Diagnostic echocardiographic features of the sinus venosus defect

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.

Sinus venosus defect of the pulmonary vein-type: An easily missed diagnosis

Atrial septal defects are one of the most common forms of congenital heart disease, however sinus venosus communications, particularly pulmonary vein-type defects, are rare and are easily misdiagnosed. Patients with pulmonary vein-type sinus venosus defects often present earlier than those with ostium secundum defects with significant right heart dilation. Correct diagnosis has important implications for management. We discuss the clinical courses and review multimodality imaging of three patients correctly diagnosed with pulmonary vein-type defects after an initial diagnosis of an ostium secundum atrial septal defect, in order to promote understanding of the unique anatomy of this entity.

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.

The Parasternal Short-Axis View Improves Diagnostic Accuracy for Inferior Sinus Venosus Type of Atrial Septal Defects by Transthoracic Echocardiography

BACKGROUND

Sinus venosus defects (SVD) of the inferior vena cava (IVC) type, or inferior SVDs, are an uncommon form of atrial communication located outside the confines of the fossa ovalis and involve override of the IVC. Despite numerous studies describing the anatomical and echocardiographic features of the inferior SVD, distinguishing this defect from a large secundum atrial septal defect (ASD) by echocardiography is often challenging. Accurate diagnosis of an inferior SVD and correct differentiation from a secundum ASD is essential for appropriate presurgical planning. Absence of the posterior rim in the parasternal short-axis views may serve as a useful clue in diagnosing inferior SVDs. We sought to determine the utility of using the presence or absence of a posterior atrial rim in the parasternal short-axis view to help distinguish an inferior SVD from a secundum ASD. This sign may help clinch the diagnosis when subcostal imaging is suboptimal.

METHODS

We retrospectively reviewed transthoracic echocardiograms from 15 patients with a known surgical diagnosis of an inferior SVD between 2004 and 2015. The presence or absence of a posterior rim in the parasternal short-axis view was determined by two primary investigators. The posterior rim was also evaluated in 14 patients with a secundum ASD repair as controls. Echocardiograms were then reviewed blindly by attending-level echocardiographers and cardiology fellows in training. Diagnostic accuracy was assessed both with and without the use of the posterior rim criterion. Statistical analysis was used to determine the effect of using the rim criterion on inferior SVD diagnosis. We also reviewed all surgically diagnosed secundum ASDs that were incorrectly diagnosed as inferior SVD by preoperative imaging and determined whether use of the posterior rim criterion would have resulted in the correct diagnosis.

RESULTS

The posterior rim was absent in all 15 patients with a surgical diagnosis of inferior SVD and present in all 14 patients with a secundum ASD. For all observers, there was a statistically significant increase in diagnostic accuracy of inferior SVDs with the use of the rim criterion (P < .0001). We noted that secundum ASDs with inferior extension also have persistent posterior rims. The rim criterion correctly classified all large secundum ASDs with inferior extension that were previously misdiagnosed by echocardiogram preoperatively.

CONCLUSIONS

Absence of the posterior rim ("bald" posterior wall) is a consistent finding in patients with an inferior SVD and distinguishes an inferior SVD from a large secundum ASD with inferior extension. Parasternal short-axis evaluation of the posterior atrial rim is a helpful tool for all levels of physician training in improving diagnostic accuracy for detecting inferior SVDs and in distinguishing them from secundum ASDs.

