Sizing Balloon-Induced Tear of the Atrial Septum

Atrial septal defects (ASD) are increasingly being subjected to closure by percutaneous techniques.^1–3 Exact sizing of the ASD is a prerequisite for optimal selection of the occlusion device. Sizing of ASDs can be done by echocardiography (transthoracic, transesophageal or intracardiac) and by sizing balloons in the catheterization laboratory. Stretched ASD balloon diameter measured by the balloon is considered the gold standard among them. Here we report a hitherto unreported complication of rupture of the atrial septum by the sizing balloon. Case Report. A 20-year-old female was referred to our institute for percutaneous closure of ASD. Initial transthoracic echocardiography (TTE) revealed a 14 mm secumdum ASD with adequate rims. Cardiac catheterization showed a left-to-right shunt of 1.8:1, normal pulmonary artery pressure and normal pulmonary venous drainage. As part of the selection of the optimal device, sizing of the ASD was attempted with an Amplatzer sizing balloon (length - 24 mm, maximum volume - 30 ml). Initially, a good indentation was obtained at partial inflation (Figure 1) in the anteroposterior view, which slowly disappeared without further increase in the balloon volume (Figure 2). Subsequently, imaging of the inflated balloon in different planes failed to reveal any waist. TTE, followed by transesophageal echocardiography (TEE), were performed and revealed a tear of the inferior margin of the septal defect (Figure 3). The patient was referred for surgical closure. At surgery, a tear in the inferior rim of the ASD was found. The tear extended down the septum up to the opening of the inferior vena cava, and a small hematoma was found there (Figure 4). The patient underwent repair of the tear and pericardial patch closure of the ASD. Postoperative TTE revealed no residual shunt. Discussion. There are two primary considerations for effective percutaneous closure of a secundum ASD: 1) the absolute size of the ASD, and 2) the amount of supporting rim of the atrial septum. The ASD sizing and assessment of the supporting rim, and thereby the suitability for device closure, can be done by echocardiography and in the catheterization laboratory as well using sizing balloons. Previous attempts in sizing of ASDs in our institute were based on pullback of MediTech spherical sizing balloon catheters (Boston Scientific Corporation, Natick, Massachusetts) across the atrial septum. The largest balloon diameter that pulled through with a definite tug was the diameter of device being selected. As the pulling technique depends largely on the anatomy of the septum and the tension applied, it is reported to be unreliable.⁴ Presently, we use the static balloon technique⁵ in which a very compliant long Amplatzer sizing balloon catheter (AGA Medical Corporation, Golden Valley, Minnesota) is employed. This balloon is advanced over the wire, centered across the defect, and inflated with dilute contrast medium until the balloon has a definite waist that is visible on fluoroscopy. The balloon indentation can be measured by two methods: stretched-diameter by fluoroscopy and stretched-diameter by TEE. The former was used in the index case. Rupture of the interatrial septum is an unknown complication of balloon sizing. In the index case, even before the balloon was inflated to its full capacity, the septum was torn. The usual practice is to select a device 1–2 mm larger than the stretched ASD diameter.² If the septum had not torn initially and we had selected a device 1–2 mm more than the initial balloon size, there was a chance that the stiffer waist of the device could have caused a tear of the septum, resulting in dislodgement and embolization of the device, which would have been more catastrophic. This complication of sizing balloon-induced rupture of the atrial septum is unreported in the literature.

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