On-line intracardiac echocardiography alone for Amplatzer Septal Occluder selection and device deployment in adult patients with atrial septal defect.

BACKGROUND: During the last few years, several different devices have been proposed for atrial septal defect (ASD) percutaneous closure. For the Amplatzer Septal Occluder (ASO) device, accurate balloon sizing is considered of paramount importance because the prosthesis waist has to be exactly adjusted to the defect diameter (+/-1 mm). In this study, we aimed to demonstrate the possibility of marked misinterpreting of the actual defect size using the balloon technique in patients with secundum ASD and to evaluate the accuracy of intracardiac echocardiography (ICE) measurements as a new method for selecting the size of ASO device.
METHODS: Between February 1999 and December 2000, 166 consecutive adult patients underwent percutaneous transvenous secundum ASD occlusion using the ASO device. In 124 patients (control group), ASD were closed by conventional methods. In 13 patients (pilot group), balloon pulling technique was used in size selection, whereas ICE was used on-line to monitor device placement and off-line to assess its possibilities for accurate quantitative measurements and qualitative evaluation. In 31 patients (study group), ICE was used as the sole imaging tool both for guiding device selection and monitoring the procedure. All patients underwent complete transthoracic echocardiographic study before discharge and during follow-up visits at 3 and 12 months.
RESULTS: Successful device implantation was accomplished in 163 of the 166 patients (98.2%). Short-term follow-up results were available in all eligible patients at least 3 months. Complete occlusion was demonstrated in 91.4% and 92.2% of patients in the control and pilot groups, respectively, increasing to 97.3% in the study group (p<0.01 vs. both control and pilot groups). There were no significant differences in mean ASO diameters in the control and pilot groups (20+/-7.7 and 22+/-5.4 mm, respectively), whereas the mean size of the devices used in the study group was significantly larger (27.4+/-6.2 mm, p<0.01 vs. both control and pilot groups). In the pilot group, the underestimation effect of the balloon strategy was evident, with a mean 12.3% larger diameter required on ICE measurements. Moreover, a misalignment between the ASO and the atrial septum was seen on ICE in 9 of 13 patients of the pilot group, whereas good apposition of the ASO on the septum secundum was seen in all patients of the study group.
CONCLUSION: ICE is a safe and effective method for selecting ASO size and continuous monitoring of the procedure. In contrast to the previously reported implantation procedure (device-to-defect ratio 1:1), a device 10-20% larger than invasively measured stretched defect diameter should be chosen and implanted on the basis of the ICE data.