• Closing Holes in the Heart

     
     
    11/15/2014

     

    Holes (also known as persistent connections) in the heart or large heart vessels sometimes close on their own, over time, in babies. However, if a hole does not close, the baby may need to undergo 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 who have a hole in the heart. These procedures can be performed in the cardiac catheterization lab. Minimally invasive procedures (called interventions) are performed by cardiologists specially trained in the use of very small, flexibly tubes (catheters) that can be thread through the blood vessels to deliver treatments, such as patches to close holes in the heart. The specialists are called interventional cardiologists and, if they have even more specialized training in treating children, they are known as pediatric interventional cardiologists.

    For more complex situations, a combination of surgery and minimally invasive procedures (called hybrid techniques) may be considered to take advantage of the benefits of both procedures at the same time. In these cases, a specially trained heart surgeon and an interventional cardiologist will work together to plan and perform the hybrid treatment.

    Atrial Septal Defects

    Atrial septal defects (ASDs) are holes between the two upper chambers of the heart (atria). The septum is a wall between two heart chambers that is 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 does not fully fuse, one or more holes (atrial septal defects) are left behind. These are the holes in the heart that must be corrected. 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 cannot be closed with catheter-delivered devices and require surgery instead.

    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. There are several devices that are available worldwide to close secundum ASDs. Currently, there are two main types that have been approved in the United States:  the Amplatzer Atrial Septal Occluder (ASO) and the Gore HELEX device.

    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 babies 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 (these veins are the 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 in the heart generally require surgery, both to close the hole and to redirect the pulmonary veins to the correct side of the heart.

    Patent Foramen Ovale (PFO)

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

    When the septal wall does not close on its own, the hole is called patent foramen ovale (or PFO). This is not uncommon, occurring in 20-25 percent of the general adult population. The small pathway that exists between the two upper chambers of the heart often does not cause any problem. However, studies have found that some people with PFO suffer cryptogenic stroke -- a stroke in the absence of any other identified factors – and that these strokes may be related to PFO.

    There is much debate as to whether PFOs should be closed with devices or with blood-thinning medications. There also has been some suggestion that migraine headaches may be related to PFOs and that closing PFOs may improve these symptoms. These are controversial topics. If these issues apply to you and if you have been diagnosed with a PFO, work with your doctors to determine what is right foryou.

    Ventricular Septal Defects

    The heart has two lower pumping chambers that are called ventricles. Holes in the wall between the ventricles are called ventricular septal defects (VSDs). As with atrial septal defects, 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 (the 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 sound that can be heard with a stethoscope when the blood passes through the hole. This sound is called a heart murmur.

    In many situations, muscular VSDs close by themselves over time as the heart muscle naturally becomes thicker. Even if a muscular VSD does not completely close, it may not require any therapy at all. Larger muscular VSDs can cause symptoms of congestive heart failure in babies 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 lower chambers of the heart is called the crux. Like muscular VSDs, these holes can close by themselves over time, often when tricuspid valve tissue clogs and seals the opening over time.

    Sometimes smaller perimembranous VSDs can be related to leakage of the aortic valve (a condition called aortic insufficiency). These holes often require closure to prevent progression of aortic valve leakage.

    Large perimembranous VSDs are typically closed by surgery, although some VSDs can be closed with catheter-based devices. There is currently no device approved by the U.S. Food and Drug Administration that is specifically used for closing perimembranous VSDs. Perimembranous VSDs can also be associated with other congenital heart defects.

    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. They are more common in Asians. These also are also typically closed by surgery.

    Post-infarction VSDs

    Sometimes a hole can develop in the heart after a heart attack (myocardial infarction). This type of VSD may develop if tissue in the wall between the two lower chambers of the heart is severely damaged from the heart attack to a heart attack. The area weakens and then ruptures, causing a new hole where one did not exist previously. When this happens, the patient can become very ill very 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. In fact, there is ittle blood flow through the lungs before birth. It is the ductus arteriosus that 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, when the baby’s lungs have taken over the job of providing oxygen to the blood, an elegant process takes place. The tissue of the ductus arteriosus is programmed to naturally constrict and close. This usually happens within the first week of life. Persistent (or Patent) Ductus Arteriosus (PDA) occurs when this natural connection stays partially open (instead of fully closing).

    Persistent ductus arteriosusoccurs more commonly in premature babies. This condition creates a situation where the blood cannot flow efficiently. Oxygenated blood travels is forced to travel from the aorta back into the lung vessels through the PDA. If the PDA is causing problems for the baby, his or her doctor may recommend treatment with one of many catheter-delivered devices that can be used to permanently close the PDA. Some very large PDAs, particularly in premature babies, may require surgical closure.

    New Innovations

    Catheter-based devices are continually being developed to try to treat holes in the heart without surgery. The ideal device to close a hole in the heart would allow tissue to grow over the device and then the whole device would melts away. This device has not yet been developed, but is an area of active research.