Asian Cardiovasc Thorac Ann 2004;12:159-161
© 2004 Asia Publishing EXchange Ltd
Double Outlet Left Ventricle, Transposition of Great Vessels and Pulmonary Stenosis
Ganesh Shanmugam, MCh,
James Pollock, FRCS,
Kenneth Macarthur, FRCS
Department of Cardiac Surgery, Royal Hospital for Sick Children, Scotland, UK
For reprint information contact: Kenneth Macarthur, FRCS Tel: 44 141 201 0269 Email: kjdmaca{at}aol.com Department of Cardiac Surgery, Royal Hospital for Sick Children, Dalnair Street, Glasgow G3 8SJ, Scotland, UK.
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ABSTRACT
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A 4 year-old boy with double outlet left ventricle, transposition of the great vessels, severe pulmonary and subpulmonary stenosis, and subaortic ventricular septal defect underwent successful surgical intervention. The surgical techniques and management plan for double-outlet left ventricle are reviewed.
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INTRODUCTION
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Double outlet left ventricle (DOLV) is a rare congenital malformation wherein both great arteries arise entirely or predominantly from the left ventricle (LV). The heterogeneous morphology has contributed to a lack of consensus concerning its diagnosis, classification, and surgical management.
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CASE REPORT
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A 4-years old boy presented with severe cyanosis at birth. Echocardiography revealed transposition of the great vessels, DOLV (Figure 1A
) with a subaortic ventricular septal defect (VSD) and severe pulmonary stenosis (Figure 1B). Rashkind atrioseptostomy was performed, followed by a 4 mm modified right Blalock-Taussig shunt.An angiogram (Figure 1C) confirmed the diagnosis. There was no gradient between the LV and the aorta. The left and right coronary arteries arose from the left and right coronary sinuses, respectively. The cardiac morphology was situs solitus, ventricular d-loop, and atrioventricular concordant connection. The aorta lay to the right and slightly anterior to the pulmonary artery (PA). The right ventricle (RV) and the tricuspid valve were normal. Cardiopulmonary bypass was established through ascending aortic-bicaval cannulation, and the shunt was ligated. Moderate hypothermia and antegrade cold crystalloid cardioplegia were used. An oblique right atriotomy and a distal right ventriculotomy were performed. The large subaortic VSD extended to the tricuspid annulus. The aorta arose predominantly from the LV. The PA exited the LV posteriorly, to the left of the aorta. The pulmonary valve was bicuspid and stenotic. There was subvalvar stenosis due to a restrictive subpulmonary infundibulum. The VSD was closed with a Dacron patch. A 20 mm valved bovine conduit was interposed between the pulmonary trunk and the right ventriculotomy. The pulmonary valve was closed using continuous polypropylene sutures. The patient was rewarmed and separated from bypass easily. Intraoperative echocardiography (Figures 2A & 2B) showed good ventricular contraction. The systolic pressure gradients across the conduit immediately after surgery and at follow-up one year later were 15 and 10 mmHg, respectively. The postoperative course was uneventful. The patient was well at follow-up one year later.
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Figure 2. Epicardial echocardiograms showing (A) the contoured patch on the ventricular septal defect, and (B) the right heart conduit. AO = aorta; LV = left ventricle; RV = right ventricle.
