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Ann Thorac Surg 2000;69:S264-S269
© 2000 The Society of Thoracic Surgeons
a Division of Cardiovascular Surgery, The Montreal Children’s Hospital, Montreal, Québec, Canada
b Wayne State University School of Medicine, Children’s Hospital of Michigan, Detroit, Michigan, USA
Address reprint requests to Dr Tchervenkov, Division of Cardiovascular Surgery, The Montreal Children’s Hospital, 2300 Tupper, Suite C-829, Montreal H3H 1P3, Canada
Presented at the International Nomenclature and Database Conferences for Pediatric Cardiac Surgery, 1998–1999.
Abstract
Double outlet left ventricle (DOLV) is a type of ventriculoarterial connection in which both great arteries arise entirely or predominantly from the left ventricle. Although it was initially believed that bilateral absence of conus is a prerequisite for such diagnosis, all possible conal configurations have been described in this malformation. The morphology of DOLV is encompassed by a careful description of the ventricular septal defect (VSD) with its relationship to the semilunar valves, the presence or absence of pulmonary outflow tract obstruction (POTO) and aortic outflow tract obstruction (AOTO), and the presence or absence of associated cardiac lesions. The preferred surgical treatment involves the connection of the right ventricle to the pulmonary circulation by an intraventricular tunnel repair connecting the VSD to the pulmonary semilunar valve. This ideal surgical therapy is not always possible, because of the presence of confounding anatomical barriers. Several alternative surgical procedures have been devised to accommodate these more complex situations. A framework for the development of the DOLV module of a pediatric cardiac surgical database is proposed.
I. Background
Double outlet left ventricle (DOLV) is a rare congenital cardiac malformation in which both the aorta and main pulmonary artery (MPA) arise entirely or predominantly from the morphologic left ventricle. Similar to that of double outlet right ventricle (DORV), there is great variability among patients with DOLV in terms of pathologic morphology and associated cardiac defects. This heterogeneity, together with the relatively small number of cases, has contributed to the lack of consensus concerning its diagnosis, classification, and surgical treatment. The purpose of this paper is to propose a hierarchical classification of DOLV based on a review of historical as well as currently accepted nomenclature, classification, and surgical options. Discussion in this paper is limited to hearts with two ventricles and concordant atrioventricular connection. DOLV type ventriculoarterial connection in single ventricle hearts and DOLV with discordant atrioventricular connections are covered elsewhere in this supplement.
Historical aspects and review of nomenclature
DOLV was considered to be embryologically impossible until the mid 1960s [1]. Sakakibara and associates were the first to suggest the existence of this type of ventriculoarterial connection in 1967, when they reported the first case of successful surgical repair [2]. This diagnosis was irrefutably proved anatomically in 1970 by Paul and associates when they reported the first case of DOLV with intact ventricular septum [3]. They described a heart with situs solitus, concordant atrioventricular connection, a right ventricle with an atretic infundibulum, no ventricular septal defect (VSD), bilaterally absent coni and both great arteries arising from the left ventricle. Subsequently, many morphologic variations of this malformation have been reported [4–8].
Bharati and associates proposed in 1978, a classification of DOLV based on a review of 45 cases (8 surgical and 37 autopsy) [9], where great importance was placed upon the position and interrelations of the great vessels, as well as the position of the VSD related to them.
In the most extensive review of DOLV consisting of 109 cases, including the 45 cases from Bharati and coworkers [9], Van Praagh and associates [10] proposed a classification based mainly on the presence or absence of two well developed ventricles and the location of the VSD relative to the great arteries. In two ventricle hearts, DOLV is currently classified according to the position of the VSD relative to the great arteries. This is similar to the classification used for DORV, (ie subaortic, subpulmonary, doubly committed, and noncommitted VSD). Because this is a familiar classification, and is relevant in selecting the appropriate surgical treatment, we retain it as the basis of our current classification.
The embryology of DOLV was first explained by the differential conal growth hypothesis by Paul and associates [3]. This hypothesis emphasized that infundibular growth beneath the semilunar valves represents one of the most important factors in the morphogenesis of normal and abnormal relations between the great arteries. This hypothesis implies that bilateral absence of conus is a prerequisite for DOLV. An alternative hypothesis was proposed by Anderson and associates in 1974 to account for the different conal patterns that had been reported in DOLV [7]. They suggested that the development of DOLV could be explained by the differential conal absorption hypothesis. No single hypothesis has been able to explain all known cases of DOLV to date.
