Closing Holes in the Heart

Overview

Holes in the heart or between large heart vessels sometimes close on their own, over time, in children. However, in many congenital heart disease (CHD) defects, a hole doesn’t close on its own, and the child may need treatment to close it. In the past, treatment almost always involved surgery, but now there are minimally invasive procedures that will work for many babies and children who have a hole in the heart. Minimally invasive interventional procedures are performed by cardiologists specially trained to use very small, flexible tubes (catheters) that can be thread through the blood vessels to deliver treatments, such as patches or plugs, to close holes in the heart. The catheters are inserted through a small skin puncture, much like an IV, without the need for incisions, scalpels, or stitches. One of the major advances of catheter-based repair is the fast recovery time compared to traditional open-heart surgery, with most children able to go home from the hospital within 24 hours of having the procedure done.

The following are different types of holes in the heart.

Atrial septal defects (ASDs)

ASDs are holes between the two upper chambers of the heart (the left atrium and right atrium). The septum is a wall between two heart chambers that’s made up of many segments that fuse together as the baby grows inside the mother’s womb. In most babies, the wall closes completely on its own as the heart develops. When the septum doesn’t fully fuse, one or more holes (ASDs) are left behind. If the ASD is large enough to cause enlargement of the right side of the heart, the ASD should be closed. There are several types of ASDs:

• Primum ASDs – Primum ASDs occur toward the bottom of the septal wall, near the heart’s mitral and tricuspid valves. These valves may be associated with holes between the bottom pumping heart chambers (ventricles). Typically, primum ASDs can’t be closed with catheter-delivered devices and require surgery instead.
• Secondum ASDs – Secondum ASDs occur toward the middle of the septal wall. Heart tissue surrounds these holes, making it possible for devices to be attached to close the hole. These devices are delivered through a catheter and typically consist of a disk-shaped device that can be attached to each side of the atrial septum in order to close the hole.
• Multifenestrated ASDs – Multifenestrated ASDs have several holes within the atrial septum, making the wall look a bit like Swiss cheese. In many situations, a single catheter-delivered device can be used to cover all of the holes at the same time. Occasionally, more than one device may have to be used.
• Sinus venosus ASDs – Some children may have sinus venosus ASDs—one or more holes toward the top and bottom of the atrial septal wall close to the major veins that drain blood into the heart (superior vena cava and inferior vena cava). Sinus venosus ASDs are often associated with abnormalities in how the pulmonary veins return to the heart (anomalous pulmonary venous return). These holes have traditionally been closed with surgery, but in some cases, they can be closed with catheter-based techniques.

Patent foramen ovale (PFO)

Before birth, all babies have a natural hole between the upper chambers of the heart. This hole is called a fossa ovalis. In most babies, the hole closes shortly after birth as a natural flap seals shut. In some cases, this sealing won’t occur until a week, or even several months, after a baby is born.

When the septal wall doesn’t close on its own, the hole is called patent foramen ovale (PFO). This is fairly common. The small pathway that exists between the two upper chambers of the heart is normally present in 20%–25% of adults and usually doesn’t cause any problem. In very unusual situations, a PFO can be associated with stroke in children, and a history of stroke in a child may be an indication to close the PFO with a catheter-based device. The devices used to close PFOs are very similar to the devices used to close ASDs.

Ventricular septal defects (VSDs)

The heart has two lower pumping chambers called ventricles. Holes in the wall between the ventricles are VSDs. As with ASDs, there are several types of VSDs and their treatment may be based on their location.

• Muscular VSDs – Muscular septal defects exist in the thicker, muscular part of the wall between the two ventricles (ventricular septum). There can be just one hole, but often there may be several along the wall. These kinds of VSDs are commonly detected shortly after birth because they cause a heart murmur that can be heard with a stethoscope when the blood passes through the hole.

In many situations, muscular VSDs close by themselves over time as the heart muscle naturally becomes thicker. Even if a muscular VSD doesn’t completely close, it may not require any treatment. Larger muscular VSDs can cause symptoms of congestive heart failure in children and may need to be closed. Some muscular VSDs can be closed with special catheter-delivered devices, while others are best closed by surgery.

• Perimembranous VSDs – Perimenbranous VSDs are found in the thin area of the ventricular septum, near the middle of the heart. This area of the wall between the heart's lower chambers is called the crux. Like muscular VSDs, these holes can close by themselves over time when they are small. Large perimembranous VSDs are typically closed by surgery, although in rare cases, some VSDs can be closed with catheter-based devices.
• Outlet and supracristal VSDs – Holes may be found near the large blood vessels that deliver blood from the heart to other parts of the body (the aorta and pulmonary artery). These holes are known as outlet VSDs and supracristal VSDs. Outlet VSDs that are near the aorta may be associated with other heart defects such as with Tetralogy of Fallot, double outlet right ventricle, and truncus arteriosus. Outlet VSDs are almost always closed by surgery. Supracristal VSDs are found near the pulmonary artery; these also are also typically closed by surgery.
• Post-infarction VSDs – Sometimes, a hole can develop in the heart after a heart attack. This type of VSD may develop if tissue in the wall between the two lower chambers of the heart is severely damaged from a heart attack. The area weakens and then ruptures, causing a new hole where one didn’t exist previously. When this happens, the patient can become very ill quickly. Usually, patients are too sick to undergo emergency heart surgery. However, special catheter-delivered devices can sometimes be used to close post-infarction VSDs.

Persistent (patent) ductus arteriosus

The ductus arteriosus is a natural connection between the two large arteries that leave the heart (the pulmonary artery and the aorta). This connection occurs in all babies in their mother’s womb because the placenta (not the baby’s lungs) provides oxygen to the baby. There’s little blood flow through the lungs before birth. The ductus arteriosus allows blood to flow through the baby’s right ventricle to the pulmonary artery to the descending aorta so that blood can flow to the lower part of the baby’s body.

After birth, an elegant process takes place when the baby’s lungs have taken over the job of providing oxygen to the blood. The tissue of the ductus arteriosus is programmed to constrict and close naturally. This usually happens within the first week of life. Patent ductus arteriosus (PDA) occurs when this natural connection stays partially open (instead of fully closing).

PDA occurs more commonly in premature babies and creates a situation where the blood can’t flow efficiently. Oxygenated blood is forced to travel from the aorta back into the lung vessels through the PDA. If the PDA is causing problems for the baby, the doctor may recommend treatment with one of many catheter-delivered devices that can be used to close the PDA permanently. In some cases, the PDA is closed with traditional open-heart surgery.

New innovations

Catheter-based devices are continually being developed to treat holes in the heart without surgery. Recently, specific devices have been developed to close the PDA in premature infants as small as 2 pounds. The ideal device to close a hole in the heart would allow the tissue to grow over the device, and then the whole device would melt away. This device hasn’t yet been developed but is an active research area. Other devices are being developed to deliver stitches through a catheter to close PFOs, without implanting a patch and to close different types of VSDs more effectively.