Ostium Secundum Atrial Septal Defect Closure Thomas Hoy April 14, 2004 Department of Biomedical Engineering BME 273 Senior Design

Significance of Project Isolated secundum atrial septal defects account for ~ 7% of congenital cardiac defects. Isolated secundum atrial septal defects account for ~ 7% of congenital cardiac defects. CHD of significance occur in ~ 8 in 1000 live births. CHD of significance occur in ~ 8 in 1000 live births. If untreated can cause: If untreated can cause: Congestive Heart FailureCongestive Heart Failure Pulmonary Vascular DiseasePulmonary Vascular Disease

Existing Solutions Invasive Approach Transcatheter Approach Direct suture FDA approved devices Pericardial patchExperimental devices Pericardial patchExperimental devices

Transcatheter Approach

Problems with Existing Devices Difficulty centering the device in larger defects [57] Difficulty centering the device in larger defects [57] Wire related problems Wire related problems Wire fractures [58]Wire fractures [58] Atrial / mitral valve perforation [59]Atrial / mitral valve perforation [59] Wire migration [60]Wire migration [60] Difficulty in device retrieval [61]Difficulty in device retrieval [61] Expense Expense

Project Design Goals Develop a less costly / more simplistic occlusion deviceDevelop a less costly / more simplistic occlusion device Develop a device that is easily centered on the ASDDevelop a device that is easily centered on the ASD Ensure ease use in the medical environmentEnsure ease use in the medical environment Stimulate endotheliazation of the deviceStimulate endotheliazation of the device Increase the possible success rate in the application of the deviceIncrease the possible success rate in the application of the device

Design Proposal Double Balloon Catheter Double Balloon Catheter Inflate across the septumInflate across the septum Positioned on the ASDPositioned on the ASD Fixate across septum via biodegradable stentFixate across septum via biodegradable stent Deflate the balloon to form a thin membraneDeflate the balloon to form a thin membrane Extract lead wireExtract lead wire Endotheliazation encompasses device at 3-5 weeks after implantation [62]Endotheliazation encompasses device at 3-5 weeks after implantation [62] Stent begins to degrade at 6 months with full degradation at 12 months [63]Stent begins to degrade at 6 months with full degradation at 12 months [63]

Advantages No wire related problems No wire related problems Double balloon device requires a septal rim slightly larger than the defect [64,65] Double balloon device requires a septal rim slightly larger than the defect [64,65] Spherical shape of the device is ideal for centering; however is quite bulky Spherical shape of the device is ideal for centering; however is quite bulky Biodegradable stent allows for structural support of device until endotheliazation takes over Biodegradable stent allows for structural support of device until endotheliazation takes over

Biodegradable Stent The Igaki-Tamai stent (Igaki Medical Planning Co., Kyoto, Japan) is a self- expanding biodegradable stent made of poly-l-lactic acid monopolymer. The Igaki-Tamai stent (Igaki Medical Planning Co., Kyoto, Japan) is a self- expanding biodegradable stent made of poly-l-lactic acid monopolymer. Stent has a self-expanding capability - the implantation of the stent requires balloon expansion with a heated dye Stent has a self-expanding capability - the implantation of the stent requires balloon expansion with a heated dye Material requires 13 seconds to expand by itself at 50 o C and 20 minutes at 37 o C Material requires 13 seconds to expand by itself at 50 o C and 20 minutes at 37 o C By adhering the stent to the double balloon a structure lattice will be inplace to support the device until endotheliazation can occur. By adhering the stent to the double balloon a structure lattice will be inplace to support the device until endotheliazation can occur.

Future Work Developing a cost analysis of the overall device compared to those already in market. Developing a cost analysis of the overall device compared to those already in market. Developing a theoretical computer model of the device with the appropriate dimensions for use. Developing a theoretical computer model of the device with the appropriate dimensions for use.

