The nature of the superior sinus venosus defect

Transcatheter versus surgical treatment for isolated superior sinus venosus atrial septal defect

BACKGROUND

The superior sinus venosus atrial septal defect is a congenital communication between the left and right atria. Open surgical approach by patch closure has historically been the only treatment option. Recently, a transcatheter approach has been developed. This study aims to compare the efficacy and safety of surgical and transcatheter approach in treatment of sinus venosus atrial septal defect.

METHODS

Between March 2010 and December 2020, 58 patients (median age: 45.4, range 14.8-73.8) underwent either surgical or transcatheter correction of superior sinus venosus atrial septal defect with partial anomalous pulmonary venous drainage.

RESULTS

Twenty-four patients (median age: 35.4, range 14.8-66.8) underwent surgery while 34 patients (median age: 46.8, range 15.5-73.8) had a transcatheter treatment. During the catheterization era, 41 patients was considered suitable for a transcatheter closure. In 5 patients, surgery was the patient's or referring physician's choice. In 2 cases, the procedure was unsuccessful; the remaining 34 were successfully closed (94.4% of cases). Intensive care unit stay (median of 1 day, range 0.5-4, vs. 0, range 0-2, p < 0.0001) and hospital stay (median 7 days, range 2-15 vs. 2 days, range 1-12, p < 0.0001), were significantly longer in the surgery group. Total early complication rate, consisted on procedural and in-hospital complication, were higher in the surgical group (62.5% vs. 23.5%; p = 0.005). However, complications in both groups were clinically mild. At follow-up, a small residual shunt was present in 6 patients (surgery group: 2 pts; catheterization group: 4 pts; p: NS). Imaging studies showed significant improvement of right ventricular size and unobstructed pulmonary venous return in all patients. No late complications occurred at follow-up.

CONCLUSIONS

Transcatheter correction of sinus venosus atrial septal defect is effective and safe in selected patients and may be considered as a valid alternative to surgery.

Role of Cross-Sectional Imaging in Pediatric Interventional Cardiac Catheterization

Management of congenital heart disease (CHD) has recently increased utilization of cross-sectional imaging to plan percutaneous interventions. Cardiac computed tomography (CT) and cardiac magnetic resonance (CMR) imaging have become indispensable tools for pre-procedural planning prior to intervention in the pediatric cardiac catheterization lab. In this article, we review several common indications for referral and the impact of cross-sectional imaging on procedural planning, success, and patient surveillance.

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.

Partial Anomalous Pulmonary Venous Connection Repair: Customized Approach and Outcomes

Alternative options for the correction of partial anomalous pulmonary venous connection (PAPVC) have been proposed. Each can be associated with variable risk for dysrhythmias, caval or pulmonary venous (PV) obstruction. A selective customized strategy to address PAPVC taking into account atrial shunt (AS) and growth potential was pursued. Between September 2014 and August 2018 21 PAPVC patients were identified. Two levels of reference determined the chosen repair strategy; azygous vein (AzV) and cavoatrial junction (CAJ). Six (Group-A) with PAPVC entering SVC cephalad to AV underwent a combined in-situ cavoatrial autologous reconstruction with atrial appendage advancement flap (CARAF). PAPVC entering caudally to AzV (Group-B) underwent alternative repair (caval division/Warden-type or intraatrial rerouting) (n = 15). Age was 8.3 (IQR:4.2-18.5) years for Group-A (vs 11.9; IQR:8.8-34.7 in Group-B) (p = 0.07). In Group-A 5(83%) had AS (vs 12[80%] Group-B; p = 0.9). None had left SVC in Group-A (vs 1 in Group-B; p = 0.9). Preoperative advanced imaging and echocardiographic hemodynamic evaluation was undertaken. Follow-up was complete (median 2.9; IQR:1.2-3.7 years). Freedom from atrial dysrhythmias, caval or PV obstruction was assessed. There were no early or late deaths. ICU and hospital length of stay were 1.8 ± 1.1 and 3.2 ± 0.5 days, respectively. No atrial dysrhythmias occurred postoperatively in Group-A (vs 1 in Group-B; p = 0.9). No permanent pacemaker was implanted. All patients remained in normal sinus rhythm. There were no early or late caval/PV obstruction. A customized approach reserves the advantages of each technique tailored to patient's needs. Expanding surgical capacity with favorable outlook for all PAPVC variations, irrespective of association with AS, can maximize efficiency and reproducibility paired with the lowest morbidity.

