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Ann Thorac Surg 2000;69:S56-S69
© 2000 The Society of Thoracic Surgeons
a Division of Pediatric Cardiology, Duke University Medical Center, Durham, North Carolina, USA
b Division of Cardiothoracic Surgery, Duke University Medical Center, Durham, North Carolina, USA
Address reprint requests to Dr Ungerleider, Duke University Medical Center, Box 3178, Durham, NC 27710
e-mail: unger002{at}mc.duke.edu
Presented at the International Nomenclature and Database Conferences for Pediatric Cardiac Surgery, 1998–1999.
Abstract
The extant nomenclature for pulmonary venous anomalies is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. All efforts were made to include all relevant nomenclature categories using synonyms where appropriate. The basis for classification are the prenatal errors of embryologic development. The major categories include: partially anomalous pulmonary venous connection, totally anomalous pulmonary venous connection, atresia of the common pulmonary vein, cor triatriatum, and stenosis or abnormal number of pulmonary veins. A comprehensive database set is presented that is based on a hierarchical scheme. Data are entered at various levels of complexity and detail that can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented that will allow for data sharing and would lend itself to basic interpretation of trends. Potential diagnostic-related risk factors are presented.
I. Background
Pulmonary venous anomalies comprise a broad spectrum of relatively uncommon disorders of cardiac development. It has long been appreciated that this varied group of disorders is best understood by consideration of the embryologic basis of each anomaly [1–3]. Lucas and colleague have proposed a cogent, all-inclusive, classification of pulmonary venous anomalies that follows from earlier embryologic work [4]. A modification of Lucas’ classification is shown in Table 1 and will serve as the outline for the material presented herein. Figures 1 and 2 illustrate the embryologic principles upon which this classification is based.
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Partially anomalous pulmonary venous connection has been noted in 0.6% to 0.7% of autopsies, but clinical studies have noted fewer such occurrences [4]. As the permutations of anomalously draining pulmonary veins and their site of connection are quite large, no concise classification system has been proposed for this disorder. An interatrial communication may or may not be present with PAPVC.
One subgroup of PAPVC, which has received separate attention in the literature, is that of the scimitar syndrome. This is a group of anomalies in which the right pulmonary vein(s) connect anomalously to the inferior vena cava or to the right atrium at the insertion of the inferior vena cava. The name of the syndrome arose because the descending vertical vein resembles a scimitar, or Turkish sword, on the frontal chest radiograph. The following anomalies are frequently associated with the scimitar syndrome: hypoplasia of the right lung with bronchial anomalies; dextroposition and/or dextrorotation of the heart; hypoplasia of the right pulmonary artery; and anomalous subdiaphragmatic systemic arterial supply to the lower lobe of the right lung directly from the aorta or its main branches. Some would require the presence of these associated anomalies to make the diagnosis of the scimitar syndrome, while others would require only the presence of APVC from the right lung to the inferior vena cava [5, 6].
Totally anomalous pulmonary venous connection (TAPVC)
In TAPVC, all of the pulmonary veins connect anomalously with the right atrium or to one or more of its venous tributaries. None of the pulmonary veins connects normally to the left atrium. Thus, an interatrial communication is an obligate part of this anomaly. As with PAPVC, synonyms such as complete anomalous pulmonary venous connection have been used. "Connection" is preferred to "drainage" or "return." This disorder comprises 1% to 5% of cases of congenital heart disease in various series [7]. Various classification schemes have been proposed for TAPVC. Those that remain extant are discussed below.
Neill classified TAPVC on an embryologic basis [3]. Much more recently, Lucas modified this classification slightly by substituting "connection" for "drainage" [4]. In this embryologic classification, anomalous connections are classified as: (1) connected to the right atrium; (2) connected to the right common cardinal system (superior vena cava or azygous vein); (3) connected to the left common cardinal system (left innominate vein or coronary sinus); or (4) connected to the umbilicovitelline system (portal vein or ductus venosus).
