DORV PDF - Double Outlet Right Ventricle

C hapter 41 Double Outlet Right Ventricle Vimala J, Vijayalakshmi IB, Prasanna Simha Mohan Rao IntRODuCtIOn the aorta and pulmonary trunk malali...

C hapter 41 Double Outlet Right Ventricle Vimala J, Vijayalakshmi IB, Prasanna Simha Mohan Rao IntRODuCtIOn the aorta and pulmonary trunk malaligned with respect to the ventricles resulting in DORV, dextroposed aorta and/or Double outlet right ventricle (DORV) is a term that tetralogy of Fallot (TOF).5 encompasses a wide range of cardiac malformations with varied clinical presentation. DORV comprises 1 to 3 percent gEnEtICs of all congenital heart defects.1 The congenital heart surgery nomenclature and database project has defined DORV as In most cases, the defect is sporadic in nature and there is no a spectrum of congenital heart diseases, in which both the identifiable genetic cause. A small number of familial cases great arteries arise entirely or predominantly from the RV.2 have been reported and the defect has been produced in animal This spectrum ranges from ventricular septal defect (VSD) models by the deletion of particular genes, especially those with overriding aorta at one end to DORV with subpulmonic associated with neural crest migration. 22q11 micro deletion VSD (Taussig-Bing anomaly), which resembles transposition has been associated with some cases of DORV.6 In a literature of great arteries (TGA) at the other end. The clinical survey of 140 case reports of DORV; various chromosomal manifestations vary depending on the relationship of the great anomalies were reported in 40 percent of the patients.1 vessels to each other and location of the VSD and the presence or absence of stenosis of the semilunar valves. Though an mORphOlOgy attempt to classify DORV was attempted by Neufield, the widely accepted classification was described in 1972 by Lev Ventricular septal Defect and Bharati.2 Double outlet right ventricle can be diagnosed: Ventricular septal defect is the only outlet of the left ventricle 1. If the aorta and the pulmonary artery are related to the and is an integral part of DORV. It is usually unrestrictive. In morphologic RV either by both arising from the conus/ 10 percent of cases, the VSD is restrictive and in 13 percent infundibulum of cases, VSDs are multiple. Rarely, it may be absent when 2. One great artery arising from the conus and the other the DORV is part of a complex anomaly associated with great artery having fibrous continuity with only the right hypoplasia of the mitral valve and left ventricle.2 DORV as ventricular portion of the atrioventricular (AV) valve. part of a univentricular heart shall not be discussed in this chapter. EmbRyOlOgy position of the Ventricular septal Defect In the developing heart persistence of a primitive relationship of the truncoconal structures with the ventricles without The location of the VSD is described in relation to the great leftward shifting results in DORV with the primitive VSD arteries. It is described as subaortic, subpulmonary, doubly- (bulboventricular defect) persisting as the only outlet of the committed or non-committed (remote). These terms do not left ventricle.3,4 Neural crest cells have been implicated in the strictly mean that one of the borders of the VSD is formed formation of the aorticopulmonary septum of the developing by any of these great arteries. This relationship of the VSD outflow tract. Partial ablation of the cardiac neural crest has to the great arteries has a special implication in the clinical been shown to lead to normal aorticopulmonary septum with manifestation and also surgical management.  41 DOUBLE OUTLET RIGHT VENTRICLE Figure 1: Double outlet right ventricle with subaortic ventricular Figure 2: Double outlet right ventricle with subpulmonic ventricular septal defect. A = Anterior ; Ao = Aorta; IS = infundibular septum; septal defect. A = Anterior ; Ao = Aorta; IS = infundibular septum; P = Posterior; PA = Pulmonary artery; RA = Right atrium; RV = Right P = Posterior; PA = Pulmonary artery; RA = Right atrium; RV = Right ventricle; SMT= Septomarginal trabeculation. ventricle; SMT= Septomarginal trabeculation. Subaortic ventricular septal defect: This is the most common type. The VSD is located beneath the aortic valve and