Classification of TAPVC

Classification of TAPVC

Total anomalous pulmonary venous connection (TAPVC) has been classified into four types by Craig JM, Darling RC and Rothney WB in 1957 [1]. It is popularly known as Darling classification. According to this classification, TAPVC is divided into four types based on the anatomic site of the anomalous connection. Type 1 is a supracardiac, type 2 is an intracardiac, type 3 is infracardiac and type 4 a mixed variety. This is the most commonly used classification.

Supracardiac TAPVC (Type I)
Supracardiac TAPVC (Type I)

In the supracardiac variety, the four pulmonary veins drain into a common venous chamber which drains to the left brachiocephalic vein through a vertical vein. In type 2, the pulmonary veins drain to the coronary sinus or directly into the right atrium.

Intracardiac TAPVC (Type II)
Intracardiac TAPVC (Type II)

In type 3, the pulmonary veins connect to a vertical vein which drains below the diaphragm, either into the portal vein or its branches.

Infracardiac TAPVC (Type III)
Infracardiac TAPVC (Type III)

Type 4 or mixed type is usually a combination of types 1 and 3 [2]. The commonest variety is the supracardiac or type 1, which constitutes about half the number of cases. Types 2 and 3 are almost equally seen in about one fifth of cases and type 4 in about one tenth of the cases.

Another simple classification has been proposed by Smith B et al, which simply divides TAPVC into 2 groups [3]. They are supradiaphragmatic without pulmonary venous obstruction and infradiaphragmatic with pulmonary venous obstruction [2].

Several other classifications have been published like a detailed classification by Herlong JR et al [4] and a classification of the mixed type by Chowdhury UK et al [5].

References

  1. Craig JM, Darling RC, Rothney WB. Total pulmonary venous drainage into the right side of the heart; report of 17 autopsied cases not associated with other major cardiovascular anomalies. Lab Invest. 1957 Jan-Feb;6(1):44-64.
  2. Kao CC, Hsieh CC, Cheng PJ, Chiang CH, Huang SY. Total Anomalous Pulmonary Venous Connection: From Embryology to a Prenatal Ultrasound Diagnostic Update. J Med Ultrasound. 2017 Jul-Sep;25(3):130-137.
  3. Smith B, Frye TR, Newton WA Jr. Total Anomalous Pulmonary Venous Return: Diagnostic Criteria and A New Classification. Am J Dis Child 1961;101(1):41-51.
  4. Herlong JR, Jaggers JJ, Ungerleider RM. Congenital Heart Surgery Nomenclature and Database Project: pulmonary venous anomalies. Ann Thorac Surg. 2000 Apr;69(4 Suppl):S56-69.
  5. Chowdhury UK, Malhotra A, Kothari SS, Reddy SK, Mishra AK, Pradeep KK, Venugopal P. A suggested new surgical classification for mixed totally anomalous pulmonary venous connection. Cardiol Young. 2007 Aug;17(4):342-53.