References [57] Sideris EB, Leung M, Yoon JH, et al. Occlusion of large atrial septal defects with a centering buttoned device. Am Heart J 1996;131; [57] Sideris EB, Leung M, Yoon JH, et al. Occlusion of large atrial septal defects with a centering buttoned device. Am Heart J 1996;131; [58] Prieto LR, Foreman CK, Cheatham JP, Latson LA. Intermediate-term outcome of transcatheter secundum atrial septal defect closure, using the Bard Clamshell septal occluder. Am J Cardiol 1996;78: [58] Prieto LR, Foreman CK, Cheatham JP, Latson LA. Intermediate-term outcome of transcatheter secundum atrial septal defect closure, using the Bard Clamshell septal occluder. Am J Cardiol 1996;78: [59] Silvert H, Babic M, Ensslen R. Transcatheter closure of large atrial septal defects with the Babic system. Cathet Cardiovasc Diagn 1995;36: [59] Silvert H, Babic M, Ensslen R. Transcatheter closure of large atrial septal defects with the Babic system. Cathet Cardiovasc Diagn 1995;36: [60] Rao PS, Sideris EB, Hausdorf G, et al. International experience with secundum atrial septal defect occlusion by the buttoned device. Am Heart J 1994; 128: [60] Rao PS, Sideris EB, Hausdorf G, et al. International experience with secundum atrial septal defect occlusion by the buttoned device. Am Heart J 1994; 128: [61] Agarwal SK, Ghosh PK, Mittal PK. Failure of devices used for closure of atrial septal defects mechanisms and management. J Thorac Cardiovasc Surg 1996;112: [61] Agarwal SK, Ghosh PK, Mittal PK. Failure of devices used for closure of atrial septal defects mechanisms and management. J Thorac Cardiovasc Surg 1996;112: [62] Sideris E, Sideris S, Kaneva A, Monulopoulos S. Transcatheter occlusion of experimental atrial septal defects by wireless occluders and patches. Cardiol Young 1999;9(Suppl):22. [62] Sideris E, Sideris S, Kaneva A, Monulopoulos S. Transcatheter occlusion of experimental atrial septal defects by wireless occluders and patches. Cardiol Young 1999;9(Suppl):22. [63] Takafumi Tsuji MD,, Hideo Tamai MD, Keiji Igaki MD, Eisho Kyo MD,, Kunihiko Kosuga MD,, Tatsuhiko Hata MD,, Masaharu Okada MD,, Takuji Nakamura MD,, Hidenori Komori MD,, Seiichiro Motohara MD, and Hiromu Uehata MD. Biodegradable Polymeric Stents. Current Interventional Cardiology Reports 2001, 3: [63] Takafumi Tsuji MD,, Hideo Tamai MD, Keiji Igaki MD, Eisho Kyo MD,, Kunihiko Kosuga MD,, Tatsuhiko Hata MD,, Masaharu Okada MD,, Takuji Nakamura MD,, Hidenori Komori MD,, Seiichiro Motohara MD, and Hiromu Uehata MD. Biodegradable Polymeric Stents. Current Interventional Cardiology Reports 2001, 3: [64] Sideris EB, Sideris SE, Thanopoulos BD, Ehly RL, Fowlkes JP. Transvenous atrial septal defect occlusion by the buttoned device. Am J Cardiol 1990;66: [64] Sideris EB, Sideris SE, Thanopoulos BD, Ehly RL, Fowlkes JP. Transvenous atrial septal defect occlusion by the buttoned device. Am J Cardiol 1990;66: [65] Das GS, Voss G, Jarvis G, Wyche K, Gunther R, Wilson RF. Experimental atrial septal defect closure with a new, transcatheter, self-centering device. Circulation 1997;96(Suppl):I [65] Das GS, Voss G, Jarvis G, Wyche K, Gunther R, Wilson RF. Experimental atrial septal defect closure with a new, transcatheter, self-centering device. Circulation 1997;96(Suppl):I-3177.