is separated from it by the presence of subaortic conus (Figure 1). About three-fourths of the patients with subaortic VSD have bilateral conus and a little less than one-fourths have only subpulmonary conus. Most patients with mitral-aortic continuity have either subaortic or doubly-committed VSD.7 Subpulmonary ventricular septal defect (Taussig-Bing anomaly): About 30 percent of cases who undergo surgery have subpulmonary VSD (Figure 2).8 These VSDs are large and lead to early development of pulmonary arterial hyper- tension. Bilateral conus or only subaortic conus occur with equal frequency. If there is a subpulmonary conus, the VSD is separated from the pulmonary artery by a variable distance; if there is pulmonary-mitral continuity with no subpulmo- nary conus the pulmonary valve will override the VSD (also called as juxta-pulmonary VSD). If subpulmonary conus is Figure 3: Double outlet right ventricle with remote ventricular present, the infundibular septum (conus) is so oriented that it septal defect. A = Anterior ; Ao = Aorta; IS = infundibular septum; does not form a part of the interventricular septum, but serves P = Posterior; PA = Pulmonary artery; RA = Right atrium; RV = Right ventricle; SMT= Septomarginal trabeculation. to commit the VSD to the pulmonary artery. Hypertrophy of the infundibular septum and parietal band may give rise to subaortic obstruction and may be the cause for the aortic arch vessels arising 200 percent from the RV and a double conus9; the obstruction, which is commonly associated with the Taussig- term noncommited/remote or uncommitted is not anatomical, Bing anomaly. but only descriptive that the VSD is at a considerable distance Non-committed (remote) ventricular septal defect: The away from the outflow tracts. These are either inlet VSDs term non-committed was introduced by Lev et al in 1972.8 without perimembranous extension, muscular VSDs or even These VSDs are far from either the aorta or the pulmonary any of the other VSDs, where the conus is long and separates artery. They are separated from the great arteries by muscular the VSD from the great arteries. The inlet VSDs may occur as tissue (Figure 3). Though some have described DORV with part of the DORV with atrioventricular canal defect. Remote remote VSD as VSD separated from both the great arteries by VSDs are present in 10 to 20 percent of patients who undergo a distance more than the aortic diameter or as both the great surgery.2 595  8 the left-sided conus. Since, the VSD is almost always subaortic in these cases, it is considered amenable to CYANOTIC HEART DISEASES corrective surgery.7 assOCIatED anOmalIEs pulmonary stenosis Pulmonary stenosis is commonly seen in association with DORV with subaortic VSD or doubly-committed VSD. It occurs in approximately 70% of patients with malposition of great arteries. It is not commonly associated with the Taussig- Bing type of DORV. Though more often the obstruction is at the infudibulum, obstruction at the valve, annulus and main pulmonary artery levels may also be seen; pulmonary atresia has also been reported.2 Figure 4: Double outlet right ventricle with doubly committed ventricular septal defect. A = Anterior ; Ao = Aorta; IS = infundibular subaortic stenosis septum; P = Posterior; PA = Pulmonary artery; RA = Right atrium; RV = Right ventricle; SMT= Septomarginal trabeculation. As described earlier, subaortic obstruction is seen in about a third of the cases of DORV with subpulmonary VSD. The subaortic obstruction may be caused by the narrowed left ventricular Doubly-committed ventricular septal defect: It is reported outflow tract (LVOT), AV valve tissue or accessory valve tissue. in 10 percent of patients with DORV, who have been surgically Aortic arch obstruction may be present in such patients.2 treated.2 The VSD lies beneath the aortic and the pulmonary valves (Figure 4). The pulmonary and aortic valves are conti- Coronary artery anomalies guous as the infundibular septum is absent. The conus may be deficient bilaterally or a single conus may be present beneath In DORV, the left coronary artery arises more posteriorly both the great arteries. and the right coronary artery arises more anteriorly. When the aorta is right and anterior, the coronary artery anatomy gREat aRtERy