Embolization of Immediate Release Transcatheter Patch for Atrial Septal Defect Occlusion: The Causes and the Pitfalls to Avoid

ABSTRACT: We report embolization of a bioabsorbable immediate-release patch for closure of atrial septal defect into left atrium with forward movement into and out of the mitral valve during each cardiac cycle. The dislodged device was ultimately explanted by a surgical operation and the defect was closed. We discuss causes and recommend tips to prevent such a serious potential complication. We also suggest some modifications to the device for making it more safe and effective.

J INVASIVE CARDIOL 2012;24(3):E60-E63

Key words: atrial septal defect, ASD closure, complications, transcatheter patch closure

_____________________________________________

The transcatheter patch (TP), invented by the innovative senior interventional cardiologist Dr Eleftherios Sideris, has been used for closure of atrial septal defect (ASD) since 1999.¹ Deployment of the immediate-release transcatheter patch (IRP), a later version of this device, which is made of a polyurethane foam patch and a balloon within it, has been reported in 10 cases in 2009 with an immediate and 1-month full-occlusion rate of 100%.² The IRP has the advantages of being bioabsorbable and wireless with no thrombogenicity. In 2010, transcatheter closure of ASD in 10 piglets was also reported using this new device. To our knowledge, to date, there is no other published report of complications regarding using this device. Since, worldwide, there are relatively few cases using this device for transcatheter closure of ASD, experience regarding the complications and the ways to prevent them or the tips to tackle the complications are scant. We report a case of embolization of the IRP in a 5-year-old girl and also discuss two other cases of complications that occurred after using this device for closure of ASD, one leading to embolization and the other resulting in delayed significant residual shunt. We consider the predisposing factors and the ways to prevent these complications.

Case Report. A 5-year-old girl was admitted for elective ASD closure. On physical examination, she was well-developed, well-nourished, and acyanotic with normal pulses. The child had normal S1, fixed splitting of S2 and a grade 3/6 ejection systolic murmur heard best at the upper left sternal border. Electrocardiogram showed right axis deviation and right ventricular enlargement. Chest x-ray revealed a cardiothoracic ratio of 55% and increased pulmonary vascular markings. Transthoracic echocardiogram revealed the presence of a secundum ASD measuring 17 mm with adequate rims and right heart enlargement.

Cardiac catheterization revealed normal pulmonary artery pressure and the Qp/Qs ratio was 2:1. Transcatheter ASD closure was performed using a medium-sized IRP (Custom Medical Devices). An expert operator deployed the device under transesophageal echocardiography guidance according to the technique already reported.1 Immediately after the procedure, transesophageal echocardiography revealed the presence of a medium amount of residual shunt on both sides of the patches; furthermore, at the site of the puncture, where the string (thread) exits the skin, bleeding continued longer than usual. However, according to the expert operator’s view, the device was not redeployed.

Approximately 15 hours later, transthoracic echocardiogram demonstrated dislodgment of the patch with excessive motion into and out, across the mitral valve (Figures 1A, 1B, and 1C; Video 1). The patient was operated on 36 hours after the procedure. At surgery, the device was completely in the left atrium and both  lateral right atrial patches had stuck together around the stalk of the balloon (Figure 2F). The device was removed and the ASD was closed surgically. The patient was discharged in good clinical condition.

Discussion. IRPs have been recently introduced.^2-5 Overall, we have observed 3 cases of complications with this device that all could be amenable to prevention by effecting modifications to the design of the device system. These complications included two cases of embolization into the left heart (ie, this 5-year-old girl with device embolization into the left atrium and another 20-year recently married woman with embolization into the left ventricle at another center) and one case of significant residual shunt 1 year after the procedure in a 7-year-old boy. We address three issues regarding this device, including embolization and improper apposition of the device patches to the atrial septum, challenges with device retrieval in case of embolization, and more than usual local hemorrhage immediately after the procedure. The causes of these complications and the tips for prevention will also be discussed below.

