Atrial septal defects (ASD) are the most common congenital heart defects diagnosed in adults. If left unrepaired, an ASD may lead to right ventricular volume overload, pulmonary hypercirculation, and congestive heart failure. Transcatheter device closure of an ASD has become the preferred treatment strategy for isolated secundum ASD due to its high efficacy and low complication rate compared to surgical repair.
Transcatheter ASD closure may lead to major complications, including perforation of the atrial wall, device embolization, and atrial arrhythmia. Successful device deployment may become technically challenging with less residual tissue surrounding a large, and smaller rims as well as the use of large devices may increase the risk of atrial perforation. Current guidelines do not take into account whether transcatheter closure of large, hemodynamically more significant ASD may pose an increased risk compared to device closure of smaller defects. The study is done to assess the efficacy and safety of transcatheter ASD closure in patients requiring a large device compared to patients in whom the use of smaller devices was appropriate.
Using a single-centre, prospective registry of adult patients undergoing transcatheter ASD closure, patients receiving a large closure device (waist diameter ≥25 mm, n = 41) were compared to patients receiving smaller devices (waist diameter ≤24 mm, n = 66). The study analysed pre-interventional clinical, hemodynamic and echocardiographic data, interventional success and complication rates, and 6-month clinical and echocardiographic outcomes.
The primary efficacy outcome was successful ASD closure achieved by a single procedure and confirmed by lack of a significant residual shunt at 6 months. The primary safety outcome was a composite of device embolization, major bleeding, and new-onset atrial arrhythmia occurring within 6 months.
Transcatheter ASD closure using large devices was successful in 90 % compared to 97 % of patients receiving smaller devices as defined by the primary efficacy outcome (p = 0.20). The primary safety outcome occurred in 4 patients of the large and 6 patients of the small device group, resulting in an event-free rate of 90 and 91 %, respectively (p = 0.89).
Similar significant symptomatic improvement was observed in both treatment groups after 6 months, indicated by a 50 % increase in the fraction of patients in NYHA class I (p < 0.0001 vs. baseline).
The most feared complications, such as device embolization and atrial perforation, might be associated with device size. Smaller rims surrounding a large defect may technically complicate successful device placement thus increasing the risk of embolization.
Two cases of device embolization occurred, one each in the large and small device group. Furthermore, deficient anterior–superior rims of large ASD may increase the chance of contact between the device and the atrial wall, particularly in case of device oversizing, which may result in atrial perforation. Most atrial perforations occur within the first 3 months after device implantation, and have also been reported after implantation of small closure devices.
Transcatheter closure in this cohort of patients with large or small ASD was effective with similar complication rates during short-term follow-up irrespective of the size of the implanted device.