RElatIOnshIp appears similar to that of TGA with RCA arising from the posteriorly facing sinus and the LCA arising from the anterior The great artery relationships fall into two basic categories, facing sinus.2 The origin and proximal course of the coronary spiraling normally related great arteries or parallel great arteries vary depending on the proximity of the facing sinuses arteries. This classification is important to determine the to the atrioventricular or the interventricular grooves.11 Single appropriate type of corrective surgery. coronary artery has been reported in upto 11 percent of the patients with DORV.12 In all cases of DORV with L-malposition normally Related great arteries of the great vessels, the right coronary artery passes anterior to the pulmonary outflow tract, which is of surgical significance.7 The great arteries are normally related and spiral around each other. The aorta is right and posterior to the pulmonary artery. Conduction system The VSD in these cases is usually subaortic.2 In DORV, the AV node lies in the usual position of the AV parallel great artery Relationships septum. The bundle of His lies along the posteroinferior margin of the VSD in DORV with juxtatricuspid defects like i. Rightward and side-by-side aorta: The VSD is usually the subaortic, subpulmonary and doubly-committed VSDs. subpulmonary. When the defect is separated by muscular tissue from the ii. Right and anterior aorta: In a study by Guo et al, in 50 tricuspid valve, the bundle runs within the muscular tissue and percent of angiographically studied patients, the aorta is not present at the posteroinferior part of the VSD.2 was either directly to the right or right and anterior to the pulmonary artery.10 ClInICal pREsEntatIOn iii. Aorta directly anterior to the pulmonary artery. 596 iv. Left and anterior aorta (L–malposition): This is the least The clinical manifestations of DORV vary depending on the site common great artery position. The aorta arises from of the VSD, relationship of the great arteries to each other and to  41 the VSD and the presence or absence of stenosis of the semilu- nar valves. The clinical presentation of DORV may be classified DOUBLE OUTLET RIGHT VENTRICLE as the VSD type, tetralogy of Fallot (TOF) type, transposition of the great arteries (TGA) type, and remote VSD type.2 VsD type VSD type (DORV with subaortic VSD without pulmonary stenosis, DORV with doubly-commited VSD without pulmo- nary stenosis). The blood from the left ventricle is directed into the aorta through the VSD. Hence, the presentation is similar to children with a large VSD and pulmonary hypertension. These children present with poor feeding and poor weight gain. They may have mild cyanosis or no Figure 5: Parasternal long-axis shows double outlet right ventricle with cyanosis at all. These children are likely to develop early large nonrestrictive ventricular septal defect with pulmonary stenosis. pulmonary arterial hypertension. Ao = Aorta; LA = Left atrium; LV = Left ventricle; PA = Pulmonary artery; RA = Right atrium; RV = Right ventricle. tOF type TOF type (DORV with subaortic VSD and pulmonary stenosis, border of the cardiac silhouette shows a bulging vascular DORV with doubly-commited VSD and pulmonary stenosis). shadow with no discrete pulmonary segment observed.7,10 The clinical picture is similar to that of TOF. Cyanosis is Two-dimentional echocardiography shows both great present from early months of life; a systolic murmur is audible arteries arising from the anterior RV. The features in parasternal in the new born period. These children may have progressively long-axis view (Figure 5) are inability to identify a great worsening cyanosis with cyanotic spells. artery arising from the left ventricle and the lack of continuity between the anterior mitral leaflet and any semilunar valve tga type caused by the conus. The conus is seen either as a dense echo (fibromuscular) or as a muscular conus separating the two TGA type (DORV with subpulmonary VSD without pulmonary valves and producing a separation and a more superior postion stenosis). The clinical presentation is similar to that of TGA of the semilunar valve.13 There is no other outflow to the left with VSD. The children are cyanosed in the newborn period ventricle