What're the treatment options for atrial septal defects?
Prior to correction of an ASD, an evaluation is made of the severity of the individual's pulmonary hypertension and whether it is reversible. The evaluation includes a right heart catheterization. This involves placing a catheter in the venous system of the heart and measuring pressures and oxygen saturations in the SVC, IVC, right atrium, right ventricle, pulmonary artery, and in the wedge position. Individuals with a pulmonary vascular resistance (PVR) of less than 7 wood units show regression of symptoms (including NYHA functional class). On the other hand, individuals with a PVR of greater than 15 wood units have increased mortality associated with closure of the ASD.
If the pulmonary arterial pressure is more than 2/3 the systemic systolic pressure, there should be a net left-to-right shunt of at least 1.5:1 or evidence of reversibility of the shunt when given pulmonary artery vasodilators prior to surgery. (If eisenmenger's physiology has set in, it must be proven that the right-to-left shunt is reversible with pulmonary artery vasodilators prior to surgery.)
Once an individual is found to have an atrial septal defect, a determination of whether it should be closed has to be made. Surgical mortality due to closure of an ASD is lowest when the procedure is performed prior to the development of significant pulmonary hypertension. The lowest mortality rates are achieved in individuals with a pulmonary artery systolic pressure of less than 40 mmHg.
If Eisenmenger's syndrome has occurred, there is significant risk of mortality regardless of the method of closure of the ASD. In individuals who have developed Eisenmenger's syndrome, the pressure in the right ventricle has raised high enough to reverse the shunt in the atria. If the ASD is then closed, the afterload that the right ventricle has to act against has suddenly increased. This may cause immediate right ventricular failure, since it may not be able to pump the blood against the pulmonary hypertension.
Closure of an ASD in individuals under age 25 has been shown to have a low risk of complications, and individuals have a normal lifespan (comparable to a healthy age-matched population). Closure of an ASD in individuals between the ages of 25 and 40 who are asymptomatic but have a significant shunt is controvertial. Those that perform the procedure believe that they are preventing long-term deterioration in cardiac function and preventing progression of pulmonary hypertension. If closure of an ASD is performed after age 40, there is improvement in symptoms compared to individuals who were treated medically. However, risk of cardiovascular problems were not decreased compared to the medically treated group. Methods of closure of an ASD include surgical closure and percutaneous closure.
An atrial septal defect is most commonly closed by open-heart surgery. The surgeon may be able to directly close the hole with sutures or, depending on the size and shape of the hole, may need to close it with a patch.
Depending on the size and the area of the septum involved, many atrial septal defects may be closed by placement of a device called an Amplatzer Septal Occluder during a cardiac catheterization. This device, which was approved by the FDA in December 2001, is inserted through a catheter and covers the ASD by attaching to the atrial septum. The benefits of being able to close an atrial septal defect with an Amplatzer device is that it can be put in place without stopping the patient's heart or utilizing cardiopulmonary bypass, it doesn't have the psychological trauma related to open-heart surgery and it doesn't create a scarring across the chest the way open-heart surgery does.
More information on atrial septal defect
What is an atrial septal defect? - An atrial septal defect (ASD) is a group of congenital heart diseases that involve the inter-atrial septum of the heart. The inter-atrial septum is the tissue that separates the right and left atria from each other.
What causes atrial septal defect (ASD)? - Some congenital heart defects may have a genetic link, either occurring due to a defect in a gene, a chromosome abnormality, or environmental exposure, causing heart problems to occur more often in certain families.
What are types of atrial septal defects? - There are many types of atrial septal defects. They are differentiated from each other by whether they involve other structures of the heart and how they are formed during the developmental process during early fetal development.
What are the symptoms of an atrial septal defect? - Many children have no symptoms and seem healthy. However, if the ASD is large, permitting a large amount of blood to pass through to the right side of the heart, the right atrium, right ventricle, and lungs will become overworked, and symptoms may be noted.
How is an atrial septal defect diagnosed? - Most individuals with a significant ASD are diagnosed in utero or in early childhood with the use of ultrasonography or auscultation of the heart sounds during physical examination.
What are treatment options for atrial septal defect? - An atrial septal defect is most commonly closed by open-heart surgery. The surgeon may be able to directly close the hole with sutures or, depending on the size and shape of the hole, may need to close it with a patch.