Inferior sinus venosus defects: anatomic features and echocardiographic correlates

Inferior sinus venosus defects (SVDs) are rare imperfections located in the inferior portion of the atrial septum, leading to an overriding inferior vena cava (IVC) and an interatrial connection. These defects have increased risk of anomalous pulmonary venous return (PAPVR) and often are confused with secundum atrial septal defects (ASDs) with inferior extension. The authors sought to review their experience with inferior SVDs and to establish at their institution an echocardiographic definition that differentiates inferior SVDs from secundum ASDs with inferior extension. The study identified 161 patients 1.5 to 32 years of age who had undergone repair of a secundum ASD with inferior extension or inferior SVD over the preceding 10 years. All surgical notes, preoperative transthoracic echocardiograms (TTEs), and preoperative transesophageal echocardiograms (TEEs) were reviewed. Based on the surgical notes, 147 patients were classified as having a secundum ASD (147/161, 91 %) and 14 patients (9 %) as having an inferior SVD. The study identified PAPVR in 7 % (1/14) of the patients with inferior SVDs and 3.5 % (5/14) of the patients with secundum ASDs. Surgical diagnosis and preoperative TTE correlated for 143 (89 %) of the 161 patients. Using a strict anatomic and echocardiographic definition with a blinded observer, the majority of the defects (14/18, 78 %) were reclassified correctly after review of their TTE images, and 100 % of the defects were correctly reclassified after TEE image review. Accurate diagnosis of inferior SVDs remains challenging. The data from this study demonstrate that use of a strict anatomic and echocardiographic definition (a defect that originates in the mouth of the IVC and continues into the inferoposterior border of the left atrium, leaving no residual atrial septal tissue at the inferior margin) allows for accurate differentiation between secundum ASDs with inferior extension and inferior SVDs. This differentiation is extremely important in planning for surgical versus device closure of these rare defects.

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

BACKGROUND

Differentiation of the so-called sinus venosus defect from other defects permitting shunting between the atrial chambers remains problematic. The lesion is not a true septal defect, and current theories to explain the existence of the sinus venosus defect fall short. The presence of persistent systemic to pulmonary venous connections has been proposed to explain the existence of the sinus venosus defect.

METHODS

Clinical histories and radiological findings of six patients are reviewed. Three patients have veno-venous bridges, two have partial anomalous pulmonary venous connections, and one patient has a sinus venosus defect. The clinical information is reviewed, along with current developmental and morphological considerations.

DISCUSSION

We provide radiographic, developmental, and morphological evidence to support the theory that a so-called sinus venosus defect is the consequence of persistence of foetal systemic to pulmonary veno-venous bridges, rather than of deficiencies in atrial septation.

The surgical anatomy and treatment of interatrial communications

Holes permitting shunting between the atrial chambers can take various anatomical forms, varying from the patent oval foramen, which shunts only from right-to-left, to the so-called sinus venosus defect, which is associated with anomalous connection of the pulmonary veins. Our review deals with all forms of interatrial communications, except for the so-called 'primum' defect, since although the lesion produces interatrial shunting of blood, the atrioventricular septal defect with common atrioventricular junction but separate valvar orifices for the right and left ventricles, is strictly an atrioventricular septal defect. In addition, the review illustrates in detail the morphological features of interatrial communications, and describes surgical challenges and approaches.

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.

The nature of the superior sinus venosus defect

The location, and morphology, of the superior sinus venosus interatrial communication remains contentious. As part of a clinical study, we examined anatomic specimens and echocardiograms so as to clarify the arrangement of the normal atrial septal structures, and compared them with the arrangement found in the superior sinus venosus defect. The pathognomonic diagnostic criterion in the abnormal hearts was overriding of the intact muscular rim of the oval fossa by the mouth of the superior caval vein. This muscular rim is, in reality, a tube of myocardium which encloses a core of extracardiac adipose tissue. Understanding of this anatomic conundrum clarifies the understanding of the structures of both the normal atrial septum and sinus venosus defects.

Anatomical criteria for the diagnosis of sinus venosus defects

BACKGROUND

The diagnosis of sinus venosus defects remains a matter of debate. It is crucial to provide solid anatomical criteria, by identifying the very nature of the atrial septum relative to sinus venosus defects, to diagnose and differentiate them from other interatrial communications.

OBJECTIVE

This study was designed to reestablish the anatomical criteria for the diagnosis of sinus venosus defects.

