You recently had surgery to clean out a carotid that was 99 percent blocked How certain is it that you may have coronary disease as well?

Arthrosclerosis affects all blood vessels. The blocking of your carotid is a symptom, not the disease itself. Surgery on the carotid solves the problem there, but the overall problem is still present. Though you can't put numbers on it, i'd say you have a high chance of some degree of sclerosis on your coronaries, which doesn't mean you will need coronory surgery as well (though it doesn't prove you won't either).