Bicuspid Aortic Valve in Children: Symptoms, Causes and Treatment

Bicuspid aortic valve in children is a condition in which the valve at the entrance of the aorta, the main vessel that pumps clean blood from the heart to the entire body, develops congenitally with only two leaflets. In a normal and healthy heart, this valve has three leaflets that allow it to open and close completely. This anatomical difference, which occurs while the baby is still in the womb, mechanically makes it difficult for blood to pass from the heart to the main vessel, paving the way for narrowing of the valve or for clean blood to leak backward because the leaflets cannot close completely. This structural condition, which is one of the most common congenital heart abnormalities, may increase the workload of the heart and cause the heart muscle to become tired over time.

What Is a Bicuspid Aortic Valve and How Does It Develop in the Womb?

The developmental process of congenital heart diseases is actually based on an extremely complex interaction between genetic predispositions and environmental factors. When we think of a healthy heart anatomy, the aortic valve consists of three symmetrical and perfectly functioning leaflets. We can compare these leaflets to strong double-winged doors that open exactly from the middle and do not allow even air to leak when closed. When the heart contracts, these doors open fully and allow blood to be pumped to the body with high pressure, without encountering any obstruction. When the heart relaxes, they close tightly to prevent the pumped blood from flowing backward. However, in a bicuspid aortic valve, due to some defects that occur during the stages of cellular migration and division in the embryological development process, the right and left leaflets usually remain fused together. As a result, a slightly asymmetrical valve structure with only two leaflets and leaflets of unequal size emerges.

When statistics are examined, approximately eight to ten out of every thousand live-born babies are found to have a congenital heart anomaly. Within this extremely broad spectrum, bicuspid aortic valve stands out as the most common congenital heart malformation encountered in society, with varying incidence rates. This condition, which also has familial inheritance characteristics, has a genetic background. Especially in children whose first-degree relatives, that is, mother, father, or siblings, have a similar anomaly, the probability of this valve being seen shows a considerably high tendency to recur. Therefore, if there is someone in the family who has received this diagnosis, it is of great importance that the other children also undergo a heart check-up.

In the embryonic period, that is, in the most sensitive first weeks of pregnancy when the baby’s organs are just beginning to form, the development of the heart is also directly affected by some external factors to which the mother is exposed. Some chronic diseases present in the mother or some infections experienced during pregnancy may disrupt the baby’s heart development.

Factors that increase the risk during pregnancy are as follows:

• Diabetes
• Phenylketonuria
• Obesity
• Febrile illnesses
  • Rubella
  • Influenza

In addition, certain medications or high-dose vitamin supplements that the mother uses unconsciously during pregnancy may also prevent the normal development of the outflow tracts of the heart.

How Does a Bicuspid Aortic Valve Affect Heart Anatomy and Function?

The fact that the valve has only two leaflets instead of three creates a mechanical problem, just like a door with rusty or incorrectly installed hinges that cannot open fully. This condition causes the left ventricle of the heart to work against much higher resistance while pumping blood into the systemic circulation. Valvular aortic stenosis, which is the most common form of the conditions we call left ventricular outflow tract obstructions in children, which prevent blood from leaving the heart, occurs through this mechanism.

The heart is a muscle, and just like the muscles of an athlete who lifts weights become more prominent, it develops an adaptive response to withstand this constantly increasing pressure and begins to thicken over time. This is called hypertrophy. As the heart muscle thickens, it loses its flexibility and the cavity inside it narrows. At the same time, the asymmetry of the edge structures of the valve leaflets and the defective hinge points cause the valve not to close completely during the relaxation phase. Some of the blood leaks back into the heart through this incompletely closed gap. This condition is called aortic regurgitation. In childhood, this insufficiency usually progresses very mildly and remains in the background, but as age advances and the valve wears down due to years of collisions, this backward leakage becomes more pronounced.

