STANDARD TRANSCATHETER CLOSURE TECHNIQUE

All patients are scrutinized for the indication of atrial septal defect (ASD) closure. Preferably all patients should have a pre-procedure TTE and TEE. TEE imaging in small or paediatric patients is usually performed during the procedure. TEE imaging of all complex defects is usually done with 120 degrees sweeping in addition to the standard imaging angles at 0, 45 and 90 degrees. The size of the defect, shape of the defect, number of defects and location with regard to mitral valve and aortic valve are noted. Each of the important rims is measured and documented. Malalignment and aneurysm should also be noted.

Patients selected for transcatheter closure are given a loading dose of an antiplatelet agent (aspirin 300 mg or 4 mg/kg) one day before the procedure. Local anaesthesia, mild sedation and TTE during procedure are standard for all adult patients. General anaesthesia is used for all paediatric patients, and TEE can be used as per institutional protocol in all/selective cases. Femoral venous access is commonly used for transcatheter closure, while femoral arterial access is used for invasive pressure monitoring during the procedure. Anticoagulation should be achieved using 100 U/kg unfractionated heparin, with activated clotting time (ACT) maintained between 250 and 300 seconds throughout the procedure. Femoral venous access is then used for crossing the defect using a 5F/6F Cournard or multipurpose catheter with 0.035″ hydrophilic guide wire. After crossing the defect the Cournard catheter is parked in left or right upper pulmonary vein. This catheter is then exchanged for 0.038″ super stiff wire for supporting the long device-delivery sheath. The respective device is then loaded and delivered.¹

MODIFIED TECHNIQUES FOR COMPLEX ASD CLOSURES

The ASD closure with standard deployment technique fails many patients, but modified techniques can be used. In some patients, with very large devices/floppy rims, one can straight away attempt the modified techniques.²

BALLOON SIZING OF DEFECTS

ASD sizing balloon with stop-flow technique can be used upon the operator’s discretion. In cases where there is a malalignment defect, defects with septal aneurysm and where there is suboptimal sizing with TEE, balloon sizing with a stop-flow echo technique and fluoroscopic measurement can be an extremely useful method.

PULMONARY VEIN DEPLOYMENT TECHNIQUE

In this method, the left atrial disc is completely deployed in the pulmonary vein; keeping the disc in pulmonary vein, the whole device is stretched out to open the right atrial disc. Momentary release of the left atrial disc is done when the right atrial disc fans out to catch the two sides of the septum. This technique can be attempted in left upper, right upper and sometimes in left lower pulmonary vein.

LEFT ATRIAL ROOF DEPLOYMENT METHOD

This uses the same principle as in pulmonary vein deployment, but the left disc is opened against the left atrial roof.

MODIFIED/CUT SHEATH APPROACH

Here the operator cuts the sheath tip in an oblique fashion to allow for asymmetric expansion of the left atrial disc to catch the rims of the defect, followed by the asymmetric deployment of the right atrial disc. This method is used in cases of malaligned septum.

DILATOR/CATHETER-ASSISTED METHOD

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