Veno-venous bridges: the forerunners of the sinus venosus defect

The Sinus Venosus Veno-Venous Bridge: Not a septal defect

This review provides an update on the morphology of the sinus venosus defect. It was earlier believed that a 'common wall' separated the right pulmonary veins from the superior caval vein. In the sinus venosus defects, this wall was absent. Current evidence shows that the superior rim of the oval fossa, rather than forming a second septum or representing a common wall, is an infolding between the walls of the caval veins and the right pulmonary veins. The sinus venosus defect is caused by the anomalous connection of one or more pulmonary veins to a systemic vein. However, the pulmonary vein(s) retain their left atrial connections, leading to a veno-venous bridge that allows interatrial shunting outside the oval fossa. True atrial septal defects are located within the oval fossa or in the anteo-inferior buttress, while sinus venosus defects, ostium defects and coronary sinus defects are morphologically distinct from them.

Transcatheter closure of sinus venosus defect: First-in-human implant of a dedicated self-expanding VB stent system

The paper describes the first-in-human use of a dedicated, self-expandable covered stent system (VB stent) for closure of sinus venosus defects.

Left pulmonary veins draining into persistent left superior caval vein in presence of unroofed coronary sinus

We report a case of 5-year-old girl with double outlet right ventricle with a rare combination of partial anomalous pulmonary venous drainage into a persistent left superior caval vein in the presence of an unroofed coronary sinus while highlighting its possible embryological origins and therapeutic implications.

Multimodality imaging in delineation of complex sinus venosus defects and treatment outcomes over the last decade

BACKGROUND

Diagnosis of sinus venosus defects, not infrequently associated with complex anomalous pulmonary venous drainage, may be delayed requiring multimodality imaging.

METHODS

Retrospective review of all patients from February 2008 to January 2019.

RESULTS

Thirty-seven children were diagnosed at a median age of 4.2 years (range 0.5-15.5 years). In 32 of 37 (86%) patients, diagnosis was achieved on transthoracic echocardiography, but five patients (14%) had complex variants (four had high insertion of anomalous vein into the superior caval vein and three had multiple anomalous veins draining to different sites, two of whom had drainage of one vein into the high superior caval vein). In these five patients, the final diagnosis was achieved by multimodality imaging and intra-operative findings. The median age at surgery was 5.2 years (range 1.6-15.8 years). Thirty-one patients underwent double patch repair, four patients a Warden repair, and two patients a single-patch repair. Of the four Warden repairs, two patients had a high insertion of right-sided anomalous pulmonary vein into the superior caval vein, one patient had bilateral superior caval veins, and one patient had right lower pulmonary vein insertion into the right atrium/superior caval vein junction. There was no post-operative mortality, reoperation, residual shunt or pulmonary venous obstruction. One patient developed superior caval vein obstruction and one patient developed atrial flutter.

CONCLUSION

Complementary cardiac imaging modalities improve diagnosis of complex sinus venosus defects associated with a wide variation in the pattern of anomalous pulmonary venous connection. Nonetheless, surgical treatment is associated with excellent outcomes.

Transcatheter Closure of Atrial and Ventricular Septal Defects: JACC Focus Seminar

The field of congenital interventional cardiology has experienced tremendous growth in recent years. Beginning with the development of early devices for transcatheter closure of septal defects in the 1970s and 1980s, such technologies have evolved to become a mainstay of treatment for many atrial septal defects (ASDs) and ventricular septal defects (VSDs). Percutaneous device closure is now the preferred approach for the majority of secundum ASDs. It is also a viable treatment option for selected VSDs, though limitations still exist. In this review, the authors describe the current state of transcatheter closure of ASDs and VSDs in children and adults, including patient selection, procedural approach, and outcomes. Potential areas for future evolution and innovation are also discussed.

Complex connections: A young man presenting with shortness of breath, hypoxemia, right lumbar pain and left limb swelling

A 43‐year‐old Caucasian man was admitted to hospital due to shortness of breath, right lumbar pain and lower left limb swelling. Arterial blood gas sample showed mild hypoxemia and respiratory alkalosis. CT scan confirmed pulmonary embolism, splenic and bilateral renal ischemic lesions. Echocardiography showed right ventricular and coronary sinus (CS) dilatation. Using contrast echocardiography, a superior sinus venous atrial septal defect and persistent left superior vena cava (PLSVC) draining in CS were suspected. Cardiac CT confirmed the diagnosis and showed overriding right superior vena cava (RSVC) draining in both atria. The patient underwent successful surgical correction.

