The human body is filled with pairs. Eyes, ears, nostrils, lungs, arms. legs, breasts, kidneys, ovaries, testicles. In no instance is the right one the same as the left one. There are always differences in size, shape, placement - the works.
The same is going to be true for the cardiovascular system. Left / right differences are nothing to get bent out of shape over. There is already enough hysteria around the whole CCSVI idea. We don't need to add any more fuel to the fire.