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.

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