Most of us have less veins & arteries feeding the left kidney. I’ve seen a right kidney have as many as 5, where as the left one usually has 2 or 3. That’s why the CT scan which is actually a CT arteriogram is used to determine which kidney ultimately gets chosen to be removed. Less vessels = bigger vessels which reduce the chances of post-op blood clots. It makes both surgeries technically easier to to as well. :)