An uncommon case of congenital thoracic venous anomaly and extracardiac sinus venosus defect in an asymptomatic adult first presenting with brain abscesses: a case report

Background

Congenital thoracic venous anomalies (CTVAs) with right-to-left shunt constitute an uncommon source of paradoxical embolization in adults. We present a case of a healthy and physically fit individual with a rare asymptomatic anomaly first presenting with brain abscesses after a visit to the dental office; persistent left superior vena cavae (PLSVC) without bridging vein, over-riding right-sided superior vena cavae (RSVC) connected to the left atrium (LA), and an extracardiac sinus venosus defect.

Case summary

A 29-year-old male presented to the neurosurgical unit due to intracranial abscesses requiring intervention following a visit to his dentist. The abscess cultures isolated bacteria commonly found in the normal oral flora. Transthoracic echocardiography revealed an enlarged coronary sinus consistent with PLSVC. An agitated saline study was performed and raised suspicion of simultaneous extra- and intracardiac shunting. Magnetic resonance angiography confirmed the presence of a PLSVC and revealed an RSVC connected to the LA; however, no intracardiac shunt was evident. Electrocardiogram-gated computed tomography was therefore conducted and discovered the rudimentary remains of the physiologic RSVC forming a connection to the right atrium, explaining the bilateral contrast loading seen on the agitated saline study and diagnosing an extracardiac sinus venosus defect (SVD). The patient recovered and has been referred for surgery.

Discussion

This case illustrates a CTVA and a forme fruste type SVD resulting in a severe complication in a healthy adult. We highlight the diagnostic challenges posed, suggest early usage of agitated saline studies, and discuss the rationale for surgical correction of this patient.

Clarifying the anatomy of the superior sinus venosus defect

OBJECTIVES

We sought to clarify the variations in the anatomy of the superior cavoatrial junction and anomalously connected pulmonary veins in patients with superior sinus venosus defects using computed tomographic (CT) angiography.

METHODS

CT angiograms of 96 consecutive patients known to have superior sinus venosus defects were analysed.

RESULTS

The median age of the patients was 34.5 years. In seven (7%) patients, the defect showed significant caudal extension, having a supero-inferior dimension greater than 25 mm. All patients had anomalous connection of the right superior pulmonary vein. The right middle and right inferior pulmonary vein were also connected anomalously in 88 (92%) and 17 (18%) patients, respectively. Anomalous connection of the right inferior pulmonary vein was more common in those with significant caudal extension of the defect (57% vs 15%, p=0.005). Among anomalously connected pulmonary veins, the right superior, middle, and inferior pulmonary veins were committed to the left atrium in 6, 17, and 11 patients, respectively. The superior caval vein over-rode the interatrial septum in 67 (70%) patients, with greater than 50% over-ride in 3 patients.

CONCLUSION

Anomalous connection of the right-sided pulmonary veins is universal, but is not limited to the right upper lobe. Not all individuals have over-riding of superior caval vein. In a minority of patients, the defect has significant caudal extension, and anomalously connected pulmonary veins are committed to the left atrium. These findings have significant clinical and therapeutic implications.

Myocardial overexpression of ANKRD1 causes sinus venosus defects and progressive diastolic dysfunction

AIMS

Increased Ankyrin Repeat Domain 1 (ANKRD1) levels linked to gain of function mutations have been associated to total anomalous pulmonary venous return and adult cardiomyopathy occurrence in humans. The link between increased ANKRD1 level and cardiac structural and functional disease is not understood. To get insight into this problem, we have generated a gain of function ANKRD1 mouse model by overexpressing ANKRD1 in the myocardium.

