What Is Total Anomalous Pulmonary Venous Return

  • Samreen Noman Master's degree, Biomedical Sciences, General, Bonn-Rhein-Sieg University of Applied Sciences, Germany

Total anomalous pulmonary venous return (TAPVR) is a rare cyanotic congenital anomaly, characterized by a malformation in the pulmonary venous system.1,2 It has an incidence of 7.1 per 100,000 live births in the United Kingdom, Sweden, and Ireland between 1998 and 2004.3 TAPVR represents 1% to 5% of congenital heart disease cases4, and in 30% of cases it may be associated with other complex cardiac anomalies and visceral syndromes5. TAPVR is fatal for almost all infants without intervention.3

Anatomy and physiology

The cardiovascular system (heart, arteries, and veins) is one of the first important systems to develop in the embryo. It supplies the embryo's demand for oxygen and nutrients. During the process, four pulmonary veins (two left and two right) are developed to transport blood rich in oxygen from the lungs to the left atrium, an important step for the subsequent distribution of blood throughout the body.6 However, in TAPVR, all four pulmonary veins, through an anomalous connection (resulting from embryonic changes), connect to the superior or inferior vena cava or right atrium instead of connecting to the left atrium.1,2,4,6 This anatomy results in the drainage of blood rich in oxygen from the lungs back to the right side of the heart.6

Thus, in TAPVR, the entry of blood flow into the left atrium depends on the existence and size of a communication between the atria, known as interatrial communication. The size of this communication impacts the passage of blood flow from the right to the left atrium, and consequently in pulmonary pressure, cardiac output, systemic oxygenation, and newborn survival.7

Classification

According to the place of pulmonary venous circulation connection, TAPVR is classified as:

  • Supracardiac – pulmonary veins are connected to the right common cardinal system (superior vena cava or azygous vein).
  • Cardiac–pulmonary veins are connected to the right atrium.
  • Intracardiac - characterized by drainage below the diaphragm – pulmonary veins are connected to the right atrium via the inferior vena cava.
  • Mixed - the anomalous connection is characterized by two or more types. Supracardiac is the most common type of TAPVR,3 followed by cardiac,8 and infracardiac TAPVR types.2,4

Intracardiac type presents pulmonary stenosis and blood flow obstruction,5 higher venous obstruction incidence, and is an independent risk factor for death.7

Causes and risk factors

The causes of TAPVR are unknown. However, it may be associated with genetic or chromosomal causes. Maternal use of drugs during pregnancy may also be a risk factor for TAPVR.1

Antenatal diagnosis

Only 1.9% of TAPVR cases are diagnosed during the antenatal period using current screening methods.3 Therefore, if there is a family history of TAPVR or any cardiovascular abnormality detected during antenatal screening, such as increased thickness of nuchal translucency, echocardiography should be recommended.9,10 Diagnosis of isolated TAPVR may be readily and accurately established using standard ultrasonographic techniques.5 The antenatal diagnosis of TAPVR is crucial as it allows for planning management in the delivery room and clinical and surgical treatment, which may save lives, even in cases with blood flow obstruction.10

Clinical presentation

After birth, variability in TAPVR anatomy results in a range of clinical presentations. For isolated unobstructed TAPVR, symptoms presentation and severity are related to the interatrial communication size. Thus, the clinical presentation might start at birth or shortly thereafter, and occasionally, the diagnosis might occur after months or years.5,7 Symptoms manifest as a combination of mild cyanosis flows and normal or mild arterial desaturation (due to the right to left shunt at the atrial level) associated with symptoms of pulmonary hyperperfusion (tachypnea, feeding difficulties, failure to thrive) and difficulty gaining weight5. However, if the atrial communication is small, there is higher pulmonary hypoperfusion with cyanosis, respiratory difficulty, pulmonary oedema, and circulatory collapse.7

Obstructive TAPVR leads to pulmonary hypertension, with cyanosis and the circulatory collapse occurs during the first days after birth.5

Newborn pulse oximeter screening, a mandatory screening for all newborns before going home, can detect TAPVR through the detection of low amounts of blood oxygenation or through a difference in oxygenation between the right and left sides.1

Imaging diagnostic

Thoracic radiography reveals cardiomegaly resulting from an enlarged right heart and pulmonary hyperperfusion. In the supracardiac type, the cardiovascular anomaly resembles a snowman: the head of the snowman is formed by the superior vena cava on the right, while the enlarged right atrium forms the body of the snowman. In the intracardiac type, heart size is typically normal, but there is severe interstitial pulmonary edema and diaphragm depression.11

