The Immediate Release Patch in the Correction of Experimental Atrial Septal Defects

Objectives: The purpose of this study was to evaluate the safety and efficacy of the Immediate Release Patch (IRP) in the occlusion of experimental Atrial Septa! Defects (ASDs). Background: The IRP consists of a polyurethane foam patch, supported by a balloon catheter which incorporates a detaching mechanism. This mechanism allows for withdrawal of the catheter from the balloon/patch complex. After release, the device is held in position using a bioabsorbable safety thread, which is sutured subcutaneously at the groin. Methods: Experimental ASDs, 10-14 mm in diameter, were created in ten piglets. The ASDs were then corrected using IRPs 12-16 mm in diameter, under fluoroscopy and echocardiography. The animals were followed for one to four months, and were then euthanized and autopsied. A RAST test, which detects the presence of IgE antibodies for latex, was performed in seven animals. Results: All procedures, except for one, resulted in full occlusion of the defects, without serious complications. No devices embolized, and in less than two months, the balloons had deflated and the area of the device had decreased significantly. The autopsies revealed complete endothelialization as well as no thrombus formation on the device or the thread. The thread was absorbed after one month. In a single case, infection was detected on the right side of the device. Latex antibodies were not detected. Conclusion: The IRP was effective and safe in the animal model of an ASD. There was evidence of bio-absorption of the complete device over time, without adverse reaction to latex. Clinical application is justified. (c) 2010 Wiley-Liss, Inc.