DEVICE CLOSURE OF COMPLEX ATRIAL SEPTAL DEFECT IN ADULTS- ISSUES AND SOLUTIONS
Masood Sadiq, M.D., The Children's Hospital/The Institute of Child Health, Lahore. Pakistan
A complex ASD is defined as presence of a large- >20mm (stretched diameter = 26 mm) ASD associated with a deficient (= 4 mm) rim located at the anterior, inferior, or posterior portion of the atrial septum, two separate ASDs within the atrial septum (distant or close to each other); and multi-fenestrated septum, defects associated with a floppy, redundant, and hyper mobile atrial septum (excursion = 10 mm), considered to be aneurysmal, irrespective of their size.
The logic of a rim is to be understood as for a circular or an oval orifice it may be not be logical to have a fixed number of rims. Ideally the entire circumference must have rims and need to be interrogated. The complex anatomy of IAS does not allow this interrogation. It is important to know as what is an adequate rim- 5mm is considered as sufficient. But is it true for all the rims and what about superior rim (6-7mm is considered borderline) and is the length only issue? What about thin and/or floppy margins? It is important to know as which ones are suitable for device closure, for example a deficient aortic rim. Which ones increase the likelihood of complications and which ones to avoid completely. Similarly which ones cannot be closed like any large ASDs >38mm diameter and those with absent or truly deficient IVC rim, SVC rim, superior rim (PVs rim), inferior (AV valves) rim, those with absent rims in >2 areas and where device is too large to fit in the atria.
The ones which increase likelihood of complications include deficient aortic and posterior rims, deficient superior rim, floppy rims, small child with a large ASD and an unusually placed ASD? Balloon sizing is very useful to understand tissue characteristics and size in large defects with floppy margins and deficient rim and an unusually placed- If there is a waist there is a way! Balloon assisted technique seems to be a solution to all difficult and complex ASDs.
In conclusion large ASDs can be closed but in addition to size- rims and stability of the septum define limits. Use of an “adequate” size device that safely fits is ideal. If IVC rim is completely absent or >2 rims are significantly deficient it may be better NOT to do it. Always ask you- I can do it but shall I do it?