A new technique for sizing of atrial septal defects

This article evaluates a new compliant balloon catheter for sizing of Atria l Septal Defects (ASDs) in vitro and in vivo using X-ray and echo measureme nts. A phantom consisting of a plastic plate with 17 circular holes varying from 8 to 30 mm was used to determine the accuracy of the measurements. Th e catheter has a 7 Fr shaft with a double lumen. The balloon is made from a 0.002 " plastic membrane. Four platinum marker bands on the shaft of the c atheter allow radiographic measurements. The balloon catheter was placed th rough Various holes of the phantom and inflated with 38% contrast medium. X -ray measurement by video and cine recording were performed and compared wi th the true measurement of the model. The study was carried out in a double blind fashion. For echo measurements, the plastic model was immersed in a water bath. The balloon was inflated with water and measured in a long-axis view. The actual diameters were compared with the measurements obtained by video, cine, and echo recordings. One young pig with a surgically created ASD was used for in vivo measurement. The balloon catheter was passed throu gh the ASD over an exchange wire, inflated with diluted contrast medium unt il a waist was observed, which was measured by video and cine techniques. T he animal was euthanized, and the defect was measured by a tapered measurin g probe. The difference between the actual size and measurements obtained b y video recordings was 0.54 +/- 0.30 mm, by cine 0.62 +/- 0.20mm, and by ec ho measurements 0.60 +/- 0.43 mm. All measurements were less than 1 mm in e rror except for four measurements (<1.5 mm). A strong correlation was prese nt between each two groups (r = 0.99, P < 0.0001), In the in vivo study, th e size of the video and cine recordings (14.2 and 13.9 mm, respectively) we re very closer to the actual size (14 mm) as measured by a probe in the pos tmortem specimen. The new balloon catheter provides a more rapid and precis e determination of the stretched diameter of atrial septal defects. It elim inates the error of pulling a catheter through the communication. This new technique should be of benefit to all investigators using septal occlusion devices and will facilitate the selection of the properly sized Amplatzer s eptal occluder. (C) 1999 Wiley-Liss, Inc.