I was denied my medical card for my commercial driver license with an aortic aneurysm 4.7. Why isn't it safe to drive a commercial vehicle with this?

The DOT Guidelines. Allow a 1 year card for asymptomatic AAA over 4 but less than 5cm but only with clearance from cardiovascular surgeon. If you have no symptoms and a clearance statement from a cardiovascular surgeon and no other disqualifying conditions then you should be certified for a maximum of 1 year.