Blood that spurts under pressure through a restricted and asymmetrical opening loses its normally calm and smooth fluidity, just like water spurting from a garden hose whose end you squeeze with your finger. Instead of moving straight through the hose, the water acquires a turbulent and swirling character. This condition creates strong localized vortices right at the entrance of the aortic vessel.

The negative effects caused by these blood vortices are as follows:

• Endothelial damage
• Cellular wear
• Loss of elastic fibers
• Weakening of the vessel wall
• Dilation of the aortic vessel

In particular, the continuous impact of this asymmetrical jet flow on the inner wall of the ascending aorta with every heartbeat for years causes the elastic fibers in that area to stretch, wear out, and the main structure of the vessel to deteriorate. In a significant proportion of children with bicuspid valves, dilation of the aortic vessel, that is, the condition we call aortic aneurysm, is observed in later years. This dilated vessel wall loses its mechanical strength, becomes thinner, and may pave the way for extremely serious life-threatening conditions such as rupture at much older ages.

What Are the Symptoms of Bicuspid Aortic Valve in Children?

The clinical picture in children with bicuspid aortic valve follows an extremely wide spectrum. This situation may sometimes surprise families, because the vast majority of cases continue their lives completely healthily throughout childhood without any complaints. Although there is an abnormality in the structure of the valve, if the stenosis or leakage it causes is mild, thanks to the heart’s excellent ability to adapt, children’s physical development, weight gain, running and playing, or daily activities are not affected even in the slightest. In these cases, the diagnosis is usually made completely incidentally during routine health examinations performed for nursery, school, or sports club registration, when the physician hears an extra sound called a “murmur” caused by that turbulent blood flow while listening to the heart.

However, in some cases, especially because the two leaflets in the valve are highly fused together or due to the accumulation of calcification in the valve with advancing age, the stenosis may reach serious levels. When the stenosis increases, the pumping power of the heart becomes unable to meet the body’s oxygen needs, especially those of an active child. When sufficient blood cannot be pumped outward, the blood flow going to the brain, muscles, and the heart’s own vessels decreases.

Symptoms that may be seen in older children and adolescents are as follows:

• Easy fatigue
• Shortness of breath
• Chest pain
• Feeling of palpitations
• Dizziness
• Blackout sensation
• Fainting

Dizziness and fainting that occur especially while playing or running are a very critical warning sign. This indicates that the blood flow to the brain has been momentarily interrupted and that the stenosis in the valve has reached a very dangerous, critical level.

In addition, there is another patient group in whom the event progresses in a much more different and dramatic way: newborn babies. The situation is extremely urgent in newborn babies born with very critical and severe aortic stenosis. While in the womb, the baby is quite healthy because the baby’s blood circulation, thanks to a special vascular connection, bypasses the lungs and is distributed to the body without passing through that narrow part of the heart at all. However, within the first few days immediately after birth, this special vascular connection begins to close as a natural requirement of its nature. When this connection closes, blood can no longer go to the body through the narrowed bicuspid valve.

Dangerous symptoms seen in newborns born with critical stenosis are as follows:

• Pale skin color
• Bluish discoloration in the body
• Weak pulse
• Rapid breathing
• Grunting
• Feeding difficulty
• Constant sleepiness

These babies suddenly enter a severe heart failure picture. In neonatal intensive care units, because this stormy and severe picture sometimes gives symptoms very similar to severe blood infections seen in babies, specialists must be extremely careful and quickly distinguish the condition.

Which Methods Are Used to Diagnose Bicuspid Aortic Valve?

Even if the child has no symptoms, a careful physical examination by a good pediatric health specialist provides the first clues of this condition. The sounds heard while listening to the heart with a stethoscope are like a radio broadcast that reflects the fluidity problems inside the heart to the outside. In bicuspid aortic valve, during the forced opening of that stiff and fused valve with blood pressure, a very characteristic sound similar to a crack, which we call a “click”, is heard. Then, a harsh murmur sound produced as blood passes forcibly through the narrow area is heard. Even by simply touching the neck vessels or placing a hand on the chest wall, that vibration felt inside can be understood.

