記住我
Abstract
Double-outlet left ventricle (DOLV) is a rare congenital cardiac anomaly in which both the aorta and pulmonary artery arise completely or predominantly from the left ventricle. DOLV is a spectrum and can be classified depending on the position of the ventricular septal defect (VSD) relative to the great vessels, the relationship of the great vessels, and the presence or absence of pulmonary or aortic outflow obstruction. In the absence of tricuspid atresia or hypoplastic right ventricle, two ventricle repair is the preferred surgical treatment. We report a 31-day-old, 2.1 kg neonate with DOLV, subaortic VSD who underwent a successful arterial switch with VSD closure.
Keywords: Double-outlet left ventricle, arterial switch, transposition of great arteries, neonate, ventricular septal defect.
How to cite this article: Introduction 
Double-outlet left ventricle (DOLV) is a rare congenital cardiac anomaly (5% of all double outlet ventricles) in which both the aorta and pulmonary artery (PA) arise completely or predominantly from the left ventricle (LV). DOLV is a spectrum and can be classified depending on the position of the ventricular septal defect (VSD) relative to the great vessels, the relationship of the great vessels, and the presence or absence of pulmonary or aortic outflow obstruction. In the absence of tricuspid atresia or hypoplastic right ventricle, two ventricle repair is the preferred surgical treatment.[1] A neonate in respiratory distress diagnosed with transposition of great arteries was referred for surgical management. On detailed evaluation with two-dimensional echocardiography (2-D echo), found to be a case of DOLV. The patient was managed with an arterial switch operation.
Case Report A 2.1 kg, 31-day-old child was brought with saturation in the 60s, irritability, and difficulty in feeding. 2-D echo showed situs solitus with atrioventricular (AV) concordance and ventriculoarterial discordance [Figure 1]a, [Figure 1]b, [Figure 1]c. The AV valves were normal with well-developed ventricles. Outflow tracts were parallel. PA was from LV and anterior to the aorta unlike dextro-Transposition of the great arteries (dTGA). There was aortomitral continuity with 50% commitment of the aorta to both ventricles. Careful assessment of 2-D echo with posterior to anterior sweep would help delineate DOLV from TGA. In DOLV, it would show the aorta first arising above the VSD committed to both ventricles and the anterior PA arising completely from the LV, while in dTGA, the PA would be posterior structure and the aorta would be anteriorly arising from the right ventricle (RV).
Figure 1: (a) Preoperative 2-D echo image showing the aortamitral continuity. (b) PLAX- parasternal long-axis view showing VSD. (c) Parasternal short-axis view showing aorta and pulmonary artery. 2-D echo: 2-dimensional echocardiography, VSD: Ventricular septal defectIntraoperatively, the coronary pattern was 1LR2Cx. Aorto-bicaval cannulation and antegrade del Nido cardioplegia was given. Aorta was transected first, and the coronary anatomy was confirmed. The VSD- was subaortic and appeared that RV could be routed to the aorta without obstruction. PA was transected next and its complete commitment to LV was confirmed. It was decided to do an arterial switch. The coronary buttons were harvested and mobilized to comfortably reach the neo-aortic root. With the buttons excised the working space increased and VSD was closed through neo-pulmonary root with a 0.4mm polytetrafluoroethylene patch. The lower end was anchored with 7-0 polypropylene 8 mm half-circle pledgetted sutures along the inferior margin of VSD. The upper part of the patch was anchored and tied over pledgets in the left coronary artery (LCA) coronary bed outside the heart to the muscle in the roof of the LV [Figure 2] and [Figure 3].
Figure 2: Diagrammatic representation of the technique of VSD closure with patch anchored to the coronary bed. VSD: Ventricular septal defect
Figure 3: Intraoperative image showing harvested coronary sinus buttons and VSD closed through aortic (neo-pulmonary) root and anchored onto LCx coronary harvest. VSD: Ventricular septal defectThe buttons were then anastomosed to neo-aortic root, the LCA button was anastomosed high up and the button comprising the left anterior descending (LAD) and right coronary artery (RCA) was anastomosed with a medially-based trapdoor. There was redundant PA, which was excised and was used to reconstruct the sinus-1 [Figure 4]a, [Figure 4]b, [Figure 4]c. The neo-aortic anastomosis was done without the Lecompte maneuver, as the neo-aortic root was anterior. The cross-clamp was removed, the sinus-2 was reconstructed with an autologous unfixed pericardial patch, and the neo-pulmonary anastomosis was completed. The cross-clamp time was 110 min, and the bypass time was 150 min.
Figure 4: (a) Great vessels their relationship and the LAD taking the shortest route to open into the aortic sinus (the probable theory behind the coronary pattern). (b) VSD and the coronary pattern and the orientation of the great vessels. (c) The coronary transfer and the neo pulmonary sinus reconstruction with redundant tissue from the pulmonary artery and the VSD closure with the PTFE patch. (*Abbreviations: VSD – Ventricular septal defect, LAD- Left anterior descending artery, LCx – Left circumflex artery, RCA- Right coronary artery, RAV- Right atrioventricular groove, LAV- Left atrioventricular groove, RV- Right ventricle, LV- Left ventricle, RVOT- Right ventricular outflow tract)The child was weaned-off cardiopulmonary bypass with minimal inotropic support. Intraoperative 2-D echo showed adequate ventricular function and unobstructed outflow tracts. The chest which was electively left open was closed in the following day. The child was extubated after 48-h and the further postoperative course of the child was uneventful. The child reviewed after 2 weeks showed good ventricular function, no residual VSD, competent valves, and unobstructed outflow tracts. On follow-up after 6 months, a 2-D echo revealed unobstructed left as well as right ventricular outflow tracts, the previous aortic valve routed to RV and forming the neo-pulmonary valve and the continuity between the mitral and neo-pulmonary valve was well appreciated. The postoperative LV and neo-aortic valve, which was the previous pulmonary valve showed the complete commitment of the pulmonary valve to LV [Figure 5]a, [Figure 5]b, [Figure 5]c, [Figure 5]d. There was no aortic regurgitation or pulmonary regurgitation, and the flow pattern was laminar with no turbulence.