Darling and associates classified TAPVC according to the anatomic level of connection of the anomalously draining veins [8]. This is probably the most widely used classification. It is a simple anatomic approach and does not require knowledge of embryology to understand. In type I, the anomalous connection was at the supracardiac level, either to a remnant of the left superior vena cava or to the right superior vena cava. In type II, the anomalous connection was to the heart, either to the right atrium directly or to the coronary sinus. In type III, the anomalous connection was at the infracardiac level (below the diaphragm), with the pulmonary venous return entering the right atrium ultimately via the inferior vena cava. Type IV TAPVC simply represented a mixed form in which the anomalous connection was at two or more of the above levels.
Burroughs and Edwards [9] classified TAPVC by the length of the anomalous venous channel. Short, intermediate, and long routes were discussed. Short routes included connections to the heart; intermediate routes were those to the left innominate vein; and long routes were those that ultimately terminated in the inferior vena cava. This classification system attempted to incorporate the degree of obstruction to pulmonary venous return into the scheme. The degree of obstruction was felt to be related to the length of the anomalous channel.
Smith and associates combined elements of the previous two classification schemes [10]. Recognizing that most connections above the diaphragm were not obstructed, while almost all those below the diaphragm were obstructed, these investigators grouped TAPVC into supradiaphragmatic and subdiaphragmatic types.
Some of the above classification schemes incorporate the presence or absence of obstruction into the rubric. Obstruction to pulmonary venous drainage dictates the mode of presentation, the physiology, and the prognosis of patients with TAPVC. Obstruction may be either at the level of the anomalous channel itself or at the interatrial septum. Some have advocated balloon atrial septostomy as a palliative procedure for patients with obstruction at the interatrial septum [11]. Others simply recommend early corrective surgery [12]. When obstruction is present within the anomalous channel itself, it may be due either to intrinsic narrowing, to the long length of the channel or to extrinsic compression. Obstruction may occur with any type or connection, but it is almost always present with infracardiac (infradiaphragmatic) connections. Possible sites of obstruction are listed in Table 2.
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Cor triatriatum (stenosis of the common pulmonary vein)
In this anomaly, a membrane divides the left atrium into a posterior chamber that receives the pulmonary veins and an anterior chamber that communicates with the mitral valve. This subdividing membrane inserts proximal to the left atrial appendage and is thereby distinguished from a supramitral stenosing ring. The pulmonary venous chamber may communicate with the left atrium through an opening in the membrane, or it may communicate with the right atrium either directly or indirectly via an anomalous venous channel [4]. Such an anomalous venous channel has been called an anomalous vertical vein, but Edwards prefers the term "levoatriocardinal vein" for such a connection [14].
Synonyms for "cor triatriatum" include "cor triatriatum sinister" and "triatrial heart." What some have called "cor triatriatum dexter" is not a disorder of pulmonary venous development and will not be discussed. (Cor triatriatum dexter is a rare congenital malformation in which a membrane divides the right atrium into two chambers.)
Proposed classifications of cor triatriatum include those of Loeffler, Niwagama, Grondin, and Lucas. Loeffler provided the first classification of cor triatriatum. He divided the lesions into: (1) those without a communication between the common pulmonary venous chamber and the left atrium proper, and (2) those with such a communication; his third category was that of partial cor triatriatum with some veins draining into the stenotic common pulmonary venous chamber and others draining normally [15]. Niwagama likewise placed an emphasis on the opening in the dividing septum, and classified lesions as those with no opening in the septum, those with a small opening in the septum, and those with a wide opening in the septum [16]. Grondin and associates viewed those anomalies in which there is no communication between the pulmonary venous chamber and either atrium as cases of anomalous pulmonary venous connection, and thus classified only those lesions in which there is an opening in the dividing septum as cor triatriatum [17]. Lucas has recently combined elements of each of these classification systems into a comprehensive classification, which is given in Table 3 and illustrated in Figure 3 [4].