other than the VSD. The left ventricular outflow tract and develop worsening breathlessness, poor feeding and poor may have a tunnel-like configuration. There is hypertrophy of weight gain. Associated coarctation may be present and such the RV. children may present with heart failure in the early newborn Identifying the location of the VSD is essential in period. planning the type of surgical intervention. Subaortic or subpulmonary defects can be seen in parasternal or subcostal Remote VsD type long and short-axis views. Doubly-committed VSD is seen as a defect that is nearly equally committed to both the Remote VSD type: They present like patients with single great arteries. Non-committed VSDs are usually complete ventricle. Children have mild cyanosis and the pulmonary AV septal defects and isolated or multiple muscular VSDs. blood flow may be balanced, increased or decreased. These are best seen in the apical or subcostal four chamber views. A restrictive VSD may be seen as an anatomically InVEstIgatIOns small defect with turbulent flow and causes LVOT obstruction. The degree of restriction may be assessed by Electrocardiogram shows right ventricular hypertrophy doppler echocardiography.14 and in some cases biventricular hypertrophy. Conduction In the parasternal short-axis view, the features are abnormalities may be found.9 simultaneous imaging of both great arteries in an anterior Chest X-ray findings vary widely depending on the type of location and lack of a clockwise wrap around of the aorta by DORV. At one end of the spectrum, radiological features may the right ventricular outflow tract. A double-circle appearance resemble that of VSD with moderate enlargement of the heart of the great arteries may be seen. The great arteries may be with varying degree of increased vascularity. At the other end, side-by-side, D-malposed or L-malposed.15 the heart may be 'boot-shaped' with decreased vascularity Transesophageal echocardiography (TEE) would furnish resembling TOF. In DORV with L-malposition, the left upper extra details about the position of the VSD and its relationship 597  8 to the great arteries. Longitudinal planes would delineate angiographic Illustrations the right and left ventricular outflow tracts and the great CYANOTIC HEART DISEASES arteries. These views demonstrate the typical features of There are 16 possible variations of DORV based on the great the predominant commitment of both great arteries to the artery relationships and the location of the VSD and it may be RV. Additional defects of the AV valves and their chordal associated with pulmonary stenosis or with pulmonary artery attachments may also be delineated well by TEE. hypertension (Figures 7A and B). The various illustrations Fetal echocardiography: Careful visualization of the four include a case of dextrocardia with situs inversus with DORV chamber view and outflow tracts in fetal echocardiography (Figures 8A and B). is diagnostic.16 The VSD is almost always seen in the four The side-by-side relationships of the great arteries with chamber view. While viewing the outflow tracts, both the subaortic VSD is the most frequently encountered type of great vessels are seen arising from the RV and are often seen DORV (Figure 9A). The aorta is to the right of the pulmonary to be side-by-side (Figure 6). artery (Figure 9B). The aortic valve and the pulmonary valve are at approximately the same horizontal level. The VSD is the only outlet from the LV, hence it is an obligatory shunt. To do the LV angiogram one has to have a patent foramen ovale or an atrial septal defect (Figure 10) or a large VSD. The true subpulmonary VSD, the Taussig-Bing anomaly, is relatively rare. The great arteries are in a side-by-side relationship (Figure 11). Because pulmonary stenosis does not occur in these cases, the pulmonary trunk is markedly dilated. The VSD is anterosuperior (supracristal) and immediately subjacent to the pulmonary valve (subpulmonary VSD). The right ventricular angiogram demonstrates that the great arteries are in a side-by-side relationship The classic finding on the early phase of the right ventricular angiogram is a high VSD related directly to the pulmonary valve. The doubly committed, subaortic and subpulmonary, VSD is closely related to both