An atrial septal defect (ASD) is a small hole between the two upper cavities of the heart, which is naturally found in all of us when still at the fetal stage (inside the womb). The ASD closes automatically within the first months or years of life. In a small percentage of children this hole remains open. ASD closure in childhood is recommended only when the blood flow through it is significant, hence volume overload of the right ventricle is observed (right heart ventricular dilatation / cardiomegaly).

ASD 

• The recommendation to close hemodynamically significant communications in childhood is in order to avoid further heart dilation in adult life. In the past, the only way to close these communications was surgical. During open heart surgery, the heart stops and the surgeon closes the hole with the use of a patch or direct suturing.
• Surgery is a successful and safe method, but it leaves a permanent scar. Over the past four decades, an alternative therapeutic method has been developed, through cardiac catheterization. Transcatheter ASD closure is suitable for most patients, but not for all. The suitability for transcatheter ASD closure or not, is decided by the Interventional Cardiologist.

Catheterization

• The procedure is performed under general anesthesia.
• The ASD is thoroughly examined with an endoscopy-type procedure which is called transesophageal echocardiogram (TOE). With the TOE, a final check is performed, to confirm that the defect is suitable for device closure. The size of the device to be implanted is also decided at this point via TOE. Access for closure of the defect is gained through the large central vein in the groin.
• The most common type of device that is used to close an ASD is shown below (left). In the picture on the right the closure method is shown step-by-step.
• The patient stays in hospital for 1-2 days.
• After discharge from the hospital, the patient is treated with aspirin for a total of 6 months, when the device has been completely covered by native tissue (endothelialisation).

Frequently asked questions related to ASD closure 

• Could the device be rejected after successful implantation?

“..Rejection of the device by the body cannot happen, instead, the device is coated with endothelium and incorporated into the atrial septum within 6 months from implantation…”

• Can the device be embolized (move from its position) after implantation or injure the heart (immediate or long-term)?

“… Device embolisation can occur a. in patients who are not properly selected and do not have sufficient tissue rims where the umbrella can anchor, or b. when the operator choses a smaller device than appropriate. Heart injury has been reported in approximately 0.1%. Central defects with good rims have almost zero chances of embolization or heart injury.

The final decision of suitability for device closure, as well as device size is decided by an experienced Interventional Cardiologist who performs the method regularly.

• Are there studies comparing the open surgical and the transcatheter method?

“…Yes. A randomised controlled study performed in the United States has shown that the percentage of morbidity with the open surgical method is higher than the transcatheter method, while hospitalization and the total cost is significantly higher (see: Comparison between transcatheter and surgical closure of secundum atrial septal defect in children and adults: results of a multicenter nonrandomized trial. Du ZD, Hijazi ZM, Kleinman CS, Silverman NH, Larntz K; Amplatzer Investigators. J Am Coll Cardiol. 2002 Jun 5;39:1836-44). To minimise the incidence of complications with the transcatheter method, it is important that the cardiac intervention takes place in organized centers with cardiac surgical support.