Definition and Overview
Septostomy is a life-saving surgical procedure that involves creating a small hole in between the atria, the heart’s upper chambers, or widening the foramen ovale for the treatment of dextro-transposition of the great arteries (d-TGA), a cyanotic congenital defect in which the two main arteries that carry blood out of the heart are reversed.
d-TGA is a serious congenital condition that can be detected in infants before or as soon as they are born. It is characterized by the complete transposition of the pulmonary artery and aorta, the two main arteries of the heart. Usually, the aorta is found at the back of the pulmonary artery, but in d-TGA, it is located at the front and right side resulting in complications in breathing, oxygenation, and efficiency of blood circulation.
In a baby with no heart defect, deoxygenated blood enters the right side of the heart and flows to the lungs through the pulmonary artery. Once the blood is oxygenated, it returns to the rest of the body including the heart through the aorta. In a baby with d-TGA, the blood still enters the right side of the heart but proceeds to the aorta where it goes back to the rest of the body such as the heart. In the meantime, oxygenated blood that should proceed to the heart goes back to the lungs through the pulmonary artery.
In many cases, babies who are born with d-TGA may also present other heart conditions such as ventricular septal defect, where a hole is found in between the right and left ventricles (lower chambers of the heart).
Who Should Undergo and Expected Results
Septostomy is usually performed on newborns who are two to three weeks old and whose atrial septum (walls of the atria) is still thin.
Despite the grave seriousness of the condition, babies with d-TGA are able to slightly delay its full effect due to the presence of foramen ovale, which allows blood to flow from the left to the right atrium. However, this usually closes a few days after birth as the function of the lungs improves and the pressure in the left atrium increases than that of the right.
So far, there’s no other immediate treatment option for babies with d-TGA than atrial septostomy, and there are very limited evidence that can describe the efficacy of the treatment. However, in one of the studies, 95 percent of patients who underwent endovascular atrial septostomy experienced immediate hemodynamic effect, which indicates more oxygenated blood in systemic circulation.
However, the procedure doesn’t cure the condition, and a definitive surgery has to be carried out at a later time. While waiting for such surgery, the infant is typically prescribed with medications to help regulate blood pressure and breathing, among others.
How Does the Procedure Work?
There are two general techniques used for atrial septostomy: static balloon atrial septostomy and endovascular atrial septostomy (Rashkind’s procedure). Static balloon septostomy is typically considered if endovascular procedure cannot be performed (e.g., the foramen ovale has already closed) or has failed. In both of these procedures, the infant is administered with either general anesthesia or sedative.
In atrial septostomy, an incision is made through the femoral artery found in the leg or the umbilical vein. A sheath is used to guide the balloon catheter, which is inserted into the skin and threaded towards the right atrium.
If it is endovascular atrial septostomy, the catheter crosses the foramen ovale, where the balloon is inflated to make the hole bigger and prevent it from closing up entirely. The inflation and deflation of the balloon may be performed a couple of times before the deflated balloon and the catheter are removed.
In a static balloon septostomy, a hole is made in the interatrial wall, which divides the two halves of the heart, using a blade that is threaded together with the catheter. A balloon is then used to expand the hole. The blade can also be used in endovascular atrial septostomy if the wall of the heart has thickened.
Possible Risks and Complications
Septostomy presents common surgical risks including allergic reactions to anesthesia, infection or septicemia, blood loss, and mild to serious injury to the cardiac tissue as the hole is made or as the catheter is introduced into the heart.
In some cases, the procedure may introduce other heart-related problems like arrhythmia, or abnormalities in the rhythm of the heart. In one of the studies analyzed by the National Institute for Clinical Excellence (NICE) in the UK, three out of 248 patients suffered complications of the procedure that resulted in death, while in other research, between 2 and 3 percent of the patients died.
Law, MA; Grifka RG; Mullins CE; Nihil MR (May 2007). "Atrial septostomy improves survival in select patients with pulmonary hypertension.". Am Heart J. 153 (5): 779–84. doi:10.1016/j.ahj.2007.02.019. PMID 17452153.
Jump up ^ Rothman, A; Sklansky MS Lucas VW; Kashani IA; Shaughnessy RD; Channick RN; Auger WR; Fedullo PF; Smith CM; Kriett JM; Jamieson SW (1999-09-15). "Atrial septostomy as a bridge to lung transplantation in patients with severe pulmonary hypertension.". Am J Cardiol. 84 (6): 682–6. doi:10.1016/S0002-9149(99)00416-6. PMID 10498139.