Definition
DOLV is defined as a type of ventriculoarterial connection in which both great arteries arise entirely or predominantly from the morphologic left ventricle.
DOLV has been reported with either situs solitus or inversus, concordant or discordant atrioventricular connections, with or without intact ventricular septum, and with univentricular or biventricular hearts [3, 9, 10]. For the current review, the discussion of DOLV is limited to hearts with concordant atrioventricular connections and two ventricles, as DOLV in single ventricle hearts and DOLV with atrioventricular discordance are covered in the manuscripts in this Supplement on single ventricle and on atrioventricular discordance respectively.
Controversies
Controversial topics related to DOLV are relatively rare in the literature. We believe that this is mainly due to the scarcity of cases seen in clinical practice. Because DOLV may be considered to be a mirror-image malformation of double-outlet right ventricle (DORV), all controversies surrounding DORV are potentially applicable to DOLV.
One area of controversy centers on the assignment of great arteries according to the degree of arterial override above the interventricular septum. Readers can gain appreciation of this controversial point by looking at the similar situations encountered in the sections on tetralogy of Fallot (TOF) and DORV. This point is addressed in the TOF article by Dr Marshall L. Jacobs in this supplement with the following discussion:
"The distinction between DORV and TOF is controversial. Some authors use the term DORV when the pulmonary artery arises from the right ventricle and more than 50% of the aorta arises from the right ventricle. Other authors only use the term DORV when the pulmonary artery arises from the right ventricle and 90% or more of the aorta arises from the right ventricle. Still others use the term DORV when there is absence of fibrous continuity between the aortic and mitral valves."
The distinction between DOLV with aortic override and transposition with VSD and the distinction between DOLV with pulmonary stenosis and TOF, therefore depends on an arbitrary selection of either the 50% or 90% rule. As has been pointed out in the manuscript on DORV, even if one is to accept the more popular 50% rule, it may still be difficult to decide whether the aortic override is 40% or 60%.
The difficulty in assigning the origin of the great arteries is highlighted by cases of DOLV with doubly committed VSD. In such cases, both great arteries override the interventricular septum to various degrees, and the distinction between DOLV and DORV can be very difficult. In fact, this type of malformation has been referred to as "double outlet both ventricles" by Kirklin and Barratt-Boyes [11].
A related controversy is whether bilaterally absent coni and aortic-mitral and pulmonary-mitral continuity is essential for the diagnosis of DOLV. This was initially thought to be a prerequisite for the diagnosis of DOLV based upon the original description by Paul and associates of a pathologic specimen of DOLV with intact ventricular septum and bilaterally absent coni [3]. However, it is now clear that DOLV is possible with all four conal configurations [10].
The definition of DOLV in this discussion is deliberately broad, and leaves it to each individual to decide if the great arteries arise predominantly from the morphologic left ventricle.
Morphology
DOLV occurs most commonly in the form of atrial situs solitus with atrioventricular concordance. This will be the main focus of our discussion unless otherwise specified. The position of the aorta, relative to the pulmonary artery, can be to the right and posterior (normal), to the right and side-by-side, to the right and anterior (D-malposition) and to the left (L-malposition). Similar to DORV, DOLV is classified in terms of the location of the VSD relative to the great arteries [10]. Further variations of its morphology include the presence of pulmonary outflow tract obstruction (POTO), the location and presence of a conus, and the presence of aortic outflow tract obstruction (AOTO). DOLV with situs inversus is extremely rare.