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.

Sinus Venosus Atrial Septal Defect: A Challenging Diagnosis

Sinus venosus atrial septal defect (SVASD) is a rare adult congenital heart disease which permits shunting of blood from the systemic to the pulmonary circulation and is commonly associated with anomalous pulmonary venous return.

We report a case of a 27-year-old man with a history of premature birth and unilateral cryptorchidism who was admitted for syncope. Electrocardiogram (ECG) demonstrated atrial fibrillation (AF)and S1Q3T3 pattern along with an incomplete right bundle branch block. Transthoracic echocardiography (TTE) suggested the presence of right ventricular pressure and volume overload and severe right ventricular and right atrial enlargement. The agitated saline study was negative suggesting no inter-atrial communication. Transesophageal echocardiography (TEE) demonstrated a superior SVASD and raised the possibility of an anomalous pulmonary venous connection. Chest computed tomography identified the right superior pulmonary vein connection to the superior vena cava.

The diagnosis of SVASD poses multiple challenges from the variety of symptoms to the selection of appropriate imaging and the complexity of surgical treatment. 

Early experience of transcatheter correction of superior sinus venosus atrial septal defect with partial anomalous pulmonary venous drainage

AIMS

Superior sinus venosus atrial septal defect (SVASD) is commonly associated with partial anomalous pulmonary venous drainage (PAPVD). We aimed to describe the first series of percutaneous SVASD and PAPVD correction using a two-step simulation for procedural planning.

METHODS AND RESULTS

Patients with SVASD and right PAPVD with a clinical indication for correction were selected. They underwent an ex vivo procedural simulation on a 3D-printed model followed by an in vivo simulation using balloon inflation in the targeted stent landing zone. The percutaneous procedure consisted in deploying a 10-zig custom-made covered stent in the SVC-RA junction. Five patients were referred for preprocedural evaluation and were deemed suitable for percutaneous correction. The procedure was successful in all patients with no residual interatrial shunt and successful redirection of the pulmonary venous drainage to the left atrium. At a median clinical follow-up of 8.1 months (2.6-19.8), no adverse events were noted, and all patients showed clinical improvement. During follow-up, transthoracic echocardiography and multidetector cardiac tomography in four patients or invasive angiography in one patient demonstrated a patent SVC stent, and no residual SVASD and unobstructed PV drainage in all patients.

CONCLUSIONS

In selected patients using a two-stage simulation strategy, percutaneous correction of SVASD with PAPVD is feasible and safe, and led to favourable short-term outcomes.

MR Imaging of Thoracic Veins

MR imaging of thoracic veins is performed to evaluate the heart and thoracic vasculature. The protocol can be customized to the clinical question. In the embryo, systemic and pulmonary vein development is closely related to heart development. Congenital anomalies of the thoracic veins are strongly associated with other cardiac and situs abnormalities. Acquired venous abnormalities are often iatrogenic, or secondary to malignancy. This article discusses development and anatomy of the thoracic venous systems, clinical MR imaging methods for their evaluation, and illustrates the MR imaging appearance of congenital and acquired abnormalities of systemic thoracic veins, coronary sinus, and pulmonary veins.

Inferior-type caval vein defect--echocardiographic and surgical description of a large series of patients

AIM

This study was carried out to define the anatomical criteria for the diagnosis of inferior-type caval vein defect and compare the echocardiographic findings with surgical findings.