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We will not include disorders involving abnormal numbers of pulmonary veins, even though this is common, because such disorders are not surgically important.
II. Analysis: a unified pulmonary venous anomalies nomenclature system
In formulating a classification and characterization system for pulmonary venous anomalies, we have used the following principles. The broad classification of lesions by embryologic principles is logical and well accepted; we will therefore follow this. We agree with the standard definitions, which are proposed above. We have chosen Darling’s classification of anomalous pulmonary venous connections because of its simplicity and wide acceptance, and have included as synonyms the rubric of others.
We chose to include those cases of cor triatriatum with no opening between the pulmonary venous confluence and the left atrium as subcategories of cor triatriatum rather than as cases of totally anomalous pulmonary venous connection, though we have provided appropriate synonyms for those who would choose otherwise. We chose to categorize these lesions as cases of cor triatriatum because the surgical approach to them allows the simple creation of a fenestration in the membrane that separates the pulmonary venous confluence from the left atrium, whereas with anomalies of pulmonary venous connection, an anastomosis must be made between the pulmonary venous confluence and the left atrium.
For those disorders that involve anomalies of pulmonary venous connection (that is, PAPVC and TAVPC and some types of cor triatriatum), we propose subclassifying the connections anatomically as well as by the presence or absence of pulmonary venous obstruction. The exact anatomy (vein[s] involved and site of anomalous connection) should be specified in each case. The presence or absence of pulmonary venous obstruction should be included because this dictates the mode of presentation and the prognosis of the patient.
In like manner, we propose to subclassify individual pulmonary venous stenoses by the specific vein(s) involved and by the type of stenosis. This is because the type of stenosis dictates the therapeutic options that are available. Stenosis of individual pulmonary veins is the only pulmonary venous anomaly that may be acquired as well as congenital, so classification in this manner would also be prudent.
The classification system based upon the above considerations is presented in Table 4. For those conditions that involve anomalies of pulmonary venous connection, further precise anatomic and physiologic classification may be obtained by filling in the fields shown in Table 5. For those conditions that involve stenoses of pulmonary veins, precise anatomic and physiologic classification may be obtained by filling in the fields shown in Table 6.
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TAPVC hierarchy level 1
TAPVC hierarchy level 1 definition
Total anomalous pulmonary venous connection (TAPVC)
All of the pulmonary veins connect anomalously with the right atrium or to one or more of its venous tributaries. None of the pulmonary veins connects normally to the left atrium.
TAPVC hierarchy level 2
TAPVC hierarchy level 2 definitions
Partial TAPVC, type 1 (supracardiac)
The anomalous connection is at the supracardiac level, either to a remnant of the left superior vena cava or to the right superior vena cava.
TAPVC, type 2 (cardiac)
The anomalous connection is to the heart, either to the right atrium directly or to the coronary sinus.
TAPVC, type 3 (infracardiac)
The anomalous connection is at the infracardiac level (below the diaphragm), with the pulmonary venous return entering the right atrium ultimately via the inferior vena cava.
TAPVC, type 4 (mixed)
The anomalous connection is at two or more of the above levels.
TAPVC hierarchy level 3
TAPVC hierarchy level 4
PAPVC hierarchy level 1
PAPVC hierarchy level 1 definition
PAPVC
PAPVC is the anomaly in which some, but not all, of the pulmonary veins connect to the right atrium or to one or more of its venous tributaries.
PAPVC hierarchy level 2
PAPVC hierarchy level 2 definitions
PAPVC, scimitar
All cases of partially anomalous pulmonary venous connection of one or all right pulmonary veins to the inferior vena cava.
Cor triatriatum hierarchy level 1
Cor triatriatum hierarchy level 1 definition
Cor triatriatum
A membrane divides the left atrium into a posterior chamber that receives the pulmonary veins and an anterior chamber that communicates with the mitral valve.