In suspected cases, the primary, most reliable, and most widely used method for the definitive diagnosis of the disease is transthoracic echocardiography. This method is the imaging of the heart with ultrasound waves through the chest wall.

The advantages provided by the echocardiography device are as follows:

• It does not contain radiation
• It is painless
• It gives instant results
• It provides detailed imaging

With echocardiography, the abnormal two-leaflet structure of the valve, the thickening status of the leaflets, the severity of the stenosis based on the valve area, how much blood it leaks, how much the left ventricle of the heart has thickened, and the diameter of the ascending aorta are measured and evaluated clearly, millimeter by millimeter.

Today, with ultrasound technology and device resolutions reaching incredible levels, a very large portion of congenital heart diseases can be diagnosed even while the baby is still in the womb. Fetal echocardiography examinations performed between the 18th and 20th weeks of pregnancy, focusing directly on the baby’s heart, show heart development down to the finest detail. Detecting such an anomaly in the heart during the fetal period is extremely valuable. In this way, the family’s birth planning is carried out in a much safer hospital, in a center where the pediatric cardiology team is ready, and the crises the baby may experience immediately after birth are prevented, creating the chance for immediate intervention.

In addition to echocardiography, there are other methods used in diagnosis and follow-up. Electrocardiography (ECG), which maps the electrical activity of the heart and records the rhythm pattern and how much the heart muscle has thickened due to strain in waves on paper, is frequently used. In addition, a chest X-ray may be taken to examine the general size of the heart within the chest cavity and the rough outlines of the dilation in the aortic vessel. If ultrasound waves cannot provide a clear image due to the chest structure or if the entire course of the dilation in the aortic vessel after it exits the heart is desired to be mapped millimetrically, much more advanced imaging methods such as cardiac magnetic resonance imaging or three-dimensional computed tomography angiography are used to draw the definitive roadmap before surgery or intervention.

What Are the Non-Surgical Treatment Options for Bicuspid Aortic Valve?

One of the issues that families wonder about most is whether there is a syrup or pill that will correct the valve. However, unfortunately, there is medically no drug treatment that can dissolve the structural, congenital anatomical defect or fusion of the bicuspid aortic valve at the cellular level and turn it back into a normal three-leaflet valve. The medical drugs used are prescribed only to reduce the workload of the heart, regulate its rhythm, or, if the child has accompanying high blood pressure, to control it and reduce the pressure on the vessel wall.

In severe valve stenosis that develops during childhood, the first preferred treatment method is not open heart surgery in which the chest wall is opened, but percutaneous balloon valvuloplasty, an interventional method performed in technologically equipped angiography laboratories. This procedure is an extremely delicate intervention performed by reaching the heart through the vessel with a completely closed method.

During the procedure, the child’s groin area is numbed under local anesthesia or, in younger children whose cooperation is difficult, under general anesthesia, and cleaned in a sterile manner. After entering the groin artery with a very thin needle and reaching the vascular access, a flexible guidewire as thin as a strand of hair is slowly advanced inside the vessel up to the heart. Under the guidance of a special X-ray imaging device, over this wire that is followed step by step from the outside, a specially produced durable balloon with its tip deflated is delivered exactly to the center of the narrowed aortic valve. The balloon is inflated and deflated for a few seconds at the exact center of the fused valve leaflets with the help of pressurized fluid. The mechanical force created during this inflation separates and tears the congenitally fused membranes from each other and instantly widens the opening area of the valve.