METHODS AND RESULTS

Ankrd1 is expressed non-homogeneously in the embryonic myocardium, with a dynamic nucleo-sarcomeric localization in developing cardiomyocytes. ANKRD1 transgenic mice present sinus venosus defect, which originates during development by impaired remodelling of early embryonic heart. Adult transgenic hearts develop diastolic dysfunction with preserved ejection fraction, which progressively evolves into heart failure, as shown histologically and haemodynamically. Transgenic cardiomyocyte structure, sarcomeric assembly, and stability are progressively impaired from embryonic to adult life. Postnatal transgenic myofibrils also present characteristic functional alterations: impaired compliance at neonatal stage and impaired lusitropism in adult hearts. Altogether, our combined analyses suggest that impaired embryonic remodelling and adult heart dysfunction in ANKRD1 transgenic mice present a common ground of initial cardiomyocyte defects, which are exacerbated postnatally. Molecular analysis showed transient activation of GATA4-Nkx2.5 transcription in early transgenic embryos and subsequent dynamic transcriptional modulation within titin gene.

CONCLUSIONS

ANKRD1 is a fine mediator of cardiomyocyte response to haemodynamic load in the developing and adult heart. Increased ANKRD1 levels are sufficient to initiate an altered cellular phenotype, which is progressively exacerbated into a pathological organ response by the high ventricular workload during postnatal life. Our study defines for the first time a unifying picture for ANKRD1 role in heart development and disease and provides the first mechanistic link between ANKRD1 overexpression and cardiac disease onset.

Biatrial Drainage of the Right Superior Vena Cava: Imaging Findings

Biatrial drainage of the right superior vena cava (SVC) is a rare form of interatrial shunting that can have substantial clinical consequences. Cross-sectional imaging techniques (CT and MRI) are well suited for evaluation and surgical planning. This review article focuses on the embryologic development, hemodynamics, and imaging features to enable a timely diagnosis. Biatrial drainage of the right SVC has important clinical implications, and knowledge of its imaging appearance and hemodynamics is essential in diagnosis and treatment planning. © RSNA, 2020.

Right superior vena cava draining into the left atrium in a patient with sinus venosus defect

Right superior vena cava draining into the left atrium is an extremely rare anomaly of systemic venous return. It can be isolated or it can be associated with other congenital heart defects, thus clinical presentation may vary. A case of a 9-year-old asymptomatic patient with sinus venous defect and bilateral superior vena cava with the right-sided draining into the left atrium is described.

A Review of the Surgical Management of Anomalous Connection of the Right Superior Caval Vein to the Morphologically Left Atrium and Biatrial Drainage of Right Superior Caval Vein

The present perspective is a synthesis of published investigations in the setting of anomalous connection of the right superior caval vein to the morphologically left atrium or biatrial drainage of the right caval vein. We identified 57 suitable cases from 97 investigations, reviewing the clinical presentation, diagnostic modalities utilized, surgical techniques used, and their outcomes. Clinical presentation, radiographic findings, saline contrast echocardiography, computed tomographic angiocardiography, radionuclide perfusion scan, magnetic resonance imaging, and angiocardiography provided the diagnostic information and were used to define the disease entities before surgery. We have also addressed several issues concerning the influence of the so-called heterotaxy: the establishment of the diagnosis, the variation in clinical presentation, and subsequent management. For the overall group of patients undergoing either surgical intervention or transcatheter treatment with an Amplatzer vascular plug, the operative mortality remains high at 9.5%. We submit that an increased appreciation of these disease entities will contribute to improved future surgical management.

The morphogenesis and associated anomalous pulmonary venous drainage in sinus venosus defect

BACKGROUND

Sinus venosus defect (SVD) is an unusual type of interatrial communication (IAC) and is virtually always associated with partial anomalous pulmonary venous drainage (PAPVD) of the right pulmonary veins (RPV) to the superior vena cava (SVC) or right atrium (RA). However, its definite morphogenesis is still elusive, and diagnostic fallibility continues.

METHODS

We conducted a retrospective review of the echocardiograms, cardiac catheterization data, computed tomographic findings, and surgical notes of 44 children with surgery-confirmed isolated SVD from 1977 to 2016. We investigated the location of the IAC and its boundaries within the atrial septum and its anatomic relationship with the adjacent structures, including the anomalously draining RPV. We also tried to explore any possible associated abnormalities which might be implicated in the morphogenesis of SVD.

RESULTS

Two distinct types of IAC were defined. Forty patients had an IAC that was located posterosuperior to the intact fossa ovalis (superior type), and all were associated with PAPVD of the right upper and often the right middle pulmonary veins to the SVC. The remaining 4 patients had an IAC that was located posterior to the intact fossa ovalis (inferior type), and all were associated with PAPVD of all the RPV to the RA. Another consistently associated abnormality was a defect between the anomalously draining RPV posteriorly and the SVC or RA anteriorly. All these 44 patients underwent successful surgical baffling the associated PAPVD via the IAC into the left atrium.

