Pediatric “5 Ts” (Cyanotic CHD) #5: Total Anomalous Pulmonary Venous Return — “Total”

1. Core Concept

Total anomalous pulmonary venous return (TAPVR), also termed total anomalous pulmonary venous connection (TAPVC), is a congenital malformation in which none of the pulmonary veins connects normally to the left atrium (LA). Instead, the entire pulmonary venous return reaches the systemic venous circulation or right atrium through an anomalous pathway.

TAPVR is conventionally classified as supracardiac, cardiac, infracardiac, or mixed, according to the route by which pulmonary venous blood reaches the systemic venous circulation [1]. Although this anatomic classification determines operative exposure and reconstruction, the most important physiologic distinction is often unobstructed versus obstructed pulmonary venous drainage. In neonatal series, infracardiac and mixed anatomy are particularly associated with complex or obstructed pathways and frequently require urgent repair [1,2].

Because oxygenated pulmonary venous blood returns to the right side of the circulation, survival requires an interatrial communication, usually an ASD or PFO, through which mixed blood can enter the LA and support systemic output. TAPVR is therefore a complete admixture lesion, with the severity of cyanosis and hemodynamic compromise determined primarily by pulmonary blood flow, pulmonary venous resistance, pulmonary vascular resistance, and adequacy of atrial-level communication.

2. Anatomic Patterns

In many patients, the individual pulmonary veins join a common pulmonary venous confluence (CPV) behind the LA. The confluence then drains through an anomalous collector rather than directly into the LA. The surgeon must define not merely the traditional subtype, but the drainage of each individual pulmonary vein, the size and location of the confluence, the site of obstruction, and the spatial relationship between the confluence and posterior LA.

Supracardiac TAPVR

In the classic supracardiac configuration:

Pulmonary veins → common pulmonary venous confluence → vertical vein → innominate vein → SVC → right atrium

Obstruction may occur along the vertical vein or where the anomalous channel traverses surrounding structures. The length and geometry of this extracardiac pathway make careful assessment for narrowing essential.

Cardiac TAPVR

Cardiac TAPVR most commonly drains through an enlarged coronary sinus or directly into the right atrium. Coronary-sinus-type anatomy can often be repaired by unroofing the coronary sinus toward the LA and reconstructing the atrial septum to direct pulmonary venous return to the systemic ventricle [1].

Infracardiac TAPVR

In infracardiac TAPVR, the common confluence drains inferiorly through a descending vein toward the portal vein, ductus venosus, hepatic venous system, or inferior vena cava. The anomalous channel may cross the diaphragm and encounter substantial resistance, explaining the strong association between infracardiac drainage and pulmonary venous obstruction [1].

Mixed TAPVR

Mixed TAPVR contains more than one anomalous drainage pathway. This anatomy is particularly important surgically because a separate pulmonary vein or venous group may be missed if the anatomy is interpreted only according to the dominant confluence. Mixed anatomy has also been associated with increased postoperative pulmonary venous obstruction (PVO) in neonatal series [2].

3. Complete Admixture and the Role of the ASD/PFO

TAPVR produces complete admixture physiology because systemic and pulmonary venous blood both enter the right-sided circulation.

Mixed blood in the right atrium has two principal pathways:

• across the tricuspid valve to the RV and pulmonary artery, or
• across an ASD/PFO to the LA, LV, and systemic circulation.

Consequently, systemic blood flow depends on right-to-left flow across the atrial septum. The ASD or PFO is therefore physiologically obligatory rather than simply an associated lesion.

A restrictive atrial communication may reduce LV preload and systemic output even when the extracardiac pulmonary venous pathway itself is relatively unobstructed. Thus, preoperative assessment should distinguish obstruction of the pulmonary venous confluence or collector from inadequate atrial-level decompression.

In a contemporary cohort of 127 neonates undergoing isolated TAPVC repair, approximately one-quarter had preoperative PVO, demonstrating how frequently obstruction contributes to neonatal presentation [2].

4. Unobstructed TAPVR

When the anomalous pulmonary venous pathway is widely patent, pulmonary venous blood reaches the right atrium without a major pressure gradient. As pulmonary vascular resistance falls after birth, pulmonary blood flow may become excessive.

The right atrium and RV receive both systemic venous return and the entire pulmonary venous return, producing substantial right-sided volume loading. Effective systemic output remains dependent on atrial-level right-to-left flow.

