The small atrial septal defect--operate or procrastinate?

Morphological variations of fossa ovalis atrial septal defects (secundum): feasibility for transcutaneous closure with the clam-shell device

OBJECTIVE--To assess the morphology of fossa ovalis atrial septal defects (FOASD; secundum atrial septal defect) to determine in what proportion percutaneous closure with the clam-shell device might be feasible. DESIGN--Review of the intraoperative description of the morphology and size of FOASD. PATIENTS--106 consecutive patients with FOASD. SETTING--A regional children's cardiac referral centre. MAIN OUTCOME MEASURES--Determination of morphology and size of FOASD. RESULTS--Morphological variations in the FOASD were found: (1) central FOASD, 70 (66%); (2) superior FOASD, 4 (3.7%); (3) inferior FOASD, 8 (7.6%); (4) posterior FOASD, 2 (1.9%); (5) subtotal absence of atrial septum, 3 (2.8%); (6) completely fenestrated FOASD, 10 (9.4%); (7) partially fenestrated FOASD, 9 (8.5%). Depending on its site, the edge of the FOASD may be close to important atrial structures such as the orifices of the superior and inferior caval veins, coronary sinus, and right pulmonary veins. The shape of the FOASD was usually oval with the major diameter ranging from 10 to 50 mm with a mean (SD) of 27.8 (0.93) mm. The minor diameter ranged from 4 to 30 mm with a mean (SD) of 15.3 (5.9) mm. The ratio of the major to minor diameter ranged from 1.0 to 5.0 with a mean of 2.01. Based on intraoperative measurement and description, it is postulated that it should be possible to close about 50% of these defects with the clam-shell device.

The natural history of small atrial septal defects; long-term follow-up with serial heart catheterizations

Thirty-nine patients with a small ASD of the secundum type were followed clinically for 5 to 21 years (mean 11.6 years); no evidence of deterioration was found. In 26 of these cases recatheterization was carried out with a mean follow-up period of 9.8 years. No significant changes were found in most patients; in four patients, however, the left-to-right shunt had increased significantly. Our recommendations are that we will continue to advise surgery in patients with large ASD's, whereas we still do not recommend surgery in patients with small ASD's; the latter patients should be followed for longer periods to ensure that no deterioration occurs. The decision as to whether an ASD should be regarded as large or small in our opinion not only should be based on a chosen limit of pulmonary-to-systemic flow ratio, but clinical factors such as diastolic flow murmurs, ECG changes, the heart size, and the pulmonary vascular markings should also be taken into consideration.