METHODS

Five specimens with sinus venosus defects from the cardiopathological museum were examined. Study of the abnormal hearts was supplemented by examining the extent and structure of the atrial septum in 10 normal hearts. The echocardiograms and surgical notes were reviewed from 18 patients seen between July 1991 and August 1996 at the Royal Brompton Hospital in London diagnosed preoperatively to have a sinus venosus defect.

RESULTS

The nature of the oval fossa and its muscular borders were identified in the normal hearts. In all three autopsied specimens of the superior variety of sinus venosus defect, the mouth of the superior caval vein was overriding the intact muscular anterosuperior border of the oval fossa. Two specimens thought initially to have the inferior variety of sinus venosus defect were re-classified as having defects within the oval fossa as it was the deficient oval fossa itself, rather than its intact muscular border, that was overridden by the mouth of the inferior caval vein. Sixteen patients had been diagnosed echocardiographically as exhibiting the superior variant of the defect. Retrospective review showed overriding of the superior caval vein across the upper rim of the oval fossa in 12 patients. These findings were confirmed by surgery in 11 patients with the 12th awaiting operation. Overriding of the fossa by the caval vein was not found in the other four patients. Surgery in all of these showed the defect to be within the oval fossa. In two patients diagnosed echocardiographically as having inferior defects, the surgical findings confirmed a biatrial connection of the inferior caval vein in one patient, the findings in the second were equivocal.

CONCLUSIONS

The key anatomical criterion for the diagnosis of sinus venosus defects is overriding of the mouth of the superior or inferior caval vein across the intact muscular border of the oval fossa. The interatrial communication is then formed within the mouth of the overriding vein, and is outside the confines of the oval fossa.

Diagnosis of sinus venosus atrial septal defect with transesophageal echocardiography

BACKGROUND

Sinus venosus atrial septal defect (SVD) is underdiagnosed with transthoracic echocardiography because of its posterior (far field) location. Transesophageal echocardiography (TEE) should be ideally suited to diagnose SVD, given the proximity of the transducer to the defect.

METHODS AND RESULTS

A retrospective study was undertaken that used the medical history, echocardiographic findings, and surgical data of patients identified from computer records as having the diagnosis of SVD during the period in which TEE has been in use (1987 to 1995). Twenty-five patients (14 females and 11 males; median age, 45 years; range, 10 to 75 years) with SVD had TEE between 1987 and 1995. Prior transthoracic echocardiography clearly defined the SVD in 3 of these patients, and it was suspected in another 11 on the basis of color-flow imaging. Ten patients had unexplained dilatation of the right side of the heart, which prompted TEE examination. SVD was visualized with TEE in all 25 patients and ranged in size from 1 to 3 cm. Thirty-seven right-sided anomalous pulmonary venous connections were identified in 23 patients. No left-sided anomalous pulmonary venous connections were detected. Anatomic confirmation was obtained in all 23 surgical patients. No patient required preoperative cardiac catheterization for diagnosis.

CONCLUSIONS

TEE is accurate for the diagnosis of SVD and should be undertaken in any patient with unexplained dilatation of the right side of the heart. The associated pulmonary venous abnormalities can be identified with TEE. Cardiac catheterization for diagnostic purposes should not be required before surgical correction.

Echocardiographic imaging techniques with subcostal and right parasternal longitudinal views in detecting sinus venosus atrial septal defects

Sinus venosus atrial septal defects are frequently missed and difficult to visualize with conventional two-dimensional echocardiographic views. Using modified subcostal and right parasternal longitudinal views, nine patients were found to have a sinus venosus atrial septal defect. The modified subcostal view showed a sinus venosus atrial septal defect in all nine patients; three patients had secundum atrial septal defects as well. The right parasternal view detected only six patients with sinus venosus atrial septal defect. Partial anomalous pulmonary venous return was diagnosed in seven patients using these views. The combination of subcostal and right parasternal longitudinal imaging views will improve the detection of sinus venosus atrial septal defects.

