Percutaneous closure of atrial septal defects—more roads lead to Rome than meets the eye

The commendably successful series of percutaneous closure of atrial septal defects (ASDs) in children and adults of the pediatric cardiologists in Marseille, France [1], is both stimulating and thought provoking. They calculate that 80% of ASDs can be closed percutaneously reducing the need for surgical closure to about 20%. For difficult cases (about 20% of their cases), they use a modified balloon-catheter support technique. Of these cases, 20% were not successful. Is this as good as it gets? Not really. First, they only approached ASDs that would otherwise be accepted for surgery. Historically, surgical ASD closure is limited to defects producing a Qp/Qs 1.5. We can assume from their experience and other publications [2] that all the smaller defects can be closed percutaneously. No shunt is always better than even a small shunt regarding longterm volume overload of both atria and the right ventricle. One can anticipate that even patients with shunts considered too small to warrant surgery have a higher risk of atrial fibrillation at a younger age than people with no heart defect. Moreover, the risk of paradoxical emboli mostly talked about in the realm of the patent foramen ovale (PFO) hovers also over small ASDs. Second and complementary to first, small ASDs can be closed with a very simple approach requiring neither general anesthesia nor echocardiographic guidance with virtually no risk of failure or complications. Hence, small ASDs not considered to be an indication for open heart surgery should not per se be excluded from percutaneous closure. Their technique and results are undistinguishable from that of PFO closure [3]. As the attempted ASDs get larger, the technique gets more demanding and intricate. The easiest trick is to deploy the left disk plus part of the right atrial disk in the left atrium before passing the defect. This makes sure that the device stays centered in the defect and reduces the risk of prolapse of the left disk into the right atrium during deployment. The next trick is to deploy the device as perpendicular to the septum as possible without any traction during deployment. Sheath modifications proposed for that are mentioned in the paper. The double curved sheath introduced for left atrial appendage closure a couple of years ago appears to be the ideal choice [4]. If that fails with the largest available device (left disk diameter of 56 mm), one of the support techniques in the paper may come to action. Using all these knacks, one can assume that more than 80% of ASDs described can be closed satisfactorily with the catheter-based technique. Adding the ASDs too small to be worthy of a surgical approach, it can be anticipated that before long 90% of all ASDs worldwide will be closed nonsurgically with excellent results. What is the risk of approaching an ASD with the percutaneous technique that is too large to be closed? If recognized before device release an unnecessary venous puncture plus some wasted X-ray exposure are all that is to worry about. Nonimplanted devices will be replaced for free by the manufacturer. If the device is released and there is too much residual shunt this can be corrected with a second device either during the same intervention or at the later date. If this is tried during the same intervention there is a small risk of destabilizing the initial device. There is no such risk if the second device is implanted once the initial device has been overgrown by tissue which takes a couple of months. Should a second device not be deemed feasible, the patient will go for elective surgery where the device is either removed and the ASD patch-closed or the device is left in place and the residual rent is sutured. Open heart surgery would have been necessary anyway if the percutaneous closure had not been attempted. This holds true for heart surgery required to remove an embolized device. This will typically be a large device as embolizations are more likely with large defects and small devices can typically be retrieved nonsurgically. Large