Stenosis simply means the narrowing of the entrance to a blood vessel.
This could have devastating effects, especially in cardiovascular pathologies.
The two main and common forms of stenosis are the Pulmonic and Aortic stenosis.
Pulmonic stenosis is a narrowing at the entrance to pulmonary artery.
Stenosis may occur from infundibular hypertrophy or when the valve is restricted.
Resistance to blood flow casues the right ventricular hypertrophy.
A person with problems related to circulation of blood in left ventricle develops hypertrophy and increased demands for coronary blood supply.
Back up of blood into the left atrium may cause increased pressure in that chamber and the pulmonary veins, resulting in pulmonary vascular congestion.
A serious form of critical aortic stenosis may occur during the neonatal period.
Symptoms of left ventricular failure are respiratory distress, faint peripheral pulses, and severe physical limitations occur during the first 2 weeks of Life.
Children with less severe stenosis may not show signs as fainting, epigastric and anginal pain, exercise intolerance and dizziness after prolonged standing may occur.
A serious consequence is sudden death after exertion as a result of a severely ischemic heart.
A murmur is typically heard with aortic stenosis from blood flow through the valve.
It is heard best at the upper right sternal border to second interspace (aortic space) and radiates to the suprasternal notch, clavicular area, and neck.
Sometimes it is transmitted along the left sternal border to the apex.
It is usually associated with a thrill.
The second heart sound is characteristically affected.
This is because the closure of the aortic valve is delayed, the normal splitting of S2 is narrowed.
With severe stenosis, the left ventricular ejection may be so prolonged that the closure of the pulmonic valve occurs simultaneously or preceded that of the aortic valve.
In the former instance there is no splitting.
In the latter event, the usual splitting of S2 narrows with inspiration (the pulmonic component being delayed) and widens with expiration (paradoxic splitting).
Diagnostic evaluation Diagnosis may be made on the history and physical findings alone.
A cardiac catheterization is necessary to determine the stenotic area, especially in those children with minimal symptoms who are at risk for acute myocardial ischemia.
It is also diagnostic in terms of the surgical approach.
If a thin membrane is present, it is easily removed with excellent results.
Roentgenographic studies may confirm • Left-sided heart enlargement • Released pulmonary vascularity • Dilated aorta in the poststenotic area Electrocardiogram may show • Left ventricular hypertrophy or may be normal in mild defects unless taken during a period of exercise • Depression of the ST segment indicates myocardial ischemia and is very important in determining the need for surgery.
Echocardiography may show a thick, poorly contractile left wall and an abnormal aortic valve.