The clinical phenotype may include:

• mild or moderate cyanosis,
• tachypnea,
• feeding intolerance,
• failure to thrive,
• right atrial and RV enlargement,
• pulmonary overcirculation, and
• heart-failure physiology.

The LA and LV are often relatively small because their preload is supplied through the atrial communication rather than through normal pulmonary venous connections.

Unobstructed TAPVR is therefore usually better tolerated than obstructed TAPVR, but it still represents an abnormal circulation requiring surgical correction. Contemporary series demonstrate that even relatively stable infants may develop important postoperative complications, particularly pulmonary venous obstruction [2,3].

5. Obstructed TAPVR: A Surgical Emergency

Pulmonary venous obstruction fundamentally changes the physiology.

Obstruction may involve:

• the common pulmonary venous confluence,
• the vertical or descending venous collector,
• the connection between the anomalous channel and systemic vein,
• or, functionally, restrictive atrial-level communication.

When pulmonary venous blood cannot escape freely, pulmonary venous and capillary pressure rise, producing interstitial and alveolar pulmonary edema. Pulmonary artery pressure and pulmonary vascular resistance increase, imposing major pressure load on the RV. At the same time, restricted pulmonary venous return limits the amount of oxygenated blood available for systemic output.

The resulting clinical picture may include:

• profound cyanosis,
• severe respiratory distress,
• pulmonary edema,
• pulmonary hypertension,
• metabolic acidosis,
• low cardiac output, and
• circulatory shock.

Obstructed neonatal TAPVR therefore represents an anatomic surgical emergency. A series of 88 neonates with obstructed TAPVC required emergency repair, illustrating the limited role of prolonged medical stabilization when the fundamental lesion is mechanical pulmonary venous obstruction [1].

Preoperative condition also has major prognostic importance. Across contemporary retrospective cohorts, preoperative PVO, acidosis, mechanical ventilation, intubation, cardiopulmonary resuscitation, and low body weight have been associated with increased mortality [2-4].

6. Preoperative Assessment

Echocardiography remains central to diagnosis and should establish:

• drainage of each pulmonary vein,
• presence and morphology of the common confluence,
• route of anomalous venous drainage,
• Doppler evidence and location of obstruction,
• size and flow direction of the ASD/PFO,
• RV size and systolic function,
• estimated pulmonary artery pressure, and
• associated congenital cardiac abnormalities.

CT angiography can provide detailed three-dimensional definition when pulmonary venous anatomy is complex or incompletely delineated by echocardiography. However, additional imaging should not delay definitive treatment in a critically unstable neonate with clearly identified obstructed TAPVR.

From the operative perspective, the essential question is whether a broad, non-tensioned, geometrically favorable connection between the pulmonary venous pathway and LA can be created while avoiding distortion of the individual pulmonary veins.

7. Conventional Surgical Repair

The fundamental objective of repair is to establish a wide, low-resistance pulmonary venous connection to the LA and abolish the anomalous systemic venous pathway.

For the common supracardiac configuration, conventional repair generally involves:

1. exposure of the posterior pulmonary venous confluence,
2. a generous opening of the confluence,
3. creation of a corresponding opening in the posterior LA,
4. a broad confluence-to-LA anastomosis, and
5. interruption or functional elimination of the vertical vein.

In cardiac TAPVR draining through the coronary sinus, repair may instead involve coronary-sinus unroofing and atrial septal reconstruction [1].

The technical goal is more than immediate anastomotic patency. A small, irregular, tensioned, or distorted anastomosis can predispose to subsequent obstruction. Long-term success therefore depends on both the initial size of the connection and preservation of unobstructed geometry as the child grows.

8. Sutureless Repair

Postoperative PVO remains one of the most important complications after TAPVR repair. This concern led to increasing use of the sutureless technique, particularly in anatomically high-risk patients.

In a sutureless repair, the opened pulmonary venous confluence and individual venous openings are incorporated into a neoatrial chamber by suturing the surrounding posterior pericardium to the LA rather than placing the anastomotic suture line directly on pulmonary venous tissue. This strategy is intended to reduce manipulation, distortion, and scar formation around the pulmonary vein ostia [5].

