Device closure of ASD is suitable for secundum ASD with a good rim all around for holding the two discs together. Trans esophageal echo (TEE) is done to assess the superior, aortic and mitral rims as well as the total septal length. It is ideal to have TEE guidance during the procedure as well. A guidewire is introduced through the femoral vein into the inferior vena cava and further through the right atrium across the ASD. The tip of the wire is placed in the pulmonary vein and a long venous sheath is introduced. Once the sheath is in position, the device attached to the delivery cable is introduced into the sheath under water to avoid air bubbles in the system. Bubbles in the system can get embolized during delivery with air emboli going into the systemic circulation. It it reaches the cerebral circulation, transient giddiness and altered sensorium can occur. ST segment elevation and hypotension may occur if the air bubbles find their way into the coronary circulation. Oxygen inhalation and other supportive care usually takes care of minor air embolism as the manifestations are often transient.
Once the device reaches the left atrium, the left atrial disc of the device is released first and brought in contact with the left atrial side of the ASD. When the position is judged ideal, the right atrial disc is allowed to form by withdrawal of the sheath. Once the two discs are in position with the waist across the ASD, slight wiggling is done to make sure that the device is perfectly fitting and has no tendency for dislodgement. Position is confirmed by TEE with special care to see that the device does not interfere with the function of the AV valves. Once everything is fine, the device is released by unscrewing the delivery cable. The device usually used is the Amplatzer device.
An unstable device can occasionally get dislodged either into the left or right atrium. It may be possible to snare out the dislodged device, depending on the position where it gets lodged. Rarely surgical intervention may be needed to retrieve a dislodged device.
One of the dreaded long term complications of ASD device closure is aortic erosion, which is more likely to occur if the aortic rim is deficient. Fortunately it is very rare due to precautions at the time device implantation and pre implant assessment.