METHODS

The records of 19 patients - 13 male and six female patients in the age group of 18 months to 27 years, who were diagnosed as inferior-type caval vein defect with or without anomalous drainage of right pulmonary vein(s) on echocardiography - were retrospectively reviewed and compared with surgical findings.

RESULTS

Surgical diagnosis of inferior-type caval vein defect was confirmed in 17 of the 19 patients. In two patients, the surgical diagnosis was that of a large fossa ovalis atrial septal defect - confluent defect and fossa ovalis atrial septal defect with deficient inferior rim in one patient each. Surgical diagnosis of anomalous drainage of pulmonary vein(s) was based on the course of the superior rim of the defect in relation to the pulmonary veins. Our echocardiographic impression of the pulmonary veins appearing in its normal position but showing abnormal drainage to right atrium was in agreement with the surgical notes. Discrepancy was found in the number of pulmonary veins draining anomalously. The discordance was related to overdiagnosis of anomalous drainage in all except one, that is, three out of four. In one, only the right lower pulmonary vein was diagnosed to be anomalous, whereas both right upper and lower pulmonary veins were found to be anomalous.

CONCLUSIONS

Echocardiography provides definite diagnosis of inferior-type caval vein defect. Inferior caval vein straddling and an intact fossa ovalis are prerequisites for diagnosis. Anomalous pulmonary venous drainage of the right pulmonary veins is very common in our series, although accurate diagnosis of the number of pulmonary veins was not possible in all cases. Multiple views on transthoracic echocardiography starting from the subxiphoid views delineate the morphology accurately. Transoesophageal echocardiography is required only in patients in whom the windows, especially the subxiphoid, are not adequate.

CT appearance of persistent left superior vena cava, anomalous right superior pulmonary venous return into the right-sided superior vena cava and a sinus venosus-type atrial septal defect

We present findings of persistent left superior vena cava, anomalous right superior pulmonary venous return into the right-sided superior vena cava and a sinus venosus-type atrial septal defect detected incidentally by CT pulmonary angiography. To our knowledge, there has been no previous case report with all of the above findings detected by CT. In addition to the radiological findings and their clinical significance, the anatomy and embryological explanation of each anomaly is discussed.

Management of sinus venosus defects

Sinus venosus defects are not atrial septal defects, but are intra-atrial communications outside of the boundaries of the atrial septum. The superior type is located above and separate from the fossal ovalis, usually adjacent to the superior vena cava and the right upper pulmonary vein. The inferior type is located near the orifice of the inferior vena cava and the right lower pulmonary vein. The goal of surgical repair is closure of the defect with unobstructed drainage of the pulmonary veins to the left atrium and of the vena cava to the right atrium. Numerous techniques have been described, particularly for the repair of the superior vena cava type of defect. Mortality and morbidity should be minimal. The risk of either vena cava or pulmonary vein obstruction is low. Sinus node dysfunction can occur postoperatively, particularly when an incision has been made across the superior vena cava/right atrial junction. There is little long-term data on the functional outcomes following repair of these defects.

Sinus venosus syndrome: atrial septal defect or anomalous venous connection? A multiplane transoesophageal approach

OBJECTIVE

To discuss the anatomical features of sinus venosus atrial defect on the basis of a comprehensive transoesophageal echocardiography (TOE) examination and its relation to surgical data.

METHODS

24 patients (13 men, 11 women, mean (SD) age 37 (17) years, range 17-73 years) with a posterior interatrial communication closely related to the entrance of the superior (SVC) or inferior vena cava (IVC) who underwent TOE before surgical repair. Records of these patients were retrospectively reviewed and compared with surgical assessments.