Transthoracic echocardiography can confirm diagnoses, define anatomical connections, and assess hemodynamic consequences, including pulmonary hypertension, as well as hypertrophy and dilation of the right cardiac chambers. Doppler echocardiography may show the vessel's draining pattern.5

Treatment approaches

Surgery is the definitive TAPVR treatment. In all unobstructed forms of TAPVR, elective surgical therapy is recommended within a few days or weeks of diagnosis, following the newborn's clinical stabilization.5 However, an intracardiac TAPVR associated with venous obstruction is considered a surgical emergency.7

Before surgery, during clinical stabilization, mechanical ventilation, oxygen, diuretics, nitric oxide, and intravenous prostaglandin E infusion may be required.5

Despite specific surgical techniques used for different anatomic variants of TAPVR, the procedure consistently involves sternotomy, standard cardiopulmonary bypass, and circulatory arrest. The surgical focus is on re-establishing continuity between the pulmonary veins and the left atrium, restoring normal blood flow through the heart, and minimizing the risk of secondary pulmonary venous obstruction.1,5

Wherever possible, all associated cardiac anomalies should be repaired concomitantly. Nevertheless, this increases the complexity of the procedure, is technically challenging for surgeons, and leads to an increased surgical risk.5,12 In cases of associated complex congenital heart disease, additional palliative procedures are required.12

Prognosis and complications

Over the past decades, improvements in antenatal diagnosis and surgical treatment techniques have reduced mortality rates in isolated TAPVR. TAPVR mortality is classified in early (within 30 days after surgical repair) and late (occurring after 30 days and during the follow-up period).12 In France, early mortality rates significantly decreased from 42.1% in the seventies to 7.4% after 2010.8 In Taiwan, between 2004 and 2022, the early mortality rate was 6.9%, and with an overall 10-year survival rate after primary repair, the mortality rate reached almost 15%.12 In Melbourne, 88% of patients who underwent surgical procedures between 1973 and 2014 were still alive between 10 and 20 years after the procedure.13 Survival rates do not significantly differ based on the type of TAPVR,12 and most survivors are asymptomatic, showing normal functional hearts.13 Australian adults (ages 18 to 50), TAPVR repair survivors, have quality-of-life outcomes similar to age-matched controls.14

Several factors contribute to higher mortality rates, including the size of pulmonary veins and pulmonary venous confluence, associated complex cardiac lesions, postoperative pulmonary hypertension, postoperative obstructions, prolonged extracorporeal circulation time, and surgical procedures performed during the neonatal period.5,13 Anomalies associated with TAPVR increase the risk of death by 50% when compared to isolated TAPVR.5 Neonatal surgery could be an independent predictor of early death (2.5% in children vs. 11% in neonates) since this period represents the most severe end of the TAPVR spectrum, often requiring emergency operations.13

Complications, such as pulmonary venous obstruction and pulmonary hypertension, are important causes of morbimortality after surgery.7,12 Clinical treatment for pulmonary hypertension and management of pulmonary hypertension crisis, based on optimizing cardiac output with inotropes, volume restriction, diuretics, mechanical ventilation and pulmonary vasodilators, are generally effective.7

Pulmonary venous obstruction may develop in 10% to 16% of patients after TAPVRC repair5,12 and is significantly associated to the need for reoperation procedures and higher long-term mortality rates after primary TAPVC repair, with mortality reaching 40% during the first three years after primary repair.12

Support and resources

Considering the potential genetic origin of TAPVR, families should be referred to a multidisciplinary support network, which includes genetic counselling for parents and screening for siblings of TAPVR patients. This approach allows for necessary surgical interventions before the onset of symptoms and the development of severe congestive heart failure.15

Conclusion

TAPVR is a critical and rare congenital anomaly, lethal without timely medical intervention, making accurate diagnosis, stabilization after birth and surgical correction imperative. Advancements in prenatal diagnostics and surgical techniques have substantially improved outcomes, reducing mortality rates over the years.

Understanding the TAPVR anatomy is crucial for both diagnosis and treatment planning (clinical and surgical). Variability in clinical presentations, from mild cyanosis to severe respiratory distress and cardiocirculatory collapse, underscores the importance of individualized care. Imaging exams, such as echocardiography, are crucial to confirm the diagnosis and to evaluate hemodynamics as well as to plan clinical management until stabilization and surgical treatment.

Surgery remains the definitive treatment, and its focus lies in reestablishing the continuity between the pulmonary veins and the left atrium, ensuring normal blood flow and minimizing the risk of complications. Pulmonary hypertension and pulmonary venous obstruction are the main complications. However, while pulmonary hypertension usually is effectively treated, pulmonary venous obstruction is associated with high morbimortality.

