To rule out the possibility of the image being in error from the scan, which can happen, it is worth the
angiogram. There are different types of coronary artery anatomy, if you look up right, left and co-dominant you will see a few examples. I believe that in most cases the right artery also reaches down into the apex on one side, I know mine does according to my angiograms. However, during the angiogram I'm sure they will shoot some dye down both sides to see if there are any problems.