The criteria considered in the decision for intervention are as follows:

• High pressure gradient in an asymptomatic patient
• Complaints in symptomatic patients
  • Chest pain during exertion
  • Findings of ischemia on ECG
  • History of fainting
  • Rapidly developing heart fatigue
• Impairment in heart functions

This balloon procedure performed with a closed method in children is a highly pleasing and successful method that sometimes delays the need for open heart surgery for decades. However, due to the nature of the method, it has some limitations. During the balloon’s forced opening of the valve, unwanted small tears may occur, and this may cause the valve to leak blood backward, that is, aortic regurgitation. Nevertheless, the fact that a growing child’s chest is not opened and that the child can walk home the next day is a tremendous advantage that makes this risk worth taking.

What Are Surgical Treatment and the Ross Operation for Bicuspid Aortic Valve?

In valves where the balloon method cannot be applied, where the valve has become as hard as limestone, or where the valve begins to leak blood excessively after ballooning, open heart surgery methods become inevitable in order to completely correct that defective structure. In surgical planning, the first rule and goal is always to preserve the child’s own natural tissue as much as possible and try to repair the valve from the inside with patch or suture techniques. However, in shrunken and severely deformed valves where repair is impossible, that valve must be cut out from there and a new valve must be placed in its position.

At exactly this point, when the patient in question is an active growing child, artificial prosthetic valves that can be used comfortably in adults create very serious disadvantages and dangers.

Problems caused by synthetic or animal valves in children are as follows:

• Obligation to use blood thinners
• Rapid calcification
• Early tissue deterioration
• Inability to adapt to the child’s growth
• Need for repeated surgery

Carbon-alloy mechanical valves placed in adults and lasting a lifetime require the child to use very strong blood-thinning medications every day throughout life to prevent clot formation on the valve. For a child who constantly runs, rides a bicycle, falls, scrapes the knee, and plays ball, the blood not clotting means the risk of having an unstoppable, life-threatening internal bleeding even with a tiny head trauma. Biological valves produced from pig or cow pericardium, which are another option, do not require blood thinners; however, because of the incredibly rapid calcium metabolism during the period when children’s bones grow, these valves calcify and decay within the child’s body in a few years, losing their function. This means that the child would have to undergo heavy open heart surgery three or four times before childhood ends.

The solution that solves all these dilemmas at once and is the most excellent and physiologically suitable solution reached by pediatric cardiovascular surgery is the “Ross Procedure”. In this extremely complex operation requiring mastery, a magnificent exchange game is played. The child’s diseased aortic valve is completely removed from its place. Instead, the healthy pulmonary valve, which is on the right side of the child’s own heart, pumps blood to the lungs, and has never worn out until that day because the pressure is low, is carefully cut out and taken, then sewn in place of the aortic valve on the left side. In place of the pulmonary valve left empty on the right side, a cadaver valve obtained from human tissue and stored frozen under special conditions is placed.

The unique advantages that the Ross operation provides to children are as follows:

• Growth potential
• Freedom from medication/A life without medication use (only aspirin in some cases)
• Perfect fluidity
• Normal heart size
• Long life expectancy

Because the new aortic valve is the child’s own living cellular tissue, as the child grows taller and grows, that valve also continues to grow millimeter by millimeter together with the heart. Thus, when the child reaches adolescence, the valve does not remain small. In addition, because this valve is the child’s own tissue, there is no need to use those dangerous blood-thinning medications for life. Since it provides blood flow that is so smooth and natural that no artificial carbon valve can imitate it, the fatigue on the heart is completely erased and the heart rapidly returns to its normal healthy size.

Why Is Endocarditis Dangerous in Patients with Bicuspid Aortic Valve?

It would be incomplete to think that the bicuspid valve only creates a mechanical stenosis problem. The defective surface in that asymmetrical valve and the high-speed turbulent flow created by blood spurting through the narrow area cause continuous microscopic injury and destruction in the inner tissue of the valve. We can compare this to the surface of a Teflon pan being constantly scratched with a metal fork. This scratched tissue loses its normal smooth state.