Understanding cardiac anatomy: the prerequisite for optimal cardiac surgery

If advances in cardiac surgery are to continue into the twenty-first century, it will be necessary to concentrate on details of matters such as the anatomy of the heart. This will be achieved best when anatomy is described as it is observed. This approach is obscured when words are used in inappropriate fashion, or else assigned a function separate from their everyday meaning. Examples of how the congenitally malformed heart and the normal heart have been described in the past are examined within the framework of using words in their vernacular meaning. Suggestions are made to improve descriptions and understanding for the 21st century. Using the example of the "univentricular heart", it is shown how conventions debarring ventricular status to discrete chambers within the ventricular mass are, of necessity, artificial. Similar examples are used to distinguish septal from parietal structures within the heart and to elucidate the structure of some congenital malformations. For values, it is shown how proper description requires assessment of these structures in their closed as well as their open positions. Understanding of cardiac anatomy, truly a prerequisite for successful cardiac surgery, will be facilitated in future if words are used in their generally accepted sense, and if artificial conventions are avoided.

Morphological study of defects of the atrial septum within the oval fossa: implications for transcatheter closure of left-to-right shunt

OBJECTIVE

To determine the anatomical variability of the oval fossa in cases of atrial septal defect and to find out which factors might make such defects suitable or unsuitable for closure by umbrella or clamshell devices.

DESIGN

100 specimens with defects of the atrial septum within the oval fossa were studied, especially the position of the defects within the fossa; the area of the defect in relation to the total area of the oval fossa; the shape of the rims and flap valve of the oval fossa; and the anatomical variability in the eustachian and thebesian valves.

RESULTS

The oval fossa was displaced to the mouth of the inferior caval vein in four cases; displaced to the mouth of superior caval vein in two cases; placed on the middle of the interatrial wall in 43; or placed slightly towards the inferior caval vein in 51. Because of their shape 29 of the hearts were considered to be unsuitable for transcatheter closure of the defect. This was because the defect was too large (16 hearts); the oval fossa was displaced to the mouth of the inferior caval vein (four hearts) or to the superior caval vein (two hearts); lacked its anterior rim (two hearts); lacked the posteroinferior rim (one heart); because a thick eustachian valve was displaced posteriorly forming a false posteroinferior rim (one heart); or because the strand of insertion of the floor of the oval fossa was too distant from the left atrial aspect (three hearts).

CONCLUSION

68 hearts appeared to be ideal candidates for transcatheter closure; 3 would probably have been suitable; but 29 were unsuitable. These morphological variations might explain why the procedure has been unsuccessful in so many cases. Patients should be screened before any attempt is made at transcatheter closure.

Transoesophageal echocardiographic assessment of primum, secundum and sinus venosus atrial septal defects

We compared the ability of transthoracic and transoesophageal echocardiography to determine the presence and site of an atrial septal defect and associated anomalous pulmonary venous connexions in 13 school age children (aged 5 to 15 years) and 12 adults (aged 25 to 68 years). Transthoracic echocardiography detected atrial septal defects in 12 children and 6 adults. Transoesophageal echocardiography confirmed the position of 16 (13 secundum, 3 primum) of these 18 defects but altered the diagnosis from a secundum defect to a sinus venosus defect in one and from a sinus venosus defect to a high secundum defect in another. In addition to these 18, transoesophageal echocardiography diagnosed a defect in 5 adults (3 secundum and 2 sinus venosus defects) and 1 child (secundum defect). In an adult with inconclusive transthoracic findings, transoesophageal echocardiography enabled clear visualisation of the atrial septum and excluded an atrial septal defect. Transoesophageal echocardiography showed anomalous attachment of a pulmonary vein into the region of a sinus venosus defect (n = 3) but did not show anomalous connexions to the superior caval vein (n = 3) or the inferior caval vein (n = 1). Transoesophageal echocardiography provides a reliable method of diagnosing or excluding an atrial septal defect in patients with inconclusive transthoracic findings and is of particular diagnostic value in sinus venosus defects.