semilunar valves and lies in a superior position, The VSD is quite large and extends in an oblique course beneath both great arteries. On angiogram one cannot Figure 6: Fetal echocardiography outflow tract view shows double differentiate this type from the Taussig-Bing anomaly because outlet right ventricular with subpulmonary ventricular septal defect on the lateral view of the RV this VSD is high, anterior, (Taussig-Bing). Ao = Aorta; LV = Left ventricle; PA = Pulmonary artery; RV = Right ventricle; VSD = Ventricular septal defect. superior and directly related to both semilunar valves. It is A B Figures 7A and B: A. Right ventricle (RV) angiogram shows simultaneous opacification of both the great arteries with post stenotic dilatation of main pulmonary artery; B. RV angiogram in double outlet RV with pulmonary hypertension shows simultaneous opacification of both the 598 great arteries with dilatation of pulmonary artery due to pulmonary hypertension. Ao = Aorta; LV = Left ventricle; MPA = Main pulmonary artery; PA = Pulmonary artery.  41 DOUBLE OUTLET RIGHT VENTRICLE A B Figures 8A and B: A. Left ventricle (LV) angiogram in right anterior oblique view in a one-year-old boy with dextrocardia with situs inversus, double outlet right ventricle (RV), shows smooth-walled LV with ventricular septal defect committed to aorta (Ao), which is to the right of pulmonary artery (PA) and with a right sided aortic arch (mirror image dextrocardia). B. RV angiogram in frontal view illustrates simultaneous opacification of PA (dilated due to post stenotic dilatation) and aorta (Ao), with long segment narrowing of left pulmonary artery (LPA - arrow) and its upper lobe branch. A B Figures 9A and B: A. Left ventricle (LV) angiogram in frontal view in a case of double outlet right ventricle with large ventricular septal defect (VSD) (right heart catheter has entered LV through the VSD) illustrates the side-by-side relationship of the great arteries with both the pulmonary valve (PV) and the aortic valve (AV) at the same level; B. LV angio in a frontal view shows VSD committed to the aorta (Ao) and aorta is to the right of the pulmonary artery (PA) impossible to recognize whether the VSD is related to the The relationship of the great arteries may be observed i.e. pulmonary valve or to both semilunar valves. aorta right and anterior or aorta to the right of pulmonary valve, The DORV with remote VSD, as a case with multiple VSDs aorta anterior to the pulmonary valve, aorta left and anterior not committed to both the great arteries, is illustrated in Figure to the pulmonary valve.10 In DORV with L-malposition, 12. The angiographic findings other than the great artery aortography shows left sided anterior ascending aorta with relationships, are not different from those observed with side- right coronary artery passing anterior to the pulmonary by-side great arteries and remote VSD. The malposition of the valve.7 aorta can be seen in both frontal and lateral views (Figure 13 A Computed tomography angiography and magnetic and B). The left ventricular angiogram also demonstrates that resonance imaging: The spatial relationship between semilunar the VSD is the only outlet from the left ventricle. valves and VSD can be accurately assessed by CT angiography 599  8 CYANOTIC HEART DISEASES Figure 10: Right heart catheter through atrial septal defect entered Figure 11: Left ventricle (LV) angiogram in left anterior oblique view left ventricle (LV). The LV angiogram in left lateral view shows the illustrates subpulmonic ventricular septal defect opacifying dilated ventricular septal defect committed to the aorta (Ao) pulmonary artery (PA) more than the aorta (Ao), that is to the right and anterior (Taussig-Bing anomaly) Figure 12: The left ventricle (LV) angiogram in left lateral view illustrates two ventricular septal defects (VSDs) opacifying the trabeculated right ventricle (RV), in turn opacifying both the great arteries simultaneously, indicating that VSDs are not committed to both the great arteries. Ao = Aorta; PA = Pulmonary artery. 