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DISCUSSION
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The embryology of DOLV was explained by the differential conal growth and absorption hypotheses.1 According to Goor and Lillehei,2 conotruncal inversion involves counterclockwise rotation of the conoventricular junction, followed by similar rotation of the truncus and the semilunar valves, thereby transferring the aortic valve to the same posterior position as the aortic conus. Failure of truncal inversion leaves the aortic valve in its early embryological position, anterior and to the right above the RV. The VSD in a DOLV can be subaortic, subpulmonary, doubly committed, or non-committed.3 The aorta overrides the interventricular septum to a variable degree, and the lesion represents an anatomical continuum with transposition of the great arteries with VSD. The aorta can be normal, parallel to the PA, or in D or L malposition. Pulmonary stenosis is particularly prevalent in patients with subaortic VSD and it can be subvalvar, valvar, or both.3 There is a substantial incidence of tricuspid valve abnormalities and right ventricular hypoplasia in DOLV. Double outlet LV is classified surgically into type 1 where the RV is normal, and type 2 where the RV is hypoplastic. The choice of biventricular repair or a Fontan type procedure is determined by the degree of hypoplasia of the RV. Type 1 is further classified depending on the presence or absence of pulmonary stenosis.4
In type 1 DOLV with no pulmonary stenosis, complete intraventricular repair is possible, and a contoured patch is placed into the VSD so that the RV now ejects into the PA while the LV continues to eject into the aorta. With subaortic VSD, biventricular repair can also be accomplished using a RV-aorta baffle combined with either an atrial or arterial switch.5 These are less frequently performed procedures. However, intraventricular repair is unsuitable in the presence of pulmonary or subpulmonary stenosis. It is difficult to place a transannular patch because the left anterior descending coronary artery lies in front of the pulmonary ring. In cases of subpulmonary stenosis, DeLeon and colleagues4 and Chiavarelli and colleagues6 have demonstrated translocation of the main PA and valve when the obstruction is predominantly subpulmonary and the valve and annulus are normal. With valvular stenosis, when the valve itself is stenotic or the annulus is small and obstructive, pulmonary root translocation is not possible. Translocation of the divided main PA onto the right ventriculotomy and reconstruction can be performed. If the distal main PA does not easily reach the RV, a Lecompte maneuver may be necessary by dividing the aorta.7 Compared to pulmonary root translocation, these procedures do not involve relocating the native pulmonary valve. Translocation procedures provide an unobstructed repair, avoid an extracardiac conduit, and minimize RV dysfunction secondary to pulmonary insufficiency. However, they can be performed only when the pulmonary stenosis is mild, and the long term results and complications need to be assessed before they are more widely adopted.
In type 2 DOLV, when the RV is hypoplastic, a bidirectional cavopulmonary anastomosis is performed, followed by a Fontan operation at a later date. In this patient, the valve was severely stenotic and the subpulmonary obstruction was narrow and long, therefore, a valved conduit was necessary. We have had good long term results with bovine conduits, and we anticipate that a 20 mm conduit will serve this patient well. However, external conduits cannot grow and are subject to late conduit obstruction and replacement. Valveless conduits have been placed, and though initially well tolerated, often result in progressive RV dysfunction due to pulmonary insufficiency.8 Close postoperative follow-up is required in those who receive conduits. Factors determining surgical repair in DOLV include the degree of RV hypoplasia, the presence, location, and severity of valvular and/or subpulmonary stenosis, the commitment of the VSD which determines the type of patch or baffle used for an intraventricular repair, and the presence of associated cardiac defects.
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REFERENCES
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- Anderson R, Galbraith R, Gibson R, Miller G. Double outlet left ventricle. Br Heart J
1974;36:554–8.[Free Full Text]
- Goor DA, Lillehei LW. The embryology of the heart. In: Congenital malformations of the heart. New York: Grune and Stratton, 1975:38.
- Van Praagh R, Weinberg PM, Srebro JP. Double outlet left ventricle. In: Van Praagh R, Van Praagh S, editors. Diagnostic and surgical pathology of congenital heart disease. Vol 2. Washington: Health Video Dynamics, Inc., 1991:1106–30.
- DeLeon SY, Ow EP, Chiemmongkoltip P, Vitullo DA, Quinones JA, Fisher EA, et al. Alternatives in biventricular repair of double-outlet left ventricle. Ann Thorac Surg
1995;60:213–6.[Abstract/Free Full Text]
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- LecompteY, Neveux J, Leca F, Zannini L, Tu TV, Duboys Y, et al. Reconstruction of the pulmonary outflow tract without prosthetic conduit. J Thorac Cardiovasc Surg
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- Stegmann T, Oster H, Bissenden J, Kallfelz HC, Oelert H. Surgical treatment of double-outlet left ventricle in 2 patients with D-position and L-position of the aorta. Ann Thorac Surg
1979;27:121–9.[Abstract]
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ABSTRACT
INTRODUCTION
