OBJECTIVETo study the morphological features of secundum atrial septal defect (ASD) in adult and the implications for transcatheter closure.

METHODSTranscatheter closure using Amplatzer duct occluder was performed in 272 adult patients with ASD from September 1997 to December 2005. The morphological features were evaluated by transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE). The size, length and thickness of rims, occluder diameter, the complete closure rate, residual shunt rate and complications were compared in patients with deficient and/or thin rims (Group A, n = 135) and patients with well-developed rims (Group B, n = 137).

RESULTSThe complete closure rate was 97.8% (132/135) in group A and 99.3% (136/137) in group B. There were 74 cases with deficient rims, 39 cases with thin rims and 22 cases with both deficient and thin rims in group A. Gender distribution, age, operation successful rate, residual shunt rate and complication rate were similar between the 2 groups. The defect diameters measured by TTE (18.9 +/- 5.5 mm vs. 16.5 +/- 4.8 mm, P < 0.01), TEE (22.7 +/- 5.0 mm vs. 20.0 +/- 5.5 mm, P < 0.01) and occluder diameters used (29.1 +/- 5.7 mm vs. 26.0 +/- 5.9 mm, P < 0.01) were significantly larger in groups A than that in group B. The systolic pulmonary artery pressure was also significantly higher in groups A than that in groups B (36.9 +/- 11.9 mm Hg vs. 32.6 +/- 9.1 mm Hg, P < 0.01). There are significant correlations between occluder diameters and defects measured by either TTE or TEE in both groups (group A, TTE: r = 0.709, TEE: r = 0.850; group B, TTE: r = 0.716, TEE: r = 0.915, P all < 0.01).

CONCLUSIONSPoor residual rims were found in around 50% of adult patients with ASD. Transcatheter closure of these defects could be successfully performed with larger occluders. The defect diameters measured by TTE and TEE, especially the latter, could guide the occluder selection.