Cor triatriatum hierarchy level 2
Cor triatriatum hierarchy level 3
Cor triatriatum hierarchy level 4
Pulmonary venous stenosis hierarchy level 1
Pulmonary venous stenosis hierarchy level 1 definition
Pulmonary venous stenosis
Any pathologic narrowing of one or more pulmonary veins.
Pulmonary venous stenosis hierarchy level 2
Pulmonary venous stenosis hierarchy level 3
Pulmonary venous stenosis hierarchy level 4
III. Nomenclature for treatment options for pulmonary venous anomalies
Although pulmonary venous anomalies have similar embryological origins, the clinical presentations may be quite different. Children with obstructed TAPVC often present in extremis with acidosis and multisystem organ failure before repair. Occasionally, some surgeons feel that a child may be so severely ill that a period of extracorporeal membrane oxygenation (ECMO) before repair may be life saving.
Historically, TAPVC is a very lethal anomaly, with over 80% mortality in the first year of life. The outlook has improved significantly, and currently the operative mortality for uncomplicated TAPVC repair should be less than 5%. The subgroup of mixed TAPVC can present a technical challenge in that individual anastomosis of pulmonary veins can lead to early and late restenosis. Controversy continues concerning the potential contributions of the different types of repairs to the development of late stenosis of the pulmonary veins. It is likely that late restenosis is not at the level of the confluence anastomosis, but is due to involution or scarring at the orifices of the individual pulmonary veins. Thus, a widely patent anastomosis may become restrictive with time. If there appears to be restriction at the anastomosis between the confluence and the heart, then reoperation may be curative. However, if restenosis occurs at the level of the individual vein, these patients do not respond well to either operative or to catheter interventions, and ultimately progress to irreversible pulmonary hypertension. At this point, lung transplantation may be the only option. There has been some limited experience with intraoperative stent placement into the individual vein with or without some type of plasty repair of the veins. This has been successful in anecdotal cases and is an option.
The therapeutic options for repair of TAPVC initially depend upon the classification of the defect as either: supracardiac, infracardiac, cardiac or mixed-type TAPVC. The important decision points in the repair involve: "How is the main pulmonary venous confluence anastomosis fashioned? What is done with the ASD? If the ASD was closed, how was it closed? What suture is used for the pulmonary vein anastomosis? What patch material is chosen? What is done with additional anomalous pulmonary veins as with mixed variety if anything?"
Partially anomalous pulmonary venous connections are less nefarious and often present like ASDs with large shunts. In general, surgical principles of PAPVC repair involve separation of the pulmonary and systemic venous returns. Therapeutic options for repair of partially anomalous pulmonary venous connection revolve around whether an intracardiac baffle is created to redirect pulmonary venous return to the left atrium or if the anomalous pulmonary vein is connected to the left atrium directly. If there is an ASD, is it closed or not. Occasionally, there is hypoplasia of a lung or lobe of lung, as with the case of scimitar syndrome, and lung resections are sometimes indicated. This is an important point, as the surgical mortality and morbidity associated with scimitar syndrome is significantly higher than for simple anomalous pulmonary venous connection.
The diagnosis of cor triatriatum is the indication for repair because the mortality for the unrepaired lesion is quite high. The surgical decision making revolves around whether to approach the membrane through the left atrium or through the right atrium and through the interatrial septum. The interatrial communication is generally closed if present.
Pulmonary vein stenosis may be either a postoperative complication as discussed above or a congenital lesion. As a group, these lesions have a very poor prognosis. The congenital lesions can be classified as to whether the pulmonary veins are diffusely hypoplastic, long segment focal (tubular) stenosis, or ostial (discrete) stenosis. The patients with diffuse hypoplasia of the pulmonary veins that extends into the periphery of the lung have a very poor prognosis, and often the only therapy is heart-lung or lung transplantation. The patients with tubular long segment hypoplasia of the pulmonary veins with reasonably normal intraparenchymal pulmonary veins also have a poor prognosis, but occasionally operative repair can result in long-term survival. This can be accomplished with patch plasty, stent placement, or a combination of both. Those patients with short segment or ostial (discrete) pulmonary vein stenosis have perhaps the best outlook. Repair can often be accomplished by stent placement or by patch augmentation. Open cardiotomy stent placement may be very well suited to this lesion. In general, these lesions portend a very poor prognosis and lead to severe pulmonary hypertension and decompensation with time.
