Applied Radiology

Dr. Hijazi is Chief of the Section of Pediatric Cardiology and a Professor of Pediatrics and Medicine, and Dr. Cao is an Assistant Professor of Pediatrics at The University of Chicago, Chicago, IL.

Case Summary

The patient in this case is a 6.5-year-old girl (weight 15.6 kg) who was referred for catheter closure of a secundum atrial septal defect (ASD). A heart murmur was detected on routine physical examination. The work-up included an EKG that demonstrated evidence of right heart enlargement and a transthoracic echocardiogram that demonstrated the presence of a large secundum ASD measuring approximately 14 mm that was located in the posterior-inferior part of the atrial septum. Her right ventricular end-diastolic dimension was 26 mm.

Catheterization Procedure

She underwent cardiac catheterization with the intention to close the defect using the Amplatzer septal occluder (AGA Medical Corp., Golden Valley, MN). A 9F sheath was inserted percutaneously in the right femoral vein for hemodynamic evaluation and device delivery. An 11F sheath was inserted in the left femoral vein for intracardiac echocardiographic (ICE) assessment using the AcuNav catheter (Acuson Corp., Mountain View, CA). The catheter was connected to a Cypress machine (Acuson Corp.) equipped with the proper software. Her right heart pressures were normal. The calculated Qp/Qs ratio was 2.3:1. ICE was performed continuously throughout the procedure. This revealed the presence of a large ASD located in the posterior portion of the atrial septum that measured 16 mm with a deficient posterior rim (Figure 1A; Figure 2A). The defect was crossed and an exchange length wire was positioned in the left upper pulmonary vein (Figure 1B). Over this wire, a sizing balloon (AGA Medical Corp.) was advanced until it reached the defect. Under ICE and fluoroscopic guidance, the balloon was inflated until disappearance of the shunt was evident by ICE and the appearance of waisting was visible by cine fluoroscopy (Figure 1C, Figure 2B). The stretched diameter of the defect was 17.5 mm. A 18-mm Amplatzer septal occluder device was loaded and advanced inside a long 9F sheath positioned in the left upper pulmonary vein. The device was advanced until it reached the tip of the sheath. The left atrial disc of the device was deployed in the middle of the left atrium (Figure 1D, Figure 2C). However, multiple attempts to align the left atrial disc parallel to the septum failed. Each time the waist and right atrial disc were deployed, the device would prolapse through the defect (Figure 1E, Figure 2D). Therefore, a 22-mm device was also attempted, but again, we encountered similar problems. Therefore, the 18-mm device was preloaded inside an 8F coronary Judkins right guiding catheter with inner lumen of 0.089-in (Cordis, a Johnson and Johnson Co., Miami, FL). The guide catheter (with the device and cable) was advanced through the 9F sheath until the guide catheter reached the tip of the sheath. The sheath was then retracted back into the inferior vena cava leaving the guide catheter in the middle of the left atrium. Retracting the catheter over the cable deployed the left atrial disc. The left atrial disc was parallel to the septum (Figure 1F, Figure 2E). Then part of the waist was deployed in the left atrium and the remainder of the waist was deployed in the defect. Further retraction of the guide catheter over the cable deployed the right atrial disc in the right atrium (Figure 2F). ICE and cine angiography confirmed good device position. Once correct device position was confirmed, the device was released (Figure 1G, Figure 2G). Repeat ICE and angiography confirmed good device position and no residual shunt (Figure 2H). A quick transthoracic echocardiography (TTE) was performed in the catheterization laboratory. This demonstrated good device position with no residual shunt (Figure 1H). Hemostasis was achieved and the patient was allowed to recover overnight. The fluoroscopy time was 25 minutes and the total procedure (venous sheaths in and out the femoral veins) time was 106 minutes. The following day, the patient had a TTE and chest radiograph, both of which documented good device position and no residual shunt. The patient was discharged home on 81 mg of aspirin per day for 6 months.

Discussion

Closure of ASDs associated with deficient rims (<5 mm) is feasible. ¹ We have demonstrated that the aortic rim is the least important when using the Amplatzer septal occluder. The presence of at least three sufficient rims is essential to the success of the closure. The most important rim is the superior "from the mouth of the superior vena cava to the defect." Moreover, for successful closure, the three other rims should be of sufficient length (>5 mm). As demonstrated in this case, closure of an ASD associated with a deficient rim can be challenging. This was evidenced by the inability to align the left atrial disc against the atrial septum. The use of the Judkins right coronary guiding catheter with its curve enabled us to align the left atrial disc against the septum. The use of ICE in this case was invaluable. The patient did not require endotracheal intubation and, furthermore, during various stages of device deployment, the images obtained were of superior quality, even using a low-end machine.

Conclusion

We have been using the Cypress system for 1 year and have used it on more than 100 cases performed in children and adults with single or multiple secundum ASDs or patent foramen ovales. The patients ranged in age from 2.5 to 85.5 years and in weight from 12.7 to 120 kg. The major advantages of ICE include avoidance of general anesthesia and transesophageal echocardiography. *