Defects Causing An Obstruction to Blood Flow

A narrowing that causes an obstruction to blood flow is called stenosis.  A complete  obstructions to blood flow (no flow) is called atresia.
 


Pulmonary Stenosis: The Pulmonary valve allows blood to flow from the right ventricle to the lungs.  Stenosis can occur at the level of the valve or directly below it (subpulmonary Stenosis).  For pulmonary valve Stenosis, a "valvotomy" is performed, which means surgically opening the valve, to relieve the obstruction.  For subpulmonic Stenosis, the obstructive tissue below the valve is removed.  Both of these operations are performed through a midline sternotomy incision.

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Aortic Stenosis: The aortic valve allows blood to flow from the left ventricle to the body.  Stenosis can occur at or below the valve.  This Stenosis impedes blood flow to the body.  Valvular Stenosis surgery involves opening the valve to relieve this obstruction.  Subaortic Stenosis surgery involves opening the aorta and working through the aortic valve to remove the obstruction that lies just below the aortic valve.
 
 


 
 


 
 













 
 
 


Tetralogy of Fallot is a congenital heart defect containing four components:
1)  Ventricular Septal defect (VSD)
2)  Pulmonary Stenosis
3)  Right Ventricular hypertrophy - the right ventricle 
     becomes more muscular than normal because it must 
     pump against the obstructed outflow tract.
4)  Overriding Aorta - the aorta, rather than sitting in its 
     normal position coming from the left ventricle, sits 
     over or "overrides" the ventricular Septal defect.

This defect may cause cyanosis (blue spells), fainting spells, and rapid breathing, resulting form a decrease in blood flow to the lungs.  The surgery may be either a staged approach or a complete repair at the first operation. The staged operation involves doing a Blalock-Taussig Shunt until the baby is ready for a complete repair.  The complete repair involves removing the pulmonary outflow obstruction, closing the ventricular Septal defect, and if the pulmonary artery is too small, enlarging it with a patch.



 
   

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