Aortic Valve Stenosis
(See also Overview of Heart Defects.)
Aortic valve stenosis is a narrowing of the valve that opens to allow blood to flow from the left ventricle into the aorta and then to the body.
This defect makes the heart work harder to pump blood to the rest of the body.
When valve narrowing is mild, most children have no symptoms.
When valve narrowing is more severe, children may gradually develop symptoms such as fatigue, chest pain, and shortness of breath.
Infants with severe aortic valve stenosis usually become very ill within the first weeks of life.
The diagnosis is suspected when a heart murmur is noticed during a doctor's examination and confirmed by echocardiography (ultrasonography of the heart).
Surgery or a catheter procedure may be needed to fix the valve. Very abnormal valves may need to be replaced.
To propel blood through the narrowed aortic valve, the left ventricle must pump under very high pressures. Sometimes, not enough blood is pumped to supply the body with oxygenated blood. In newborns, the left ventricle may be suddenly stressed after birth and may not pump well.
Infants with severe aortic valve stenosis become irritable and have poor food intake, sweating while they are eating, difficulty breathing, an unnatural pale or gray color to the skin, cool hands and feet, decreased number of wet diapers, and a rapid heartbeat.
Most older children with aortic valve stenosis do not have any symptoms. As the narrowing becomes more severe, however, they may develop fatigue, shortness of breath, palpitations (sense of racing heart beat), fainting, or chest pain during sports or other vigorous activity.
In adolescents, severe aortic valve stenosis may lead to sudden death, presumably because of an erratic heart rhythm caused by poor blood flow through the coronary arteries to the heart.
A doctor suspects aortic valve stenosis after detecting a particular heart murmur and sometimes a clicking sound when listening to the heart. A heart murmur is a sound created by turbulent blood flow through narrowed or leaking heart valves or through abnormal heart structures.
The pulses in the arms and legs may be weaker than normal. Infants with severe aortic valve stenosis may be critically ill with low blood pressure, signs of poor blood flow to the hands and feet, breathing distress, an enlarged liver, and acid build up in the bloodstream.
Echocardiography will show the abnormal aortic valve and can measure the "tightness" of the valve. Valve leakage (in which some blood flows back from the aorta into the heart) may also be present. Echocardiography will also show whether the left ventricle is thickened or stretched due to the stress of pumping blood through the narrowed valve.
Cardiac catheterization may be used to determine the severity of the narrowing.
In infants with severe aortic valve stenosis, doctors may need to immediately give a drug, prostaglandin, that will reopen the ductus arteriosus, a blood vessel that connects the pulmonary artery and the aorta (see also Normal Fetal Circulation). Normally, the ductus arteriosus closes soon after birth. The reopened ductus can temporarily help supply blood to the body when too little is getting through the tight aortic valve. The drug is given by vein (intravenously). Urgent surgery or balloon valvuloplasty is needed soon after diagnosis.
For children with severe narrowing or symptoms, the aortic valve must be widened or replaced. Widening the valve can be done during cardiac catheterization by a procedure called balloon valvuloplasty, or by surgery. For balloon valvuloplasty, a thin tube (catheter) with a balloon at its tip is passed through a blood vessel in the groin into the narrowed valve. The balloon is inflated and used to stretch the narrowed opening of the valve.
Surgery is needed instead of a catheterization procedure when the valve is unusually small or is both leaky and narrowed. Surgery is also done if the child has additional heart problems that must be treated surgically. It is desirable to fix the valve if possible. If the valve cannot be fixed, it can be replaced with a metal artificial valve, with a tissue valve, or with the child's own good pulmonary valve (this is called the Ross procedure).
Children with a metal artificial valve must take an anticoagulant drug, such as warfarin, to prevent blood clots from forming.
Some children need to take antibiotics before visits to the dentist and before certain surgeries (such as on the bowel or bladder). These antibiotics are used to prevent serious heart infections called endocarditis.