600 A B Figures 13 A and B: Right ventricle (RV) angiogram in double outlet RV (DORV) with malposed side by side great arteries, running parallel to each other. B:RV angiogram in DORV with anterio-posterior malposition of the great arteries  41 DOUBLE OUTLET RIGHT VENTRICLE A Figure 14: Computed tomographic angiogram illustrates double outlet right ventricle with aorta anterior and side by side with pulmonary B C artery Figure 15: Separation between the tricuspid valve (Tric. V) and pulmonary valve (PV) is critical in determing the anatomic suitabilty for an intraventricular baffle repair. A. There is adequate separation (Figure 14) and magnetic resonance imaging (MRI) and could between the PV and Tric. V so that the pathway from the ventricular provide additional information to the conventional imaging in septal defect (VSD) to the aorta is unobstructed. B. When PV is very the assessment of VSD. MRI would provide accurate additional close to Tric. V a Rastelli repair may be appropriate. PV lies within the baffle necessiating division and oversewing of main pulmonary anatomic information, which would be helpful in presurgical artery. C. Separation of the Tric. V and PV is less than the diameter of planning and in follow-up of patients.17 the aortic annulus. Intraventricular repair is likely to result in subaortic stenosis either immediately or postoperatively. AV = Aortic valve; PA = Pulmonary artery; RV = Right ventricle. Reprinted with permission management from reference 21. There is no specific medical management for DORV. Those infants who are having congestive heart failure need repair will be possible. In extremely unroutable VSD’s, a decongestive therapy. single Fontan correction may be used if the pulmonary artery size and vascular resistance permits. surgery for Double Outlet Right Ventricle9,18-21 Double Outlet Right Ventricle Subaortic VSD Surgery for DORV has got two requirements—closure of Without Pulmonary Stenosis the VSD and unobstructed outflow from the corresponding ventricles to the great arteries. An adequately sized ventricle An intraventricular tunnel repair is possible in most patients. is a necessary caveat for a biventricular repair in DORV. The patch forms a tunnel and in essence forms a part of the Since both great arteries arise from the RV, the outflow path LVOT and so has to be liberal so as to not cause subaortic will necessarily have to be through the VSD. The position stenosis. Initial inspection should be done and the possibility of the VSD (in relation to the great arteries) is the primary of transposing any obstructing tricuspid chordae has to be determinant of the hemodynamic status of the child. The status planned. If the VSD is small, suitable enlargement by excision of the pulmonary arteries are also to be considered. of the superior and lateral margins are done, to avoid the A subaortic VSD with pulmonary stenosis acts like a TOF conduction system. A suitable patch or portion of a tube graft and if there is no pulmonary stenosis, it behaves like a VSD. A is used to construct a nonobstructive tunnel. If the generous subpulmonic VSD makes the child behave like a transposition patch were to cause RVOT obstruction, then augmentation of with a VSD. A doubly committed and a non-committed VSD the RVOT with a patch may be required. will behave depending on how the blood streams to the great arteries. Apart from the VSD, the relation of the great Double Outlet Right Ventricle Subaortic VSD with arteries, outflow tract obstructions, chordal connections of the Pulmonary Stenosis tricuspid valve and the distance between the pulmonary valve and the tricuspid valve will also determine the management. If the pulmonary artery size is inadequate then the child may The tricuspid–to–pulmonary annulus distance has been shown need an aortopulmonary shunt to enable growth of the pulmo- to be a useful predictor for the feasibility of intraventricular nary arteries to enable intracardiac repair later. baffle repair (Figure 15).21 The size of the ventricles will also This can be equated to a TOF repair. If the override is not 601 determine whether a biventricular repair or a univentricular excessive and the RV infundibular narrowing is not excessive,  8 a liberal VSD patch and if required RVOT patching to allow mortality and in the current era associated arterial switch unobstructed right ventricular outflow, can be done. If the has reduced the mortality by reducing the complexity of the CYANOTIC HEART DISEASES override