TAPVC therapeutic options
TAPVC treatment hierarchy level 1
TAPVC treatment hierarchy level 2
TAPVC treatment hierarchy level 3
TAPVC treatment hierarchy level 4
PAPVC therapeutic options
PAPVC treatment hierarchy level 1
PAPVC treatment hierarchy level 2
Cor triatriatum treatment hierarchy level 1
Cor triatriatum treatment hierarchy level 2
Cor triatriatum treatment hierarchy level 3
Cor triatriatum treatment hierarchy level 4
Cor triatriatum treatment hierarchy level 5
Pulmonary vein stenosis therapeutic options
Pulmonary vein stenosis treatment hierarchy level 1
Pulmonary vein stenosis treatment hierarchy level 2
Additional comments regarding therapeutics
In addition to the above basic treatment options, 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, "mini-thoracotomy"], 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, Bovine pericardium, autologous pericardium [free autologous pericardium and in situ autologous pericardium], gluteraldehyde-fixated autologous pericardium, atrial wall patch [ie, atrial wall used to patch a stenotic pulmonary vein], homograft patch, etc). Finally, if additional procedures are performed during one of these procedures, these additional procedures would be coded in detail separately. (For example, if one performs an ASD repair during repair of TAPVC, the ASD would also be coded as a secondary procedure, and the type of ASD repair done [primary closure vs patch repair] would be coded in detail as part of this secondary procedure coding.)
IV. Diagnosis and procedure short lists
V. Potential diagnostic-related risk factors
Potential preoperative risk variables
Potential operative risk variables
Potential postoperative risk variables
References
This article has been cited by other articles:
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  J. R. Dillman, S. G. Yarram, and R. J. Hernandez Imaging of Pulmonary Venous Developmental Anomalies Am. J. Roentgenol., May 1, 2009; 192(5): 1272 - 1285. [Abstract] [Full Text] [PDF]
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 F. Saremi and S. Krishnan Cardiac Conduction System: Anatomic Landmarks Relevant to Interventional Electrophysiologic Techniques Demonstrated with 64-Detector CT RadioGraphics, November 1, 2007; 27(6): 1539 - 1565. [Abstract] [Full Text] [PDF]
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 M. Ando, Y. Takahashi, and T. Kikuchi Total anomalous pulmonary venous connection with dysmorphic pulmonary vein: a risk for postoperative pulmonary venous obstruction Interactive CardioVascular and Thoracic Surgery, December 1, 2004; 3(4): 557 - 561. [Abstract] [Full Text] [PDF]
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 E. Villa, E. Le Bret, A. Batisse, and P. Vouhe Obstructed right pulmonary venous drainage and ipsilateral lung hypoplasia Eur. J. Cardiothorac. Surg., May 1, 2004; 25(5): 899 - 901. [Abstract] [Full Text] [PDF]
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 S. K. Prasad, N. Soukias, T. Hornung, M. Khan, D. J. Pennell, M. A. Gatzoulis, and R. H. Mohiaddin Role of Magnetic Resonance Angiography in the Diagnosis of Major Aortopulmonary Collateral Arteries and Partial Anomalous Pulmonary Venous Drainage Circulation, January 20, 2004; 109(2): 207 - 214. [Abstract] [Full Text] [PDF]
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 B. N. Joe, M. Poustchi-Amin, and P. K. Woodard Case 56: Cor Triatriatum Dexter Radiology, March 1, 2003; 226(3): 701 - 705. [Full Text] [PDF]
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