A noninvasive sizing method to choose fitted Amplatzer septal occluder by transthoracic echocardiography in patients with secundum atrial septal defects.

To simplify the conventional procedure, we developed a technique for transcatheter closure of atrial septal defects (ASDs) under transthoracic echocardiographic (TTE) sizing without balloon sizing. At present, device closure of interatrial communication has become a well-established technique to adequately treat severe left-to-right shunt associated with ASDs. During the traditional procedure, fluoroscopy with the waist of a compliant balloon is used to determine the appropriate size of the closure device and defect sizing. Choice of adequate closure device using transthoracic echocardiography (TTE) has been hitherto unreported. Between December 2002 and August 2004, 40 patients (15 males, 25 females, mean age 11.7 +/- 7.8 years) with secundum ASDs underwent transcatheter closure at our institution. In group 1, 30 patients had the procedure by balloon sizing and TTE sizing. In 10 patients (group 2), TTE sizing was used as the sole tool for selecting device size and the device size was chosen to be based on the Amplatzer septal occluder (ASO) size and TTE size ratio in group 1. The procedure was performed under continuous transesophageal echocardiographic monitoring with general anesthesia. A correlation was found between TTE and stretched balloon sizing diameter SBD (y = 1.2645x - 1.4465; R2 = 0.9861), and between TTE size and ASO size (y = 1.3412x - 1.2864; R2 = 0.9929) in group 1. In group 2, a statistical correlation between TTE and ASO (y = 1.3419x - 0.1172; R2 = 0.9934) was also found. Good linear regression between TTE size and ASO chosen size was noted in group 1 and group 2 (R2 = 0.99). In group 2, successful device implantation was accomplished in all patients whose device size was chosen to be based on the ASO and TTE ratio in group 1. Transthoracic echocardiographic sizing is a safe and ideal method to measure interatrial defect and choose the occluding device, respectively. With our experience, the sizing based on TTE is generally easier than measurement from the balloon sizing.