CONCLUSION

A defect between the RPV posteriorly and the SVC or RA anteriorly will result in SVD, and an unusual type of IAC, and PAPVD of the RPV to the SVC or RA. The IAC is not a true atrial septal defect in the atrial septum proper, but it actually represents the left atrial orifice of the unroofed RPV.

Cavopulmonary window: case report of an unusual variant of a sinus venosus defect

Introduction

Isolated partial anomalous pulmonary venous return (PAPVR) with intact atrial septum is a rare finding. A cavopulmonary window is a side-to-side veno-venous communication of the right upper pulmonary vein with the superior vena cava which in its course retains connection to the left atrium.

Case presentation

We present a case of this unusual variant of a sinus venosus defect far from the atrial roof. Haemodynamic significance of the shunt was confirmed by enlargement of right heart cavities, elevation of pulmonary artery pressure, and significant left-to-right shunting using multimodality cardiac imaging (transoesophageal echocardiography, cardiac magnetic resonance imaging, and right heart catheterization). The defect has been successfully repaired using minimally invasive axillary thoracotomy.

Discussion

Partial anomalous pulmonary venous return prevalence is low and about 0.4–0.7% in autopsy series of patients with congenital heart disease. This patient’s unusual variant of a sinus venosus defect with a window between a pulmonary vein and the superior vena cava far from the atrial roof shows that a sinus venosus defect is not a true atrial septum defect. Left-to-right shunting generally increases with age. Usually, surgical treatment is considered in cases of significant left-to-right shunt (Q_p:Q_s > 1.5–2.0) and right heart dilatation.

A rare case of a systemic-to-pulmonary veno-venous connection: a pause during development of pulmonary and systemic venous separation

A 45-year-old man with dyspnoea and palpitations exhibited a unique systemic-to-pulmonary veno-venous connection on preoperative CT images. A window of 31.5-mm diameter was evident between the superior caval vein and the middle pulmonary vein, which was normally connected to the left atrium via a 30-mm-diameter orifice. The atrial septum was intact.

Understanding the spectrum of sinus venosus interatrial communications

BACKGROUND

It is still thought by some that a common wall is to be found in the normal heart between the attachments of the caval and pulmonary veins, with absence of this wall underscoring the presence of sinus venosus defects. Recent findings using episcopic microscopy in developing mice have shown the deficiencies of this notion. Understanding that the superior rim of the oval fossa is a fold, rather than a true septum, which can be distorted in the presence of partially anomalous pulmonary venous drainage, has provided an alternative explanation for the morphogenesis of sinus venosus defects.

METHODS

We reviewed our experience with patients suspected of having a sinus venosus defect from August, 2011, through October, 2015, analysing the findings in light of the current hypotheses used to explain the development of the defects, along with correlations made by inspection of autopsy specimens.

RESULTS

We evaluated findings from 16 patients, with a mean age of 7.7 years, ranging from 2.7 to 15 years. Of the group, 13 were ultimately diagnosed with a superior sinus venosus defect, two with an inferior defect, and one with isolated anomalous pulmonary venous connection in the absence of an interatrial communication. Initially, two patients were thought to have oval fossa defects, one from each subtype, but were correctly diagnosed following cardiac magnetic resonance interrogation. Anomalous pulmonary venous connections were present in all cases.

CONCLUSION

Appreciation of the changes occurring during normal cardiac development helps in understanding the anatomical substrate underscoring the spectrum of sinus venosus defects. The lesions are veno-venous connections due to partially anomalous pulmonary venous connections, producing interatrial communications outside the confines of the interatrial septum.

A case of biatrial drainage of the right superior vena cava

Biatrial drainage of the right superior vena cava resulting from a sinus venosus defect is a rare congenital malformation. It can result in severe desaturation although a sinus venosus defect usually presents as a left-to-right shunt. A male baby was noted to have cyanosis while nursing and was referred to us for medical treatment on his second day of life. Echocardiography showed that most of the blood flowing through the superior vena cava drained into the left atrium. He underwent successful surgery to correct this defect at the age of 2 years.