Early single-center experience demonstrated that primary sutureless repair could be performed with favorable pulmonary venous patency, although the initial series were small and nonrandomized [5]. Another comparative neonatal cohort found similar death and pulmonary-vein reoperation rates between primary sutureless and conventional repair despite greater anatomic risk in the sutureless group, with more favorable reduction in RV pressure after sutureless repair [6].

The strongest comparative evidence among the supplied studies is a meta-analysis of seven studies including 1,293 patients. Primary sutureless repair was associated with lower postoperative PVO (OR 0.52) and lower PVO-related reoperation (OR 0.28) compared with conventional repair, while mortality was not significantly different [7].

A separate retrospective study focusing specifically on infracardiac TAPVC also associated primary sutureless repair with improved survival and less postoperative PVO compared with conventional repair [8].

These findings support the concept that sutureless repair may reduce postoperative venous obstruction, particularly in higher-risk anatomy. However, available evidence remains predominantly retrospective, and selection of conventional versus sutureless reconstruction should therefore remain individualized.

9. Early Postoperative Physiology

Successful anatomic repair abruptly converts the circulation from complete admixture to a normal series circulation. Pulmonary venous blood now enters the LA directly, while the previously volume-loaded RV loses the recirculated pulmonary venous component.

Patients with severe preoperative obstruction may nevertheless have persistent:

• pulmonary hypertension,
• pulmonary edema,
• impaired lung compliance,
• RV dysfunction,
• low cardiac output, or
• residual pulmonary venous gradients.

Postoperative management should therefore integrate anatomic and physiologic assessment. Important parameters include systemic perfusion, RV function, pulmonary artery pressure, LA filling, pulmonary venous Doppler patterns, oxygenation, ventilation, and central venous pressure.

Mortality after repair varies substantially among reported series, reflecting differences in patient age, anatomy, preoperative illness, and institutional practice. Contemporary cohorts in the supplied evidence reported early or operative mortality ranging approximately from 4% to 21.6% [9,10].

Importantly, mortality appears to correlate more consistently with severity of preoperative illness and operative complexity than with the choice of anastomotic technique alone. Reported adverse factors include low weight, metabolic acidosis, preoperative PVO, intubation, CPR, prolonged cardiopulmonary bypass, and adverse postoperative hemodynamics [2,4,10].

10. Postoperative Pulmonary Venous Obstruction

Postoperative PVO is the major disease-specific complication after TAPVR repair.

In the 127-neonate series, postoperative PVO occurred in 11.8% and was associated with mixed TAPVC anatomy, preoperative acidosis, and prolonged cardiopulmonary bypass [2]. These associations reinforce that postoperative venous obstruction is not purely a technical anastomotic problem; intrinsic pulmonary venous anatomy and severity of the preoperative disease may also contribute.

The clinical consequences can be severe. In one two-center cohort, all three patients who developed postoperative pulmonary vein stenosis died, although the small number limits generalization [9].

Obstruction may occur at:

• the confluence-to-LA anastomosis,
• individual pulmonary vein ostia,
• or more diffusely within the pulmonary venous system.

Recurrent obstruction produces pulmonary venous hypertension, increased pulmonary vascular resistance, elevated RV and pulmonary artery pressure, respiratory symptoms, and eventually RV dysfunction.

Long-term surveillance should therefore assess both pulmonary venous anatomy and RV/PA pressure-flow physiology rather than considering an initially unobstructed anastomosis equivalent to permanent cure.

11. Long-Term Surveillance

Follow-up after TAPVR repair should focus on early detection of recurrent or progressive pulmonary venous obstruction.

Concerning findings include:

• increasing pulmonary venous Doppler velocity,
• loss of normal phasic pulmonary venous flow,
• rising RV systolic pressure,
• progressive RV hypertrophy or dysfunction,
• recurrent pulmonary edema,
• unexplained tachypnea,
• exercise intolerance, or
• deterioration in oxygenation.

Echocardiography is the principal surveillance modality, but CT, MRI, or catheterization may be required when pulmonary venous anatomy or hemodynamics remain uncertain.

Current evidence is insufficient to establish uniform long-term surveillance intervals or to determine whether sutureless repair reduces late pulmonary hypertension and reintervention across all anatomic subtypes. Most comparative studies remain retrospective and heterogeneous [6-8].

12. Clinical and Surgical Takeaways

TAPVR can be understood through four key questions:

1. Where does the pulmonary venous blood drain?

Supracardiac, cardiac, infracardiac, and mixed anatomy determine the route of anomalous return and influence operative strategy.