is excessive and there is annular narrowing, then a tunnel. A DORV with subaortic VSD has a current mortality transannular patch or an RV to pulmonary artery conduit (all of that of a VSD or a tetralogy repair. The introduction of the the more if there are major coronaries crossing the RVOT) arterial switch for the Tausig-Bing anomaly has reduced the may need to be implanted. mortality from as high as 50 percent to 5–15 percent. Double Outlet Right Ventricle with COnClusIOn Doubly Committed VSD The prognosis of DORV with pulmonary stenosis resembles These cases can usually be managed like a DORV with a that of TOF. In the Taussig-Bing type of DORV, course of subaortic VSD. events are worse than TGA with large VSD. A number of surgical maneuvers have achieved satisfactory anatomical Double outlet right ventricle with a subpulmonic VSD repair and long-term survival.The precise timely diagnosis is The Taussig-Bing anomaly presents a unique problem, very important. where the pulmonary valve is interposed between the aorta and the VSD necessitating a circuitous patch as described The physician's highest calling, his only calling, is to make by Kawashima (especially, if the great vessels are side- sick people healthy -- to heal, as it is termed. to-side), after resecting the subpulmonic infundibulum to — Samuel Hahnemann allow reaching the aorta which may necessitate closing the pulmonic orifice at times with an RV to pulmonary artery aCknOwlEDgmEnt conduit, if the distance between the pulmonary valve and the tricuspid valve is not sufficient to allow an unobstructed I would like to express my thanks to Dr Bhushan Chavan for pathway. More commonly the subpulmonic VSD is converted his help in completion of this chapter and Ms Sujatha for her into a “subaortic” VSD by performing an arterial switch and secretarial help. now the intraventricular tunnel is shorter, the probability of subaortic stenosis is reduced and the need for a conduit is REFEREnCEs avoided. 1. Obler D, Juraszek AL, Smoot LB, et al. Double outlet right ventricle, etiologies and associations. J Med Genet. Double Outlet Right Ventricle with an Uncommitted VSD 2008;45:481-97. The repair is dictated by the position of the VSD. A circuitous 2. Walters HL 3rd, Mavroudis C, Tchervenkov CI, et al. tunnel repair may be needed and an arterial switch may be Congenital Heart Surgery Nomenclature and Database Project: double outlet right ventricle. Ann Thorac Surg. 2000;69: combined to make the baffle less circuitous. Attention to the S249-63. conduction system needs to be kept in mind during the baffling 3. Angelini P, Leachman RD. The spectrum of double outlet procedure. Multiple patches to create the circuitous baffle right ventricle: An embryologic interpretation. Cardiovasc has been described by Barbero Marciel. In complex DORV, Dis. 1976;3:127-149. where routing may not be easy or impossible, a variation of 4. Angelini P. Embrology and congenital heart disease. Tex Heart the Fontan operation may be adopted. Inst J. 1995;22:1-12. 5. van den Hoff, Moorman AFM. Cardiac neural crest: the holy COmplICatIOns grail of cardiac abnormalities? Cardiovasc Res. 2000 ;47:212- 6. Severe hemolysis can occur due to the circuitous patch. 6. Wilkinson J. Double outlet right ventricle. Orphanet Residual VSDs, heart blocks and late onset of LVOT obstruction Encyclopedia, Feb 2005. can occur. Damage to the septal arteries and left anterior 7. Lincoln C, Anderson RH, Shinebourne EA, et al. Double outlet right ventricle with L-malposition of the aorta. Br Heart J. descending artery can occur during enlargement of a restrictive 1975;37:453-63. VSD. Patients with RVOT conduits are exposed to all the late 8. Belli E, Serraf A, Lacour-Gayet F, et al. Double-outlet right complications related to conduit implantation and stenosis. ventricle with non-committed ventricular septal defect. Eur J Cardiothorac Surg. 1999;15:747-52. REsults 9. Lacour-Gayet F, Haun C, Ntalakoura K, et al. Biventricular repair of double outlet right ventricle with non-committed Double outlet right ventricle being a wide spectrum has ventricular septal defect (VSD) by VSD rerouting to the 602 a differing mortality. Uncommitted VSD’s have a higher pulmonary artery and arterial switch. Eur J Cardiothorac Surg. 2002;21:1042-8.