail: charlesf{at}bcm.tmc.edu
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Abstract
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An 11-month-old girl was transferred for consideration of cardiac transplantation. She had previously undergone repair of complete atrioventricular septal defect at another institution. Her postoperative course was notable for severe mitral regurgitation, pulmonary hypertension, and heart failure. At reoperation, the left atrioventricular valve was considered irreparable with a very small (11 mm) annulus. Using a technique to enlarge the mitral annulus, a 17-mm prosthetic valve was placed. Her postoperative course was unremarkable and she is doing very well at 3 years follow-up.
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Introduction
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Valve repair in complete atrioventricular septal defect (AVSD) can be challenging in patients with deficient or dysmorphic valve tissue. Although some degree of AV valve regurgitation may be well tolerated, severe insufficiency results in pulmonary hypertension and congestive heart failure. Although every effort should be made to repair the AV valve, in some individuals, prosthetic valve replacement may be the only reasonable option. We describe a technique used to implant a prosthetic mitral valve in a small child with severe left AV valve insufficiency and very hypoplastic annulus.
The patient was an 11-month-old girl (non-Down’s) weighing 5.2 kg with a history of complete AVSD previously repaired at 2 months of age using a single patch technique. Her postoperative course was complicated by second degree AV block requiring placement of an epicardial pacing system. The patient had residual severe left AV valve insufficiency. Despite maximal decongestive therapy, she remained in severe congestive heart failure. She was referred to our institution for consideration of cardiac transplantation. Echocardiographic study and cardiac catheterization revealed severe left AV valve insufficiency with preserved ventricular function. We believed prosthetic valve replacement was preferable.
At operation, the former right atriotomy incision was reopened. The right AV valve was deficient in functional valve tissue and had moderate regurgitation. The atrial portion of the previous patch was unhinged and the left AV valve was explored. The valve was stenotic and would not admit an 11-mm probe. There was deficiency of leaflet tissue and the valve seemed irreparable. After the resection of the valve tissue, the annulus was still too small for a prosthetic valve. Therefore, the ventricular septal defect patch was cut longitudinally down towards the crest of the ventricular septum to create a larger mitral annulus. A patch of autologous pericardium was used to augment the anterior portion of the ventricular septal defect patch (Fig. 1). A 17-mm St. Jude Medical hemodynamic plus (HP) mitral prosthesis (St. Jude Medical Inc, St. Paul, MN) was sewn to the newly created mitral annulus using interrupted sutures. The atrial septal defect patch was reattached to the atrial septum. The patient was weaned from the bypass without difficulty. A postoperative transesophageal echocardiogram revealed excellent function of the valve prosthesis without perivalvular leak or left ventricular outflow tract obstruction. There was mild tricuspid regurgitation.
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Fig 1. (A) View of previous patch through right atriotomy. (B) The former atrial septal defect patch was unhinged and the left atrioventricular valve was exposed. (C) The patch was cut longitudinally toward the crest of the ventricular septal defect. (D) A patch made of autologous pericardium was sewn to augment the ventricular septal defect patch, which was carried up onto the atrial septal defect patch. A 17-mm St. Jude Medical hemodynamic plus (HP) prosthesis was sewn to the newly created annulus. (E) The atrial septal defect patch was augmented and reattached to the septum.
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The postoperative course was uneventful with hospital discharge on postoperative day 12. The patient is currently in good health on Digoxin (Glaxo-Welcome, Ontario, Canada) and Coumadin (Du Pont Pharmaceuticals, Wilmington, DE) at more than 3 years follow-up. Follow-up echocardiograms have documented good ventricular contractility with excellent prosthetic valve function. Tricuspid valve regurgitation remains mild.
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Comment
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Residual left AV valve regurgitation is a frequent cause of morbidity after repair of complete AVSD, although the incidence has decreased considerably with refinements in technique and better understanding of anatomy. There is general agreement that every attempt should be made to repair even very dysmorphic valves to avoid prosthetic replacement [1–4]. Drawbacks of prosthetic valve placement in children include the requirement of long-term anticoagulation and the potential of compromising annular growth. In particular, mitral valve replacement in complete AVSD is associated with high morbidity and mortality [5]. In some patients, however, the valve may have multiple anatomical abnormalities not amenable to repair even with an extensive reconstruction.
Prosthetic valve implantation in a severely hypoplastic annulus, as seen in small children, poses a surgical challenge. High profile tissue prostheses have a potential for left ventricular outflow tract obstruction, poor hemodynamic performance in small sizes, and rapid degeneration. Low profile mechanical prostheses represent the best option. In cases with severe annular hypoplasia, a supraannular placement may be the only option [5]. However, in the patient with AVSD, the annulus may be enlarged without injuring fibromuscular tissue separating the right and left AV valves by augmenting the ventricular septal defect patch. In this patient, the hypoplastic annulus was enlarged from 11 mm sufficiently to allow insertion of a 17-mm St. Jude prosthesis.
A drawback associated with this procedure may be the potential development of tricuspid insufficiency because of concomitant annular enlargement. This was not a significant problem with this patient.
We conclude that this technique provides an additional surgical option for left AV valve replacement after AVSD repair with significant annular hypoplasia. It allows augmentation of the valve annulus and insertion of a prosthetic valve with minimum risk of complication.
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References
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Lamberti J.J., Jensen T.S., Grehl T.M., et al. Late reoperation for atrioventricular valve regurgitation after repair of congenital heart defects. Ann Thorac Surg 1989;47:517-523.[Abstract/Free Full Text]
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Bonnets P.L., Goldberg S.J., Copeland J.G. Frequency of left atrioventricular regurgitation postoperatively after repair of complete atrioventricular defect. Am J Cardiol 1994;74:1157-1160.[Medline]
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Michielon G., Stellin G., Rizzoli G., et al. Left atrioventricular valve incompetence after repair of common atrioventricular canal defects. Ann Thorac Surg 1995;60:S604-S609.
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Permut L.C., Mehta V. Late results and reoperation after repair of complete and partial atrioventricular canal defect. Semin Cardiovasc Surg 1997;9:44-54.
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Kadoba K., Jonas R.A., Mayer J.E., Castañeda A.R. Mitral valve replacement in the first year of life. J Thorac Cardiovasc Surg 1990;100:762-768.[Abstract]
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Abstract
Introduction