I. Embolization and Improper Apposition of the Device Patches to the Interatrial Septum

Predisposing factors and recommendations for prevention. In April 2011, we observed two cases of embolization of this patch into the left heart. One was the present case and the other was at another center. We also observed a third case who had significant residual shunt across ASD 1 year after the procedure. The following technical flaws, described in chronological sequence as to the procedural steps, can lead to these complications during the procedure:

1. Improper initial knotting: improper initial knotting, before introducing the device, can lead to loosening or release of the “patch-balloon assembly.” This leads to immediate dislodgment.
2. Improper initial deployment: the device should theoretically lie across the septum with the two right atrial parts of the patch within the right atrium, each abutting one side of the interatrial septum to keep the functional patch for closure in close approximation to the interatrial septum on the left atrial side (Figure 1A).⁶ However, it was not easily possible to ensure proper alignment because of lack of radio-opaque markers on the two right atrial parts of the patch. When the balloon is properly inflated at the septum, its motion becomes restricted. Thus, excessive motion on fluoroscopy is an initial warning sign and should raise concern (Video 2). It is suggested to make the two right atrial parts of the patch “radio-opaque” in order to enable the operator to confirm the proper placement of the patches. The second point is that the patches should be of such physical property that they repel each other instead of sticking together. The third modification that is speculated to assist proper apposition of the patches to the right side of the interatrial septum is the use of a hypothetical two-connected balloon system as shown in Figure 2. The round balloon will be inflated in the left atrium and the second ellipsoid-shaped balloon will be inflated in the right atrium. The inflation of this second balloon assists proper apposition and spread of the patches to the right atrial side of the septum. In our third case, who was a 7-year-old boy with a 12 mm ASD, residual shunt across the ASD and foreign material in the right atrium more than 1 year after transcatheter closure was observed (Figure 2D and Videos 3 and 4).This complication seems to result from the physical tendency of the patches to come close to each other. In fact, in the real environment of the patient’s heart, the patches did not flatten over the septum, as previously stated by the manufacturing company.^2-4,6
3. Overinflation of the balloon: oversizing of this device, through excessive inflation of the balloon, can interfere with proper alignment. We inflated the balloon with 4.5 mL of diluted contrast. Overinflation of the balloon caused undue distance between the balloon and the interatrial septum and prevented it from proper alignment. The two right atrial parts of the patch came together around the stalk of the balloon. The  balloon with a handle moved out of the right atrium and was mobile in the left atrium, moving freely into and out of the mitral valve (Figures 1A, 1B, and 1C). 
 

4. Change in the length of the thread: this can occur due to:
1. Inability to make a firm suture at the end of the procedure in the inguinal area due to patient’s obesity, technical flaw, etc. can lead to change in the length of the thread. This happened in an obese adolescent girl (case two) with embolization of the device into the left ventricle.
2. Undue positional change of the patient, such as excessive bending or escessive hyperextension, within the first 24 hours after deployment can alter the change and stability of the thread, of which one end is in the heart and the other is in the patient’s inguinal area. The length of the thread should be designed to be fixed and independent of the patient’s position in order to ensure the fixed apposition of the balloon across the interatrial septum. In case of dislodgment, designing an easy transcutaneous adjustable system can be of great use.

• In the first two cases, dislodgment occurred into the left heart. Dislodgment into the left atrium can cause hemodynamic instability due to obstruction to the flow across the mitral valve or interference with pulmonary venous drainage into the left atrium.

5. Lack of attention to residual shunt from both sides of the patch-balloon assembly: bilateral residual shunt immediately at the end of the procedure is an important initial warning sign indicative of improper deployment.

The two right atrial parts of the patch and the stalk of the balloon should be of a physical property that repels each other. Otherwise, filled with diluted contrast with a lower density relative to blood, the assembly of the balloon with “stuck right atrial parts of the patch” has a tendency to move like a toy balloon in the direction of blood.