2. Can blood reach the left heart adequately?

Because all pulmonary venous blood initially reaches the right-sided circulation, systemic output requires adequate right-to-left flow through an ASD/PFO.

3. Is the pulmonary venous pathway obstructed?

This is the major determinant of neonatal urgency. Obstruction produces pulmonary edema, severe hypoxemia, pulmonary hypertension, acidosis, and shock and requires urgent surgical relief.

4. How can a durable pulmonary venous pathway be created?

Conventional repair establishes a broad confluence-to-LA connection. Sutureless repair minimizes direct manipulation of pulmonary venous tissue and, based on current retrospective and meta-analytic evidence, appears to reduce postoperative PVO and PVO-related reoperation without a clearly demonstrated mortality benefit [7].

The most clinically useful framework is therefore anatomy + obstruction + adequacy of atrial communication + pulmonary venous repairability.

For the congenital heart surgeon, successful TAPVR repair is not merely the creation of an anastomosis. The objective is a large, geometrically favorable, low-resistance pulmonary venous pathway that remains durable with growth. Early outcome is strongly influenced by the patient’s preoperative physiologic condition, whereas long-term outcome depends heavily on prevention and early recognition of recurrent pulmonary venous obstruction.

References

[1] Zheng J, Gao B, Xu Z, Liu J. The Research on Operation of Obstructed Total Anomalous Pulmonary Venous Connection in Neonates. ScientificWorldJournal. 2014. doi:10.1155/2014/576569.

[2] Ji E, Qiu H, Liu X, Xie W, Liufu R, Liu T, Chen J, Wen S, Li X, Cen J, Jian Z. The Outcomes of Total Anomalous Pulmonary Venous Connection in Neonates—10-Year Experience at a Single Center. Front Cardiovasc Med. 2021. doi:10.3389/fcvm.2021.775578.

[3] Lee Y, Cho J, Kwon OY, Jang W. Outcomes of Surgery for Total Anomalous Pulmonary Venous Return without Total Circulatory Arrest. Korean J Thorac Cardiovasc Surg. 2016. doi:10.5090/kjtcs.2016.49.5.337.

[4] Singh G, Mazalan SL, Ramachandran S, Shan OY, Jasid AM, Leman H. Total Anomalous Pulmonary Venous Drainage: Overall Results, Comparison of the Sutureless Versus the Conventional Approach, and Predictors of Adverse Events: A 17 Years Single Centre Experience. SAS J Surg. 2026. doi:10.36347/sasjs.2026.v12i01.012.

[5] Mueller C, Dave H, Prêtre R. Primary correction of total anomalous pulmonary venous return with a modified sutureless technique. Eur J Cardiothorac Surg. 2013. doi:10.1093/ejcts/ezs376.

[6] Yanagawa B, Alghamdi A, Dragulescu A, Viola N, Al-Radi OO, Mertens L, Coles J, Caldarone C, van Arsdell GV. Primary sutureless repair for “simple” total anomalous pulmonary venous connection: midterm results in a single institution. J Thorac Cardiovasc Surg. 2011. doi:10.1016/j.jtcvs.2010.10.056.

[7] Wu Y, Wu Z, Zheng J, Li Y, Zhou Y, Kuang H, Jin X, Wu C. Sutureless technique versus conventional surgery in the primary treatment of total anomalous pulmonary venous connection: a systematic review and meta-analysis. J Cardiothorac Surg. 2018. doi:10.1186/s13019-018-0756-z.

[8] Liufu R, Liu X, Liu T, Chen J, Wen S, Cen J, Jian Z. Primary sutureless repair for infracardiac total anomalous pulmonary venous connection. Eur J Cardiothorac Surg. 2021. doi:10.1093/ejcts/ezaa470.

[9] Al-Radi OO, Elmahrouk A, Ismail M, Helal A, Hamouda TH. Total anomalous pulmonary venous drainage repair: the effect of anatomical type and pulmonary vein stenosis on outcomes. Cardiothorac Surg. 2020. doi:10.1186/s43057-020-0016-6.

[10] Nahle A, Hamdar H, Soqia J, Diab M, Ataya J, Al-Dairy A. Factors associated with early postoperative mortality after total anomalous pulmonary venous connection repair: a retrospective cohort study. Medicine. 2024. doi:10.1097/MD.0000000000038285.