The outcome of transcatheter closure in ostium secundum atrial septal defects is determined by the morphology of the defects. Modified techniques such as balloon assistance, pulmonary vein deployment, left atrial roof technique, and so on are used for circumventing the anatomic complexities and increasing the success rates.

We planned a prospective study looking at the outcomes of transcatheter closure in secundum atrial septal defects with modified techniques in different anatomic complexities identified in transoesophageal echocardiography and their association with outcome of transcatheter closure.

Transcatheter closure was successful in 295 out of 346 (82%) patients with modified techniques. Balloon-assisted technique offered a success rate of 87%. The mean defect size was 34.7±2.78 mm (95% confidence interval (CI) 30.67–43.1 mm) with success and 40.16±4.5 mm (95% CI 32.16–44.7) with failure (p = 0.02). The mean total septal length was 38.11±0.63 (95% CI 35.21–40.56 mm) with success and 42.54±0.34 (95% CI 38.79–43.21 mm) with failure. The defect to septal ratios were 0.82 and 0.94 in success and failure groups, respectively (p=0.02). However, the absence of a retro-aortic margin, septal aneurysm, and multiple defects did not affect the success rate. Deficient inferior vena caval margin, deficient posterior margin, and size⩾40 mm had a high risk of failure with transcatheter closure. The odds ratio for procedural failure was 25.3 (4.3–143.8) in patients with malaligned septum, 8.3(1.4–48.5) with deficient inferior vena caval margin, and 4.1(2.5–19) for size⩾40 mm.

The modified techniques for device deployment offer substantial chances of success in transcatheter closure of secundum atrial septal defects with anatomical complexity (82%). Variants such as defect size of⩾40 mm and deficient inferior and posterior margins have high failure rates with a modified technique.