II. Challenges with Retrieval

During retrieval, if puncture of the balloon fails, then retrieving the balloon either antegrade from the descending aorta or retrograde across the mitral valve is hazardous. 

III. Local Hemorrhage

Prolonged bleeding at the puncture site was observed in our case. A thread passing through the femoral vein may cause prolonged hemorrhage and delayed hemostasis through stenting open the vein. The large delivery sheath also contributes to prolonged bleeding. The manufacture of a lower-profile device is therefore recommended.

Useful tips for operators. There are six tips for operators to decrease the rate of complication:

1. Attention to the two clues for failure of initial proper deployment: excessive balloon motion on fluoroscopy and bilateral residual shunt immediately after the procedure.
2. Serious attention must be given to the inguinal sutures, particularly in obese patients with folded skin in the inguinal area.
3. Observation of the patient and immediate investigation of any arrhythmias or hemodynamic change within the 24 hours after the procedure.
4. Operator training for proper deployment. It is recommended that an explicitly detailed instruction booklet be included in every device package.
5. Emphasis on training for retrieval techniques.
6. Avoiding oversizing and overdistension of the balloon.

Conclusion. Transcatheter patch closure of ASDs using the IRP, although physiologically very appealing, is technically quite demanding even in the hands of expert operators. The device needs to be further revised to increase its safe and effective use in children.

Acknowledgments. The authors deeply appreciate professor Ziyad M.Hijazi for graciously reviewing the manuscript and providing invaluable comments and guidance. We are also very thankful to Ms. Ghadimi for providing the photo of the explanted device at the operating room and to Dr. Bahman Rastkar, Associate Professor of Pediatric Cardiology of Tabriz University of Medical Sciences for kindly sending us the angiographic movies of a related case.

References

1. Sideris EB, Zeinaloo A, Zanjani K, Borisova B, Pursanov M. Atrial septal defect occlusion using an immediate release patch method: early clinical experience. J Am Coll Cardiol. 2010;55(10A).
2. Sideris B, Sideris E, Calachanis M, Papantoniou V, Moulopoulos S. The immediate release patch in the correction of experimental atrial septal defects. Cathet Cardiovasc Interv. 2010;76:572-577.
3. Sideris E, Macuil B, Prieto L, Zamora R, Calachanis M. Abstract 3049: long-term results of transcatheter patch occlusion of atrial septal defects: benefits and problems of a frameless bioabsorbable device. Circulation. 2008;118:S808.
4. Sideris BE, Coulson JD, Sideris EB. Transcatheter patch closure. In: Transcatheter closure of ASDs and PFOs: A Comprehensive Assessment. Hijazi ZM, Feldman T, Abdulllah Al-Qbandi MH, Sievert H. Cardiotext Publishing, Minneapolis, Minnesota: 2010: pp. 373-382.
5. Sideris EB, Toumanides S, Macuil B, et al. Transcatheter patch correction of secundum atrial septal defects. Am J Cardiol. 2002;89:1082-1086.
6. Custom Medical Devices for the Occlusion of Heart Defects. Available at: www.custommedicaldevices.net

_____________________________________________

From the ¹Children’s Medical Center and ²Rajaie Cardiovascular Medical and Research Center, Tehran University of Medical Sciences (TUMS), Tehran, Iran.
Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.
Manuscript submitted August 10, 2011, provisional acceptance given September 27, 2011, final version accepted November 3, 2011.
Address for correspondence: Elaheh Malakan Rad, MD, FACC, Associate Professor of Pediatric Interventional Cardiology, Children’s Medical Center (Pediatrics Center of Excellence), Tehran University of Medical Sciences (TUMS), No. 62, Dr. Gharib’s Street, End of Keshavarz Boulevard, Tehran 1419733151, P.O. Box:14155-6386 Iran. Email: erad@tums.ac.ir and emalakanrad@gmail.com