Genetic counselling, family support, and close monitoring are integral components of comprehensive care. Despite challenges, enhanced diagnostic techniques, and the development of surgical methodologies, most TAPVR individuals have a standard quality of life without cardiac impairments.

References

  1. CDC. Centres for Disease Control and Prevention. 2019. Congenital heart defects - facts about tape | CDC. Available at: https://www.cdc.gov/ncbddd/heartdefects/tapvr.html
  2. Vyas HV, Greenberg SB, Krishnamurthy R. MR imaging and CT evaluation of congenital pulmonary vein abnormalities in neonates and infants. Radiographics. 2012;32(1):87–98.
  3. Seale AN, Uemura H, Webber SA, Partridge J, Roughton M, Ho SY, et al. Total anomalous pulmonary venous connection: morphology and outcome from an international population-based study. Circulation. 2010;122(25):2718–26.
  4. Herlong JR, Jaggers JJ, Ungerleider RM. Congenital heart surgery nomenclature and database project: pulmonary venous anomalies. Ann Thorac Surg. 2000;69(4 Suppl):S56-69.
  5. Emmel M, Sreeram N. Total anomalous pulmonary vein connection: diagnosis, management, and outcome. Curr Treat Options Cardiovasc Med. 2004;6(5):423–9.
  6. Murillo H, Cutalo MJ, Jones RP, Lane MJ, Fleischmann D, Restrepo CS. Pulmonary circulation imaging: embryology and normal anatomy. Semin Ultrasound CT MR. 2012;33(6):473–84.
  7. Atik FA, Irun PE, Barbero-Marcial M, Atik E. Drenagem anômala total das veias pulmonares: terapêutica cirúrgica dos tipos anatômicos infracardíaco e misto. [Total anomalous pulmonary venous drainage: surgical therapy for the infra diaphragmatic and mixed anatomical types]. Arq Bras Cardiol [Internet].2004;82:259–63. Available at: https://www.scielo.br/j/abc/a/VPhg3s65XM7dr6DkxGGHtCF/
  8. Lemaire A, DiFilippo S, Parienti JJ, Metton O, Mitchell J, Hénaine R, et al. Total anomalous pulmonary venous connection: a 40 years’ experience analysis. Thorac Cardiovasc Surg. 2017;65(1):9–17.
  9. Seale AN, Carvalho JS, Gardiner HM, Mellander M, Roughton M, Simpson J, et al. Total anomalous pulmonary venous connection: impact of prenatal diagnosis. Ultrasound Obstet Gynecol. 2012;40(3):310–8.
  10. International Society of Ultrasound in Obstetrics and Gynecology, Carvalho JS, Allan LD, Chaoui R, Copel JA, DeVore GR, et al. ISUOG Practice Guidelines (Updated): sonographic screening examination of the fetal heart. Ultrasound Obstet Gynecol. 2013;41(3):348–59.
  11. Ferguson EC, Krishnamurthy R, Oldham SAA. Classic imaging signs of congenital cardiovascular abnormalities. Radiographics. 2007;27(5):1323–34.
  12. Hu SY, Chou HW, Chen YS, Huang SC. Total anomalous pulmonary venous connection: surgical outcomes and risk factors for postoperative pulmonary vein obstruction. Acta Cardiol Sin. 2023;39(2):254–65.
  13. Yong MS, Yaftian N, Griffiths S, Brink J, Robertson T, D’Orsogna L, et al. Long-term outcomes of total anomalous pulmonary venous drainage repair in neonates and infants. Ann Thorac Surg. 2018;105(4):1232–8.
  14. Yong MS, Zhu MZL, Huang L, Griffiths S, Brink J, Brizard CP, et al. Long-term quality of life outcomes in adult survivors after anomalous pulmonary venous drainage repair. Ann Thorac Surg. 2020;110(2):654–9.
  15. Kim HS, Jeong K, Cho HJ, Choi WY, Choi YE, Ma JS, et al. Total anomalous pulmonary venous return in siblings. J Cardiovasc Ultrasound [Internet]. 2014;22(4):213–9. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4286644/
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Ana Silvia Scavacini Marinonio

PhD in Health Sciences, UNIFESP, São Paulo, Brazil

Ana Sílvia is a physiotherapist with extensive experience in clinical practice, medical affairs, and clinical research. She completed her master's, Ph.D., and postdoctoral studies. She is skilled in big data management and analysis, as well as spatial analysis tools. Additionally, she has a strong background in creating and editing documents and scientific articles.

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