RESULTS

In 13 patients, TOE showed a deficiency in the extraseptal wall that normally separates the left atrium and right upper pulmonary vein from the SVC and right atrium. This deficiency unroofed the right upper pulmonary vein, compelling it to drain into the SVC, which overrode the intact atrial septum. In three patients, TOE examination showed a defect in the wall of the IVC, which continued directly into the posterior border of the left atrium. Thus, the intact muscular border of the atrial septum was overridden by the mouth of the IVC, which presented a biatrial connection. In the remaining eight patients, the defect was located in the muscular posterior border of the fossa ovalis. A residuum of atrial septum was visualised in the superior margin of the defect. Neither caval vein overriding nor anomalous pulmonary vein drainage was present.

CONCLUSIONS

Sinus venosus syndrome should be regarded as an anomalous venous connection with an interatrial communication outside the confines of the atrial septum, in the unfolding wall that normally separates the left atrium from either caval vein. It results in overriding of the caval veins across the intact atrial septum and partial pulmonary vein anomalous drainage. It should be differentiated from posterior atrial septal defect without overriding or anomalous venous connections.

Interatrial communication through the mouth of the coronary sinus

OBJECTIVES

We describe the structure of, and suggest an etiology for, the interatrial communication which can occur through the mouth of the coronary sinus. Based on the study of human embryos, we propose that the defect is best explained by dissolution of the wall of the coronary sinus adjacent to the left atrium, permitting shunting between the atriums through the right atrial orifice of the sinus.

BACKGROUND

An interatrial communication across the mouth of the coronary sinus defect was first described in 1965 by Raghib and colleagues, its existence being predicated on the basis of incomplete formation of the left "atriovenous fold". Their hypothesis implies that the coronary sinus never develops, and thus the atrial septum itself is incomplete.

METHODS

We have studied the development of the coronary sinus in a series of human embryos. Based on this work, we present the anatomical findings in 6 specimens with varying degrees of dissolution of the walls of the coronary sinus, and ten specimens with isomerism of the right atrial appendages, in which the sinus has never been formed.

RESULTS

The coronary sinus defect is not a hole within the atrial septum, but a communication between the atriums through the mouth of the sinus. There was a range of defects in our series of specimens with usual atrial arrangement, extending from complete absence of the walls which normally separate the coronary sinus from the left atrium, to small fenestrations between this vessel and the left atrial cavity. In the hearts with isomerism of the right atrial appendages, however, we never observed an orifice of the coronary sinus. Thus, a coronary sinus defect cannot exist in this setting.

CONCLUSIONS

Our findings indicate that the defect requires initial formation of the walls of the coronary sinus, but with subsequent dissolution of the wall adjacent to the left atrium. This produces a communication between the atriums through the mouth of the sinus.

Clinical anatomy of the atrial septum with reference to its developmental components

Knowledge of development is of crucial importance and can help clarify mechanisms of maldevelopment, but it must be properly validated. Concepts of development must be consistent with the anatomy seen in postnatal life. Such consistency is not always achieved. We have reviewed new and old accounts of cardiac embryology with regard to the definitive structure of the atrial septum. The key to understanding is to distinguish between folds of the atrial wall and true interatrial partitions. The flap valve of the oval foramen, and its inferior rim, are true septal structures, whereas the other rims, particularly the antero-superior rim, are infoldings enclosing extracardiac fat. During embryonic life, the systemic venous tributaries must achieve entrance only to the right side of the primary atrium. Development of the pulmonary venous component is a late event, with the canalizing vein using the dorsal mesocardium to gain access to the left side of the atrium. Once the systemic venous tributaries have achieved their rightward shift, the primary septum, together with the mesenchymal cap, grows between the systemic and pulmonary venous orifices. Closure of the primary foramen is achieved by fusion of the mesenchymal cap of the primary septum with the atrioventricular endocardial cushions and the vestibular spine (an additional mesenchymal structure carried on the right side of the pulmonary venous orifice). The superior margin of the newly formed secondary foramen is produced by an infolding of the atrial walls. Historically these mechanisms received appropriate recognition, but not all receive their proper due in current writings.