Figure 5: (a) Postoperative echo at 6 months follow-up showing unobstructed left ventricular outflow tract. (b) Postoperative echo showing right ventricular outflow tract. (c) Postoperative echo showing the previous aortic valve routed to the right ventricle and forming the neo-pulmonary valve. The continuity between the mitral and neo-pulmonary valve can be appreciated. (d) The postoperative left ventricle and neo-aortic valve, which was the previous pulmonary valve show the complete commitment of the pulmonary valve to the left ventricle. Discussion In 1967 when Sakakibara reported the first successful surgical repair,[2] DOLV was defined as a ventriculo-arterial connection in which both the great arteries arise entirely or predominantly from morphologic LV. It has also been reported in situs inversus, AV discordant connections, and with intact ventricular septum and functionally single ventricle hearts. DORV is much more common than DOLV because every heart in its development passes through a stage of DORV with LV connected to the outflow tracts through the bulbo-ventricular foramen. In DOLV the sub-pulmonary infundibulum is possibly resorbed and the PA arises from LV completely and is placed anteriorly.[1],[3],[4]
Surgical options for biventricular repair in DOLV include –
Rastelli-type procedure – disadvantage being using a conduit in a neonatePulmonary root translocation – this operation was first proposed in 1992[5] for the treatment of DOLV and has not been reported in neonates.[6] Probably because of the lack of infundibulum in DOLV, the harvest of the root could mean a considerable loss of functional myocardium especially if there is no pulmonary stenosis. Interestingly, most of the neonatal repair cases reported have a single coronary artery or LAD and RCA from the same sinus, where in LAD would be travelling anterior and close to the pulmonary root making root harvest dangerousArterial switch procedure – this procedure has been reported in a 32-day 4 kg child.[7],[8] The authors proposed to keep the sutures for the upper margin of the patch within the sinus – there is a risk of injuring the neo-pulmonary cusp by the suture knots. Our child was only 2.1 kg and cusps were delicate. We propose to fix the superior aspect of the VSD patch outside the heart, onto the base of the mobilized circumflex artery. This serves three purposes: (a) opens up the RV outflow tract and makes it roomy, (b) avoids sutures near the cusp of the neo-pulmonary valve, (c) provides hemostasis on the floor of the bed from where the circumflex artery has been mobilized. Advantages of our technique as mentioned before being -avoiding the cusp, opening up the RV outflow tract- and hemostasis from the coronary harvest bed [Figure 3].Usually, LAD and RCA have a common origin or a single coronary artery. This has an embryological explanation. The coronary artery develops in two AV grooves as RCA and LCx and the LAD develops in the anterior interventricular groove and establishes a connection with the coronary bud which arises from the aortic root to form the coronary pattern.[9] In the normal heart, the development of the sub-pulmonary infundibulum makes it difficult for the interventricular coronary to establish a connection with the right bud. In DOLV, the absence of sub-pulmonary infundibulum makes it easier for the interventricular artery to establish a connection with the right bud resulting in the common origin of LAD and RCA as has been reported [Figure 4].
Arterial switch in the presence of common origin of RCA and LAD needs more mobilization depending on the length of proximal stem available. It is safer to reconstruct the sinus while the clamp is still on and this sinus should not be bulging to prevent further stretching of the coronary. In cases where there is a risk of stretching of RCA and kinking of LAD, a coronary lengthening procedure, or dissection of the epicardial adventitia between the coronary artery may allow the coronaries to move independent of each other and avoid coronary ischemia.[10] In addition, the differences between ASO in TGA, Taussig Bing, and DOLV are notable. The aorta is a posterior structure and there is mitral-aortic continuity, the VSD, however, is more easily routable to the RV. In echocardiography, during posterior to anterior sweep, PA is the structure that arises from LV and the aorta is anterior from RV in TGA. In DOLV, the aorta is posterior and PA is more anterior and is from LV. The coronary pattern is expected to be RCA and LAD from the common sinus when it is DOLV, the embryologically possible reason is discussed. Lecompte maneuver is not necessary in DOLV as the PA is already anterior and needs to go behind. The closure of VSD is technically easy after mobilization of coronaries through the posterior aorta and making sure that it is directed without obstruction to the RV. The superior portion of the patch can be anchored outside the heart on the bed of the mobilized circumflex artery.[1],[4],[8]
Conclusion Careful assessment using echocardiography with posterior to anterior tilt using subxyphoid and parasternal long-axis views would help identify this entity which can easily be mistaken for TGA or VSD. A Lecompte maneuver is not needed during the arterial switch. Closing the VSD after great vessel transection and coronary harvest facilitates its closure and has advantages. The surgeon has to be prepared to deal with common LAD and RCA origin.
Animal and Human Rights Statement All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent
Informed consent was obtained from the participant included in the study.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given his consent for images and other clinical information to be reported in the journal. The guardian understands that names and initials will not be published and due efforts will be made to conceal the identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References 
Correspondence Address:
Dr. Dhruva Sharma
Department of Cardiothoracic and Vascular Surgery, SMS Medical College and Attached Hospitals, J L N
Marg, Jaipur - 302 001 Rajasthan
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/apc.apc_150_21
留言 (0)