Ventricular septal defect
To the best of our knowledge, DOLV with intact interventricular septum has not been reported with two well developed ventricles. Therefore, DOLV can be classified according to the location of the VSD relative to the great arteries: subaortic VSD, subpulmonary VSD, doubly committed VSD, and noncommitted VSD. In the series of Van Praagh and associates of 109 cases, 71 are situs solitus with atrioventricular concordance and two well developed ventricles [10]. Among them, 53 (75%) had subaortic VSD, 11 (15%) had subpulmonary VSD, and 7 (10%) had doubly committed VSD. We are aware of one case of noncommitted VSD in the series by Bharati and associates [9]. The subaortic VSD of DOLV can extend to the tricuspid annulus or be separated from it by a band of muscle, similar to hearts with DORV. The aorta can override the interventricular septum to a variable degree, and the lesion probably represents an anatomical continuum with transposition of the great arteries with VSD. In the second most common type, DOLV with subpulmonary VSD (the conal septal defect type), the conal septum tends to be very deficient, there may be tenuous pulmonary-mitral fibrous continuity, and the pulmonary artery tends to override the interventricular septum to various degrees [9, 10]. When the VSD is doubly committed it is by definition, juxta-arterial. In this case it may be difficult to determine whether the heart lesion is DOLV or DORV, because both great arteries form the superior border of the defect and override the interventricular septum to variable degrees. This variant has been referred to as double outlet ventricles [11].
Pulmonary outflow tract obstruction
Pulmonary stenosis affects the majority of patients with DOLV, and can occur at the valvar and subvalvar level. POTO is particularly prevalent in patients with subaortic VSD occurring in almost 90% of the cases [10]. On the other hand POTO occurs in less than 20% of cases of DOLV with subpulmonary VSD, and has not been observed in the patients with doubly committed VSD in the series of Van Praagh and associates [10]. Malalignment of the infundibulum and the great arteries relative to the underlying ventricles and ventricular septum is believed to be the major cause of POTO.
Aortic outflow tract obstruction
Aortic stenosis is very common in the patients with DOLV and subpulmonary VSD, occurring in almost 80% of these cases in the series of Van Praagh and associates [10]. On the other hand, AOTO was very uncommon in DOLV with subaortic VSD occurring in less than 10% of the cases and has not been seen in any of the patients with doubly committed VSD [10].
Subaortic and subpulmonary coni
Most commonly, there is aortic-mitral continuity and no subaortic conus. A subpulmonary conus is frequently present; however, when the subpulmonary conus is absent there is pulmonary-mitral continuity. Rarely, bilaterally present or bilaterally absent coni are found.
Conduction system
The atrioventricular node and bundle of His are normally positioned in DOLV with atrioventricular concordance. When the VSD is juxtatricuspid, the bundle runs along its infero-posterior free edge and is at risk for injury during repair. When there is a band of muscle between the defect and the tricuspid valve annulus, the conduction system does not run along the free edge of the VSD. This relationship of the VSD to the conduction tissue is identical to that of DORV.
Associated cardiac abnormalities
The most common associated lesions in DOLV are POTO and AOTO, as described in the preceding sections. In addition, AOTO was consistently accompanied by coarctation of the aorta or by interrupted aortic arch in the patients with DOLV and subpulmonary VSD [10]. In patients with only one developed ventricle, DOLV has been seen with tricuspid atresia, mitral atresia, double-inlet left ventricle (LV), asplenia, and the Ebstein’s anomaly [10]. DOLV occurs with situs inversus and with atrioventricular discordance both in situs solitus and situs inversus [10].
Pathophysiology
In DOLV, the pathophysiology is largely dominated by the presence or absence of POTO and AOTO. The majority of patients are cyanotic because of the presence of pulmonary or subpulmonary stenosis. In the absence of POTO, the patient may be in congestive heart failure and be only mildly cyanotic. In the presence of AOTO, particularly with critical coarctation of the aorta or interrupted aortic arch, patients can be acutely ill in the neonatal period, with the descending systemic circulation being ductal dependent.
Database requirements for the morphologic description of DOLV
The database requirements for the morphologic description of DOLV can be divided into the following headings: the VSD, the pulmonary outflow tract (POT), the conal anatomy, the aortic outflow tract (AOT), and all other associated cardiac abnormalities.
