What are vertical commisures regarding to bicuspid aortic valve and aortic valve stenosis

My son just had a follow-up 6 month echo done on November 8, 2010.  There was no significant change from the one he had 6 months ago except for that it talks about vertical commisures.  This is how the report reads so i give it to you in the right context.

Dilated left ventricle, mild.  Bicuspid aortic valve.  There are vertical commisures.  Normal left ventricular systolic function.  12mmHg aortic valve gradient.  18mmHg peak aortic valve gradient.  Mild to moderate valve insufficiency.
Asc aorta 3.1cm(4.8 Z-score), Ao Root diameter 2.4cm (0.21  Z-score) LA dimensions 3.4 cm (3.4 Z-score) LVIDs 3.4 cm (2.4 Z-score), LVIDd 5.1 cm ( 2.1 Z-score), RVDd 1.0cm (-2.1 Z-score).  He is 40 kg and 146 cm tall and he just turned 10 years old.

What are vertical commisures in relation to my son's condition?  Do you need further information

Thank you Shelly

[Jeffrey R Boris, M.D.]

Dear Shelly,

A commissure is the line of coaptation, or resting together, that the valve leaflets (or cusps, in this case) have.  The normal aortic valve has 3 commissures that, when looked at by ultrasound, appear similar to a "peace sign" or a Mercedes symbol.  In bicuspid aortic valve, there are a couple of ways the valve can be abnormal.  Sometimes, two of the commissures can be partially or completely fused.  However, in some valves, one of the cusps doesn't completely form.  In this case, what is seen is what appears to be a straight, or vertical, line where the cusps meet at the commissure.  The term, vertical commissure, is not a widely used term, so it is understandable how it could be confusing.