Published online by Cambridge University Press: 18 April 2005
We report a novel technique using an Amplatzer atrial septal occluder to close a defect located in the inferior-posterior portion of the interatrial septum that extended into the mouth of the inferior caval vein. Because of the close relation of the defect to the inferior caval vein, the right atrial disc was opened into the inferior caval vein and pushed toward the right atrium by use of the delivery cable. There was no residual shunting immediately and 3 months after the intervention. We conclude that even defects located infero-posteriorly within the oval fossa may be successfully closed by transcatheter techniques using the Amplatzer device.
Whereas transcatheter methods for closure of atrial septal defects located in the oval fossa have become widely accepted as an alternative to surgical closure, defects located in the infero-posterior portion of the interatrial septum have, to our knowledge, not yet been reported to be amenable to transcatheter closure.1, 2 Even though many interventionists would classify defects located infero-posteriorly as inferior sinus venosus defects, demonstration of overriding of the intact inferior muscular border of the oval fossa by the mouth of the inferior caval vein is the anatomical prerequisite of that diagnosis, whereas abnormal drainage of an inferior pulmonary vein is not required.3 Without direct inspection of the interatrial septum, either during surgery or at post-mortem, these distinctions remain difficult, and have provided a matter of debate even for those using modern transesophageal echocardiographic equipment.3–7 Whereas it may not be of clinical importance whether a defect of the inferior-posterior portion of the interatrial septum is classified as inferior sinus venosus defect or an atrial septal defect extending into the mouth of the inferior caval vein, it is important in our opinion to emphasize that such defects may be amenable to transcatheter closure, and their diagnosis should certainly not preclude an attempt at transcatheter closure. We report here, therefore, a novel technique for occlusion of such defects by opening the right atrial disc of an Amplatzer atrial septal occluder into the inferior caval vein and pushing it upwards toward the mouth of the inferior caval vein.
A 4-year-old patient was diagnosed by transthoracic echocardiography as having a defect within the oval fossa, and was referred for transcatheter occlusion of the defect. Cardiac catheterization was performed under deep sedation using a femoral venous approach. Hemodynamic measurements revealed a significant left-to-right shunt, with a ratio of pulmonary to systemic flows of 2.1. Transesophageal echocardiography revealed the defect to be within the inferior part of the oval fossa. But, in addition, the transesophageal study revealed a second defect located infero-posteriorly in close relation to the mouth of the inferior caval vein (Fig. 1a). To evaluate whether both defects could be closed by transcatheter means, we performed simultaneous balloon sizing using 2 Arrow sizing balloons (Arrow, Reading, PA, USA) introduced from both femoral veins through sheaths of 6 French dimensions. The stretched diameter of the infero-posterior defect was 10 mm, and the stretched diameter of the other defect within the oval fossa was 8 mm. In addition to transesophageal echocardiography, the location of the infero-posterior defect was evaluated by angiography in the right upper pulmonary vein using a Berman angiography catheter. During angiography, the balloon catheter was positioned to occlude the infero-posterior defect (Fig. 1b). The two defects were directly adjacent, as evidenced by the short distance between the balloon catheters during sizing. To confirm left-sided pulmonary venous drainage, and a sufficient distance from the mouth of the lower right pulmonary veins to the defect, wedge angiography of the right pulmonary artery was performed with layered contrast medium. For closure, a 12 mm Amplatz atrial septal defect occluder was introduced into the long sheath across the infero-posterior defect. The left atrial disc, and the central part of the device, were opened and pulled into the defect. The right atrial disc was released from the long sheath into the inferior caval vein. The delivery cable of the Amplatzer device was then pushed cranially, and the right atrial disc formed in close contact to the infero-posterior portion of the rim of the oval fossa.
Transesophageal echocardiography confirmed an adequate position for the device, with a sufficient distance to the coronary sinus, pulmonary veins, and the hinges of the atrioventricular valves. The device covered both defects with no residual shunting (Fig. 2). Angiography into the delivery sheath confirmed a perfect position for the device, revealing unobstructed flow of blood from the inferior caval vein into the right atrium. The device was then released from the delivery wire. The patient was returned to the ward and discharged 48 h after the procedure, after transthoracic echocardiography and fluoroscopy had confirmed the excellent result of the implantation. Follow-up echocardiography and fluoroscopy 4 weeks after the occlusion again demonstrated a perfect position of the device, and no residual shunt.
Sinus venosus defects are rare forms of interatrial defects. Albeit that the criterions for their clinical diagnosis remain controversial,3–7 morphological studies have led to the opinion that the anatomical prerequisite for diagnosis of a sinus venosus defect is overriding of the intact muscular border of the oval fossa by the mouth of the inferior or superior caval vein, whereas partially anomalous pulmonary venous drainage, although usually present, is not an essential feature for diagnosis. Even up-to date transthoracic and transesophageal echocardiography have a high failure rate in correctly identifying inferior sinus venosus defects. The biatrial nature of the inferior caval vein can be very subtle, and may not become evident during transesophageal echocardiography and subsequent interventional closure. According to Al Zaghal et al.3 in order to diagnose a sinus venosus defect, it is necessary to demonstrate the intact borders of the oval fossa. Most often, this cannot be achieved echocardiographically, and can therefore only be confirmed during surgery or at post-mortem. In our patient, therefore, we avoided labelling the second defect closed by the transcatheter technique an “inferior sinus venosus defect” , even though we believe most clinicians would have agreed with that diagnosis.
If closure of these defects is attempted, careful evaluation of the anatomy, with exclusion of partially anomalous pulmonary venous drainage and establishment of sufficient distance to the orifice of the coronary sinus and pulmonary veins, is of importance. This may necessitate right upper venous angiography and right pulmonary arterial “wedge” angiography, since transesophageal echocardiography may fail exactly to delineate the anatomy of the inferior and posterior region of the interatrial septum.3 To exclude entanglement of the device in the Eustachian valve, it may be prudent to open the right atrial disc within the inferior caval vein and advance it into the right atrium. Furthermore, with this technique, inadvertent left atrial deployment of the device can be excluded. Based on our experience, we submit that defects located infero-posteriorly within the interatrial septum may now safely be closed using the Amplatzer device.