Surgical treatment options for DOLV
A complete intracardiac repair was first described by Sakakibara and associates in 1967, where a patch intraventricular tunnel repair was used to connect the VSD to the pulmonary semilunar valve [2]. Kerr and associates in 1971 reported a case where right ventricular to pulmonary artery continuity was established by using a pericardial patch to construct a roof enclosing the ventriculotomy and pulmonary arteriotomy [5]. Reconstruction using a valved conduit connecting the right ventricle to the main pulmonary artery was described by Pacifico and associates in 1973 [6]. Arterial correction of DOLV using pulmonary root translocation onto the right ventricle including the intact pulmonary valve was proposed by Chiavarelli and associates in 1992 [12]. A Fontan type repair for DOLV with hypoplastic RV was first reported by Sharratt and associates in 1976 [13].
Complete intraventricular repair
Complete intraventricular repair is possible when the VSD can be repaired such that the right ventricle (RV) outflow is tunneled to the pulmonary artery. This is usually achieved through a distal, vertical or transverse right ventriculotomy. The subpulmonary obstruction, when present, is resected through the tricuspid valve, the pulmonary valve, a right ventriculotomy. The first case of DOLV ever reported had a complete intracardiac repair [2].
Patch reconstruction between right ventricle and pulmonary artery
Kerr and associates established continuity between the right ventriculotomy and the pulmonary arteriotomy incisions with a pericardial patch sutured laterally to the surface of the RV outflow tract, following closure of the VSD [5].
Pulmonary root translocation onto the right ventricle
Usually, a completely intraventricular repair is not possible because the subpulmonary obstruction is long and narrow. It is not possible to place a transannular patch because the left anterior descending coronary artery runs immediately inferior to the pulmonary valve ring. In this situation, when the pulmonary valve annulus and pulmonary valves are normal, a repair can be accomplished using pulmonary root translocation [12, 14].
Pulmonary artery translocation onto the right ventricle
When the POTO consists of a diseased and stenotic pulmonary valve, or it is associated with a small and obstructive pulmonary valve annulus, then the pulmonary root translocation is not possible. Under those circumstances, translocation of the divided main pulmonary artery onto the right ventriculotomy incision, and reconstruction with a transannular patch can be performed (personal experience, C.I.T). The proximal stenotic pulmonary valve still connected to the LV is oversewn. This is feasible when the aorta is to the right and anterior. If the distal main pulmonary artery does not easily reach the RV, a Lecompte maneuver may be necessary by dividing the aorta [15]. The VSD is closed in the usual fashion with both techniques. Compared to the pulmonary root translocation, these procedures do not involve relocating the native pulmonary valve. Nonetheless, they provide an unobstructed repair without the need for an extracardiac conduit, and are best suited for patients with underlying pulmonary valve stenosis or hypoplasia, where the pulmonary vascular resistance remains low. To the best of our knowledge, these procedures have not been reported, to date in the English literature, for the treatment of DOLV.
Rastelli type procedure
Frequently, an extracardiac valved conduit is required for proper repair. Through a right ventriculotomy, the subpulmonary stenosis is viewed through the VSD and closed with pledgeted, horizontal mattress sutures. The VSD is patched and a valved, homograft extracardiac conduit is sutured to the pulmonary artery distally and then to the right ventriculotomy proximally [6].
Single ventricular palliation
When a two ventricle repair can not be performed, a bidirectional cavopulmonary anastomosis is performed at 6 months of age. This is followed by a Fontan operation at a later date. Depending upon the presence or absence of pulmonary stenosis, a systemic-to-pulmonary artery shunt, or pulmonary artery banding, may have to be performed in early infancy as a prelude to the eventual repair.
II. Analysis: a unified nomenclature system
DOLV hierarchy level 1
DOLV hierarchy level 2
DOLV hierarchy level 3
DOLV, Subpulmonary VSD, NOS
Additional modifiers
Great artery relationships (GAR)
Although there can be a large number of GAR in DOLV, we have characterized five choices for this database:
Aortic outflow tract obstruction
Aortic outflow tract obstruction can coexist with DOLV. The obstruction can be subvalvar, valvar, or aortic arch related and these obstructions can be isolated or in various combinations.
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Pulmonary outflow tract obstruction
Pulmonary outflow tract obstruction can coexist with DOLV. The obstruction can be subvalvar, valvar, or supravalvar and these obstructions can be isolated or in various combinations.