Insights regarding the normal and abnormal formation of the atrial and ventricular septal structures

Knowledge of cardiac development can provide the basis for understanding the morphogenesis of congenital cardiac malformations. Only recently, however, has the quality of information regarding cardiac embryology been sufficient to justify this approach. In this review, we show how such knowledge of development of the normal atrial and ventricular septal structures underscores the interpretation of the lesions that provide the basis for interatrial and interventricular shunting of blood. We show that current concepts of atrial septation, which frequently depend on a suggested formation of an extensive secondary septum, are simplistic. There are additional contributions beyond growth of the primary septum, but the new tissue is added to form the ventral buttress of the definitive atrial septum, rather than its cranial margin, as is usually depicted. We show that the ventricular septum possesses muscular and membranous components, with the entirety of the muscular septum produced concomitant with the so-called ballooning of the apical ventricular component. It is expansion of the atrioventricular canal that creates the inlet of the right ventricle, with no separate formation of an "inlet" septum. The proximal parts of the outflow cushions initially form a septal structure between the developing ventricular outlets, but this becomes converted into the free-standing muscular subpulmonary infundibulum as the aortic outlet is transferred to the left ventricle. These features of normal development are then shown to provide the basis for understanding of the channels that provide the means for interatrial and interventricular shunting.

Imaging in congenital pulmonary vein anomalies: the role of computed tomography

Pulmonary venous anomalies comprise a wide spectrum of anatomical variations and their clinical presentations may vary from the relatively benign single partial anomalous pulmonary venous connection (PAPVC) to the critical obstructed total anomalous pulmonary venous connection (TAPVC). We briefly review the common anomalies encountered, while highlighting the utility that computed tomographic angiography (CTA) provides for this spectrum of extracardiac vascular malformations and connections. CTA has established itself as an invaluable imaging modality in these patients. A detailed knowledge of the CTA imaging findings in pulmonary venous anomalies is crucial to guide clinical decision-making in these patients.

The development of septation in the four-chambered heart

The past decades have seen immense progress in the understanding of cardiac development. Appreciation of precise details of cardiac anatomy, however, has yet to be fully translated into the more general understanding of the changing structure of the developing heart, particularly with regard to formation of the septal structures. In this review, using images obtained with episcopic microscopy together with scanning electron microscopy, we show that the newly acquired information concerning the anatomic changes occurring during separation of the cardiac chambers in the mouse is able to provide a basis for understanding the morphogenesis of septal defects in the human heart. It is now established that as part of the changes seen when the heart tube changes from a short linear structure to the looped arrangement presaging formation of the ventricles, new material is added at both its venous and arterial poles. The details of these early changes, however, are beyond the scope of our current review. It is during E10.5 in the mouse that the first anatomic features of septation are seen, with formation of the primary atrial septum. This muscular structure grows toward the cushions formed within the atrioventricular canal, carrying on its leading edge a mesenchymal cap. Its cranial attachment breaks down to form the secondary foramen by the time the mesenchymal cap has used with the atrioventricular endocardial cushions, the latter fusion obliterating the primary foramen. Then the cap, along with a mesenchymal protrusion that grows from the mediastinal mesenchyme, muscularizes to form the base of the definitive atrial septum, the primary septum itself forming the floor of the oval foramen. The cranial margin of the foramen is a fold between the attachments of the pulmonary veins to the left atrium and the roof of the right atrium. The apical muscular ventricular septum develops concomitant with the ballooning of the apical components from the inlet and outlet of the ventricular loop. Its apical part is initially trabeculated. The membranous part of the septum is derived from the rightward margins of the atrioventricular cushions, with the muscularizing proximal outflow cushions fusing with the muscular septum and becoming the subpulmonary infundibulum as the aorta is committed to the left ventricle. Perturbations of these processes explain well the phenotypic variants of deficient atrial and ventricular septation.

Cavopulmonary window: an extreme form of sinus venosus defect

We present an unusual variant of the sinus venosus defect in which an obvious window is formed between a single pulmonary vein and the superior vena cava, the pulmonary vein retaining its connection to the left atrium. Two patients were operated on via right anterior minithoracotomy. A large single right pulmonary vein was found connecting to the left atrium. There was a large side-to-side communication between the superior vena cava and the pulmonary vein resulting in partially anomalous pulmonary venous drainage. A side-biting clamp was applied in the superior vena cava and the pulmonary vein at both sides of the communication, and the vein was divided. The incision in both veins was closed with a running suture.