In daily life or during simple medical procedures, some bacteria occasionally leak into the bloodstream from our mouth, intestines, or respiratory tract. In a normal, healthy person, these bacteria are destroyed by the immune system within minutes. However, in a child with a bicuspid valve, these bacteria entering the bloodstream adhere to that scratched and damaged rough valve tissue in the heart almost like a magnet. The body’s defense cells cannot reach these bacteria in that intense blood current, and the bacteria multiply there and form colonies. The invasion of the inner lining and valves of the heart by these bacteria, causing severe inflammation, is called Infective Endocarditis.

The reason endocarditis is so frightening is that the bacteria multiply rapidly and literally melt and perforate the valve and create abscesses in the heart. The symptoms of the disease usually begin very insidiously. A persistent fever lasting for weeks and not going down, night sweats that soak the bed sheets, severe shaking chills, the child’s sudden loss of appetite, rapid weight loss, and constant desire to sleep are the most basic symptoms. Its diagnosis is quite difficult and is made by detecting the bacteria in blood cultures taken intermittently. Its treatment is just as troublesome; the child must stay in the hospital for at least six weeks and receive very strong doses of antibiotics intravenously. If treatment is delayed, the valve may be completely destroyed and lead the child to emergency heart surgery.

The first, most basic, and cheapest step in protection from this deadly complication is oral and dental health. Not brushing the teeth regularly, not treating tooth decay, or millions of bacteria entering the bloodstream during the extraction of a decayed tooth migrate directly to the heart. Therefore, it is absolutely vital for children with bicuspid valves to acquire a flawless tooth brushing and oral hygiene habit when their teeth are just beginning to erupt. Not only brushing, but also giving the child a protective antibiotic by mouth exactly one hour before certain medical interventions with a possibility of bleeding is necessary.

This antibiotic taken as a single dose before the procedure eliminates possible bacteria that may enter the blood before they reach the heart, ending the infection before it begins. This simple pill acts as an invisible armor that saves the child’s life.

How Does Bicuspid Aortic Valve Affect Children’s Sports and Daily Life?

The first reaction of the family of a child diagnosed with bicuspid aortic valve is usually to place the child inside a glass bell jar and forbid running, playing, and all sports activities. However, completely separating children from sports and play both opens deep wounds in their psychological development and invites other diseases such as obesity that will tire the heart even more. What matters is not banning sports, but choosing the right sport suitable for the child’s heart capacity and vessel diameter.

When doing sports, our muscles need more oxygen; to meet this need, the heart beats faster and blood pressure naturally rises. If there is a dilation and wall thinning related to the disease in the aortic vessel behind the valve, these sudden rises in blood pressure during sports exert an incredible pressure from inside on that thin wall. Especially while lifting weights, doing sit-ups, or wrestling, involuntarily holding the breath and straining (Valsalva maneuver) raises the pressure inside the chest cavity to enormous levels within seconds. This sudden and severe pressure increase is the greatest danger that can cause that weakened aortic vessel to tear like paper in an instant.

For this reason, it is essential that children never hold their breath during exertion and do not go under a load heavier than a small portion of their own body weight at one time. There are many safe options for children who have mild stenosis and a normal vessel diameter.

Permitted light-paced sports are as follows:

• Walking
• Brisk walking
• Light-paced swimming
• Cycling
• Table tennis
• Golf
• Bowling

However, if the stenosis is moderate or severe, or if the vessel diameter has exceeded a certain millimeter, contact sports that require the heart to contract rapidly, involve sudden sprints, or may involve bodily impact are absolutely dangerous.

Absolutely prohibited dangerous sports are as follows:

• Weightlifting
• Wrestling
• Boxing
• Olympic weightlifting
• Football
• Basketball
• Fast running

Which sport the child can do and at what intensity must be determined in light of echocardiography measurements performed at regular intervals. If sudden chest pain, a sharp knife-like pain radiating to the back, a serious feeling of being unable to breathe, or dizziness develops in the child while doing sports or during a simple daily activity, the activity must be stopped at that very second and the patient must be taken urgently to a fully equipped center.