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Conus
Positional VSD anatomy
The positional anatomy of the VSD should be entered in the database according to the proposal outlined by Jacobs and colleagues in their "Ventricular Septal Defect" article in this supplement. The VSD type(s) in DOLV can be coded in hierarchical detail utilizing the coding system presented in the VSD manuscript of this publication. This hierarchical VSD coding can be entered into a comprehensive database as an additional or secondary diagnosis(es) under the primary DOLV diagnosis.
Coronary artery anatomy
The coronary artery anatomy associated with DOLV type should be entered according to the hierarchical database scheme presented by Jaggers and colleagues in their "Transposition of the Great Arteries" article included in this supplement. Coronary artery anomalies associated with DOLV can be coded in hierarchical detail utilizing the coding system presented by Dodge-Khatami and colleagues in their "Anomalies of the Coronary Arteries" article in this supplement. This hierarchical coronary artery anomaly coding can be entered into a comprehensive database as an additional or secondary diagnosis under the primary DOLV diagnosis.
Other cardiac anomalies
Associated cardiac anomalies in patients with DOLV are numerous. These associated defects are best coded as additional diagnoses in the appropriate section of the database. Examples of this are patent ductus arteriosus, coarctation of the aorta, interrupted aortic arch, juxtaposed atrial appendages, and anomalies of pulmonary and systemic venous connections, to name a few.
III. Nomenclature for treatment options
This section will synthesize a formal hierchial nomenclature strategy for treatment options for DOLV consistent with that in other manuscripts. In addition to the basic treatment options for DOLV, several other therapeutic issues must be addressed and coded in other areas of the database. First, a separate part of the database must allow for coding of incisions for this and all other diagnoses (median sternotomy, submammary incision, right thoracotomy, left thoracotomy, minimally invasive incisions [partial sternotomy, parasternal incision, minithoracotomy], etc). Second, a separate part of the database must allow for coding of cardiac incisions for this and all other diagnoses (aortotomy, pulmonary arteriotomy, right atriotomy, right ventriculotomy, left ventriculotomy, etc). Third, a separate module of the database must permit coding of patch materials (Dacron, Gore-Tex [W.L. Gore & Associates, Flagstaff, AZ], bovine pericardium. autologous pericardium, gluteraldehyde fixated autologous pericardium, etc.), conduit type, conduit materials, conduit size, and use of other biologic or prosthetic materials.
Procedures directed at associated lesions (thymectomy, closure of patent foramen ovale, closure of atrial septal defect, etc) can be coded as an additional or secondary procedures under the primary DOLV procedure.
Details regarding management of cardiopulmonary bypass, myocardial protection, and associated issues will be recorded in another related and linked module of the database.
Finally, the various modifications of the bidirectional cavopulmonary anastomosis, Hemi-Fontan, and Fontan procedures are described in detail in the "Single Ventricle" article in this supplement by Jacobs and Mayer, and are not represented in detail in this article. Obviously, the hierarchical description of these procedures described in detail in the "Single Ventricle" article may be applied to certain forms of DOLV.
DOLV treatment hierarchy level 1
DOLV treatment hierarchy level 2
IV. Diagnosis and procedures short lists
V. Potential diagnostic related risk factors
Risk factors
Preoperative
Intraoperative
Postoperative
VI. Outcome analysis
References
This article has been cited by other articles:
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  D. Cassater, L. Rossetti, M. A. Prioli, G. Errico, A. Cristofaletti, R. Zanarotti, F. D. Rita, C. Vassanelli, F. Zaglia, and G. B. Luciani Two Cases of Double-Outlet Left Ventricle Detected Prenatally World Journal for Pediatric and Congenital Heart Surgery, July 1, 2011; 2(3): 505 - 508. [Abstract] [Full Text] [PDF]
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J. M. Giroud, J. P. Jacobs, D. Spicer, C. Backer, G. R. Martin, R. C. G. Franklin, M. J. Beland, O. N. Krogmann, V. D. Aiello, S. D. Colan, et al. Report From The International Society for Nomenclature of Paediatric and Congenital Heart Disease: Creation of a Visual Encyclopedia Illustrating the Terms and Definitions of the International Pediatric and Congenital Cardiac Code World Journal for Pediatric and Congenital Heart Surgery, October 1, 2010; 1(3): 300 - 313. [Abstract] [Full Text] [PDF]
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