Perimembranous VSD

My 5 yr old was diagnosed with VSD since birth. The size has reduced from 3mm, to 1mm now. However, the cardiologist says that at 1mm, the pressure induced is very high in both chambers that may result in the valve being pulled and end up with valve leakage.
What are the complications if the hole remains at 1mm and valves being pulled but no leakage?

[Jeffrey R Boris, M.D.]

Dear Harks,

WIthout seeing exactly what type of VSD your son has and the rest of his anatomy, I cannot say for sure exactly what is going on.  Based on what you have told me, I am presuming that he has a perimembranous (conoventricular) ventricular septal defect, which is just below the aortic valve.  What is happening is that the pressure is high in the left ventricle but not in the right, which causes blood to go across the defect from left to right.  That jet of blood causes suction that can deform the aortic valve, and even cause it to leak.  If the valve leaflet gets pulled down and there is no leak, then what may happen is the defect may actually get completely closed by the aortic valve leaflet.  When that happens, no further valve deformation may occur.  The only concern is if moderate, or more, leakage at the aortic valve occurs.  Anything below should be able to be observed without intervention.